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-   -   Batch with wire? (http://talk.craftweb.com/showthread.php?t=477)

David Williams 07-11-2002 03:29 PM

Batch with wire?
 
Hey can anyone give me a ballpark schedule for melting sp87 with wire elements? Tips, pointers?

David

Brian Blanthorn 07-12-2002 04:05 AM

Re: Batch with wire?
 
Quote:

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 02:16 PM

Re: Re: Batch with wire?
 
Quote:

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 02:22 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 03:33 PM

Quote:

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 04:10 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 04:19 PM

but buy a case. One beer won't be nearly enough. :dog:

David Williams 07-12-2002 04:51 PM

T

Quote:

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 05:04 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



Quote:

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 05:17 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 06:31 PM

about those S.C.R.s
 
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 08:58 AM

Quote:

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 10:08 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 12:59 PM

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 01:08 PM

Quote:

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 01:24 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 03:15 PM

Quote:

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 04:49 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 05:18 PM

Quote:

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 05:34 PM

Hmmmmmm. . .
 
Quote:

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 06:29 PM

Re: Hmmmmmm. . .
 
Quote:

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 08:32 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 07-14-2002 12:31 AM

packs and such
 
i know you'd keep the 12 pack ya smartass....lol
tom

07-14-2002 01:53 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 08:35 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


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