hi scrit, at last something about which you seem to have limited knowledge. should we mark the calender???? :lol: :lol:
anyway these days one tends not to use glass fibre resin, but one of
the other resins.
you make the outside of the mould with lego bricks or similar,
although since your kids are older, you may not have any left.
so build a wooden box about 50 % bigger than the handle. then seal it with
silicon, to stop the resin going out. now one of the names that used to be
involved in resin casting were alex tiranti, they had a shop off the
tottenham court road, still do i think.
you can get clear or even metal filled resins, i only know some of this
because i used to build 1/43 model cars which mainly were french, and of
a yellow ish resin. these tend to be made in pretty simple moulds.
as with all moulding you have to cast two halves of the female to produce the male final part. so in you case you can copy the inserts you already have, however the problem with this is that casting will involve a little
shrinkage. historically, what one has done is half fill the mould box, the wooden one you have made, with a silicon or other hard setting item that does not give off too much heat when it sets. when it is beginning to go
off, you press in the bottom half of the item to be moulded, this must be covered with a release agent that will not affect the moulding material.
once that lower part has set, release the item. then re-seat it, put some kind of thin non porous layer like baking parchment on top, and cut around the master. now pour more of the mould maker on top until it more than covers the master. let it set, break the mould apart without breaking the
whole box. lift out handles on the parchment would work.
next think about where you want to fill the mould. normally one would
make the casting box with the master upside down to ensure the smoothest
finish on that side. drill two holes, one for the casting medium, and one for the air and over fill to escape from. mix your casting medium, try to remove as much air as possible, make sure there is a release agent in the mould , often to this day people use talcuum powder, but check the tech spec of the medium, then pour. SLOWLY, try to trickle the casting medium in, so it fills up and causes less problems with air displacement. shake the moulding box a little, then set aside.
wait until the cast is set, then either curse me, or send praise, i can take either.
if the medallions are actually brass, you can even cast brass at home,
although you need a really good way of heating it.
cold resin casting medium is what you are looking for, and tiranti are i think still the best for smaller quantities.
hope that helps a bit, it is not as dauntig as it seems
paul :wink:
