The search function brought up nothing.
My question is where can I find pre-made generic bladders? Or, are there any good DIY bladder making tutorials you know of? Specifically silicone, uncured silicone bladders?
Heres the molds:
I played with bladder molding over spring break this year, and made my own bladder for a small part. Pictures here
I only pulled one part so far, as school and FSAE projects took precedence. I used a food-grade silicone called Silicone Plastique that the prototyping guys were experimenting with. It is a two part mixture that has the consistency of silly putty, and cures in an hour. They also have a liquid version that you can pour.
I extended the bladder to make a flange. The cap was clamped against the flange and pressure was applied through the fitting. It held 120psi with no leaks.
The untrimmed part:
I had a pretty severe wrinkle as my part was small compared to its circumference (and a host of other mold issues). I think a larger part would be more forgiving, but I haven’t had time to experiment yet.
Talk to the guys at Bondline (562) 921-1972
Thanks guys!
Z: Did you expirament with vaccuum AND bladder molding at the same time? Im under the impression that w/o vacuum, you will more than likely end up with surface imperfections.
Still not sure how to go about pulling vacuum while bladder molding…
You don’t need vacuum if there’s pressure on the bag. For a lot of autoclaved parts where I specify the cure cycle, the vacuum line is vented after reaching 20psi. Only sometimes do I have them pulling vacuum the whole time.
So, as long as there’s a vent hole in the tool pictured above, the pressure in the bladder should suffice. Air will be vented out and there shouldn’t be any voids.
I did not pull any vacuum. The vent was effectively the small (~.001") gap between the two mold halves, as the machining was not fantastic. Resin came out of the vent was pressure was applied. I found most of the surface to be quite good.
I just came across a way to make a bladder that is slightly smaller than the mold, to allow for the thickness of the part: Use sheet wax (available in various thicknesses) to build up a dummy part, and mold the bladder off of the wax. This will eliminate the wrinkle I had.
JRL: How are you planning on sealing the ends of your molds?
TET: Venting the mold. That cleared up a lot of questions I had.
Z: I will probably cap both ends with MDF covered in aluminum tape. A bolt through each cap should work (I hope). Will also strap the center just incase the molds try to flex. I really dont think they will, there about 3/8" thick, but who knows.
Another way we manufacture some hollow parts is to pull vacuum through the vent on the tool, and leave the bladder open to atmosphere. It’s basically internal vacuum bagging, and doesn’t try to force the tool apart like a pressurized bladder would. 
Requires a good seal between the bladder and tool, but works great. With a little thinking it’s not too difficult to figure out.