Hey guys...got a problem...shavin my bay. So far its almost dome and I havnt used any filler. ? Is there are little ( very little) nicks,pin holes and valleys from grinding and welding. How many coats of filler primer can be laid until it cracks. It's a drag car with solid mounts so there's a lot of vibration. I can't afford cracks after the car is painted.

Any help would be awsome. Also the car will be painted a flat color.( lambo retention color) will these blemishes be noticeable with the flat color????

 

u will see them....BEST is to weld and grind more metal in...if you dont want rediculous hours of that to get perfect...use some decent "iceing" and keep it thin coats

 

^^^ very true. metal being chemically bonded to underlying metal (welding) is the most ideal situation. however, a perfectly acceptable and very durable method of finishing off the metal work is to use a high quality metal filler like Evercoat's Metal Glaze or even Z Grip filler. If you prefer, you can use a short strand fiberglass filler like Evercoat's Everglass to fill larger areas. That stuff is rock solid, and with either the glass filler or the metal filler you won't have to worrk about cracking if you do it properly. Obviously you'll need to make sure you've got enough metal to build on, and if there are holes larger than pinholes then you'll need to do some more welding to plug them up. If the only thing you have to fill and finish is grind marks and pinholes it would be a waste of time to try to build up metal with welding wire and grind it back down. even then you'd need a skim coat of poly filler anyway. standard industry practice is to finish your metal work as much as you want, then come back at it with a good quality filler, block it out, then prime it and block it out again with 320 or higher.

as for primer, you can use as much as you want, as long as it's real catalyzed primer. for good hardening high build filler primer, usually 3-4 wet coats is good enough. don't even think about using rattle can primer over any kind of body work, whether it's bare metal grind marks or actually filler. after just a short time or after any significant heating and cooling cycle the rattle can stuff will sink and look terrible. use a real 2K primer and load it on. give it more than the suggested time to cure before you block sand it. i like to wait a day or two for really important high end stuff, just to be sure it's not going to shrink up a little.

Check out this site for some of the fillers and other supplies: http://www.tcpglobal.com/autobodydepot/evercoat.aspx