Box Casting.Has anyone experienced devit?

[ted hunt]

I have just begun casting. Have completed one piece with about 4 lbs. glass and 1 in. thick. I used the 50/50 plaster/silica mix. the piece came out pretty good. Since it was a test I used float. Now to the question...What is a 'spash coat'. Please explain and tell how to to do it .

Thanks

TH

[Lauri Levanto]

Small moulds can be made by pouring into a box.
That can be done in one stage.

Sometimes it is not practical, but the mould is built up
around the piece. The process starts by splashing wet
plaster over the original. The purpose is to provide
an inner surface to the mould without bubbles or voids.
Splash layer may be 1-3 mm thick. let it settle a bit but not
completely cured.
Then the bulk of mould is hand built against the splash layer.

The splash layer may be of finer material - I use alumina and plaster - but pure plaster works too. The backup
should be stronger, with coarser refractories like grogg
or luto. Some mineral fiber improves the strenth terribly.

The splash layer must release from glass. Possible
ingredients are plaster, alumina, kaolin. The back layer
then is isolated from the glass.

-lauri

[PDXBarbara]

[quote="Judi Charlson"]
Billets are something new from Bullseve. /quote]
Don't forget that Uroboros and Spectrum have been making billets (COE 90 and 96) for quite a while. You can check out their products on their sites (see above...both are WG.com sponsors).

Barbara