I am casting a good sized sculpture from ciment fondu from a plaster cast. I decided to add a release agent of shellacc then wav to the inside of the mold earlier. Will that make it unusable for ciment as I have subsequently heard that fondu requires a damp plaster mold? Any tips guys?
Your best bet seems to be to use a polyurethane mold. However try and study this text on the subject:
http://docs.google.com/viewer?a=v&q=cache: <email> /5416/1/ MK55670.pdf+damp+plaster+mold+for+casting+ciment+fondu& hl=en&pid=bl&srcid=ADGEESiNeXJlD4-WLPkazAzrNvd6Qp- niyEkBLvT4fq7gZ0VKVvba8YMJ0QBtvwsV3zsWgSXNLJTGBmbA3L0kp jpRm9b8e4fU5RS5CEH4l_dYZtFUS1ZkH3b3wKS2TA8FG7FMP3RaYLm& sig=AHIEtbTFbeZs5kOddg9mty7FubgQvo1xMg&pli=1
Or look up :
Casting in Ciment Fondu, by Edward Folkard
I read that "Typically Ciment Fondu needs to be used as a composite material reinforced with fibre glass, building up the mould in series of layers. Fast setting, it achieves its full strength in 24 hours."
Hi there cheers for the heads up. I can access the google doc on this computer. Yeah I have used a good rubber mold for smaller fondu items but the plaster mold I had lying about was too good to go to waste and ciment seemed a far less pungent alternative to nasty nasty resin which reeks for months. I had intended too try and make a solid ciment sculpture to sit outside. Ill put a watery layer in first methinks then put in a ciment/sand mix through to the centre.
I find the plaster mold needs to be soaked first - even if you seal it with shellac, as I find it will still draw out the water from the ciment. Here is a bull I cast recently - if yours is big you want to make it hollow if the mold allows, dab/stipple on a layer of goo first, they slap/throw on small handfulls 3.1 mortar (about .5 inch thick, then strips of grp matting stippled with goo), then more goo or mortar. The mortar layer stops the grp from touching the surface of the mold and becoming exposed. Practise on scrap bits of plaster first - essential.
HI ANYBODY. i like this post on cement fondue and i like the work that went into making this fantastic sculpted piece.