I use rubber rock moulds from the US and P38 car filler .I just spread the filler in the mould so that its not too thick and take it out when its gone"green" or just about set but not actually hard ,you can then adjust it to what area it needs to fit .It works very well for me .I spray it with grey primer car paint but vinyl house paint would also do .The P38 is a bit smelly when all drying out so if you make all your castings out doors and let them cure it cuts the pong down .i think I used plaster to set the castings onto the foam undercliff .The moulds do not damage but test the compatibility first I cottoned onto this when making a model car pattern .I could see how well p38 moulds when I cast some wheel inserts and realized that it reproduces every tiny hair and speck of dust .I used the p38 for the mould and the copies .. Forgot to add ,just crack the castings with cutters to get small pieces for gap fillers and odd places .
Martin
Martin
