by mattb » Tue Jan 02, 2018 6:46 pm
This method was shown to me by Chris Etzel (Etzel Speed Classics). Chris was a great modeler and made and sold a lot of true scale Indy car kits. He is sadly missed as he passed away about 2 weeks ago. He was the guy that introduced me to resin casting back int he 90's.
Picture one shows a bumper and a thin piece of plastic. Picture 2 shows how the flat plastic is glued to the back of the bumper. After it is glued and fits tight at the seam, it is put in the mold box with room all around it and is supported by the flat plastic sticking up out of the top of the mold box. Anyway you can hang it in the box will work. Rubber is poured submerging the whole bumper, but leaving the flap sticking up out of the rubber. After curing take the bumper out of the rubber. It is easy to hold the mold open and fill the cavity with plastic and let it flow to all areas and get the air out. Let the mold close and you have a bumper molded. Easy to pull it out of the mold and trim the flap.
this will work fine for lots of pieces, I usually only do this to make a couple pieces
bumper mold.JPGbumper mold 2.JPG