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plaster casting/air bubbles

updated fri 27 oct 00

 

Marcia Selsor on thu 26 oct 00


Dear Paul,
Bob's directions are pretty exact. However, I learned a new trick after
30 years of plaster casting.
Just before you're ready to pour, squirt the top of the plaster with a
water diluted solution with denatured alcohal. This breaks the water
tension of the last of the bubbles that have risen to the top. -Richard
Notkin showed us this in a demo he had last year when his first exhibit
of Passages opened in Billings. Richard is a master mold maker. (see CM
Oct. 2000)
Marcia Selsor


(snip) the balance of the
> mold. For a separator I find that just ordinary liquid hand soap rubbed to a
> shine work very well to stop the parts from sticking. I have tried other
> things such as Vaseline, Pam spray, Crisco and they all work.
>
> If you write to USG (United States Gypsum) ask for the specs on the plasters
> that they sell. They are very generous and have a fine folder dealing with
> all the characteristics of USG products. They even describe how you
> determine the exact amount of water to use to achieve certain results.
>
> You might try doing a small casting yourself and even discover something that
> you overlooked before.
>
> Good Luck.
> Bob Wicks Prof. Emeritus HACC
>
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--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
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