I GOT IT TO WORK!!
I made an almost exact silicone plug (not really any space for the fiber…hell, I WANT it to compress the epoxy out)…
Lay up the fabric, and compress with about 20pounds.
and PERFECTION!
I really wished this damn vac. bagging worked though.
How strong is this mold? when I think silicone I think rubbery material.
Yes it’s rubbery, but it’s pretty stiff if you have sufficient thickness. We use this stuff for casting plastic parts.
It’s commonly used in filament winding. After the core is wound, silicone is wrapped around the composite material. It’s then bound with Kevlar. Then everything is heated. The silicone expands against the kevlar there by compacting the composite material.
so if its rubbery you’re pretty much gauranteed an ununiform part every time.
It depends on what Shore hardness you use. They range anywhere from 10 Shore A up to 50 Shore A. The thickness of the plug will also affect how rigid it is. You can easily get less than 0.010" variance.
It’s good for casting. But I wonder if it gets warped when you vacuum bag it.
Evan/all
Yes, it will warp under vacuum unless the mould face is flat. The fiber component of the layup has a different strain coefficient, and so it will cause the face of the mould to deform under any stress. The % deformation is a function of the shape of the mould face, and the ratio of the strain coefficients between the fiber and the silicone.
have you tryed putting a fibre glass backing on the silicon mould to give it some strength. have done this on latex moulds in the past.
you can make what i’ve hard called a “glove mold” lay down your silicon, of desired hardness for the form of the part, lay down a slightly harder silicon, and then lay up a support backing out of some cloth and mat. hopefully i’m not too late, just found this site.
I might be doing that for my next silicone project.
After my current mold dieing in the oven (ONLY 255 for an hour!!!), I’m scared to try more molds like that!
but, it was also a 2part mold by my own fault.