Technical What Kind of Primer...

… do you need before applying finish on bare aluminum? Preferably in a rattle-can, I've only got a few pieces I need to do.

 

I've had good luck with an acid etch primer [Vari Prime] on both aluminum and stainless steel. Clean it up first and a little 220 sand paper helps give it "tooth". I did some stainless and aluminum outside mirrors and it held the several years I had the car.

 

Like Rocky said scuff it up some and use self etching primer. After you scuff it you can use standard primer also.


Sent from my iPhone using The H.A.M.B. mobile app

 

I'm going to shoot some 'hot rod flat' single-stage urethane top coat that I've got left over from another project for finish, just don't want it to fall off... LOL.

The parts are just too big to fit in my powder oven, otherwise I'd coat it.

Thanks!

 

Etch primer is supposed to go over metal, only. Spraying it on other coatings can cause those to lift.

I have a former employer who learned this the hard way.

 

Trick with aluminum is not to let it sit. Aluminum oxides form very quickly. I usually try and work within a 30 min window. Scuff, clean, and prime.

When dealing with aluminum I will usually only do one piece at a time. Sand blast or sand, then clean part, hang part, final wipe, 1st coat of epoxy, start 2nd piece then prime 1st coat on 2nd piece and 2nd coat on first piece. Once everything is primed I will either apply final coat or leave the rest for body work or high build primer.

Sent from my SM-G950U using Tapatalk

 

I agree with sinisterslelds


Sent from my iPhone using The H.A.M.B. mobile app

 

After working in aviation, airlines to single seaters, I learned that aluminum needs to be very clean (as does anything you paint). The standard for aircraft painting was using a designated aluminum epoxy primer then topcoat. Not all primers are meant for aluminum. Just the way I was taught. I have never seen spray can stuff last very long in the real world, you know, outside with sun and rain.

 

I've used zinc chromate primer in a rattle can on aluminum with good results.

 

If corrosion may be a factor consider alodine.

 

Some recently told me that you need to use regular primer after using self-etching primer. Is this true? I know painting aluminum can be tricky. I thought there was a special etching process required before painting aluminum.

 

I've used ALUMIPREP 33 to etch and no primer, used it for +30 years, airplanes and hot rods, never a problem!