Solvent Pop Problem

Even though my problem may or may not be "solvent pops", the "take home" tips are the following:

1. Don't use lacquer-based spray can primer from Pep Boys over acrylic urethane primer-surfacer. (I THINK this may have been my main problem!).
2. Use self-etching primer before primer-surfacer.
3. Use products from same manufacturer (Martin Senour in my case).
4. Seal the sandable primer-surfacer with acrylic sealer before painting.
5.Spray a mid-coat adhesion promoter over the sealer just before the top coat.

Have I got these tips right? Since I now must "fix" my problem, I would like to strip the paint and primer layers without destroying the Bondo that is on part of all surfaces and took many, many hours to work. Is there some product out there that will do what I want or should I simply hand sand?? Also, are steps 4 and 5 above really necessary or just a good idea? Thanks again for all the help.

Phil

The sealer also prevented the paint from lifting the primer, but with urethane primers that is not likely to happen as there are no products except laquer that will lift the epoxy primers. And even laquer takes a long time to affect epoxy.

On trick I have used and it works very well is to use your epoxy primer as the sealer. Simpley mix the primers as usual BUT add about 50% more reducer to the mix AND add a tint to the mix to bring the color to about the same as the top coats. Your paint supplier can sell you a small amount of mixing color that should work perfectly. Use the tint sparingly as a little goes a long way.

When doing this method, do not waste time. You need to get the first top coat on as soon as you possibley can so the wet primer and wet paint can bond properly. Have the paint mixed and waiting on you. As soon as you turn loose of the primer gun, pick up the paint gun. You can clean the primer gun later if you put it in the fridge until you are through painting.

Mid coat adhesion promoters are still a very good idea if you decide to paint over dry, sanded primer. They simpley glue the paint to the underlayment. If you use the above method of primer for sealer you won't need the adhesion promoter.

AS you found out..never used spray can primer over E-prime. You would have been fine if you had not done that.

As far as removing the new paint, I would hit it with a DA sander and 120 grit paper. This will take a while but will save you time by not having to repair the bondo areas. After the 120, sand with 180 and give it one last coat of E-prime to bury the sanding scratches and smooth the surface. You may have to block out the sheet metal again to remove any waves caused by the paint removal process.

Good luck.

1.Is tinting the primer required? The reason I ask is that the Martin Senour tintable primer (5103) only comes in gallons at $100+. The primier I had planned on using from now on is MS 5101 in quarts, and the data sheet says nothing about tinting. Can I tint it anyway with a MS tint color? 2. Am I correct in my understanding that an acrylic urethane primer-surfacer is an epoxy primer? The terminology is confusisng to me. 3 Can you recommend a mid-coat adhesion promotor? I am aware of Bull Dog in spray cans and Flash Bond 300 in quarts or gallons.

Thanks again for helping out a real rookie.

Barry

1) Tinting isn't always necassary. It depends on the shade of paint and the shade of primer. You can tint any epoxy primer, it just gets hard to sand if you do. It is a waste of materials to tint each coat of primer and a waste of time trying to sand it. Just tint the last coat or the wet sealer coat prior to painting. Again, tinting isn't always necassary. No need to tint gray primer if you are going to paint the parts black or white. If you are going to paint the surface red however, then tinting MIGHT be a good idea. Blue paint over red primer? tint. Blue over yellow primer? tint. Green paint over yellow primer? probably not.

Most primers are gray or yellow now but ocassionaly you will see a red primer. It is hard to beat plan ol' gray however.

2) Epoxy type primers require an activator just like body filler or other material. If the primer uses a small amount of activator in order to bring about drying or curing, it is considered an epoxy or urethane.

3) Either of these products will work fine. Flash bond might be the better of the 2 however. Bull dog is availible in quarts also should you need more.

One thing I failed to mention the other day about stripping the paint. You can buy a spray on stripper that will only affect the paint and not touch the e-prime. This is about the quickest way to remove paint and not destroy your hard work on the primer. Just spray it on, let it set, air hose it off, wipe it down.