I'm having an unusual problem with my 66 coupe. When i purchased the car 14 months ago there was a spot on top of the passenger fender just forward the A pillar where about a 2" x 1" section of the paint looked distorted. (FWIW the paint is only 3 years old and there is one layer of paint under the currant paint) I had this repaired. The painter just sanded this area down and repainted it with base/clear. After about a month I went to an outdoor show and at the end I noticed the same thing was happening again. I think it's sun/heat related but not entirely sure. I'm reluctant to have it repainted again as I don't understand what is happening. My painter thinks the fiberglass is porous in that spot and when warm the paint softens up and settles into the glass. What can I do to rectify this? Thanks Mac

 

Mac,

It all depends on what your painter did to repair it the first time. I know you wrote: "he sanded this area down and re-painted with base/clear"...but how far down did he sand. Did he go to bare fiberglass? What did he apply on the bare fiberglass after reaching it??? (if he went that far).

This area that showed up again...what does it look like or post the best photo possible. Does it look like it is shrinking and you can see the rings of the previously applied materials...much like how a topographical map looks???

Also...it depends on what the painter used..how quick he did the job....all play into the outcome in time.

If he took it down to bare fiberglass....did he notice any discoloration in that specific area???? This is IMPORTANT! So DO NOT DISMISS this question.

Is it bubbling?

DUB

 

It all depends on what your painter did to repair it the first time. I know you wrote: "he sanded this area down and re-painted with base/clear"...but how far down did he sand. Did he go to bare fiberglass? What did he apply on the bare fiberglass after reaching it??? (if he went that far).

I don't think he understood what was happening there so he really didn't spend allot of time preparing the area for the respray. All he said was he sanded the area flat and reshot the basecoat/clear. "A little history" The car was walnut blasted in 2010 and shot with Marlboro maroon. The owner did not like the color and he had it reshot in trophy blue over the maroon.

This area that showed up again...what does it look like or post the best photo possible. Does it look like it is shrinking and you can see the rings of the previously applied materials...much like how a topographical map looks???

Yes I can see rings in the base paint and the surface is not flat, but wavy.

Also...it depends on what the painter used..how quick he did the job....all play into the outcome in time.
He works fairly quick. He probably color sanded a couple of days after the shoot.

If he took it down to bare fiberglass....did he notice any discoloration in that specific area???? This is IMPORTANT! So DO NOT DISMISS this question.

I don't think he took it down to the glass. Just a scuff and paint.

Is it bubbling?

Yes, this 1" x 2" area is wavy.

Again, it appears to be triggered by heat. The rest of the car is perfectly fine. The painter thought it may be pinholes in the glass. When I bring it back to him maybe I should have him sand the area down to the glass and seal it with something before the reshoot???

 

The "problem" ...due to your response being that you can see "rings"...is that the material he is shooting is reacting with what is currently on the car now.

Primer, sealer, basecoat and clearcoat are all made to crosslink and bond with each other. BUT...each of these products have different properties in them. So when a solvent is applied to a surface where the layers of products applied on it...and have been sanded back...and the surface looks like a "topographical map" and you can see the "rings". These rings are what will come back and haunt you ...especially in a light colored metallic/pearl color. Because often times...the materials applied for the repair will shrink and distort...and you can see it in the color. Solid colors can also do it...but it is not as noticeable at certain angles due to being a solid color.

I can not see what you are seeing. And I was not there when your painter did what he did....so....in situations like this that I have encountered. I repair it the best I can...and give it TIME. Knowing that the car will come back...I wait... and when it comes back in...I prep the clear and blend the color again and re-clear it again. When I do this...the repair is usually completed. The reason I do it this way is so I know that what I previously applied has settled completely...and the slight distortion can easy be handled in the sanding of the CLEAR..as along as I DO NOT break through the clear to the basecoat again. SO...I am using the clear as a "primer" so to speak. BUT...this is AFTER I gave it some time to cure out and settle....and the owner was told what was going to happen...so there is no shock...and that it will be handled in the future. The only other alternative...which I know they do not want to pay for...it to completely strip off ALL paint and primer and re-shoot the area...so I have nothing on the surface for solvents to react with.

Even though I bake my primers and whatever is applied on the surface before paint in a repair like this...and use good products...and then cure the paint....TIME will tell...and I can find a glitch instantly when looking at the repair area in the future. Sometimes... a year later...the repair area still looks great...it often times depends on how much it has been let out of the garage. NO ONE has a crystal ball to tell how it will look down the road...UNLESS you remove those layers that cause distortion due to solvent sensitivity.

DUB

 

Thanks again Dub for your excellent followup. I was already planning on postponing the repair until summers end to let the area settle. It makes perfect sense to me to avoid painting over the base coat, but I'm not sure if we will be able to sand the area flat without going through the clear. W'ell have to wait and see. If we do go through then I guess we will have to strip the area all the way down to the glass and start over. I'll pass this info along to my painter. More to follow............