Just curious.... Is there a way to paint frosting (not airbrushing)? I'm doing a guitar cake soon and the customer doesn't want fondant. I had planned to paint a wood grain on the cake before they decided against the fondant. Is it at all posibble to paint onto a crusting buttercream? I'm not holding my breath, but it'd be nice.
Absolutely. Get your frosting smooth. Then use airbrush colors or gel colors thinned with extracts or alcohol. Use several brushes, keep hot water on hand(to clean brushes and melt butter or shortening that clings to brush). dab on paper towels.
My spiderman cake and darth vader cake are both buttercream hand-painted. You need a soft touch, don't press to hard or you will dislodge your surface(frosting). You can't use a graining tool with fondant, but with patience, could hand paint wood grain(use a little water with the colors to thin them and get variations in your colors(use a few colors for wood- yellow, brown, a touch of black(or brown with a touch of green). This will give you a good effect. trial and error.
if you can afford it, i would invest in an airbrush, it is a real time saver (and fun). I am posting a sand castle cake later today that is half fondant(accents) and buttercream dusted with sanding sugar, graham crackers, etc- then airbrushed. I couldn't have hand painted the crumbly texture, but got a cool effect with the airbrush.