That would be the subject of this and upcoming build blogs. Most everyone here knows how to build moulds I would think, so most of what you are going to see is my attempts at improving on past mould designs, refining to increase the quality of the final moulds and going further in complexity in trying out multi part moulds and building mother moulds.
The first thing I do before even starting to build a mould is do final check over of the parts I want to duplicate for flaws or details I might have missed before. In this case I am glad I did this because I almost forgot to scribe the non-skid lines into the tops of my sail plains. I also give all the parts the finish that I want, in the case of the sail plains I wet sand up to 1500 grit and then do a French polish using Maguire’s auto polish and diaper cloth…I knew these kids I have were good for something! LOL
This time for all my moulds I am attempting to give all large parts their own resin supply channel and vent. This drastically improves my reproduction success ratio to castings as will the locations of where the sprues will enter and leave the parts. Like I’ve said earlier, I need to improve my efficiency when casting, for material cost saving and just plain old time. Production isn’t any fun when your casts work only sometimes.
This red clay is awesome to work with. It doesn’t shrink and doesn’t stick to anything (except my hands). If it’s too hard to work with because of being in cold garage, I simply apply heat using my heat gun, and because its oil based it softens right up, you can even melt it if you want. It’s expensive, but like anything else, expensive usually means it’s not crap.
Ready for the second side pour. For a release agent I use Vaseline thinned down with mineral spirits. I brush on the liquid in a thin coat, the mineral spirits evaporate and voila, no brush marks left like if plain old Vaseline is used. The mixture doesn’t affect the primer surface either; actually if you buff it into the surface of the part you get a super gloss finish…nice;
Next up is the making of my three part sail mould