prepping aluminum for paint

[flyboy]

Donna and I are in the middle of the painting process of our Patrols and we are looking at a product called Pre Kote surface treatment as an alternative to aluma prep and alodine. Does anyone have experence with this product. Thanks Dennis

[dedgemon]

I haven't used it so that gets the question out of the way.

Out of curiosity, why alodine at all. Most of the industry seems to have abandoned it in preference to simply using epoxy primer over a properly scuffed and cleaned aluminum surface. This way there is not etch (to find its way into little crevices and corrode things) and no alodine.

[Mark Goldberg]

Hi Dennis. I have done different things on my planes. But I agree with David - no real reason for alumniprep and alodine on the outside of your wings. We do that for the spars but nowhere else. I have used a light coat of self etching primer first, then the epoxy strotium chromate primer, then urethane or polyurethane color top coat. On the LSA, we just shot the epoxy strotium chromate primer after scothbriting and cleaning the wings well, and then the top coat. I have never used a clear coat top coat. Now they call what I use single stage since it does not use a clear coat. Mark

[Gavin Chester]

I am using Pre Kote on my Patrol wing pieces, it has been easy to use but I do all the pieces separate then epoxy prime with poly fiber ep420 and assemble . Only time will tell if it is any good. With Pre Kote you are just scuffing , cleaning and preping all at once.

[N3UW]

I am using Pre Kote on all the pieces before I prime with an epoxy primer. I have been very happy with it. Very easy to use.

[flyboy]

Thanks All for your input.WE will try the PreKote and hope for the best.

[Ratfink]

Dennis, I would agree with Mark... I build custom cars, hotrods, restorations for a living, shop, paint booth, etc.. I am not a fan of using ANY type of Epoxy Primers on BARE METAL ANYTHING! This is an ongoing argument in the industry and the bottom line is this... Just because you make something stickier doesn't mean it going to stick and or (more importantly) prevent corrosion, moisture, etc.... I just finished sandblasting a his and her aluminum bodied roadsters... both paint jobs are within a couple of years. Both cars were painted in two different sates and places... One used etching primer the other epoxy.... The etching primer when sandblasting was not easy to get off. It actually dyed and etched into the aluminum... As it was designed to do. The metal was pristine.... The other car, The paint practically blew off in chips, there was a surface oxidation that had gotten underneath. DONT USE EPOXY PRIMERS ON BARE METAL!!!!! Properly prep aluminum, scuff, then clean with proper degreaser. When they say to clean bare metal with proper cleaners/degreasers it means clean..... Wipe one direction with degreaser, then dry with other hand with clean cloth. Rinse and repeat until the towels you are using are spotless clean. SPOTLESS CLEAN... IS CLEAN!!! NOT KINDA, LITTLE SMUDGY, TINY DIRTY,. NO! CLEAN! SPOTLESS. Then you can directly spray to the bare aluminum the ETCHING PRIMER. Enough to properly cover as mentioned by Mark. Rinse and Repeat.

My last comment is directed to (dedgemon), I have been building cars for over twenty years and painting just as long. I have never ever ever in my life seen any type of ETCHING PRIMERS find their way into little crevices and corrode things!!!!! This is BS and total misinformation. Etching primers are designed to embed into metals and convert any surface oxidation to primer and bond on molecular levels unlike epoxies which just glue themselves to the top. Epoxy primers should never be used on bare metal regardless what the industry states. I will tell you the major aircraft manufactures still use etching primers NOT epoxy primers. Regardless your statement listed below is incorrect.... please take the time to properly research and not pass on bad info to others.... If someone were to read and believe this they may add another layer, expense and needless weight to their aircraft.

I apologize to all as I don't like to see misinfo past around and I don't wish to insult anyone. This is a pretty hot topic in the industry for the last handful of years. My paint jobs are expensive, take about two months to complete and are warranty forever. I don't want to have to redo any of them... So I do and use what works, time tested, bullet proof.... lastly, I had a rep from Dupont come out and replace 3 gallons of Epoxy Primer with Etching Primer. Its only a matter of time before the industry finds out the hard way and moves back over to etching primers for bare metal. Don't take a chance with bare metals.

[dedgemon]

one thing I've learned. There is seldom ever only one right way to achieve a good finish. If it works for you thats fine.

Also, you might try not shouting. 😊

[sjt]

Could someone tell me what Pre Kote is? I am familiar with alodine, and epoxy primers. I did not think you could get strotium chromate primer.

When I google Pre Kote it seems to be a poly urethane type primer. I do not see any etching quality to the product.

[sjt]

I would like to know what primer is in favor for steel. I sand blast, but have always been worried that the sand comes form a salt water beach.

[N3UW]

Here's the link for PreKote

http://www.pantheonchemical.com/surfacepretreatments/