Techniques for painting stripes on bombs.

In case it hasn't been covered before, New Ware [the space guys] make sets of kabuki-tape masks for various configurations of 1/48 bomb stripes.

Victory Models carry much of New Wares' stuff:

https://www.victorymodels.com/search?type=product&q=Bomb+stripes

I will make photo copies of the bomb decal sheets and use those as stencils to cut out my own masks.  

I'd just keep the decal sheet and never use the decals.  They should work forever...a 1/48 scale Mk 82 bomb will pretty much always have the same dimentions no matter who the manufacturer is.