Why??

[gsdtracker]

A freind of mine owns a body shop and on a lot of his work, if I look closely I can see all of the areas where he (or one of the employees) has used filler or putty? If I run my fingers over the area, it feels smooth like the rest of the paint but I can still see it under the paint. If spots where the filler is applied are treated correctly should you be able to notice a difference in the surface under the paint? Why would this happen? I would like to help him out by giving him some good advice..not sure if he'll take it, but if not I will have to get another shop to do the work because I really don't want to be able to see the repairs after the work is done. Any pointers would be greatly appreciated.Thanks

[barneyfzr600]

It could be poor body work or it could be shrinkage! Hard to really say without actually seeing it. Just my .02

[MARTINSR]

I'm with Barney (didn't think I would ever say that) I would bet a crisp dollar bill it's shrinkage. It comes from people asking the primer to do too much. They do less than perfect filler work and then bomb on the primer to block it out. The primer is all full of solvents, it shrinks down later and you see where the work was done.

Brian

[Len]

It could be shrinkage ir could be improperly leveled filler but no matter what is causing the problem it's a problem that shouldn't exist. When the work is done properly the repair should be invisible, perfectly level with a perfect paint match.

[gsdtracker]

Thanks guys, Would allowing the panels to dry outside in the sun cause shrinkage?

[Phil V]

Yes and no. Shrinkage is going to occur regardless of whether the car is inside in cooler temps or outside getting baked in the sun. Baking in the sun just speeds up the curing process. The problem you describe was mainly as a result from using the old tech lacquer primer which was put on too much at the same time. The newer 2-K high fill urethane primers chemcially harder as opposed to air drying so there is much less shrinkage and what shrinkage does occur happens in a matter of hours not days or weeks.

[barneyfzr600]

Another thought would be that if the primer hasn't fully cured and was blocked out, it basically will still shrink because it hasn't fully cured.

[MARTINSR]

SOLVENT, that is the magic word when it comes to failures, "Follow the solvent trail". If it is 2K, 1K, whatever, if the product is applied too heavy and "sealed" (I mean this in the theoretical term, not with a paint product called "sealer) with paint, primer,clear or what ever you are applying next, you can trap solvents. Those trapped solvents come up later.

This can happen YEARS later, even with a 2K. A "delam" base coat clear coat is an example.

Brian

[gsdtracker]

Thanks again guys, I just ordered Len's video so I may just tackle some of this body work myself. I have detailing and wet sanding/ polishing experience, but I have always been a little scared of attempting body work on my own. I do have some old fenders and hoods to practice on so I am going to give it a shot. I had no idea how technical this body work is to make a good clean repair. Maybe I was just stupid to think it was only Bondo, sanding, primer, paint and polish....Just want to say that this board is a great place to ask questions because everyone's advice is very helpful and you don't make a rookie feel stupid for asking a question!

[Len]

Don't forget that this 2 hour video is about painting not about body work. When the body work is finished this video begins but it shows the final tweaking of the surface as the paint prep is started.

101 Video Link

[gsdtracker]

I think I have enough knowledge from reading on this board to at least get get the right materials and get started and do some tests on some old panels. If I can get a good result, I may try doing to the paint myself at my friends shop. We'll see how things go, can't wait to see the video. I also have to paint the the fender flares, trim, bumper and grill on the wife's cherokee, so I thought that this video would help make the masking a little easier. Thanks