Posted by kam on December 08, 1999 at 15:03:17:

In Reply to: Topic:How is the ceramic shell applied posted by Jack Davis on January 11, 1999 at 16:59:06:

There certainly is a lot of ceramic shell voodoo out there, so let me share mine. Simply, our foundry mixes an approximate 1:1 ratio(~33lbs. each) of colloidal silica to #325 fused silica flour, with one Shellspen suspension kit- dry ingredients only. Mix 30 min. Add liquid portion of kit and mix 30 min. Allow mixture to sit 24 hrs. (Recipe per 5 gallons.)Stir slurry mixture 15 minutes before dipping.When dipping the wax patterns, we begin with a slurry- only coat & allow to dry.

(Complete drying is a must between coats.)Subsequent coats (2-4)are dipped, allowed to drain of excess slurry, and coated with fine mesh stucco (#100 fused silica). After coat 4, any reinforcement necessary is done by dipping mold in slurry, allowing to drain and applying fiberglass cloth, dipped in slurry to problem areas (ie. thin edges). After drying, continue slurry/stucco process with #50 fused silica stucco for coats 6-10.The last coat is a slurry-only coat.This method is simple, compared to some I've read about- but it's tried and true!

Follow Ups:

Bramblebush ForumsFAQ