Incompatibility

Patsdeere · Apr 11, 2023

Everybody always says, use the same brand, don't mix and match. I know there is truth to this, but how would you tell if you had incompatible paint and primer? No adhesion? Falls off? What about paint and incompatible hardener?

It as much a question if somebody brings me something to paint as it is when looking at stuff to know if there is a problem.

I'm simply curious and know they many of your know way more about this than I.

Welding man · Apr 12, 2023

My brother took his 2003 Dodge Ram to a local body shop to get it painted. These guys have been in business for years. Top notch, Do hundreds of insurance jobs a year. It takes up to 6 months to get a vehicle in. They basically disassembled his truck painted it and $5000.00 later it was done. Nicest paint job I have ever seen. It was shiny Black. Fast forward 6 months and the hood and top of the cab starts peeling off. Brother takes it back and the owner says, my god what a mess. He told my brother the paint company is going to pay for this one. He is scheduled for a repaint on May 1. Even the experts have problems. Due to the Feds air quality and exposure rules, paint is not what it used to be.

Stephen Newell · Apr 12, 2023

It's one of those things which takes a knowledge of the chemistry of the paints and experience. Some paints won't bond well with some primers and sometimes the solvents are so strong in the paint it would make the primer wrinkle up like you put paint stripper on it. If you don't have that experience you are better to stick with the rule same brand. This is especially important with automotive finishes. Oil based paints are not as picky. You could take one brand primer and mix it with brand x paint thinner as long as it wasn't the low odor stuff and topcoat it with yet another brand of oil based paint thinned with another brand thinner and it would work fine. The solvents in automotive paints are more complex, they aren't usually one chemical but a blend of solvents. The chemist that developed the paint would know best the correct blend for their paint so if you used a different brand it may be similar but might be missing one or more of the ingredients. You kind of need to look up the MSDS report on the paint and solvents to see what the ingredients are to mix brands.

Stephen Newell · Apr 12, 2023

I wonder it the paint was water based. Even the manufacturers are having trouble with it especially GM. You see cars and trucks all over with the paint pealing off the primer.

Welding man · Apr 13, 2023

I am pretty sure that they have went to water base.

showcrop · Apr 13, 2023

I had problems on my last project. The hood went well, but I didn't completely base prime over the old paint on the fenders, and the solvent in the high build primer was too much for the old paint underneath. Fortunately I was still working primer and not yet into the top coat. I would much rather have a problem in the primer than the finish coat.

circus · Apr 13, 2023

(quoted from post at 18:35:04 04/12/23) Oil based paints are not as picky..

Oil (alkyd) paint has a window of time you dare not recoat. Can be as little as an hour after or before two months. Depends. The solvents from the second coat can wrinkle the first coat. What a mess. :shock:

JD Dave · Apr 14, 2023

The newer the paint system, the more you have to adhere to the specific instructions of that manufacturer. It all depends on how fine a finish you want to achieve. You can spend $500 or $1,500 on materials. For my farm equipment, I can get a great, durable job by cleaning and prepping with 220-320 sandpaper, applying a self-etching primer, let it dry until you can no longer smell it, 2 weeks or six weeks, it doesn't really matter. Then, -- scuff it thoroughly with Scotchbrite, every crack and crevice and apply an old-fashioned alkyd enamel, first light coat followed with 1-2 full coats. It will look and last better than most factory jobs.

Incompatibility

Patsdeere

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Welding man

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Stephen Newell

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Stephen Newell

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Welding man

Well-known Member

showcrop

Well-known Member

circus

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JD Dave

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