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Silica / Flint / quartz

Posted: Sun Mar 21, 2004 6:12 pm
by Katia T.
Hi
I am very confused with the nomenclature :oops:
Can someone tell me the diference between silica, quartz and flint? I intend to make some moulds plaster /silica, and there is a new store here that sells them as diferent things. Thanks a lot
Katia

Posted: Sun Mar 21, 2004 8:23 pm
by Ralph
Katia

Essentially they should all be SiOsubscript2 (silicon dioxide). However there may be local variation in the way the names are applied according to the physical form of the material, its purity, or where it was obtained - from a beach or deep-mined for example.

For plaster/silica molds you need clean material. Start with the cheapest (probably silica) in the mesh size you want. As always, try on a small scale first.

Don't breathe in any of them when handling - all are usually very dusty and definitely dangerous over a period. A respirator is your friend.

R

Posted: Sun Mar 21, 2004 10:48 pm
by Bert Weiss
Katia

The silica flour that I have used for plaster/silica molds is 200 mesh silica. I would guess that the mesh size is the most important factor between the various products that might all be silicon dioxide. If purity is also a factor, my guess would be that the least pure is fine for mold making. It is essentially just filler.

Posted: Mon Mar 22, 2004 1:26 am
by watershed
OK, just for the dictionary-esque definitions.

Quartz: Pure ish silica crystals (this is the most dicey, please correct if necessary)
Silicon: And element on the periodical table, mostly found in various combinations, commonly Sand.

SilicA: A generic name for silicon dioxide. Silica covers the gamut of purities/impurities etc. Silica sand is generally a purer form of regular sand.

Flint: In the potter's lexicon, and olde glass, Ground sand or silica flour. Available in several mesh sizes, a founding father of Silicosis aka White lung. in the olde dayes, Flint glass was window glass. Presumably because they used ground sand (flint) instead of raw sand (Sand).

Greg

Posted: Mon Mar 22, 2004 6:11 pm
by Katia T.
Thanks
Katia