Petty4345: The best thing I have found for backing stainless is Solar Flux, Type B! I love the stuff and it has gotten me through some difficult jobs that I could not have done without it!
http://www.solarflux.com/index.htmlI admit there are some applications where it would not be feasable, but, overall it works quite well.
If you want to try it without having to buy a full pound, just for testing, I can send you an ounce or two and you can decide for yourself.
A one pound can cost $39.95 + shipping, or I found it on another website where it was $35.00+shipping. Problem is shipping ran the cost up to $43.00+, per lb.
Currently, I can sell Solar Flux for $39.95 free shipping. I don't think you can find it for less anywhere else!
To save on words and typing, the website gives the details on how to use and cleanup.
Hope this helps.
Steve