when all else fails read the directions. I have a can of Bondo right here and it says sand down to bare metal before applying. I just looked at it after reading your reply.
Fair enough. One would think the manufacturer should know what they are talking about. Ill probably use a metal based filler for my repairs just to be safe. What I really hate is the fact that I am very slow and meticulous when it comes to things like body work, so I worry about rust forming on the metal before I am done sculpting to perfection Not trying to thread jack here either, but are there epoxy primers that are actually sandable? Im trying to avoid the whole, this primer then that primer then a sealer, blah blah blah. If I can do my main bodywork, spray it with epoxy, sand it using a guide coat, fix any minor imperfections, spray another coat of epoxy, and spray my topcoat after the primer flashes, that would be swell. Is that even possible, or do I need to do main bodywork, go with an epoxy, then a 2k, sand with guide coat, fix imperfections, spray a sealer, then topcoat? Ill start another thread if anyone thinks this question doesnt contribute. Thanks
Man, for 36 years of doing body and paint I thought I knew what I was doing. Thanks for clearing that up. Dan
Sounds like either way will work fine. Just need to not have NO rust to start with then seal off the metal somehow, whether it is sealed with a special primer or with the paint. I'm pretty sure regular primer doesn't stop the moisture from getting to the metal. Then again, I'm just another idiot on the internet with an opinion.
I'm practicing my sanding technique on the fenders, the 120 grit works fine if you let the sander do the work, I don't apply anymore pressure to the sander than whats necessary to keep it on the surface, without having to change to a heavier grit I was able to work an area of heavy surface rust on the inside of the fender to good metal by varying the pressure applied and the angle... I got alot of masking to do but I'll try to get a pic up tommorrow.
I've always used bondo on bare metal. Then one day I was watching Dream Car Garage. These guys are the experts to me and put out 6 figure cars. They said always put down epoxy primer first. Geeze, I guess its like the old Ford/Chevy thing.
Cant wait to see some pics! Yeah, it seems that here recently, more shops are adopting that methodology. I have been doing alot of reading on the matter and many old timers are admitting that it does make sense to lay epoxy down before filler. Still, the manufacturers of the fillers recommend applying to bare metal. Manufacturers of epoxy primers recommend just the opposite though. I think the conclusion has been reached that either way works fine, and that it comes down to user preference. FWIW, I think I will lay down my epoxy first so I can take my time with the body work. We're only talking about a skim coat of filler anyways.
A few pics... the green paint is etching primer applied over areas that were bare metal, some areas I intentionally took to the metal because of nicks on the outside or surface rust on the inside of the fender. I primered the inside and I'll go back and apply undercoating later. The outside has turned out good so far but only AFTER I went back and sanded the fisheye out of the places I touched after I had cleaned it. Note to self: never touch a cleaned area with bare skin and get some good cloth gloves.
I keep a stockpile of those latex gloves on my workbench. I seem to use um everyday. Looking good Rick. Dan
At the rate I'm going I'll have her ready for the Roundup....in 2010. I got both fenders with the first coats of epoxy primer on and block sanded...they look great if I do say so myself, attention to detail pays dividends even if it did take 3 times longer than it should have. Example : I found myself paying TOO much attention to the area where the antennae mounts, recessing the screw holes sanding and smoothing..blah blah and then it hit me...YO ..DOOFUS thats under the antennae base, no one will ever see it. Good thing I'm not paying myself by the hour...I'd fire me...
Wow....Dan that epoxy primer is some wicked stuff, not knowing what to expect I had my spray pattern to tight and shot 3 runs on 1 fender. After some some adjusting on the gun and lowering my pressure I really like the way this stuff goes on and covers. What pressure do you set yor gun at and is it the same for the primer, sealer and paint?
Rick, I use such a variety of guns it amazes me that I can keep up with it all. I actually use a turbine to lay topcoats. Gun pressure for syphon feeds can depend on humidty, temps, etc. Primers usually are sprayed with lower pressure. Anywhere from 25 psi to 45 psi. Velvaseal will fall into that psi zone also. Basecoat can be low too. But basecoat is usually thinner in the mix so it doesnt require much, you arent putting it on to make it shine. I usually spray clear with a syphon feed from upwards of 45 psi. Like I said, humidity is a huge factor and we have high humidity along the Mississippi most all the time. Depending on air hose size and gun I usually have the regulator on the compressor set at 100 psi and use a regulator at the gun to control the pressure there. As compressor cycles and weather conditions change as you paint, you can easily monitor and adapt to what your needs are. Dan
Well 24 hours later the epoxy primer is still tacky, I shot it way to thick I guess. I'll get it right though, it's just a matter of getting the technique down. In the mean time every bug within a 1 mile radius of my shop has decided to use my fenders as a landing area
