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  #1  
Old 04-26-2021, 03:55 PM
RV701775 RV701775 is offline
 
Join Date: Jul 2019
Location: Boston, MA
Posts: 91
Default AKZO Primer Issues

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.
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  #2  
Old 04-26-2021, 03:58 PM
Wes H Wes H is offline
 
Join Date: Jun 2019
Location: Kokomo IN
Posts: 26
Default Induction time?

Are you honoring the induction time?
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RV-10 7/4/19
Emp Complete
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2021 Donation Paid
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  #3  
Old 04-26-2021, 04:00 PM
RV701775 RV701775 is offline
 
Join Date: Jul 2019
Location: Boston, MA
Posts: 91
Default

Yes, I let it sit for 30 minutes after mixing.
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  #4  
Old 04-26-2021, 04:19 PM
wirejock's Avatar
wirejock wirejock is online now
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 4,596
Default 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.
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Estes Park, CO
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Donated 01/01/2021, plus a little extra.
RV-7A #73391, N511RV reserved (2,000+ hours)
Empennage, wings, fuse, finishing kit, now FWF
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  #5  
Old 04-26-2021, 04:23 PM
RV701775 RV701775 is offline
 
Join Date: Jul 2019
Location: Boston, MA
Posts: 91
Default

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.
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  #6  
Old 04-26-2021, 04:31 PM
RV10Pilot RV10Pilot is offline
 
Join Date: Jan 2005
Location: Medford, NJ USA
Posts: 448
Default

Quote:
Originally Posted by RV701775 View Post
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.
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  #7  
Old 04-26-2021, 06:02 PM
Bandera Bandera is offline
 
Join Date: Feb 2021
Location: Gainesville, Tx
Posts: 39
Default

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.
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  #8  
Old 04-26-2021, 07:44 PM
RV701775 RV701775 is offline
 
Join Date: Jul 2019
Location: Boston, MA
Posts: 91
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Thanks for the advice. I will scuff the old primer with 400 grit to remove any loose primer and then use the prekote.
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  #9  
Old 04-27-2021, 06:58 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 6,517
Default

Quote:
Originally Posted by RV701775 View Post
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.
'
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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Last edited by lr172 : 04-27-2021 at 07:24 AM.
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  #10  
Old 04-27-2021, 08:16 AM
Taltruda Taltruda is offline
 
Join Date: Oct 2017
Location: Las Vegas, NV
Posts: 840
Default

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.
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