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#1 Randyc

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Posted 14 October 2010 - 05:39 AM

Hi guys,
I have a question for you experienced casters. I want my students to start using soapstone instead of cuttle bones for their casting project. I've found several internet sources that support this as a viable option for pewter but I'm wondering if it will handle the high heat of copper or silver casting. Can anyone advise? Thanks a lot.

#2 PTsideshow

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Posted 14 October 2010 - 06:41 AM

Biggest problem with using soapstone will be proving it is Asbestos free, Silica, and talc free. There have been some problems in the last couple of years. What was thought to be free of the inhalation toxic hazards. Have turned out to contain them.

New York soapstone commonly contains asbestos, Were Vermont soapstone are "USUALLY" asbestos free.

IF known to be asbestos free, you must use a minimum of an N95 dust respirator! But since the pieces from the same working vein can show none and the next chunk can have it. Better would be N100 dust respirator if it contains asbestos or free silica's.

Alabaster, has been suggested as a substitute for the use of soapstone(seatite) don't be conned it is same mineral.

Being in a school setting and dealing with high school students and parents. You may want to move on to something else.

The soft fire bricks can be used for carving and mold making then casting, Tufa stone is also used for silver casting Southwest Indian style silver. I would not suggest copper casting again with high schoolers due to the problems with using scrap materials for material as it can contain zinc alloys, beryllium(nasty stuff in dust or fumes). Not to mention the problems with getting a good quailty castings, not to mention the higher temps and safety equipment required.

Here is a very simple version of silver casting with tufa stone,
Two things after soaking, it must be dried extremely well, to prevent steam explosions even very small drops of moisture can result in large outwardly expanding forces.
The sooting (carbonizing) of the surfaces is used as a parting compound
Tufa carving
he also list Thunderbird supply (Jewelry) as hi supplier

You also can use pumice mixed with plaster to cast blocks to carve again they must be dried out well,
You can saw up landscape lava rock chunks into flat pieces and then carve then cast. dried out be fore use.
It is soft enough to use hand tools old saws and drill bits, chisels etc.

Which ever you choice to use, you will need very good house keeping pratices a hepa filter vac to get the dust up, washing the respirators after every use and wiping the surfaces down along with the tools.

Having spent over 33 years in a public school system, they do have more hoops you might have to jump through. Not to mention the dealing with parents when the kid goes home and say any key words that have been in the new.

If you look in my reviews for Tim McCreight's practical casting or all the other casting books you might find some edition in your local library system or inter loan system.
glen
glen

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All the usual and standard disclaimers apply. Do not try this at home, use only as directed, No warranties express or implied, for the intended use or suggested uses, Wear safety glasses, closed course, professionals only

#3 Randyc

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Posted 14 October 2010 - 07:25 AM

Thanks for the detailed response Glen. For what it's worth, the my soapstone comes from Virginia. I'm not sure if you are aware of the asbestos content there or not. I think I'll just keep using cuttle bones and pewter.
Do you think I should discontinue the soapstone sculpture project that I teach each semester? I schedule it so that the weather allows us to be outside during the carving and sanding. Thanks a lot.

#4 PTsideshow

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Posted 14 October 2010 - 08:24 AM

Well believe it or not, there are about 130,000 hits on google for Virgina Soapstone.

You should be able to contact your supplier and request a statement of asbestos free material. Like an MSDS. I really don't know much other then in the 3 different Artist materials hazards books I have it is listed. As a possible hazard as it is mostly composed of Talc, which is a magnesium silicate platy mineral (consisting of plates or flaky layers —used chiefly of soil or mineral formations). Which is resopnsible for the slippery feel of soapstone and steatites.

The talc component can cause talcosis when inhaled in large amounts.They generally contain amphibole asbestos and silica's. There are current on going disagreements on the amount of hazards the non fiberous forms are. In a nut shell some people feel that they are less toxic than the other.

Currently the USOSHA is still reviewing studies and feels that there is an increased risk of cancer. But it appears to be less than for asbestos workers.

You can check with others sources.
Alberene Soapstone Quarry

It appears that it is quite popular as booth fire pits and water bowl type features, along with counter tops and other building feature uses.

I do suggest that you check out at least this thread
Asbestos in certified asbestos free soapstone

As there are pages and pages of threads on the working of the stone etc.

You than can make an informed decision. as dealing with art materials and school age children have separate chapters in two of the three books I have.

Artist Beware book link Amazon


The artist's complete health and safety guide

This book is pretty much covered in the other two

Health Hazards Manual for Artists, 6th Edition
All are paperbacks and the used ones are pretty cheap Thew two above are used as text books in colleges and uni's now.

I'm working on the book reviews currently
hope this helps
glen

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All the usual and standard disclaimers apply. Do not try this at home, use only as directed, No warranties express or implied, for the intended use or suggested uses, Wear safety glasses, closed course, professionals only

#5 Randyc

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Posted 18 October 2010 - 12:28 PM

I like the idea of using plaster and pumice. Do you think that I could have the students create clay models and then cast the mixture around them? I'm not familiar with the material so I'm not sure how well it will cast around details.

#6 PTsideshow

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Posted 18 October 2010 - 01:29 PM

The pumice is used in annealing pans in a coarser size, and as as a water borne polish for finishing wood. I have been told that it is also can be gotten at garden centers. I have never found it locally at one. It also is used in making what is called a breeze block (light weight cement blocks) DSCF9287.JPG Is my annealing pan with pumice. Pumice and rotten stone is a link with the MSDS for each the rotten stone is a niner grade of material. The pumice is a silica containing material. True pumice is so light that it floats on water, either in chunks or powder. Another thing would be the soft fire brick like used in kilns. It is easy to pulverize and easier to locate.

Check the books reviews for one called plasterworks, it might be in a library near you I got a copy cheap from the remainder book seller I listed. Great book on plaster working.
glen

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Cicero

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All the usual and standard disclaimers apply. Do not try this at home, use only as directed, No warranties express or implied, for the intended use or suggested uses, Wear safety glasses, closed course, professionals only

#7 Randyc

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Posted 27 October 2010 - 11:50 AM

Glen,
I decided to have my students create small clay models and build clay walls around it. I used your softbrick and plaster idea to cast around the model, slow fire the new mold to about 900 F and it worked great. The recipe came out to be 1 part plaster, 1/2 crushed softbrick and 1 1/2 parts water. If you'd like, I'll post some photos the work. Thanks again.

#8 PTsideshow

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Posted 27 October 2010 - 02:28 PM

Yes please do as we always interested in how the work turns out. and if you have any students that you thing would benefit from being on here. You do know they are welcome, as long as they don't speak TXT or other short hand Posted Image [hysterical] [hysterical]
glen

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"I am not ashamed to admit, that I am ignorant of the things I do not know"!

Cicero

I am not a lawyer, and never played one on TV!

All the usual and standard disclaimers apply. Do not try this at home, use only as directed, No warranties express or implied, for the intended use or suggested uses, Wear safety glasses, closed course, professionals only




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