Painting silicone. An issue of sharpness and masking.

[Egon Spengler]

I've painted with Silicone on previous projects, but on my current one I really need sharp edges on spots on the mask I am painting. The problem I am having is getting a nice sharp edge on the spots I need to paint. Basically, I need to paint green circles with relatively sharp edge definition. If it were being painted on latex it would be so much easier but it's hard to mask off silicone when nothing sticks to it. I have tried painting petroleum jelly on test tries but the edge isn't decent enough.
Have any of you painted silicone and come up with ways to mask areas well while airbrushing it?

Thanks!

 

[Axlotl]

Can't you just cut a circle out of an index card?

 

[Egon Spengler]

Can't you just cut a circle out of an index card?

Pretty good simple idea. I just have a TON of spots to paint. I guess I should start cutting those cards as soon as it's time to paint. lol Thanks!

 

[drusselmeyer]

How did this turn out?