Sand casting question
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Sand casting question
Going to try sand casting this week. Somewhere I thought I read you shouldn't use 90 because it may stick. Is this due to the softness of the glass? Thus I shouldn't use 96 either? Is float the only option? If so, where can I get some colored float frit? Thanks!
Christyn
Christyn
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Re: Sand casting question
I never tried any of the "soft glasses" so I have no idea. As far as colored float goes, if you like gray or bronze, you are in luck. For colors there is a pale blue and a pale green, not easy to get and not worth the effort anyway. I color my glass with enamels of various sorts.Christyn Mattson wrote:Going to try sand casting this week. Somewhere I thought I read you shouldn't use 90 because it may stick. Is this due to the softness of the glass? Thus I shouldn't use 96 either? Is float the only option? If so, where can I get some colored float frit? Thanks!
Christyn
Make a test and let us know.
Bert
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Charliecharlie holden wrote:I've sand cast with Bullseye and it does fine soaking at 1500 F for an hour. I'm using a sifting of kaolin as a release on top of the sand. My sand mix is about 50% 120 olivine sand, 30% silica sand, 20% plaster.
ch
I always avoid kaolin after I had scum issues in my reusable powder. I never tried bentonite and I wonder if it is a better alternative.
Meanwhile I got samples of VERY fine and relatively coarse alumina hydrate. It looks awesome. I haven't tried it yet.
Bert
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Hi,
I have only done sand casting in molds, with a crucible drip. I'd like to try doing hot pours from the crucible. We had used an acetalyne torch to prep the sand- I am intrigued by the notion that you can sift bentonite or kaolin instead. (I don't have a torch, besides a hand held Mapp).
Can you use spray graphite?
Also, does anyone know if I can buy long tongs for picking up the crucible to pour- or is this something I need to invent?
Thanks,
Liz
I have only done sand casting in molds, with a crucible drip. I'd like to try doing hot pours from the crucible. We had used an acetalyne torch to prep the sand- I am intrigued by the notion that you can sift bentonite or kaolin instead. (I don't have a torch, besides a hand held Mapp).
Can you use spray graphite?
Also, does anyone know if I can buy long tongs for picking up the crucible to pour- or is this something I need to invent?
Thanks,
Liz
[quote="elizglass"]Hi,
I have only done sand casting in molds, with a crucible drip. I'd like to try doing hot pours from the crucible. We had used an acetalyne torch to prep the sand- I am intrigued by the notion that you can sift bentonite or kaolin instead. (I don't have a torch, besides a hand held Mapp).
Can you use spray graphite?
Also, does anyone know if I can buy long tongs for picking up the crucible to pour- or is this something I need to invent?
Thanks,
Liz[/quote
Yes, spray graphite works well.
Are we going to need another name for this process?
Everybody else in the glass world considers sand casting a hot pour.
Brock
I have only done sand casting in molds, with a crucible drip. I'd like to try doing hot pours from the crucible. We had used an acetalyne torch to prep the sand- I am intrigued by the notion that you can sift bentonite or kaolin instead. (I don't have a torch, besides a hand held Mapp).
Can you use spray graphite?
Also, does anyone know if I can buy long tongs for picking up the crucible to pour- or is this something I need to invent?
Thanks,
Liz[/quote
Yes, spray graphite works well.
Are we going to need another name for this process?
Everybody else in the glass world considers sand casting a hot pour.
Brock
My memory is so good, I can't remember the last time I forgot something . . .
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Sand bed casting? I think of it as hot casting versus kiln casting. This being a kiln casting forum I'm generally going to assume that's what we're talking about. Damn the torpedos...Brock wrote:elizglass wrote:Hi,
I have only done sand casting in molds, with a crucible drip. I'd like to try doing hot pours from the crucible. We had used an acetalyne torch to prep the sand- I am intrigued by the notion that you can sift bentonite or kaolin instead. (I don't have a torch, besides a hand held Mapp).
Can you use spray graphite?
Also, does anyone know if I can buy long tongs for picking up the crucible to pour- or is this something I need to invent?
Thanks,
Liz[/quote
Yes, spray graphite works well.
Are we going to need another name for this process?
Everybody else in the glass world considers sand casting a hot pour.
Brock
Liz, as long as the sand is cold when you pour glass on it, spray graphite or acetylene derived carbon smut will work as a release. But both will burn away in a kiln. So we use refractories instead. At the same time that the sand is hot in a kiln, the glass is cooler than it would be in hot casting. So kaolin or alumina or bentonite might react with the much hotter glass during a pour. I don't know. I do know that bentonite will stick to poured glass.
Boyce Lundstrum has pictures of tongs for crucible casting in his "Fusing Book Three". Not really an off the shelf item.
ch
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you can find crucible tongs and hand shanks from places that sell foundry supplies. http://budgetcastingsupply.com/Price_Sheet.html#Tongs
or from McMaster-Carr http://www.mcmaster.com and search under foundry tongs (page 2572)
Tony
or from McMaster-Carr http://www.mcmaster.com and search under foundry tongs (page 2572)
Tony
The tightrope between being strange and being creative is too narrow to walk without occasionally landing on both sides..." Scott Berkun
raku tongs work
and they're cheaper too
Going to be firing both BE and S96 on sand in a couple of days. Anyone tried plaster of paris or BE kiln wash as separator?charlie holden wrote:I've sand cast with Bullseye and it does fine soaking at 1500 F for an hour. I'm using a sifting of kaolin as a release on top of the sand. My sand mix is about 50% 120 olivine sand, 30% silica sand, 20% plaster.
ch
Carol
Going to be firing both BE and S96 on sand in a couple of days. My sand bed is a mixture of olivine sand and plaster (80/20 I think...Bert???) Anyone tried plaster of paris or BE kiln wash as separator?charlie holden wrote:I've sand cast with Bullseye and it does fine soaking at 1500 F for an hour. I'm using a sifting of kaolin as a release on top of the sand. My sand mix is about 50% 120 olivine sand, 30% silica sand, 20% plaster.
ch
Carol
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CarolCarol wrote:Going to be firing both BE and S96 on sand in a couple of days. My sand bed is a mixture of olivine sand and plaster (80/20 I think...Bert???) Anyone tried plaster of paris or BE kiln wash as separator?charlie holden wrote:I've sand cast with Bullseye and it does fine soaking at 1500 F for an hour. I'm using a sifting of kaolin as a release on top of the sand. My sand mix is about 50% 120 olivine sand, 30% silica sand, 20% plaster.
ch
Carol
Your olivine came premixed with 5% bentonite before we mixed in 20% plaster of paris. I have been working without any added plaster as a seperator with fine results on float.
Bert
Bert Weiss Art Glass*
http://www.customartglass.com
Furniture Lighting Sculpture Tableware
Architectural Commissions
Bert Weiss Art Glass*
http://www.customartglass.com
Furniture Lighting Sculpture Tableware
Architectural Commissions
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[quote="Bert Weiss
Your olivine came premixed with 5% bentonite before we mixed in 20% plaster of paris. I have been working without any added plaster as a seperator with fine results on float.[/quote]
Thanks Bert. Couldn't remember if there was any bentonite in there. Am doing tests with BE and S96 today, with and without plaster and KW as separator. Will report back.
Carol
Your olivine came premixed with 5% bentonite before we mixed in 20% plaster of paris. I have been working without any added plaster as a seperator with fine results on float.[/quote]
Thanks Bert. Couldn't remember if there was any bentonite in there. Am doing tests with BE and S96 today, with and without plaster and KW as separator. Will report back.
Carol