I use the same burnout as Metalcaster and have for over 30 yrs. I use only Satincast and distilled water.
Like he says, curing is a must, and also air flow in the oven. I laid my small oven on its back and drilled 12 holes 3/8 diameter so air could flow from top to bottom (lots of available oxygen, is a must). Raised flask off the bottom of the oven approx. 1inch, using expanded metal.
I cast small parts and heavy rings with no issues. There are so many small things involved in casting that it is nearly impossible to pin point problem areas unless u see an indiviuals methods and technique from start to finish.
It goes without saying, that if 60% of the B9's in use are jewelers, and there are around 1700 machines in use, and all are having their prints cast successfully (either in house or through service providers) that if u are having casting problems, u are doing something wrong.
I can't emphasize enough that u MUST CURE PROPERLY, HAVE ADEQUATE AIR FLOW, AND REACH A MINIMUM OF 1350 DEGREES F. If u do these three things, mix your investment properly, sprue correctly, don't underheat or overheat the metal, and if spin casting, dont' overwind the spring, then u should be casting with success. It is also very important that the mixing of the investment not be cut short. The reaction is chemical (your are not making a slurry of water and investment) and it needs time to take place. You will only weaken the investment if u don't do a through mixing for the min amout of time and temp. indicated by the mfg. The only thing I have changed is that I use to use 120 to 160 degree F water in mix, but now I am using room temp distilled water (approx. 70 degree F).
There are things that I can't even list because, it may just be the way u hold your mouth. Just making a point, that it could be something very simple, but know way to know unless you came to my shop and watched my process or I came to your shop and watched yours.
The last thing anyone should be doing is blaming he resin or the machine, way too many of us cast these prints everyday. Take a look at the gallery. I know it can be frustrating, but the solution is there in your technique or process.
Dance like nobody's watching!