bridge bearings

[Sumpter250]

I am not sure, what brand I was using back then. Currently I am using a german brand: "Sika". But thats not important, the stuff from Micro-Mark is very good and available in the US.
You are already on the right path. I am using slow cure resin (around 6min pot life - but depends on room temperate). I mix fast, pour fast und try to pick out the bubbles manually with a tooth pick in the remaining time. You can extend the pot life a little bit by cooling down the resin in your fridge before casting.
What also helps is dusting the mold with talcum powder. It also extends the lifetime of your mold.

The first few casting with a new mold will always have more bubbles. I am not sure why - must have something to do with the silicone.

Last, but not least, there is a way to eliminate almost all bubbles. Its called pressure pot. I will buy one as soon as I win the lottery....

I tried using vacuum, and all it did was allow the bubbles to expand, and ruin the casting. Only one more question, Just how much pressure is needed ?
If it is under thirty pounds/square inch, an old pressure cooker pot, and an air compressor ( air brush ) should work well enough.