I use Alumilite clear for all my clear parts and never had a problem. Everything Ace said is true, the mix ratio is 1:1 by weight. Clear resins as well as rubber resins require a Platinum base RTV for proper curing, the Tin base RTV will inhibit the resin and it will not cure. Alumilite clear also requires heat for parts thinner than 1/8" thick. I cast parts that are .065 to .075 thick and I always use pressure and 125 to 150 degrees F heat for four hours and let the mold cool for 10 hours.
I have been making molds for a long time, and from what you described it seems to be a bad mix. If the container was the problem then the silicone touching the container would be soft and gooey, and that would only be 1/16 to 1/8 inches soft all around the container... the rest of the silicone would be cured. If the silicone around the part is soft then the part is the problem. I may be wrong but I never heard of using 3% catalyst for silicone unless it's a new product. I use both tin base and platinum base silicone and the mix ratio is 10 to 1 (10% catalyst) which leads me too believe it was a bad mix. Again I don't know what brand of silicone you are using. If you primer your part that will do the trick.
Ace is correct. I do a lot of casting and I always vacuum the resin and use a pressure pot. The resin I use has a 20 to 25 minute pot life. I'm not sure about the low viscosity resin not creating bubbles, I have a clear resin that's almost like water and it creates more bubbles! Best bet is de-gas and use pressure for casting. Also super glue is the way for filling pin holes!
First never use black for a chrome base. The best results I have is a gray base, 10 to 40 percent gray. Chrome dose not have color, it reflects whatever is around it. I use a two part automotive urethane clear, wait 5 to 10 minutes and spray Alclad. The two part clear cures in twenty four hours and you can try rubbing the Alclad off and it will not smear.
Can you tell me where you purchased the detailed RR instructions on the engine? I have a couple Pocher kits that I will be finishing when I'm
finished with my current project. Any info would be appreciated, thanks.