Lapidaryforum.net
Rockin' Jewelry => Gold, Silver, Other Metals, Casting and Fabrication => Topic started by: PhilNM on March 16, 2015, 04:39:19 PM
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On the bulletin board at the local jewelry supply, someone has the following casting set up for sale.
Oxy acetylene torch
centerfuge
flasks
vac machine
investment
kiln
and wax.
No prices, no idea of how much or sizes or ??? So, here's the hard question. What should someone expect to pay for a used casting set up with all this stuff?
Thanks!
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Where I live we have an auction 3 times during the summer. These items usually come up one at a time. Oxy torch $25, with tank and gauges,$50 Centrafuge, vac machine and Kiln run about $100 to $150 each, Flasks, more than one $20. Investment, buy new if you don't know how old it is or exposed to atmosphere.
Hope this gives you a guide,
olgguy
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Depends on the centrifuge. The Neycrafts always fetch more as they are safer; $150 - 250. The Kerr or Chinese knockoffs are worth $50 to $100. Make sure the weight comes with it for casting larger flasks.
Kilns are generally sold used for $75 to $400, depending on the size and if it functions. The coils are pretty easy to replace, but the pyrometers get pricey. If you don't know what you're doing, try to get one that works. Satellites usually sell for $75 to $150, Paragons and Amacos go for twice as much.
Vacuum machines are expensive. Make sure it works. Pepes go for $850 or so new. You will probably have to replace the oil. It needs to pull 27 atmospheres to debubblize the investment. You want to silicon mats and the bell jar, too. The silicon is for doing vacuum casting. The bell jar is necessary for debubbling.
Flasks don't last forever; they and the rubber bases deteriorate. They're not that expensive new. The wax also deteriorates; it gets brittle. But all of them are probable useable.
The torch; who knows? Depends on what it is and the tip. If it has a "turbocharger" tip, that's a good thing. It makes melting metal so much faster. The tip alone sells for $50 or more.
The investment may or may not be any good. Someone gave me some that was 10 to 15 years old and it was still good. I've bought some that's been in airtight containers with oxygen absorbers in with it and it's gone bad in a year. You just have to try it and see; hopefully on something you don't care about too much.
Find out what they want for all of it and negotiate with all of this in mind. Go on CraigsList and Ebay and compare the prices to what they want with the brands they have.
Good luck and I hope you join me in casting hell! Once you start you never stop; molten metal is so much fun.
Debbie K
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Investment is just simple plaster. Buy it at your local big hardware store as needed.
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I don't believe that that is the case. Investment is high temperature refractory material, and it glazes a little at 1250 degrees giving a smooth finish. It is actually a ceramic material. Plaster of Paris is heated gypsum.
That said, if you have done investing and firing using Plaster of Paris successfully, I really want to hear about it. If it works, I suspect it might give a grainy finish, which may be perfectly acceptable in some cases.
Debbie K
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Investment is just simple plaster. Buy it at your local big hardware store as needed.
No, it most definitely is not. Casting investment looks like plaster, but it's a completely different formulation. Plaster will crack and break down during burnout, and ruin your casting. If for some reason it survives the burnout, it's a high risk for catastrophic failure when you put it under the stress of molten metal being flung into it at high speed.
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Interesting comments. I've been using plaster of paris now for over 40 years. I do occasionally get a bad casting but never any catastrophe.
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I really do want to know more about your experience with plaster of paris. I have an interest in doing rather larger bronzes, and the investment gets expensive. Do you mix it and debubble it like investment? Do you slow ramp it? I had considered painting investment on my larger waxes and using plaster for the balance, but was chicken. Are you vacuum or centrifugal casting? Do you steam out your waxes or burn them out?
I have a larger kiln that I can do burnout in, and was thinking about going to a junkyard for large exhaust pipes to use for flasks.
I'm not kidding, I really want to know more.
Debbie K
P.S. I use nothing but investment, and I've gotten bad casts on occasion, too.
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Interesting comments. I've been using plaster of paris now for over 40 years. I do occasionally get a bad casting but never any catastrophe.
I'm curious about your use of plaster of paris too. What types of items are you casting? What metals? What's your procedure? I've never used anything but cristobalite-based investment but my bad jewelry castings have been due to improper mixing, burn-out problems, or old investment.
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I don't do anything special. I took a college course back in '65 and have done it that way ever since. Paint with very thin layer, cast in a steel ring, debubble and heat in a burnout oven. Centrifugal cast and run water through the whole thing while hot. That's when it gets exciting. Since I left Colorado, I haven't been able to set up a new shop. That last step needs a very deep concrete sink.
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That last step needs a very deep concrete sink.
If it's just jewelry-sized castings, you can simply quench it in a 5-gallon plastic bucket. Just hold it in the water with your flask tongs, and when it stops bubbling you can drop it to the bottom.
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That last step needs a very deep concrete sink.
If it's just jewelry-sized castings, you can simply quench it in a 5-gallon plastic bucket. Just hold it in the water with your flask tongs, and when it stops bubbling you can drop it to the bottom.
One note of warning here for anyone using standard casting investment (I don't know about plaster of paris): it's wise to wear a particulate mask when quenching flasks after casting. Casting investment contains sharp particles similar to tiny glass shards that can cause serious lung problems with long-term exposure. Quenching releases clouds of those microscopic particles and it's hard to avoid breathing them. Workers in commercial casting shops are at great risk if they don't wear protection.
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One note of warning here for anyone using standard casting investment (I don't know about plaster of paris): it's wise to wear a particulate mask when quenching flasks after casting. Casting investment contains sharp particles similar to tiny glass shards that can cause serious lung problems with long-term exposure. Quenching releases clouds of those microscopic particles and it's hard to avoid breathing them. Workers in commercial casting shops are at great risk if they don't wear protection.
Absolutely, though being familiar with the hazards of the materials you work with and taking the appropriate steps to protect yourself should really go without saying. And yes, a respirator is needed for plaster of paris as well. None of that sh*t is good for your lungs.
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Absolutely, though being familiar with the hazards of the materials you work with and taking the appropriate steps to protect yourself should really go without saying. And yes, a respirator is needed for plaster of paris as well. None of that sh*t is good for your lungs.
Well, paaardon me for saying it (Steve Martin voice.) I thought maybe some beginning casters here might benefit from that info.
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Absolutely. I also wear a clear face shield and gauntlets.
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I appreciate the information; I always wear a mask while mixing, but didn't know about the release of particulates when quenching. I'm not inexperienced; have been casting for years and always read the instructions when I can and MSDS's when I can find them, but this is news to me. When I cast, I wear a burn-resistant smock, welding gloves, leather shoes and a face shield; molten metal spooks me a little. And I always do a trial run with my centrifuge to make sure it's clamped down good and solid.
Talia, lots of people don't know where to look for information so anything we can do to minimize injuries is a good thing.
I read something here or at the other forum a few weeks ago about a dangerous thing to do and why; running equipment without a fan belt guard: Guilty as charged. I plan to make one before I use the offending piece of equipment again.
I didn't know when I first started carving stone that carving dry was bad. When I first started, there wasn't much of any information available on the internet or at the library about how to do this correctly. That's why I joined the other forum in the first place, because over the years I learned about the right and wrong ways to do things and wanted to share the knowledge with other peeps.
I think it's fascinating that someone has been doing casting since 1965 using plaster of paris, and I intend to try a control flask with a copied wax next time I cast to see how it works. It would be interesting if I've been wasting my money all these years.
Debbie K
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Debbie, please post your results after your test. I'd be interested in seeing them - and I'm not doubting Slabbercabber, I'm just curious. I took 2 semesters of jewelry in high school (a long, long time ago in a galaxy far, far away) and I seem to remember using plaster of paris to invest, too.
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It is more important to wear a mask when disbursing and measuring out the powder. For quenching, just hold the flask with tongs and dunk in a bucket of water and hold it there. Also if you spill any powder on the floor, mop it up wet. Dry powder on the floor will be repeatedly kicked up into the air.
olgguy
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The only experience I have with plaster used as investment was a friends failed attempt, He was always one to get in a hurry and mixed
up hydro cal for investment. casting turned out very poor in comparison to regular investment.
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It is more important to wear a mask when disbursing and measuring out the powder. For quenching, just hold the flask with tongs and dunk in a bucket of water and hold it there. Also if you spill any powder on the floor, mop it up wet. Dry powder on the floor will be repeatedly kicked up into the air.
olgguy
What you say about measuring investment powder is true. But I don't make things up out of thin air. Quenching is dangerous whether you think so or not. First a quote and link from Charles Lewton-Brain about dust in the workshop:
“Be aware of the things you do that generate dusts; for jewelers this usually means using abrasive procedures (sanding, grinding etc.-including flexible shaft use), using powdered materials like cristobalite in casting investment (really hazardous), quenching flasks after casting (even more dangerous)…” http://www.ganoksin.com/borisat/nenam/dust.htm
And this video: http://www.ganoksin.com/benchtube/video/147/
Many jewelry investment powders contain cristobalite because it remains stable at high temperatures needed for casting jewelry metals. Nearly all commercial jewelry investment contains quartz silica which is also dangerous.