Soft masking

I use blue tac. See this article for some directions ... http://www.swannysmodels.com/IAR80C.html

Just use a piece of plane (no pun intended) paper and use blue-tac as swammy suggests.

Where can you find Blu Tac or Stick-To-It or whatever it's called?

Matt,

They have it at Walmart, Office Depot and many other stores.
Your local drugstore may carry it also as I think they have it at Rite-Aid drugstores here.

Mike

Thanks, Mike!

Also, if you can't find blue tac, use some Kleen Klay. Also, I agree with Presto as I just cut out patterns with paper or a vinyl paper (I get from my wife's scrapbooking) and put a piece of tac or clay under the paper to lift it from the surface. I often will use a few pieces of tac to balance the cutout. Spray away and the results are excellent and generally consistent.
Dmod

Make sure to keep a 90 degree angle to your target too.

Check the July 2001 FSM. There is an excellent article written by Paul Boyer that covers this from a to z. I have used his techniques several times with really good results. If you don't have the magazine you can find the article on this site.

Mike M