I have a can of Eastwood self-etching primer (high build) that I sprayed on aluminum.

I sanded the aluminum with 150 git followed by 220 grit. Then I wiped the surface with Eastwood surface cleaner (Pre-paining Prep Aerosol).

Then I gave the aluminum one light coat of the etching primer, waited 10 minutes and followed with a medium coat.
Looks good.

Product says it can be sanded in one hour. I waited 3 hours. I sanded with lightly with 320 grit. i did expose a little bare metal sanding but the primer seemed to be adhering normally.

I was going to spray 2K Urethane primer-sealer next. so I wiped the surface again with the Eastwood pre-painting cleaner and some of the Primer wiped off exposing the bare metal.

What did I do wrong? Is it the "pre-paint cleaner" causing the problem, or do I have poor adhesion of the self-etching primer to the aluminum to start with? How can I test?

I don't want to spray the urethane primer-sealer until I figure this out.

I resprayed the bare areas again with the self-etching primer. I'm just not sure if I have a problem or not (I won't wipe it again with the Eastwood cleaner in case that is the cause).

Any ideas or advise?

I have never used Etching primer on Aluminum and I cant figure for the life of me why anyone would?
If they the manufacture say's it can be used on Aluminum in there Tech sheets I would strongly suggest you follow there instructions in the Tech sheets to the letter.

I use Aluma Prep on Bare Aluminum followed by Alodine Then a Good hi quality Zinc Epoxy primer with a light scuffing followed by a good Hi build primer Sand that then do Base coat and clear.

That Estwood aerosol is essentially Wax & Grease remover which is a solvent and will dissolve fresh paint.

The use of an etch primer on aluminium is fine, in fact part of most recommended systems, and should be applied as a single, light but even coat, allowed to flash and then primed, preferably with an epoxy. Don't sand or do anything else to the etch primer, other than to wipe gently with a tack cloth, if necessary. It's purpose is to function as an adhesion promoter between the alloy and the following primer coat.

Thanks for the info. I feel better about it now.
I'm going to spray the urethane primer-surface now. I'll do the base-clear coat later (next weekend) after I finish up the other repair spots.