Paint Chipping

Painted my 1954 Ford chassis over Christmas, and everything looks great. However while working on it yesterday I let the shifter knob slip out of my hand when installing it and it chipped the paint on the trans cover. The knob fell about 12 inches. Is there something I did wrong when repainting that would cause the paint to be this easy to chip?

I used enamel paint with reducer and hardener. I used the same brand paint on the dash panel and I have had no problems with it. Hardener was 8 to 1 ratio, and reducer was between roughly 20 percent. I used gray hi-build primer on the dash and res oxide primer on the chassis.

Thanks.

Painting it around Christmas the paint hasn't fully cured yet. Even though the shifter knob should have been smooth enough it shouldn't have chipped the paint. Is it just chipped or is there a clear spot of primer showing? I think if it is just chipped it's probably just the quality of the paint. If there is a clear spot of primer showing the paint didn't bond to the primer so I would never use a power washer on the tractor. A note on the paint mixture, when using an oil based enamel use as little reducer as possible and still spray it. Too much reducer sometimes damages the integrity of the paint and actually makes it dry shower. It dries so slow anyway it won't orange peal like other paints.

Primer is showing.

The paint is on there now and there is nothing to do but touch it up when ever it chips. It's possible there was some dust or something between the paint and primer on the spot you're having trouble with. Before painting something else I would research the compatability of the paint you used with the primer. Sometimes a person can use rattle can primer which is may be a lacquer primer and topcoat it with enamel and it's not compatable. The lacquer primer needs a paint with solvents strong enough to re-wet it for good adhesion.

Like I said before I would not use a power washer on the tractor. If there is a adhesion problem with the topcoat a power washer will peal the paint off in sheets.

One of the first tractors (a John Deere B) I ever painted did this and I think it was caused one of or both of these reasons:
1-Waiting too long to paint the tractor after it was primed. To achieve chemical bonding most primer has a "window" for when the top coat should be applied for optimal results due. I didn't realize this at the time and I also didn't sand the primer down good before painting, which is advised when painting outside the "window". Which resulted in the paint not having a good chemical or mechanical bond.
2-Used too much hardener. I didn't pay much attention to measuring out my measuring technique and I realized I had use way too much hardener when I ran out way before I was through. The paint was always real brittle and flaked off to the primer if handled at all.
After the fact there wasn't much I could do except be careful with it and touch it up as it happened. I think now that probably waiting too long after applying the primer and then not sanding it was the most likely cause of the problem in my case. That was the first time I had ever painted anything and without any hands on guidance I was fortunate that it turned out any good at all.

DScott, I think you may have hit on my problem. It had been a while between when I primed the tractor and when I painted it. I did give it a good wipedown with a tack cloth to remove all the dust and even reprimed a few areas after cleaning. I painted my dash last weekend, sanding and repriming it prior to painting, using the same manufacturer's paint and same amount of hardener and have had no problem with that.

That's been my experience with hardener in paint. That's why I don't use it ! I like to paint everything apart and then assemble it. Way too much chipping with hardener.