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David Williams
07-11-2002, 02:29 PM
Hey can anyone give me a ballpark schedule for melting sp87 with wire elements? Tips, pointers?

David

Brian Blanthorn
07-12-2002, 03:05 AM
Originally posted by David Williams
Hey can anyone give me a ballpark schedule for melting sp87 with wire elements? Tips, pointers?

David

U gona blow glass from a kiln David ??

:sheep:

David Williams
07-12-2002, 01:16 PM
Originally posted by Brian Blanthorn


U gona blow glass from a kiln David ??

:sheep:

I already do that. No what I'm doing is building a pot furnace with wire elements. I checked out the moly but with my other pursuits (glass and otherwise) I can't justify sinking tha much bread into it. However I do want to melt batch. I know its taken awhile for some people to get a good melt AND get decent life out of there elements, but supposedly it can be done. And I've heard just an extended cook @2250 and long squeeze but I have a feeling there's more to it than that.

David

Pete VanderLaan
07-12-2002, 01:22 PM
The extended cook time and the 2250 are right. ten hours plus after the last charge is what I keep hearing. Size of the crucible will also be critical.
Brioni has suggested to me that element life can really be extended by using alumina support rods in the inner coil of the elements. This makes a lot of sense to me. I think that coupling up the alumina rod with an SCR could really help get a handle on element replacements. :dog:

Brian Blanthorn
07-12-2002, 02:33 PM
Originally posted by Pete VanderLaan
The extended cook time and the 2250 are right. ten hours plus after the last charge is what I keep hearing. Size of the crucible will also be critical.
Brioni has suggested to me that element life can really be extended by using alumina support rods in the inner coil of the elements. This makes a lot of sense to me. I think that coupling up the alumina rod with an SCR could really help get a handle on element replacements. :dog:

Looking at these temps U R right up there with the potters

n They tend not 2 soak

So I guess UR realy pushin everthing

Conversly a fuzy type preson is realy giving the kiln an easy life

Anything that can stop the elements drooping would help

:sheep:

Eben Horton
07-12-2002, 03:10 PM
Mark,
heres a story that will make you feel better about the chance that you might not get good glass.

It was a friday and I needed a full pot on monday, so I threw in about a bag and a half of spruce pine on top of the glass that was left in my 225 pounder I had at the time.. After I dumped the glass in, I went out to get a beer and totally forgot to turn up the furnace. It was at 2100 from a days blowing, and it sat for the weekend at 2100. On monday I came in prepared to fiddle with my partlow and it was only then that I realized that I never turned it up to charge/cook/sqeeze. I totally freaked out and figured I would have to either re-cook the batch that was unmelted, or ladle out all the uncooked crap and start over... believe it or not, the glass was totally perfect... no bubbles, no un cooked batch, no chords nothing...

so I don't see why 2250 wouldn't work with a longer soak... heck, maybe 2100 is what you might want to do and let it sit for a weekend.

eben

Pete VanderLaan
07-12-2002, 03:19 PM
but buy a case. One beer won't be nearly enough. :dog:

David Williams
07-12-2002, 03:51 PM
T

Originally posted by Eben Horton
Mark,
heres a story that will make you feel better about the chance that you might not get good glass.

It was a friday and I needed a full pot on monday, so I threw in about a bag and a half of spruce pine on top of the glass that was left in my 225 pounder I had at the time.. After I dumped the glass in, I went out to get a beer and totally forgot to turn up the furnace. It was at 2100 from a days blowing, and it sat for the weekend at 2100. On monday I came in prepared to fiddle with my partlow and it was only then that I realized that I never turned it up to charge/cook/sqeeze. I totally freaked out and figured I would have to either re-cook the batch that was unmelted, or ladle out all the uncooked crap and start over... believe it or not, the glass was totally perfect... no bubbles, no un cooked batch, no chords nothing...

so I don't see why 2250 wouldn't work with a longer soak... heck, maybe 2100 is what you might want to do and let it sit for a weekend.

eben


That makes me feel better Eric. I like to keep my weekends free for cavorting anyway.:toast:

David

David Williams
07-12-2002, 04:04 PM
First I was going to coil rubber hose around an inner sonotube and cast my element groove right into the castolite. Then I got that old kiln from my neighbor. Well that didn't work out but it got me thinking. So I called up S.P.S. and ordered one of their standard 18"x18" kilns but without the kiln sitter and with apm elements. I had them add another ring of brick at the bottom so when the pot unloads the elements'll be high and dry. And I had the make the pigtails 12" to go through the 7"frax all around. all that was just a little more than base price, because no sitter. When it gets here I'm going to carve a drain and pour 2" mizzou to anchor my hardbrick pedestal and make a better floor. For the crown I'm just going to castolite ring like a GH door with frax gasket in between and extend the existing hinges up and use the existing lid as the door. And I'm getting an SCR.

What the hell am I doing on the computer I'm so freakin behind! Til monday,

David



Originally posted by Pete VanderLaan
The extended cook time and the 2250 are right. ten hours plus after the last charge is what I keep hearing. Size of the crucible will also be critical.
Brioni has suggested to me that element life can really be extended by using alumina support rods in the inner coil of the elements. This makes a lot of sense to me. I think that coupling up the alumina rod with an SCR could really help get a handle on element replacements. :dog:

Mitcheal Veenstra
07-12-2002, 04:17 PM
Hey Pete, and any others that might know...

I had an email conversation a long time ago with a glassblower that built his own electric wire furnaces. He always melted around 2150 with a long soak and squeez to fine out.

He said it tended to make the sp87 somewhat softer.. he'd have some compatibility fit problems. But nothing to bad...

Any idea why this happens? Or does this even happen?

Thanks,
Mitcheal

Steve Stadelman
07-12-2002, 05:31 PM
David, if you get an scr with current limit like a Watlow Din-A-Mite, you will be able to lower your watt loading on your elements at your own discretion. I dont know your numbers but say your kiln draws 30amps at full load but you find out that it heats up fine at only 25amps you should find that you will dramatically lengthen thier life. Steve.

Pete VanderLaan
07-13-2002, 07:58 AM
Originally posted by Mitcheal Veenstra
Hey Pete, and any others that might know...

I had an email conversation a long time ago with a glassblower that built his own electric wire furnaces. He always melted around 2150 with a long soak and squeez to fine out.

He said it tended to make the sp87 somewhat softer.. he'd have some compatibility fit problems. But nothing to bad...

Any idea why this happens? Or does this even happen?

Thanks,
Mitcheal

There is less sodium ionization at colder temps causing sodium retention. I have demonstrated and tracked the changes in expansion based on temperature in a variety f batches over the years. SP87 produces a 96 based on melting at 2323 F. If you melt hottter, it goers down, colder and it goes up. I have sucessfully moved it over a range of 94-98. Quite a spread. :dog:

Mitcheal Veenstra
07-13-2002, 09:08 AM
Wow, 4 point spread just on how hot you melt the batch. Thats pretty amazeing. I think I understand his fit problems now a bit better.

so with more sodium retention, do you end up with less stable glass? or is that not a problem because there's enough inherant stability in spruce pines formula?

Pete VanderLaan
07-13-2002, 11:59 AM
It only takes about 150 Grams of Sodium to push the C.O.E. around a few points in 100 lbs of batch, so no, it doesn't affect stability. It can simply make colors that fit marginally not fit at all.
The first time i ran into this, I was melting a copper ruby that fit Sp87 fine. I would charge on sundays and everything was cool, filling both pots. On Wednesday I would be a bit short on the red and instead of preheating the furnace, I would chuck the red in and turn it up. It would come from the same batch mix that I used on Sunday. Any glass made from the second melt would crack. I began a logic elimination process and started measuring the glasses. It was way way off melted cold.
So then I did a tracking on the glasses melting at fixed temps and measuring the coe of each glass. That yielded the 94-98 range I referred to.

You can do this with other marginal fits as well. Opaque yellows and reds, and transparant reds and yellows can be made to go out of "fit range " if you work them long enough on the pipe. It takes about eight hours. Peiser had this problem back in the Wisteria series. Fussy stuff. :dog:

F Thumb
07-13-2002, 12:08 PM
Originally posted by David Williams
So I called up S.P.S. and ordered one of their standard 18"x18" kilns but without the kiln sitter and with apm elements.
David


Who is S.P.S. ?

:thumb:

Mitcheal Veenstra
07-13-2002, 12:24 PM
Thanks for the explination Pete, that makes sense.

Is there anything we could add to the batch in order to rig the COE back to 96 proper that would still melt so low and give us a good melt?

or should those of us who are useing wire, just melt low and live with the coe shift in order to preserve our elements. :)

What about you Thumb? what temp do you batch at in your super electric melters?

F Thumb
07-13-2002, 02:15 PM
Originally posted by Mitcheal Veenstra
Thanks for the explination Pete, that makes sense.

Is there anything we could add to the batch in order to rig the COE back to 96 proper that would still melt so low and give us a good melt?

or should those of us who are useing wire, just melt low and live with the coe shift in order to preserve our elements. :)

What about you Thumb? what temp do you batch at in your super electric melters?

2120F 24/7. But I use cullet (I like fining out in a twelve hour cycle). The hope for the ST150 is that it will melt batch and still maintain 9-12 months life cycle between element change out*. When I get my own ST100 swapped out for one of the new ST150s I was planning on trying the Gaffer batch.

:thumb:

*Though my own ST100 had to swap out elements after the first five months, it was largely due to a glass spill that ran down the bank of elements. The sister unit to that ST100 is still going strong seven months later - and with NICHROME wire. This encourages me that 9-12 months with A1 should be attainable.

Hugo Gavarini
07-13-2002, 03:49 PM
It's only my two cents on the matter of pushing the limits to Kanthal A1 wire. All from Kanthal bibliographie:

The more the wire diameter, the more the limit temperature it can bear.

The lesser the coil compression, the more energy it can release.

The more the frequency of the control signal, the more durability of the element. Or the same, the lesser the temperature oscilation, the better.

Eben Horton
07-13-2002, 04:18 PM
Originally posted by F Thumb


2120F 24/7. But I use cullet (I like fining out in a twelve hour cycle). The hope for the ST150 is that it will melt batch and still maintain 9-12 months life cycle between element change out*. When I get my own ST100 swapped out for one of the new ST150s I was planning on trying the Gaffer batch.

:thumb:

*Though my own ST100 had to swap out elements after the first five months, it was largely due to a glass spill that ran down the bank of elements. The sister unit to that ST100 is still going strong seven months later - and with NICHROME wire. This encourages me that 9-12 months with A1 should be attainable.

thumb,

I'll bet you a 12 pack that if you switch to gaffer batch your production #'s will go down. The batch's work time is almost double that of every cullet I've used. So.. thats more time you'll be squirting the ol air hose on those balls...
just my thoughts
eben

F Thumb
07-13-2002, 04:34 PM
Originally posted by Eben Horton


thumb,

I'll bet you a 12 pack that if you switch to gaffer batch your production #'s will go down. The batch's work time is almost double that of every cullet I've used. So.. thats more time you'll be squirting the ol air hose on those balls...
just my thoughts
eben

I never thought of that. I tried a different cullet once (I forget which it was) and it was SOO SLOOOW to harden it drove me nuts.

Is longer working time normal for all batches?

:thumb:

Pete VanderLaan
07-13-2002, 05:29 PM
Originally posted by F Thumb


I never thought of that. I tried a different cullet once (I forget which it was) and it was SOO SLOOOW to harden it drove me nuts.

Is longer working time normal for all batches?

:thumb:
I don't know of any commercial studio batch glasses that are "short". Eben has a point. At one time I made stemware ( I was young) and I wanted the stem to set really fast to keep the line clean. It flat wouldn't work with a slow potash glass I had worked up.
Normally a glass high in calcium is going to be really runny and set quickly. The down side is loss
of luster. You may want to stick with "what ain't broke don't need fixin.
as to Michaels questrion about offsets, sure, 50 grams of silica per hundred lbs would help bring the expansion back down, but I woudn't do it unless you are having problems with the C.O.E.. The trouble with pelletized batch is that things can't get inside the pellets so the mixing is uneven. It's not a big deal, more a minor nuisance.:
I am uncomfortable with melting at 2100F for any commercial clear currently out there. :dog:

Eben Horton
07-13-2002, 07:32 PM
Ahh I love it when I'm right.... Thumb, Ive used Gaffer a few times and I found that the gaffer has the most longest working time. It really screwed me up when I was pulling cane.. I ended up with a runny mess. batch has it place, but with your work I'd stick with the cullet. gabbert 4-c really sets up fast. Its great for stemwear, and mold blown stuff... Batch is great for blowing out bigger blown wear that requires lots of re-heats.

you can keep the 12 pack-
eben

Thomas Sodeur
07-13-2002, 11:31 PM
i know you'd keep the 12 pack ya smartass....lol
tom

07-14-2002, 12:53 AM
i have a 80 lb pot on ely's 13 gage kantholl 10 inch's of insulation.
i melt eltromelt, cook for 8 hours at 2280 squeeze for 4 hours , no bubs or cords just nice glass. so far the 13 gage are on there 6th week the 14 gage i was using only lasted 3 weeks .

mike

07-14-2002, 07:35 AM
David:

I have been melting SP87 for 3 years now in my Denver 135 # furnace.

When I charge, I usually let the furnace sit at whatever the working temp. was until I put the last of the batch in to fill the crucible. Then I ramp up to 2225 and let it cook for 10 hours, drop the temp. to 1900, let it squeeze for 2 hours then ramp up to 2050 where I work at.

I almost every time come out with beautiful clear, bubble free glass.

I am going to try Gaffer in the fall and see what happens.

Good luck,
Ed:p

Mark Wilson
07-14-2002, 08:25 AM
Originally posted by Mike Crowley
i have a 80 lb pot on ely's 13 gage kantholl 10 inch's of insulation.
i melt eltromelt, cook for 8 hours at 2280 squeeze for 4 hours , no bubs or cords just nice glass. so far the 13 gage are on there 6th week the 14 gage i was using only lasted 3 weeks .

mike

how long do you get on a set of elements? what yield do you get (lbs batch vs. lbs glass)?

Jim Vormelker
07-14-2002, 10:56 AM
In an effort to reduce dust, and because I am close enough that shipping doesn't kill me, I switched from SP87 to Gaffer (Phillips).

In my huge, 60# Denver, I work down about 60 - 65% between charges. Charge in 2 or 3, +/- 10# - 12# fills. Set to 2250 and leave it 24 hrs. Down to 2140 to work.

Clear, bubble free.
.............................

The variable is the popcorn effect when the Gaffer goes in. The pellets pop and land on the sill. There they melt and create a seal to do the door.

I like the glass (I don't work fast enough yet for slow setting to be a problem.... to me it's a virtue) but may have to go back to SP87 to be able to open the door.
Jim V

>>>>>>>>>>>>>>>>>>>
I have been melting SP87 for 3 years now in my Denver 135 # furnace.

When I charge, I usually let the furnace sit at whatever the working temp. was until I put the last of the batch in to fill the crucible. Then I ramp up to 2225 and let it cook for 10 hours, drop the temp. to 1900, let it squeeze for 2 hours then ramp up to 2050 where I work at.

I almost every time come out with beautiful clear, bubble free glass.

I am going to try Gaffer in the fall and see what happens.
Ed Kozlowski
>>>>>>>>>>>>>>>>>>>>>

Douglas Terry
07-14-2002, 12:11 PM
Preheat the batch to 950 F and it will not pop. Doug Terry

The variable is the popcorn effect when the Gaffer goes in. The pellets pop and land on the sill. There they melt and create a seal to do the door.

Kurt Walrath
07-14-2002, 06:39 PM
I got 8 months out of my 1st set of 13 ga. elements. They are $20 each from Jen-Ken.

I melt @ 2300 for 8 hours ramp to 1960 and now
work at 2075. 107# ec pot.

I made a few good changes to the design when
I put in the new elements. no time to update the
website though.

http://www.kurtwalrath.com/largeglassstudio/furnace.htm

Kurt Walrath
07-14-2002, 06:45 PM
OOpS! my elements are 15ga. They still last a long time though....I limit my output to 80%.....
another good reason to have a great controller.

07-14-2002, 11:47 PM
Originally posted by Mark Wilson


how long do you get on a set of elements? what yield do you get (lbs batch vs. lbs glass)?


3 weeks on the 14 gage.

and i get about 90% yeild on the eletromelt.

mike

07-14-2002, 11:50 PM
Originally posted by kurt walrath
I got 8 months out of my 1st set of 13 ga. elements. They are $20 each from Jen-Ken.

I melt @ 2300 for 8 hours ramp to 1960 and now
work at 2075. 107# ec pot.

I made a few good changes to the design when
I put in the new elements. no time to update the
website though.

http://www.kurtwalrath.com/largeglassstudio/furnace.htm

you got 8 mounths on elys??????????????? is this on 24/7 ??alright what am i doin wrong???

Kurt Walrath
07-15-2002, 07:50 AM
Yes for the most part 24/7 ( with a weekend
off here and there)in a production, make
a meager living off it environment.

I don't know what you are doing but I know that
my furnace design gets long life, I suspect due
to the fact that the elements are in a separate
chamber from the batch. Long element life is not all that
it's cracked up to be however. the last
few months of those elements it was taking forever
to melt as they lost power. the power loss is gradual
as they age and you don't notice it while
it's happening. you really notice it when you put
a new set in and are able to quit charging 3 hours
earlier than the last time. I think maybe I
will start looking for a surplus hourmeter to
put on my furnace to keep better track of the element life.
I hope to have the dicipline to
put new elements in next time before the old ones wear out
and quit. I charge 3 times a week and would rather
finish sooner than later.

I think that the Denver design
is so poor that it has created a concern
about "element life" that would not exist if you
never started marketing something as ill suited
to melting studio glass as their design is. I know
that some people have made it work by jumping thru
hoops but putting the elements behind the pot and
out of harms way just makes lots more sense.
No offence intended to those of you using Denvers
but I can't imagine wanting to hold at a melt temperature for 24 hours
just so you can melt a few degrees colder and try to coax a little extra
"life " out of the elements.
I already suffer in my production by not being able
to empty my pot after a days blowing and be able
to refill it quickly enough to begin blowing the
next morning. The wound elements won't put out enough power
in my design to melt, cook, fine, and
squeeze 70 - 100#'s of batch overnight. I've seen
gas fired units that pull that off with no trouble
but my furnace was cheap to build and I got what I payed for.

My oven has very low thermal mass but I regularly
finish blowing with 10-20 #'s of glass in the bottom
and pull the plug to go to a show. it cools at a rate far slower
than the 200 degrees per hour that I bring it back up. This is a small "perk" that I enjoy with
my furnace.
http://www.kurtwalrath.com/largeglassstudio/furnace.htm

F Thumb
07-15-2002, 08:09 AM
Originally posted by kurt walrath


I made a few good changes to the design when
I put in the new elements. no time to update the
website though.

http://www.kurtwalrath.com/largeglassstudio/furnace.htm


Sayyyyy, I just LOVE the new crown and door design (what was the inner ring casted out of again?).

The only worry I would have is that the inner crucible is air sealed from the furnace air chamber. I understand (from much firsthand experience) that with a small gap over the crucible there's the risk of glass pops getting on an element, but the problem I had when I tried to let the crown come down to meet the pot was that when charging it created too large of a temp differential from inside the pot to the outside of the pot and the pot pitted and went to hell 3x as fast as when I left 1" of air space between the top of the crucible and the crown. (My solution involved leaving the 1' gap and preheating my charge)

Are you fired up yet? Is this new and improved SuperKurtMelter running any more efficient than the last? Is a gathering port that's only 8" wide by 11" deep big enough?

:thumb:

Mark Wilson
07-15-2002, 08:16 AM
Originally posted by kurt walrath
I got 8 months out of my 1st set of 13 ga. elements. They are $20 each from Jen-Ken.


your heaters only cost $20? i pay a lot more than that for the kanthal apm elements i buy. could they actually be a kanthal nichrome heater? i think thumb was using nichrome for a while that someone told him were apm.

F Thumb
07-15-2002, 08:23 AM
Originally posted by kurt walrath
Yes for the most part 24/7 ( with a weekend
off here and there)in a production, make
a meager living off it environment.

I don't know what you are doing but I know that
my furnace design gets long life, I suspect due
to the fact that the elements are in a separate
chamber from the batch. Long element life is not all that
it's cracked up to be however. the last
few months of those elements it was taking forever
to melt as they lost power. the power loss is gradual
as they age and you don't notice it while
it's happening. you really notice it when you put
a new set in and are able to quit charging 3 hours
earlier than the last time. I think maybe I
will start looking for a surplus hourmeter to
put on my furnace to keep better track of the element life.
I hope to have the dicipline to
put new elements in next time before the old ones wear out
and quit. I charge 3 times a week and would rather
finish sooner than later.

http://www.kurtwalrath.com/largeglassstudio/furnace.htm

You just need to find a way to fit an extra leg of elements in there. It's like going from a flat six to a V8, and the best part is it doesn't take any extra power to hold temp with the extra elements - and charging is WAY faster. (It also gives you the ability to keep temp after the first element goes down)

As far as element longevity goes, a set really only needs to last as long as the crucible. No sense having the pot crap out a month before the elements (unless you're in the replacement furnace biz - hmmmm).

At 12 months, I can use the break anyway.

:thumb:

David Williams
07-15-2002, 01:48 PM
Man is this great. I wish ther was an archive here, now I gotta figure out how to copy all this stuff off and save it.

David

Mark Wilson
07-15-2002, 02:29 PM
Originally posted by David Williams
Man is this great. I wish ther was an archive here, now I gotta figure out how to copy all this stuff off and save it.

David

click on the printable version link at the bottom of the screen then click on print, and you are there.

Kurt Walrath
07-15-2002, 05:09 PM
(what was the inner ring casted out of again?).
2900 deg insulating castable.

You just need to find a way to fit an extra leg of elements in there.

As it says at the beginning of my furnace page
I used my spares as an extra leg after the 1st
few times I charged. The only way to get more
elements in there would be to rebuild it with
another layer of ifb in the chamber. I put 3
grooves per brick in there to begin with. If
I was to do it again I would probably make the
chamber taller so I could add more elements.
Time is money when charging and the element cost
in cheap in the long run in my situation.

your heaters only cost $20?

They are a stock replacment item from Jen - Ken
Kilns. I'm pretty sure they are Kanthal A-1.
If they are nichrome then 8 months melting 100#
of batch 3 times a week is really good.

The only worry I would have is that the inner crucible is air sealed from the furnace air chamber.

In real life I found that my frax seal between the crown and the pot burns out. there is a small ( 1/2")
gap between them after the frax goes. I dont think
that I get much stuff passing through the crack though.



Are you fired up yet? Is this new and improved SuperKurtMelter running any more efficient than the last?
It's not really new and improved. i just swapped elements
a few months ago and while I was in there I rammed
some plastic castaBLE over the place where the
drips from the sill went down and contacted the
2900 deg castable of the crown. it couldn't take the
direct glass contact and it pitted the castable
and spit tiny stones into the glass. That rammable
stuff can handle the glass contact fine and my stone
problem disappeared.

I don't think it's any more efficient than before
it just melts way faster with new elements than
with 6-8month old elements. (more power)

Is a gathering port that's only 8" wide by 11" deep big enough?

I pull some big gathers through it but I wish it
was 10" wide sometimes when I scrape the sides.

A 7-1/2" wide gather would probably make a 16"
goldenflow, it's alot of glass.

F Thumb
07-15-2002, 06:06 PM
Originally posted by kurt walrath



They are a stock replacment item from Jen - Ken
Kilns. I'm pretty sure they are Kanthal A-1.
If they are nichrome then 8 months melting 100#
of batch 3 times a week is really good.





That's what I thought for years untill Tom at Pine Ridge called Paragon for some specs to make a match for Mike down in UT (whom I eagerly await news of the new furnace from - he's using a stock ST100 crown). To my suprise I was running nichrome all this time :headbang: , and still getting 6-8 months off of them. :confused: There's another ST100 going on 7 months and he has the nichrome wire.

Might be worth the call to verify.

:thumb:

Pete VanderLaan
03-10-2003, 11:09 AM
.