05-01-2007, 05:03 PM
Hi David and Tony,
Perhaps the "playdough" may work here as well. This may not have as much shrinkage as clay. A commercial filler compound saying "no shrinkage" may also solve that problem. Anyway, you can always compensate for shrikage when making the mold. I have no experience with petroleum jelly, sounds votatile when heated! :o
Perhaps good to make a wax model of the slug, use that to make the enclosing mold, saw it open into two halves when dry (diagonal cut), optionaly repair any flaking and insert some lugs to ensure a good fit when you stick it back together pre casting.
If you build up the mould using clay or filler, another way is to make one side (left or right) first, using a wooden form for the slug and pencil thick dowels for airholes, then slap the other side over it, then trimming the block to size. Put a layer of sand between the halves to prevent sticking them togeter. If you use the same clay, shrinkage should be uniform.
This could/should turn into a nice How to .. if you take pictures and record the process. :lol:
Perhaps the "playdough" may work here as well. This may not have as much shrinkage as clay. A commercial filler compound saying "no shrinkage" may also solve that problem. Anyway, you can always compensate for shrikage when making the mold. I have no experience with petroleum jelly, sounds votatile when heated! :o
Perhaps good to make a wax model of the slug, use that to make the enclosing mold, saw it open into two halves when dry (diagonal cut), optionaly repair any flaking and insert some lugs to ensure a good fit when you stick it back together pre casting.
If you build up the mould using clay or filler, another way is to make one side (left or right) first, using a wooden form for the slug and pencil thick dowels for airholes, then slap the other side over it, then trimming the block to size. Put a layer of sand between the halves to prevent sticking them togeter. If you use the same clay, shrinkage should be uniform.
This could/should turn into a nice How to .. if you take pictures and record the process. :lol:
