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AKZO Primer Issues

RV701775

Active Member
I have been priming my RV with AKZO and using PreKote with maroon scotchbrite to prep. I previously used this primer without issue, in fact, it was bulletproof. I purchased a new batch of two gallons last year and stored it inside my finished basement which is above 50 degrees. I tried to apply it this month and it looks alright, but it peels off in patches showing bare metal simply using masking tape even after 24 hour.

Any ideas what could be wrong? Has anyone experienced this before? I am hesitant to try again and may possibly purchase a new batch, but it is not cheap.
 
Surface prep

Sounds more like a surface prep problem. Maybe an issue with Prekote. Try a same with no Prekote.
Scuff with scotchbrite and a cleanser like Bon Ami. Comet or Ajax will also work but rinse very well. Dry and spray.
 
What should I do with the parts already primed? Just scuff them up and try to remove any loose paint? I would prefer not not to try and strip them.
 
What should I do with the parts already primed? Just scuff them up and try to remove any loose paint? I would prefer not not to try and strip them.
I would aggressively scrub the parts with a red scotchbrite to remove any loose primer, then clean and respray.

I had the same issue with a batch of epoxy primer. It was because of a contaminated solvent. Blue tape just pealed the primer off. Through cleaning with clean solvent fixed the problem.
 
Even though PreKote is a cleaner I like to wash with soap and water. The current soap that I am using is AR-5 from AirMart in Mena, AR. If the surface is kinda grey and smutty looking, I will wash it with an etch solution. Then follow up with two washings with PreKote. Also, don’t wipe the surface with any sort of solvent before painting. This will remove the PreKote layer.
 
Thanks for the advice. I will scuff the old primer with 400 grit to remove any loose primer and then use the prekote.
 
Thanks for the advice. I will scuff the old primer with 400 grit to remove any loose primer and then use the prekote.

First, 400 grit won't address an adhesion problem. I would put tape all over those surfaces and see what else pulls off. If the adhesion is truly poor, you're going to have large chunks of paint delaminating down the road. The integrity of your paint job is highly dependent upon the adhesion of the first coat. I would consider scraping off any suspect primer areas. Think about checking the adhesion of a piece of tape you applied. You don't test it's strength by pressing on the tape. You do it by seeing if it pulls off at the corners.

Second, prekote is a metal surface prep, similar to acid etch or conversion coating. DO NOT use that on painted or primed surfaces. Simply scuff or sand (follow MFR guidelines on what is aggressive enough) and clean with wax and grease remover. prekote is designed as an adhesion promoter on bare metal, not as a general surface cleaner. It only promotes adhesion on metal or fiberglass surfaces. Check with Akzo. Pretty sure they will recommend against putting that directly on a painted surface prior to additional coats.
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You need to address the root cause of your adhesion problem before proceeding forward.

Most epoxy activators are only good for 6 months once the can has been opened. The smaller the amount of activator in the can, the shorter it's shelf life. Check with manufacturer on this as stale activator can cause adhesion issues.

Finally, I use SPI epoxy primers and the owner is pretty adamant about not using Ospho (phosphoric acid etch similar to prekote) prior to his epoxy application. He allows it in limited cases, but only when painters are closely following specific guidelines about rinsing and drying times. His hesitancy is due to many customer complaints about adhesion issues when it is used. Do your research and insure that you are using it properly.

Larry
 
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I wash with Bonami cleanser before scuffing. I feel that scuffing first may get the oils into the scuffed surface.. wash, scuff, wipe with acetone, prime.
 
I suspect some issues with the primer, perhaps for sitting that long or temp that it was kept. In my experience even somewhat poorly prepped piece sprayed, it would not flake off that easy.
My prep involves scuffing it with a maroon scotch brite, wash it with soap in somewhat warm water and then clean it with acetone. when sprayed is rock hard. I have had overspray on parts/area that had no prep done, dirty and probably somewhat oily and yet I have to work it to get it clean.
 
I have been following wirejock's recommendation (thanks, Larry) to clean with Bon Ami and a gray Scotch-Brite pad, making sure everything looks scuffed and I get a good water break test, and priming as soon as possible after the part dries. I've been getting good results with AkzoNobel 10P4-2NF. Once the 10P4-2NF fully cures, you can wipe it with acetone or MEK and just get a little green tint on the rag. After it cures, it passes the tape pulloff test, even using aluminum foil tape, which is a test suggested by Master Aircraft Services in Wickenburg, AZ. Dimpling doesn't remove it either.

Bon Ami and PreKote have about the same pH, FWIW. PreKote is a somewhat stronger base. I tried it a while back, and the results didn't seem to be as good as what I get with Bon Ami. But there may have been other factors involved.
 
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