[Paladin]

So after 15 years and diligent efforts to keep the truck clean especially from winter road salt, I discovered rust forming on a rear fender-well. It is just the top lip and encompasses about 4 inches long by an inch wide. I am hoping it will only require cleaning with a wire wheel and some body filler.

I have been looking into touch up paint systems and found a lot more than I bargained for.

Express Paint, APS, Dupli-Color and AutomotiveTouchUp seem to be the most prevalent.

Has anyone used any of them and what is your opinion? Do you have any other recommendations?

The weather is to cold to address the issue right now but I want to have everything ready for when the temps get consistently above 50s.

 

[Pikey]

In my experience nothing that you do will match the rest of the truck.

 

[Paladin]

I am not looking for a show finish. I just want to repair the rust damage and have a reasonably good finish.

 

[SpeedBumpFinder]

You'd be better off getting a patch panel and welding it in. The paint can only look as good as to what it's applied to. After a while body filler covering a hole that big will chip or fall out. Fiberglass cloth it or get some copper or aluminum screen if you're dead set on filler. Steel screen, even stainless screen will rust. Aluminum filler will end up getting galvanic corrosion. Don't use just plain bondo type filler in the wheel well like that unless you are sure you get it 100% sealed up. It's mostly talc and will absorb water. So don't let it get wet at all. Even when cured. The water it absorbs will prevent the paint you put over it from looking anything like what you want. If you do weld in a patch, disconnect both battery cables and the computer. Stitch weld or just do tack after tack, jumping around and letting it cool often.

But the wire wheel is a good idea to remove the existing rust. Just pull your paint and corrosion protection on the back side back at least three inches and then hit it with CLR and clean rag. Then use laquor thinner and wax and grease remover before adding any filler or welding. And don't for get to reapply the corrosion protection to the backside.

 

[Paladin]

Thanks SpeedBump.

I have worked with body filler before and know that it is not really to be used to repair damage but as final surfacer to smooth the panel.
If the fender has rusted I will definitely have to do metal replacement at that point.

 

[SpeedBumpFinder]

No problem. I just went through some classes for Auto Body and that was what one of the instructors drilled in our heads.

 

[Paladin]

With good reason.

I knew a guy that side swiped a wall putting a nice dent in his door. He took it to "friend" that did bodywork. He picked up the car about 4 days later and it looked great. About an hour later he was heading downtown when he hit a pothole. The whole clump of body filler fell off the car. Turns out his friend did not even try to pull the dent or grind the paint down to metal. He essentially filled in the whole dent with Bondo, sanded it down and painted over it.

Back in the early 80s I took auto-body in high school. It was drilled into us that body filler was only to be used as a final surfacer after getting the panel as even as possible.

 

[Dana W]

Since you originally asked about the painting aspect, wait until it is over 70 deg, and the humidity is as low as it can be, below 60% before repainting, unless you do it inside.

 

[Paladin]

Trust me there is no way I am painting before spring. Its 25 degrees right now.