paint failure

well...the lovely ford ruby red metallic paint on my 72 commando failed....the paint shop guy just left here with the pieces to do them over ..I noticed a few days ago some 'rough' places on the tank and panels...kinda like very very fine orange peel blotches....over the course of a few days they appeared in a few more locations mainly along edges...like cancer spreading......called paint shop guy and he came and got the parts and took them to shop said he had a device that could tell which of the 10 layers that it was going wonky...not going to cost me anything to get it sorted but a bummer nonetheless...any of you paint experts got an opinion as to cause?

10 layers?? PPG technical data sheet for Ruby Red recommends a good sealer (epoxy) over the prepared substrate followed by a red metallic ground coat, a tinted midcoat clear, and a clear topcoat. Was the paint solvent based or water based?

The defect sounds like topcoat shrinkage. Lots of possibilities here. Some painters like to use a clear coat from a different manufacturer than the base color they use. Most times this works, but others the clear affects the cure of the base or vice versa. There is also a maximum time lapse between shooting the basecoat and the clear. Violating this usually causes issues with adhesion/scratch resistance rather than what you describe, but possibly the defect is caused by poor adhesion between the base and clear.

I'm not an expert painter, but I did spend 40 years in paint chemistry.

painter thinks it's the last layer of clear I miscounted coats it was primer sealer 3 base coats one coated tinted clear decals applied then 2 coats clear...at any rate it's getting redone 'under warranty' ...painter will be contacting paint supplier...…..

The old “bad news , good news” story line .... hope you get things sorted in a timely fashion Alan , I think you at start of good ride weather down there .... good luck !

took tank to paint shop (they took side panels yesterday) panels were new raw steel from India tank new emgo...verdict? tiny bubbles caused by rust forming on metal under all the paint...painter said must now strip back to bare metal and acid treat and then epoxy and repaint...

Hmm. .. First I have heard of rust spots on EMGO tank. Plenty on India panels.

this sounds more like poor prep work on his part.

alan hodge said:

.verdict? tiny bubbles caused by rust forming on metal under all the paint...painter said must now strip back to bare metal and acid treat and then epoxy and repaint...

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bill said:

this sounds more like poor prep work on his part.

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I was told long ago, bare metal for even 12 hours can be trouble after painting due to microscopic rust starting .

This reminds me of a 1956 Chevrolet (not mine) beautiful paint job when bought, as the months went by tiny bubbles started to appear from underlying rust worm.... back to bare metal it went at great expense.

Time Warp....microscopic rust it is same as the '56 no expense to me to get it fixed but aggravating wait to get the parts back

In trying to reproduce NLA "wrinkle" paint in red, blue or green for my Lotus valve covers, I had to research this topic.
The orange peal effect you are having may be a result of differing types of paint layers and their differing drying speed. This is the whole principle for obtaining wrinkle paint. The amount and type of thinner and the layer thickness is possibly in your case, attacking the layer underneath resulting in wrinkling.