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The cab of my 54 Chevy was dipped and stripped then sanded with 120 grit and then shot with Dupont 615s Veriprime and
then with 4004s Dupont primer. While i was block sanding i noticed cracks in all the small inside corners that go all the way
to the metal. Did I do something wrong.
Thanks
Loy
 

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This can be a common (well, does happen sometimes) occurrence with either acid etch or epoxy.
If you look at the areas cracked its normally areas that receive overlap coats. In other words if you put two coats on the door and two on the fender than two on the rocker the front corner of the rocker got about six coats (with over laps)
Normally there may be two or three spots like this on the whole car and you can just sand those spots down and re-primer.

Short of the story is solvent were trapped in the acid etch (acid etch is made to be sprayed thin) and now are trying to come out and its shrinking as the solvents dissipate.
I should add, this never shows up until you primer and it re-flows the top coat that sealed in the solvents.
 

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BarryK said:
This can be a common (well, does happen sometimes) occurrence with either acid etch or epoxy.
If you look at the areas cracked its normally areas that receive overlap coats. In other words if you put two coats on the door and two on the fender than two on the rocker the front corner of the rocker got about six coats (with over laps)
Normally there may be two or three spots like this on the whole car and you can just sand those spots down and re-primer.

Short of the story is solvent were trapped in the acid etch (acid etch is made to be sprayed thin) and now are trying to come out and its shrinking as the solvents dissipate.
I should add, this never shows up until you primer and it re-flows the top coat that sealed in the solvents.
this is an occurrence with epoxy just buy it self??
 

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Dubz said:
this is an occurrence with epoxy just buy it self??
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I don't think, it can happen buy itself. I should say never have herd of it happening. Here is why.
The net result is to much product to fast (not enough flash time)as is the case with the overlap coats. By itself after the top coat skims solvent will at a retarded rate seep out but very slowly.
Now the immediate coating of another product such as paint or 2K primer will melt the top coat and solvents start flowing at a faster rate and normally the cracking will show up next day from contraction.
I have had one spot do this to me in 30 years and it was on the inside of a front fender a spot that I slipped with the gun when I was spraying epoxy and a few days later after I based it a 2 inch split appeared.
I do hear of this on and off but usually its when product is applied in real hot weather or in cold conditions.
Barry
 
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