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who still acid etches?

should i do the acid step?

  • Yes, Even though SEM says not required

    Votes: 26 42.6%

  • No, No need for it

    Votes: 23 37.7%

  • I am running around my house naked

    Votes: 14 23.0%
  • Total voters
    61
D

daviid

Well Known Member
I was speaking to the folks over SEM today regarding Self Etching Primer & EZCoat. The person I spoke to said for both products there was no need to acid etch. Clearly stated for the Self Etching Primer but not on the EZ Coat.

What has been the general consensus on the acid step? do it, don't do it?
 
+ 1 for etching. Not much extra effort seeing as all the parts have to be cleaned anyway..
 
Something change?

People selling self etching primer will always claim no etching required. Like any thing involving primer, many opinions but what counts is what you are comfortable with. I vote (as stated above) for belt and suspenders.
 
I started with Spray can self etching primer.
Moved to etch/ alidine/ prime and was much happier with the results.
Almost no additional work over having to clean with MEK.
 
Small parts

If the part is small enough to submerge in an acid water solution, I do that. Spent solution can legally be mixed with soda ash to neutral P.H. and poured down the drain. Otherwise, I mechanically clean with scotch-brite, soap and water. Final wipe with lacquer thinner and green death prime. Alodine is easy enough to do, disposal of the chromates in it not so much. I use alodine to prep grounds or other un-primed bits. Mostly avoid it for health and environmental reasons.
 
Last edited:
Before I painted, I experimented with etching primers. The only way I could get a good bond and one that shipping tape would not pull off, was if I scuffed the alum first.

I tried the self etching primer on;

-unprepped samples
-washed but otherwise factory finished samples
-scuffed and washed samples
-scuffed and etched and washed samples
-scuffed and etched and washed and Alodine treated samples.

Finally settled on the last as the best. Might be overkill but so is painting the design I used!
 
Pretty scary all the people running around the house naked. Too cold here to do in the winter months. That is a summer activity.
 
No etch.

Scuffed.
wiped with solvent like Lacquer thinner or mek.
Dupont Variprimed

If part was in a tough service area that expected a beating or abrasion (like wheel pant brackets), I baked the part at 250 F for ten or 15 minutes.
 
+1 for Prekote

Started out acid etch everything and chromate until I got to the parts too big to dip in a tank. Prekote + red Scotchbright was the answer for everything after that. No problem with Stewart water based primers or the solvent epoxy based primers I am using. Exterior paint prep will be Prekote & Soctchbright for sure. Watch the application window when doing large areas.

John Salak
RV-12 120116
 
I always etch. It's the best way. When your done with the etch you also get the side benifit that your surface is nice and clean. Clean is always good.
 
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