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Dave Bross
11-03-2003, 11:42 AM
I thought I would try something simple for my first attempt at home batching so I went with the recipe Pete had published a while back:

100 Sand
28 Soda Ash
14 Lime Hydrate
12 Potassium Carbonate
200 grams potassium nitrate
100 grams antimony oxide.

I divided it by ten to get around 15 lbs. of batch and converted it to grams:

4536 Sand
1270 Soda
635 Lime
544 Pot. Carb.
20 Pot. Nit.
10 Antimony

7078 grams total or 15.60 pounds

I tested for moisture in the chemicals by cooking100 grams of each all afternoon and found I had moisture contents of:

1% Sand
5% Soda
2% Lime
1% Pot. Carb.
1% Pot. Nit.

The only thing I adjusted in the formula was the soda. I multiplied the total of soda (1270) by .05 to get 63.5 so I added an extra 63 grams of soda to make up for the water. I know this isn't exactly spot on because I'm making up the difference with wet soda and ignoring the 1 or 2% of water in other stuff, but close enough? I'm thinking I want slightly less expansion if anything because I'll be encasing some things and also have lower expansion colors I can use in case of COE troubles.

I tumbled it in a plastic pail rigged up in a cement mixer for 3 hours and began charging this morning. I'm charging at 2000F and it's going flat and ready for more in about 1 hour intervals. Sweet!

Gentleman, start your hammers!!! it's peer review/whack-a-mole time....

If you see any errors...please do speak up!

I'm thinking my next attempts will be some others Pete gave me involving borax or alumina from nepheline syenite....

Or .....

Am I worrying unnecessarily over glass stability/durability on a glass that will only be used for things like jewelry and C-balls?

Some of the old formulas I've seen for jewelry and knick-nacks have scary amounts of alkalai in them and absolutely no stabilisers, such as alumina or Borax, at all.

Pete VanderLaan
11-03-2003, 02:46 PM
The simplist formulas are usually the best. That formula was a derivation I did on Dudleys original formula from back in 68. I think if it is missing anything, it is alumina but it works very well as is and never ever cords up. It takes colorants beautifully and is still used by quite a number of friends I have given it to. Despite the lack of alumina, I wouldn't mess with it since it doesn't seem to like changes in it's cage.

What you did with the soda/moisture calculation is great. My usual problem with moisture is in the potassium
carbonate. It gets very hard and caked on the surface. I will be interested in how it works for you. I recall it having a C.O.E. of about 94.5. :dog:

Franklin Sankar
11-04-2003, 11:21 AM
Dave :clap: are you melting at 2000 F . Do you thnk that you will have to go higher? If 2000F works then you have cleared the path for batch using wire furnaces .
Franklin

Dave Bross
11-04-2003, 01:07 PM
This glass is absolutely BEAUTIFUL!!!!!!!It has just a touch less sparkle/refraction than the Glasma but is very, very close to it otherwise. For me, it's nicer to work than Glasma.

and....

It does everything else I want really well too!!!!!

First, to answer Franklins' question, I did all the batching at 2000F. About an hour for the batch to go flat between charges.It took all day because I had to go do other things too. That night I cranked it up to 2200 and cooked it overnight. 8 hours to be exact. I lowered it to 2000F in the morning and it was squeezed out nicely 5 hours later.

It behaves very differently than other batch I've seen. It scared me while I was batching because there were what loked like dark unmelted lumps between the bubbles and I was worried that it wasn't going to melt down without silica stones or some other ugliness. I did use the 325 mesh silica flour.
Shortly after I turned it up to cook I was walking by and noticed a fizzing noise. When I looked in the furnace the glass was just bubbling away like a glass of freshly poured champagne and the dark spots were gone. So nice!

Now here's what else it does really well besides melt...

It is a wonderful torch working glass.

It has a lot of thermal shock resistance.

It has a combination of softness and working time that I really enjoy.

The powder is really a mess so I have to work on some things to make adding the batch a little neater. That's the only drawback so far and I can definitely live with that.

My quick version "shade tree" expansion testing, which consists of pulling threads of different glasses to compare against would seem to put it somewhere around 94-5. A little higher than FHC, very close to Gaffer, and a little lower than Spectrum.

I think a dilatometer will be a "near future" project.

I figured the oxide percentages on it and was quite surprised....

74% sand
12% soda
8% lime
6% potassium

That's a lot of sand. I'm thiking this should actually be quite durable because of that?

Question for Pete...

For historical interest if nothing else, why did you go from this recipe I just melted to:

63.25 silica
20.25 soda ash
9.06 Hydrated lime type N
2.18 Borax 5 mole
5.25 Potassium carb
100 grams antimony oxide
130 grams potassium nitrate.

and....

50 sand
20 1/4 soda ash
9 1/16 hydrated lime type N
5 1/4 Potassium carb
3 3/16th Borax 5 mole.

as a color base and clear? I haven't figured the percentages yet but it looks like the only major change is the borax?

Pete VanderLaan
11-04-2003, 01:42 PM
The first formula does have a ton of silica and it is durable and the silica content is why the glass works well in a torch. It was a glass I used that I cut and polished a lot and it polishes beautifully. That is because of the potash.

The second formula is a glass designed to fit SP87 hand in glove. I use it for my red and opal silver amber formulations when matching SP87. It also makes a very nice turquoise blue I am currently working. SP87 color base makes OK reds but the ambers are dirty from all the spars that Tom has in there, so this stuff is spar free, which is key to color glasses.

The third formula is simply wrong.

Interestingly in our drought, I have increased the amount of Soda ash in that glass from 20.25 to 20.75 to keep it in line with the Spruce Pine.

I would melt hotter than 2000F unless you rigourously follow the Corning Protocol of turning it up after the melt reaction is complete. Using 325 mesh sand is a two edged sword. It melts easier but it also clumps easier. It can get very problematic when the humidity goes up and in a cold melt, it can create silica stones. At the same time I say that, if the dusting bothers you, you can spray the batch with a nozzle from your local greenhouse that gives a fine mist. It will knock down the dusting. Mist to taste. It's kind of messy. :dog:

Franklin Sankar
11-04-2003, 05:26 PM
Seems that the lower Temp. works well for Dave so why would you want to go higher? Is it faster or some other special benefit?
If you use larger size silica sand what happens? Would it still work?
Franklin

Dave Bross
11-04-2003, 05:36 PM
Many thanks Pete! It never would have been possible to get something so incredibly nice on the first try without a whole lot of help.

More questions of course....

On the batch I just melted...

If I wanted to take the COE down to the 92-3 range to fit Fenton stuff, up to 96 to fit Spectrum, or even go completely nuts, kiss durability goodbye, and try taking it up around 102-4 to match Moretti, how would I go about it?

Would adding certain amounts of silica or soda be enough, or do the other things need to change on a percentage basis along with that?

What is the Corning Protocol?

I did melt it at 2200 after I got all the batch loaded and I'm pretty sure I would have screwed it up if I had tried at 2000.

Pete VanderLaan
11-04-2003, 06:30 PM
drop or raise the quantity of soda by one pound to move the C.O.E. about one full point - based on a 100 lb batch.
You will have to play with it but it's ballpark.

The corning protocol is simply that you want to melt as cold as you can get away with and then to turn it up after the mass has melted. The notion is that the lower the temperature, the less attack on the refractories which yields less pot wear and less cords ( up to a point). It's relative to the cording potential and general meltability of the glass. Sometimes melting cold means 2200 F and that's where I melt SP87. I have fluorine glasses I melt at 1900F. You have to be willing to experiment, and to have a few genuine disasters.

As to franklin's question. the lumps Dave saw were perilously close to staying lumps, and they were unmelted silica. I would not melt it that cold or if I did, the quantities would be tiny. The tendency in a large batch pile, say fifty or sixty pounds is for the outside to melt first and for the core to gradually heat up and fuse. You don't want that fusion to go on too slowly or you will get agglomerated big honking piles of snot- ( a highly technical phenomena well worth avoiding..)
:dog:

Jay Holden
11-04-2003, 08:32 PM
Man I'm soaking this post up like a sponge. This is great! Thank's you guys.

Franklin Sankar
11-05-2003, 08:06 AM
I know what you mean Jay. Thanks to Pete and Dave for sharing.

Dave your sand must be low iron or did the chemicals decolorize?
If I have to import the sand I would loose the benefit of reduced shipping cost. In fact when you add the cost of all the chemicals it may be more than SP but then you have to add shipping sand cast. It depends on what you want from the batch, but I remember Pete has been saying the best deal is still with SP. Dave how does it compare with SP?
Franklin

Pete VanderLaan
11-05-2003, 08:36 AM
The whole low iron sand is a red herring. It's the feldspars that turn glass coke bottle green, unless the sand is really awful. Any pottery supply silica is good stuff. :dog:

Dave Bross
11-05-2003, 10:33 AM
Thanks again Pete.

Pottery supply silica is exactly what I'm using here and the glass is gorgeous. As for freight for Franklin (Freight for Franklin, sounds like a great name for a kids book, no?)I guess Florida is about as close to Trinidad as we're going to get in the continental USA.

22 cents a pound for the silica 325 mesh, Axner pottery supply, at ...

Axner.com

I'm sure they're used to shipping to the Caribbean. They are extremely nice at Axner and may be able to get you other things you need if you ask.

All the other chemicals were right around 20-5 cents a pound in bulk, with the exception of the potassium chemicals, which were 73-5 cents a pound. Those came from Brenntag, a major chemical supplier.

I'm using an incredibly nasty fireclay crucible for the experimental melts. This thing has so much iron in the clay that there are BIG rust spots inside. The glass off the top shows perfectly clear on the cross section of a cut cane, and that is very rare not to see green or grey (from decolorizers) on the end of a cane. Glasma is the only other glass I've ever seen this clean. Once you get down in the pot a bit the green begins. Still not too bad, considering the crucible is as nasty as it is.

Another BIG plus for this glass is minimal toxic stuff. The tiny amount of antimony is the only nasty thing in it.

I'm really liking the concept of being able to batch it up and adjust the COE right here at the house. No calls to make, no freight to pay and no waiting and wondering.

The more I play with it the more I like the way it works, and the way it melted was even easier than cullet in my opinion. I've never had a glass squeeze so easily, and I'm using a tall, narrow pot so the bubs have way further to go to get to the top.

Pete VanderLaan
11-05-2003, 11:47 AM
It is true that it is a sweet squeezing glass. I think the great advantage to making it yourself is that if you make an unoxidized form of this stuff- leave out the nitrates, that while harder to fine out, if you always off-load from the mix what you want for color and then add nitrates for the clear part so you can't ever have incompatibility even if you make a mistake at the scales.

Back with your adjusting of the formula, and your decision to only mess with the soda just needs a brief observation. If the moisture content of the silica is 1 percent, that means that you are off one pound silica per 100 lbs loaded, which is not insubstantial. Usually when I am fine tuning a formula, I always do it with the silica and usually it is less than 100 grams per 100 pounds batch to move the formula to where I want it, unless I have seriously screwed up. In general, I don't like to mess with the potassium/sodium ratios at all when adjusting. The silica is very powerful as an adjusting chemical and it can be moved with very little recourse. This is never mentioned in any books on the subject and Soda is always referred to as the holy grail for adjustments. I advise you to not use the soda for that purpose or at least be cautious with that.
63 grams of soda in 15 lbs of glass is quite a bit and is probably driving the expansion up about one full point. That may be a good target amount when you want to push this stuff around. Either that or adjust the silica about the same amount..

It is by the way really heartening to me to see some of you playing in this particular sandbox. There are so few of us now and it really makes me feel that my efforts here at craftweb are worth it just from the pure educational aspects. :dog:

Brian Gingras
11-05-2003, 12:18 PM
Originally posted by Pete VanderLaan


It is by the way really heartening to me to see some of you playing in this particular sandbox. There are so few of us now and it really makes me feel that my efforts here at craftweb are worth it just from the pure educational aspects. :dog:

your efforts do not go un-noticed...I'm 2 years from lighting up my own shop, and this discussion still has had my full attention. Once I get my equipment where I want it, I plan to do the exact same thing, that is to make a glass that I like and fits my needs...having been renting time in other shops and having the base glass changed all the time, I've been fixed on doing the glass batching myself so I don'r have to deal with the changing supplies and unreliable sources.

This kind of discussion is something that all members of the glass comunity need to pay attention to.

Franklin Sankar
11-05-2003, 01:01 PM
This really is the best news, especially about where the iron comes from. Thanks Pete.
Franklin

Jeff Wright
11-05-2003, 04:18 PM
It is by the way really heartening to me to see some of you playing in this particular sandbox. There are so few of us now and it really makes me feel that my efforts here at craftweb are worth it just from the pure educational aspects.

Even though I still am a studio renter and at the whims of the studio owners, I am following this thread with a lot of interest. I'm certainly taking notes. I'm with Brian and probably at least a year and maybe two from my own shop. However I still want to learn as much as I can before firing up.

Pete, thanks for all you have done here at CraftWeb.

All, lets keep these discussions freely flowing!

:) :) :)

Bob Boyd
11-05-2003, 04:34 PM
This has been a great thread for even the newest of newbies. Makes me wanna go batch some glass. I particulary liked the discussion about cost and COE adjustments.

Pete you said this would make an excellent color base. Can I ask what chemicals/materials and quantities would be added to yield different colors?

Thanks
Bob Boyd

Pete VanderLaan
11-05-2003, 04:53 PM
Originally posted by Franklin Sankar
This really is the best news, especially about where the iron comes from. Thanks Pete.
Franklin



Well, don't get carried away, get the cleanest sand you can. And Dave, keep in mind that Nepheline Sy is really a spar.

As to the technical education, it's why I'm interested in the conference, it certainly isn't happening in the schools anymore.
:dog:

Jay Holden
11-05-2003, 06:11 PM
Pete and Dave, Thanks for the insightful post on batching. I'm following with great intrest and with pen in hand. I have an empty shed just waiting for the raw materials. So you say to use pottery silica? Everyone at work are telling me I can buy good batch from Lewis in Corning cheaper than I can batch my own. I know that GlassArt in Watkins Glen uses it in their Electroglas furnace with good results but I think I'd still like to try making it myself.

Pete VanderLaan
11-05-2003, 07:36 PM
If you want really nice glass it is probably going to contain either potash which gives lustre or barium for brightness and neither is cheap. It is not going to contain spars which are very cheap.
As to price, it probably will be cheaper from Lewis. Dave quotes 72 cents lb for potash and I pay 50. I buy a lot more. Silica should really be about 13 cents in bags and is dirt cheap in 1 ton cloth baggies. I think the difference is that you know where everything came from- you made it- and that is power.

I use SP87 for a clear when I am working it with colored glasses. I would not use it as a stand alone clear and would make either the formula Dave has listed that I wrote almost thirty years back, or a very nice 11% lead glass I pull out for special occasions. The glass should be appropriate to the project.

Just remember, get a good scale, a very good scale. I have two and I cross check every time. :dog:

Mitcheal Veenstra
11-05-2003, 07:46 PM
This is great stuff folks... It's makeing thing about trying the batch thing in my little Mark L 15 pound furnace...

Pete, would this qualify for the Classics forum? It is certainly a boon to us low timers here.

Dave Bross
11-05-2003, 07:48 PM
Pete,

Not to worry about the nepheline syenite...

After seeing this glass I believe that I too will invoke the "no spars" rule in my glass making. Much like my "no guts" rule for eating meat. You only go around once so you might as well try for the best you can get. I will melt some other glasses just for the knowledge but I am just blown away by this particular one.

I hear you on the silica adjustment. That's straightforward if I'm going down in expansion, once I figure out exactly how much it takes to move it.

I'll adjust for the 1% moisture in the sand on the next one. I think you're right about bumping it one point with the 63 grams of soda. In my rough guestimates of expansion via thread pulls it comes closer to some older gaffer clear canes that I have than anything else, and I think those are supposedly around 95.3 COE. I suppose I may be retaining a bit more soda/potash in the melt due to the lower melt temp. too. I definitely haven't quite hit 96 COE yet though.

I'm thinking I might be good at my current COE, close enough to 96 to put 96 color on the outside of the clear, and I'll have a bit of compression in the clear from the slightly lower COE if I use it to encase 96 color.

If I want to go up in COE would it be wiser to maintain the ratio between the potash and soda but increase quantities of soda/potash, or just back off on the sand?

Any suggestions on annealing temps?

And....particular thanks for pointing out the idea of mixing the color base as stock and adding the nitrates and antimony when needed.

Jay,

I'm sure you've noticed all the turmoil, sudden surprises and trouble surrounding batch and cullet supply lately, or should I say always? How about batch or cullet that is not quite on spec. like the chinese stuff? At least if I screw up on the scale or something it's a quick fix. Speaking of screwing up...I'm writing each measurement down as soon as I finish it. I know just how easily I could forget or be distracted.
I find it very exciting to have this level of freedom in having control and adjustability on what I'm using. Particularly having a "one fits all" for becoming oxidising or reducing batch on one mix.

Bob Boyd,

For me, the best general and most easily digested info when I was beginning to think about color, and actual percentage suggestions, was a copy of the book "Modern Glass Practice" by Scholes. It's out of print and hard to find but not impossible. Try Whitehouse books in Corning NY or abebooks.com

Pete VanderLaan
11-05-2003, 08:01 PM
Originally posted by Bob Boyd
This has been a great thread for even the newest of newbies. Makes me wanna go batch some glass. I particulary liked the discussion about cost and COE adjustments.

Pete you said this would make an excellent color base. Can I ask what chemicals/materials and quantities would be added to yield different colors?

Thanks
Bob Boyd

That is a loaded question. I am writing a book on it and teach a class in it once a year. I think that if you refer to "Glassnotes" you will find rudimentary coloring stuff. There are also tons of things in these archives that I have written from time to time and you should start there. Dave is also right that Scholes has some good basics as does "A textbook of Glass Technology" by Hodkin and Cousen from back around 1915. I may give a very short course at the conference, and I may not since I anticipate being a little harried.

And this is not meant to put you off, I just don't like glossing over stuff so I don't want to write a treatise right now. I will however sell you one when I finish it.

As to Daves questions, move the sand, you have tons to work with. Moving the alkaline stuff frequently causes cords and that is one very cord free batch. And yes it has occurred to me that this thread will move to classics. It's nice to be back on the subject of glass.

Is Scholes really out of print again? :dog:

Dave Bross
11-05-2003, 08:30 PM
That may or may not be correct on Scholes being out of print. I couldn't find it new when I lucked into my used copy, but that's not to say it isn't out there new.

I love my used copy, it's from 1951 and has lots of fun trivia things like glassmakers not having access to Uranium at that time for fear of the commies getting their hands on some.

Pete VanderLaan
11-05-2003, 09:52 PM
I too have a first edition and it is chock full of that sort of stuff. My copy of Tooley, which is an absolutely worthless book called "Handbook of glass manufacture" reveals such secrets as "Remmy " Brick which was a 95% Alumina brick AP Green made in the sixties and seventies was named after the AP Green president George Remmy from the 1950's. I assume that most people know that "Mizzou" is slang for Missouri, or the university. I see it mispelled all the time. Kast-o-lite is probably a lighthouse on the Mississippi or a cave in the Ozarks. I am off to Oxaca for a week to see my daughter who is in school there, so don't start any political conversations that get Bob all worked up.

One last thought. When you mix a batch, always always always stick a 3x5 card in the actual batch can or bag saying what it is. It's amazing how fast you can get them mixed up, like 45 minutes.
:dog:

Bob Boyd
11-06-2003, 11:07 AM
Originally posted by Pete VanderLaan


That is a loaded question. I am writing a book on it and teach a class in it once a year. I think that if you refer to "Glassnotes" you will find rudimentary coloring stuff. There are also tons of things in these archives that I have written from time to time and you should start there. Dave is also right that Scholes has some good basics as does "A textbook of Glass Technology" by Hodkin and Cousen from back around 1915. I may give a very short course at the conference, and I may not since I anticipate being a little harried.

And this is not meant to put you off, I just don't like glossing over stuff so I don't want to write a treatise right now. I will however sell you one when I finish it.

:dog:

Definately post when you are finished with your book Pete, I'd be interested in one. As to your class I'm thinking it will be out of my league right now, but maybe in a year or two I'll make it to one.

Bob

Jay Holden
11-06-2003, 06:08 PM
[ I use SP87 for a clear when I am working it with colored glasses. I would not use it as a stand alone clear and would make either the formula Dave has listed that I wrote almost thirty years back, or a very nice 11% lead glass I pull out for special occasions. The glass should be appropriate to the project.

Just remember, get a good scale, a very good scale. I have two and I cross check every time. :dog: [/B][/QUOTE]



Thank's Pete, Food for thought. I like the lead crystal myself. I know some of these guys probably have never had the pleasure of working a good lead glass. I'm in the process of aquiring about a ton of cullet from my employer. "They give it away". Do you believe it? I'll use it for those special projects that come up occasionaly.

Jay Holden
11-06-2003, 06:21 PM
[QUOTE]Originally posted by Dave Bross
[B]Pete,
Jay,

.
I find it very exciting to have this level of freedom in having control and adjustability on what I'm using. Particularly having a "one fits all" for becoming oxidising or reducing batch on one mix.


I know, It's a power rush when you think you are in total control of your passion. Being able to change things at will to sute your needs is a great feeling. I envy Pete and his operation down yonder. Also sounds like you have a handle on it pretty well. I need to do some studying to aquire the knowlege for this kinda thing. Right now I'm cramming so much info into my brain I'm getting headaches from it. Or so my Dr. says.

Dave Bross
11-07-2003, 12:45 PM
Jay,

Maybe think twice before getting all that lead cullet.

Enviro issues, reasonable and unreasonable, are a big burden on small businesses these days. You might have some bureaucrat hit you with some serious fines and penalties for having that stuff. Just plain old glass dust is a very hot item among the enviro enforcers at the moment. They would probably get very excited about the lead content. Particularly since you hauled it in there and it's not some leftover from the past.

I was in the scrap metal business for many years and finally had to give it up. I ran a very clean operation but enviro enforcement and declining prices finally tilted the risk to reward factors too far in the wrong direction.

I would hate to see you take a big hit right in the beginning.

It may seem like a fairly minor point at the moment, but the low toxicity of this particular batch could become quite important in the future.

Jay Holden
11-07-2003, 09:42 PM
I read you loud and clear Dave. I have checked on it and there are no restrictions on cullet lead or no lead. I had my melting dept check on it. Besides most of the lead is burned out of the cullet. When we remelt it in the tank we have to add the lead oxcide just as if we were adding clear batch. Our cullet ratio is 69% right now. I will do a test melt and if I see the tell tail yellow orange color of lead I'll blow some stemware and dump the rest and refill with a new batch or cullet melt. I really don't think I'll have any problem with it though. My biggest worry is the effects it could have on my elements.

Pete VanderLaan
11-12-2003, 05:44 PM
Well, I'm back from Oaxaca and Magic mountain is back! Jay, The lead is not "burned out" of the cullet and I don't care who told you that. The lead is a physical part of the glass and that particular glass could not exist without the lead content it has.
The risk is the cullet is mostly in the fine dusts that inherently exist in the cullet itself. For years we all used to say that the lead is bound up in the cullet and it is perfectly safe. It isn't -and that is why Lead glasses can no longer be used for decanters..

I think your headaches are a reasonable concern and I doubt that you need to add any more crap to the stew you are already ingesting. I would not say "Don't take the cullet" but I would say that it is not benign stuff. It has about 36 percent lead in it. You also are going to find that it is an absolute bitch to melt without cords. Those stirring rods really are good for something. :dog:

Dave Bross
11-17-2003, 11:04 AM
Well, I'm on my 5th pot of this stuff and I'm still just thrilled. I'm charging and melting at 2200F, working at 2050. It will squeeze in about 4-5 hours at 1900 or 2000. It will reboil if I go above the valence change on the antimony around 2100F.

Updates...

It anneals (for me) around 920-40F top ed of the anneal range ...your mileage, thermocouple, annealer, phase of the moon, or quantity of chicken blood sprinkled with incantations or arrangement of idols may vary. Of course both annealers are 10 degrees different in what they want, and that's going by the ol' slumped cane test.

I really should have done the slump test first, I turned a days worth of furnace bead cane into something Salvador Dali would have been proud of.

I get an occasional white silica snot (literally just one or two tiny ones) on the top of the melt clinging to the pot wall occasionally. No big deal, pick 'em out and continue on. I'll also get maybe one or two silica (clear) stones in some, not all melts. Also not a major issue for what I'm doing. Long cooking does not seem to change either of these so I'm thinking I may have some not-quite-enough mixing issues, or of course, higher cook/charge temp would probably help but that's not a recommended option with the wire melter.

I don't know why this is... but my nasty 'ol pot has quit throwing iron into the glass and it's coming out beautiful and clear.

I'm SO happy with this glass!!!!!

Pete,

I definitely heard you on your warnings about changing COE with the silica and not messing with the soda/potash ratio, and about how this formula is not kind to changes...but....two of the modifications I'll eventually want to try are bumping this stuff up in COE to go along with Moretti and getting a good manganese purple, which, I suspect, should require much more potassium to eliminate the brown tint.

If I try these two things what sort of trouble should I be watching for? Cords?

When I try for the Moretti match would it be wise to keep the soda and potash at the same ratio to each other as the original and up the quantities or would more of either the soda or potash be a safer way to go?
I don't mind the cost of using more potash if it will make nicer glass.

A little research turns up a recommendation for substituting 13 parts potassium carbonate for 10 parts sodiuim carbonate for equal alkaline effect. Does this match your experience?

Pete VanderLaan
11-17-2003, 11:25 AM
run your sand thru a window screen. :dog:

Steve Stadelman
11-17-2003, 11:44 AM
Dave, I don't even understand half of your glass formulation but you are my hero lately. Someday I want to get down and see what you are doing.

Dave Bross
11-17-2003, 11:45 AM
OK, thanks, I'll do it.

If you don't mind, more questions added on to the post above as an edit.

Pete VanderLaan
11-17-2003, 11:52 AM
I think you could run your potash up two lbs without messing it up and probably the soda by one lb. That will move the expansion a lot. I don't like to see the modifier falling below 8% but it is still tolerable. The silica content is still comfortably high.That glass makes a very nice manganese purple already. It also will do incredible things with selenium. A beautiful peach glass.

I have never messed with those substitution formulas. They pop up in the Manheim book but I have not had the luxury of those experiments. They are a little vague. I will try them out in the spreadsheet during the class in January. :dog:

Pete VanderLaan
11-17-2003, 11:53 AM
Also, are you screening your lime? :dog:

Franklin Sankar
11-17-2003, 12:08 PM
Pete if the sand can pass throught a window mesh are you saying it is about the correct mesh size?
Franklin

Dave Bross
11-17-2003, 12:10 PM
Pete,

Well, no, I've been lazy/bad and not screening anything except the "chunky" style potassium nitrate I got for free.

I'll change my bad habits there. That's just too easy!

Thanks for the COE and color tips! If it makes a nice purple as is I'll just leave it alone for that. Peach....hmmmmm...I'll have to try that. I've never really seen a peach glass.

I suppose when it comes time to match high COE Moretti things never will be quite right. Fortunately that's all jewelry application for me so no dishwashers anticipated.

Steve,

What's not making sense for you on batch formulation?

Hopefully I may be able to explain it as well as you have explained the Moly elements for me.

You're definitely welcome here if you're ever in the neighborhood.

Steve Stadelman
11-17-2003, 12:30 PM
Dave, READING something is one thing. DOING it is entirely another. I have read plenty about glass formulation. I will not understand it untill I have made my own silica snots.

Dave Bross
11-17-2003, 12:41 PM
So true.....

Pete VanderLaan
11-17-2003, 01:10 PM
No window screen size sand is not good. The purpose of the screening is to break up large clumps of stuff that will become snot. I screen everything. :dog:

Jay Holden
11-17-2003, 07:42 PM
[QUOTE]Originally posted by Pete VanderLaan
[B]Well, I'm back from Oaxaca and Magic mountain is back! Jay, The lead is not "burned out" of the cullet and I don't care who told you that. The lead is a physical part of the glass and that particular glass could not exist without the lead content it has.
The risk is the cullet is mostly in the fine dusts that inherently exist in the cullet itself. For years we all used to say that the lead is bound up in the cullet and it is perfectly safe. It isn't -and that is why Lead glasses can no longer be used for decanters..

I hear ya Pete. We take it for granted that the tell tail yellow orange on the top of our gloryholes is from the lead "burning out" of the glass. This color is all over the blowing room specially at the tank area. But, the company has the blowing room air tested for lead and they still say that it's below alouable standards. The headaches persist and I'm not the only one getting them now. The Drs. are stumped. Now they say it's cluster headaches and they will one day cease. I know about the decanters. I made the decanters for Steuben. I really liked making em too. I have a couple but don't keep liquids in them just for that reason.

Pete VanderLaan
11-17-2003, 08:05 PM
The yellow flame showing the lead being present doesn't mean that it is burning out, only that it is present. If you had strontium in the glass it would show a red tone.

Don't let the doc's be "stumped " Jay. I think if the problem is getting around to other workers, it is a union issue and possibly one for OSHA although I would hold that card a while. Headaches are very real and almost always are the result of something being not right. Pursue it thru the union, not personally. Don't become a target.
Reading your list of illnesses is like reading the munchhausen syndrome, but it's real.

Even so, the lead is always there and often takes a dusting form, particularly in a cullet. It's dangerous. While it can't be absorbed thru the skin, it can be breathed.:dog:

Dave Bross
11-17-2003, 08:24 PM
Jay,

If I were you I might want a second opinion on my blood levels of heavy metals. The tests are cheap and any medical lab that does testing for drugs, etc. can do them.

I would maybe look for a lab some distance from where you are, pay cash, and not tell them who you work for, just to ensure the results are on the up and up.

It's not unheard of for results to be "influenced" by the prospect of a large volume of work in return for certain results.

The "cluster headaches" term seems to activate my bullshit detector for some reason.

Rosanna Gusler
11-18-2003, 07:29 AM
jay, could you all be getting carbonmonoxide poisoning? that would not show up on chem tests. i would spring for some independant testing though. conspiracy theorys and all being believable to me. good luck, rosanna

Dave Bross
11-18-2003, 09:35 AM
I'll second Rosannas thoughts. I've had CO poisoning a few times and the most memorable thing was the headaches.

Pete VanderLaan
11-18-2003, 10:55 AM
It would be very easy to take a CO detector with you to work. :dog:

Jay Holden
11-18-2003, 09:48 PM
I noticed today that there was a foul rotten egg smell floating around my gaffers bench. The caffiteria is just down the hall and usually there is a smell of bagels and such but this morning there was no food smell and I started looking for the GAS LEAK. It was in my torch. On the inside of the control box. One of my assistants said he smelled it last week but forgot to bring it to my attention. I went and got the safety lady and she had it fixed right away. I still got the headache but we will see if it subsides now. If not I will get tested for heavy metals up in Rochester or Buffalo. Corning controls the medical people in and around Corning. We did have a high lead situation back in 1990 and we wern't aloud to work without recals on. Try to blow glass while wearing a face mask and helmet. It's an experiance I tell ya.

Jay Holden
11-18-2003, 09:57 PM
[QUOTE]Originally posted by Pete VanderLaan
[B]The yellow flame showing the lead being present doesn't mean that it is burning out, only that it is present. If you had strontium in the glass it would show a red tone.

It's not the flame that is yellow Pete. There is actually a yellow orangeish red dust or deposit on the gloryhole just above the doors. It was worse when we had the old gloryholes. It's also all over the tank area but our air sampling says alls ok. Very low airborne lead particals. Well under the legal limit. Could this deposit be from running the burner in a reduction state? Flame coming out the door.

Pete VanderLaan
11-19-2003, 03:52 PM
I have seen those deposits on the furnaces all the time and it's impossible to make the glass without the deposits. My impression is that there should not be anything coming off of the glass that would cause that on the gloryhole aside from migrant dust from the batching as you suggest. That would in my estimation be a lot of migrant dust. I don't get that on my gloryhole when I melt leads but I do have it on the furnaces.
Lead is also a drag because it doesn't leave any symptoms and I don't think it would cause headaches. As they say irt's a silent killer and all it does is to make you stupid- and I'm not trying to make a joke. I think your torch is one possibility, but only one. I'd still bring in a CO detector if you can get one. Lead shouldn't cause headaches,(again) I don't think.
:dog:

Tom Littleton
11-20-2003, 10:15 AM
By the way, lead cullet is a hazardous waste and has special (as in EPA mandated) disposal requirements. Lenoux used to pay $600.00 a ton to send their cullet to a recyler that processed it to remove the lead. There is a way to melt electrically that causes the lead to return to it's elemental form. (I don't exactly how it works, just that it does)
Tom @ SPB

Jay Holden
11-20-2003, 10:02 PM
Ok Pete, The torch is fixed and I have had no headache since. Of course this don't meen nothing right now cuz it's gone away for days and then returned. The deposits on the gloryhole are quite substantle and I checked the rest of them all 13 and they all have it as did our old glorys. I'll try to sneek a camera in and get a photo to show you. And as far as the lead cullet disposal is concerned, We have hoppers full of it sitting around. A truck comes in once a week and picks it up. I heard some guy uses it for something. They give it to him. When I asked about getting a half ton the answer was "Sure" There's no restrictions on cullet lead or no lead. At least not in NYS.

Rosanna Gusler
11-21-2003, 06:31 AM
jay, i googled CO poisoning symptoms and the stuff about chronic long term exposure is really scary. there are blood tests that will detect exposure. i was getting it from my truck. oh well after 14 years and lots of salt water, what do i ecpect? rosanna ( the chronic worrier)

Ben Rosenfield
11-21-2003, 08:43 AM
Originally posted by Pete VanderLaan
The third formula is simply wrong.
Pete, are you referring to this formula:

50 sand
20 1/4 soda ash
9 1/16 hydrated lime type N
5 1/4 Potassium carb
3 3/16th Borax 5 mole


I'd like to be clear on this because I'm taking notes and rubbing my hands together in planning for the future. Muahahah.

While we're at it ...

Originally posted by Pete VanderLaan
The first formula does have a ton of silica and it is durable and the silica content is why the glass works well in a torch. It was a glass I used that I cut and polished a lot and it polishes beautifully. That is because of the potash.
Is that in reference to this:

100 Sand
28 Soda Ash
14 Lime Hydrate
12 Potassium Carbonate
200 grams potassium nitrate
100 grams antimony oxide


And finally ...

Originally posted by Pete VanderLaan
The second formula is a glass designed to fit SP87 hand in glove. I use it for my red and opal silver amber formulations when matching SP87. It also makes a very nice turquoise blue I am currently working.
Is that in reference to this:

63.25 silica
20.25 soda ash
9.06 Hydrated lime type N
2.18 Borax 5 mole
5.25 Potassium carb
100 grams antimony oxide
130 grams potassium nitrate


Just want to be sure. Thanks. :D

Pete VanderLaan
11-21-2003, 10:59 AM
The 63.25 lb sand is correct. The formulas showing 1/16ths convert every 16th to .06. Note that the other portions of the formula are identical. :dog:

Ben Rosenfield
11-21-2003, 11:27 AM
Thank you. It's nice to get things in perspective when lots of information is heavily concentrated in one place.

So then for the formulas listed, I figured that (excuse the lack of rounding) the following would work well with your EC #5396 pot, around which I hope to eventually build an electric melter:

60.0875 lb. silica
19.2375 lb. soda ash
8.607 lb. hydrated lime type N
2.071 lb. borax 5 mole
4.9875 lb. potassium carbonate
95 g antimony oxide
123.5 g potassium nitrate

TOTAL: 95.47221 lb.

Is this correct? I figured it at 5% of the original formula.

Dave Bross
11-23-2003, 08:31 PM
On melt #8 now. Wheeeeeeeeeeeeeee!!!!!

Well, well, well, it really does do a lot better when you screen the materials. Duh!

Actually melts a bit faster and less dark snots while melting to worry over the eventual fate of.

I'm experimenting on this one. I left out the antimony since it's the only nasty thing in that batch. Oh, and by the way, look up antimony poisoning and you'll maybe want to avoid it when/if possible too. I figure I'll deal with the ugly stuff to get color but a non-toxic clear seemed like a very nice thing. Depends on how troublesome the squeeze is.

So, I know I'm going to fine OK, because I've still got the potassium nitrate, but, since I'm lacking the antimony, any advice on the squeezing? Since I'm sure Pete has already been through this with this batch while making unoxidised color I thought I would ask and maybe save some trial and error time. I'm guessing a few trips up and down in temp. will be in order but that's just a guess.

I'm doing c-balls so if I can't get it to squeeze nicely it's really not the end of the world.

Note for Jay,

The feds should scare you WAY more than the state when it comes to toxic liability. BIG fines and possible jail time.

Ben Rosenfield
11-24-2003, 11:35 AM
I reviewed the MSDS on antimony oxide. It's not fun stuff, and I'd like to avoid using it when it comes time to making my own batch. If you read the MSDS for silica, it's equally as ugly. Look up silicosis and other serious health issues that can arise from exposure. Basically, all these components require care in handling and use, but some are just plain nasty.

In any case, it is very cool and inspiring to watch your progress, Dave. Thanks for making your efforts public. Also, got any pictures you could post of all this?

Pete VanderLaan
11-24-2003, 11:51 AM
Gloves, respirators and good ventilation are a must in doing this. If you can't handle those things, don't do it. If you can, making your own glass is incredibly rewarding.

Everthing in the world is dangerous and respect is a good plan. I think what Dave is doing is fantastic.

A glass without a multi valent reducer will not squeeze well. The role is the nitrate creates the sweeping gasses and at high temps the antimony is mono valent. When the temp is dropped, the antimony reverts to a multi valent state and begins to absorb the gasses in the melt back into solution. That is what you are seeing when the bubbles begin to shrink. If you in turn over heat the glass, the valence goes back to a monovalent state and all those gasses are thrown back into the melt.That is called re boil.

Bottom line, squeezing without antimony is slow and expensive. It is necessary in unoxidized formulas using copper and silver. A little fluorspar helps change the viscosity of the glass and shortens the time up. I use the antimony. It's not going to hurt you unless you stick it in your mouth. :dog:

Dave Bross
11-24-2003, 12:02 PM
You can bet yo' ass I'm using the gloves and respirator. I'll be keeping my silica snots in the pots, not my lungs, thank you.

Even if my no antimony version is OK I'll keep using the gloves to develop the habit for when it gets to be color play time.

I'm still only doing 15 pounds at a time so I can keep the dusting down to very minimal levels. If I was doing hundred pound lots I would go for the tyvek suit and ventilation.

I just did surgery on my digital camera, and the patient actually survived, so I'll get some pics.

Pete VanderLaan
11-24-2003, 12:26 PM
Ben, you are going to have volition loss in the batch. Don't complicate your life by messing with the formula weights and percentages. If you mix too much, store it til next time.

Also, you need to consider the law of significant figures. Don't carry anything past two decimal points and do round off. While you should use a very accurate scale, you are not likely to get one that has meaningful accuracy while being capable of weighing both pounds and thousandths and tenths of thousandths of pounds. I do use two scales to check against each other. I never go beyond hundredths and I don't get really sweaty about them. Larger batches are easier than small ones since the percent margins of error become less significant. Some time ago I told Dave to never mix under 20 lb batches. Sometime soon he will see why I said that.
:dog:

Ben Rosenfield
11-24-2003, 12:36 PM
Originally posted by Pete VanderLaan
Gloves, respirators and good ventilation are a must in doing this. If you can't handle those things, don't do it. If you can, making your own glass is incredibly rewarding.

Everthing in the world is dangerous and respect is a good plan. I think what Dave is doing is fantastic.

I agree. I just think it's important to share some of the potentials for problems. I will use whatever is necessary to maintain quality, so if that means antimony oxide, then that's what it means. I'm used to using good ventilation when blowing borosilicate colors, so adding the protective gear is not that much of a step up.

Hell, I think I'm safer taking a glassblowing lesson than I am driving to work!

And yeah, Dave is definitely doing some cool stuff. Pics, Dave! :D

Pete VanderLaan
11-24-2003, 12:40 PM
I think the lampworkers are doing the most dangerous stuff with color I have seen in years. I keep seeing work rolled in chrome, which is very gassey and is a known carcinogen. Most other metals are dangerous in a flame as well. This is seriously dangerous stuff. :dog:

Dave Bross
11-24-2003, 12:43 PM
Well, If I had to guess why no less than 20 I think I will get caught when it comes to color?

Seems some of the really intense colorants like cobalt will be tough to meter out in small enough doses and the distribution in the batch could be an issue?

Which reminds me....anyone know where to get powder blue in small quantities?

Ben Rosenfield
11-24-2003, 12:59 PM
Originally posted by Pete VanderLaan
Ben, you are going to have volition loss in the batch. Don't complicate your life by messing with the formula weights and percentages. If you mix too much, store it til next time.

I smell what you're stepping in. However, if I use the formula as originally posted and only need, say half of it, how can I be sure that the portion I'm working with is homogenous? I know that sounds silly, and I bet the answer to that is in print, but I'm waiting to read my recently purchased copy of Glass Notes until I get really bored at the in-laws' house during Thanksgiving -- which should take about two hours or so after dinner.

Oh and because it seems some of these chemicals for batch are hygroscopic, let me contribute a link (I'm unaffiliated, mind you) that might help keep your stored materials dry: www.dehumidify.com. You can protect up to 66 cubic feet of enclosed space with their biggest product. And each unit can be reactivated.

Glad to hear that pics are on the way, Dave. Servin' up the virgins.

Ben Rosenfield
11-24-2003, 01:04 PM
Originally posted by Pete VanderLaan
I think the lampworkers are doing the most dangerous stuff with color I have seen in years. I keep seeing work rolled in chrome, which is very gassey and is a known carcinogen. Most other metals are dangerous in a flame as well. This is seriously dangerous stuff. :dog:

Rolling in chrome is a new one on me, but I'm sure you've seen a broader range of glass work. A lot of the opaques that are rich and dense are based in cadmium and chromium, reduce in a heartbeat, and are toxic as all hell. Any responsible flameworker will have a localized exhust above or above/in front of the range of the torch's flame. Also, the fuming process with silver and gold is nasty. Luckily, my instructor keeps a very safe shop.

Pete VanderLaan
11-24-2003, 02:18 PM
If you don't think your batch is homogenous, you aren't mixing it well and you should never try to melt it in the first place.. The old adage is "Well mixed is half melted" Trust me on this one.

What I meant by volition loss is that about 20 percent of a batch goes up the flue in the form of carbon dioxide. 100 lbs of batch usually makes about 80 lbs of glass. It varies based on the formula.

As to the chemicals rolled in pieces. Lampworkers and fusers keep doing this stuff and it is serious crap that really should not be done. Inevitably they get their noses right into it. Copper can poison you just as well as the big nasty metals. It's just a question of overkill, a great term. :dog:

Ben Rosenfield
11-24-2003, 03:28 PM
Originally posted by Pete VanderLaan
If you don't think your batch is homogenous, you aren't mixing it well and you should never try to melt it in the first place.. The old adage is "Well mixed is half melted" Trust me on this one.

I do. ;)

I appreciate your input. Thanks a lot for the replies.

Jay Holden
11-24-2003, 04:50 PM
Note for Jay,

The feds should scare you WAY more than the state when it comes to toxic liability. BIG fines and possible jail time. [/B][/QUOTE]

I've decided to melt CBG from Seattle Batch. They have a distributer in NJ. I can drive down with the truck and pick it up and save on shipping. I'm going down to Wheaton Village this spring I'll pick it up while I'm down there.
Thanks for the concern and the advice.

Pete VanderLaan
11-24-2003, 05:27 PM
Originally posted by Dave Bross


Which reminds me....anyone know where to get powder blue in small quantities? [/B]

Make your powder blue. Take 10 grams of cobalt and put it in 90 grams of your mixed batch and stir well. Then when you want a one gram cobalt glass take ten grams of the powder blue instead. Or, mix it the way you like it. :dog:

Dave Bross
11-25-2003, 10:45 AM
Thanks for the powder blue trick Pete!!!!!!

I always prefer homemade to store bought.

The simplest things are often the most elegant....and so difficult to spot for the uninitiated. It does take serious experience to get to the essence of things.

And, of course, I'm just finishing my third trip up and down in temp from 2200 to 1800F with the no antimony batch and there are STILL a few seeds in there. I think one more cycle would get it but it's for c-balls so it's going to get used as it is..... Lesson learned.....

No more no antimony batches unless I absolutely have to for reduction colors. This stuff WITH antimony will squeeze in 4-5 hours by just turning it down from melt temp. at 2200 to 1800F and then back to work temp. at 2050F. That's just too easy to do without.

I'm amazed the reduction colors don't cost more than they do, considering the time and energy useage required to squeeze the seeds. I've got a whole new respect for them now.

More Pete questions...

You mentioned some silver colors as being in the unoxidised category. which ones?

Could you use sodium flouride to lower the glass viscosity, assuming you compensated for the sodium it was adding? Just thinking along the no spars line, or does the fluorspar make for easier calculations/less error possibility at the scale?

How much flourine do you want for this? I know there are unoxidised color melts in my future. I'm just a big ol' sucker for a really good ruby.

I'm assuming if we're melting without antimony due to reduction requirements, and we're going to lower the viscosity with fluorine, that the seeds have to float to the top as opposed to going into solution as with the antimony? Or, if we're still going up and down in temp., then some of the seeds do go into solution?

Jay,

Good decision!

I get to Corning every now and then...we'll visit ...and remind me to tell you some of the enviro enforcement horror stories.

Pete VanderLaan
11-25-2003, 12:11 PM
the rules change in squeezing small pots. They don't squeeze well, I can tell you that. You have a dual problem of melting an antimony and nitrate free batch and melting it too cold. 2250 is too cold for a copper ruby. I melt them in the 2300's overnight, so thats like 12 hours at 2325. That fines out. I don't like using sodium fluoride because I don't like extra sodium coming from anywhere. Fluorspar is cheap and you can get it at your local pottery. 50 grams in 15 lbs is plenty. Good luck, you are going to need it. Ruby in a wire melter is an exercise in hematic livery reds anyway. They really want good old gas reduction. I don't know why the silver opals work as well as they do in electric. Silver transparants are hard. You can add the antimony to the melt but it doesn't function well without the nitrates andyou just can't add the nitrates. The bubbles you are seeing in the red are almost assuredly carbon dioxide. Hard to dump. :dog:

Dave Bross
11-28-2003, 11:11 AM
OK, thanks for the warning and other advice. Sounds like the reduction ruby will have to wait until I can throw together a tiny gas melter. I'm sure a gas unit might have some other advantages come color time.

Pete VanderLaan
11-28-2003, 05:15 PM
you can do it, but it's a major pain and is never as good as a Gas ruby. It's kind of like cooking on an electric stove. You can do it but Gas really is nicer. :dog:

bump