07-03-2012, 10:46 AM
Alginate is a water-based compound. The chemistry is complex but it is derived from seaweed, I believe. No, the moulds will not keep more than a few days without shrinking, distorting and drying out so the moulding and casting should be done as a piece rather than separately, where possible. 'Clear' resin for casting is likely to have a natural yellowy-gold tint. I do not know how great the tendency for such resin to degrade colour-wise is but I suspect it may be more stable than Urea or Bakelite in that respect. The type of colouring matter is more of a problem - most colours will change slightly due to age and worse when subjected to UV light. The powder colours supplied by most craft sources may be the most stable, I believe.
I do not know how Wim tints his castings, though I did once come across a video showing his process (some time ago now, so I didn't keep a track of it). If you could find it you might have a better idea of the process and what best to do.
-Tony
I do not know how Wim tints his castings, though I did once come across a video showing his process (some time ago now, so I didn't keep a track of it). If you could find it you might have a better idea of the process and what best to do.
-Tony
