I have had the same battles with rubber over the years, always trying to achieve that perfect, first time mold. It is possible, if you have lots of practise with the same type mold, same materials, same size, same tools, same climate, etc. It reminds me that it is also possible to finish an 18hole golf course in 18 shots - at least the technical experts will tell you its possible, as will a computer simulation. But the real world needs putters, sand wedges, imaginative curses and maybe even less technical perfection.
So, like it or not, you will need to know how to fix bubbles, tears and rips. It is not that difficult. Buy some glue syringes from a woodworking supplier (I like
www.leevalley.com) and just inject the bubbles with freshly mixed rubber. This is best performed before you do any casting, and any possible mold release and/or uncured rubber must be removed. Also, go to a fiber glass shop and get some 'surface veil' glass cloth - like tissue paper but made with glass. You can make bandages with this to reinforce weak or ripped sections. With a serious weakness you will have to buildup quite a bit and then grind away the 'mother mold' (if you are using one) to accomodate this new bump. Get some good, sharp, scalpel type blades and fine scissors (also leevalley).
If a quality mold is 'job one', you might try switching to the clear silicone rubbers - but I have never used them. Generally the silicones give much finer detail and are easier to work with - they are worth their weight in gold, but priced accordingly. Mostly jewellers use the clear??? So they can do difficult cuts??
ps. you might try Polytek rather than Smoothon - this is personal experience only, based on technical support issues alone. Polytek also advises pressure casting to remove the bubbles, if you still want to pursue a mechanical solution this might be the way to go - curing the mold under pressure and controlled heat.
