[vettestr]

Rebel1 has given some great advice, same method I would use to repair a low area that is greater than 2mm. Bondo or bog tends to crack or keep shrinking under the paint for about a year or less. Some resins that are lower in the food chain have the same problems. All repairs or modifications at my shop use Vinylester resin. Rather than Bondo for those small low spots a mixture made from resin, fumed silica and micro bubbles can be mixed to the same working characteristics of Bondo/bog. This mixture I call (spooge) sands a little more difficult but is far superior in every way to Bondo. Spooge is cost effective, will not cause printing, shrink or crack and bonds surface if surface is prep'd correctly. Good bodywork of repair will only need glazing putty or a filling primer at most. Bondo is only used to mock up plugs or mold filler at my place. Spooge can be pre mixed and if kept covered until ready to catalyze for use.