Casting molds for silicone resin gaskets

prusaprinters

These gasket molds were designed to meet two goals. First is the need for replacement gaskets for when the original black rubber gaskets fail since the OEM is now out of business. Second is the need for an improved gasket which unlike the original black rubber gaskets, won't leave marks on freshly sanded wood surfaces when you need to sand both sides in preparation for finishing.The original V-Clamp system offered 2 models of vacuum clamps: the single-sided VC4 clamp designed to be anchored to a workbench with screws or bolts and the double-sided VC5 clamp designed to use vacuum to hold itself on the workbench surface while holding the part that is being worked on. Both require a compressor and create a powerful vacuum by using the Venturi effect. The clamp can be adapted to smaller parts through the use of smaller gaskets (3 sizes in all).I made these molds using regular PLA but any other type of filament will do. Using TPU might be a good idea if you plan on making many gaskets. I sprayed the molds with mold release before casting the gaskets. I used BBDINO 20A 2-part silicone resin (available from Amazon and others) and obtained a density/elasticity that is very close to the original gaskets. They hold vacuum just as well as the black rubber gaskets but they don't leave marks on bare wood. Before you use them, make sure you clean the gaskets thoroughly with Isopropyl alcohol to remove all trace of mold release. Next, let them cure another 24 hours after you de-mold them. You can also put them in the oven at 300F for a few hours to speed up the process.I included a picture of the Fusion 360 gasket profile. All dimensions are in millimetres.