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top coat over self etching primer???

tcone1

Well Known Member
Trying to sort it all out. The last airplane I painted was almost 20 years ago. I'm sure there have been improvements. My process then was etch, alodine, epoxy prime, imron. I just saw that airplane last week, and it still looks great. Paint was still stuck, and very surprisingly still looked wet.

I have locals trying to talk me into skipping the etch/alodine process and going with a self etching primer. Do I spray top coat directly over this, or do I need to add a layer of "normal" primer prior to top coat?

I've rattle can self etch primed some small parts and it seems to stick well, but it doesn't seem to like the few areas I've used filler (stab tips etc.). I'm getting ready to paint the whole airplane and feel like I don't know enough about the self etching stuff. Is it better, easier, safer. If you have to prime over the self etching stuff with another layer of normal primer, why not just etch/alodine? With the self etching stuff, local expert says I have to scotchbrite the whole airplane. I don't remember needing this step with the old process.

I know this has been beaten to death in the past, and I've searched the forums (VAF has, by far, the best wheat/chaff ratio) but I am hoping to start priming next weekend.
 
I can tell you a horror story about using the green wash primer from SW that vans recomends and it ended with me stripping my still not done yet -8. Interior that is. It could have been my lapse in time before topcoating but I will be using the tried and true etch alodine and prime on my interior. I contacted the local SW store and they assured me I could just paint right over the primer with no prep. This stuff by it self seems to be a good thing but when it closes up you cant get anything to stick to it. Even scotchbriting it seems feable. It is very tough and I have it on most of all my metal on the inside. Not a problem except where I wanted to make it a pretty color not just wash green.
just my .02
results will vary
I like hearing you story about the plane that still looks good with the tried and true method.
 
Epoxy primer

Tim.... this guide from Detco might help...

http://detcomarine.com/slacguide.htm

The wash primer method comes under "most economical"

Their better processes use an epoxy primer.... their U-1201 primer is a Mil-Spec 23377 epoxy primer... and an etch/alodine step.

DuPont publishes a similar guide for their Imron and aircraft painting processes, but I can't find a reference at the moment...

gil in Tucson
 
I also used the full Imron process in 1981 on my BD4 which has held up remarkably well.

I'm using the rattle can etch paint on the interior of my RV8. I decided to use Imron for the final top coat and used an epoxy primer/sealer as a seal coat before applying the Imron. It seems to have worked well and is resistant to scratching.

In retrospect, I'm not sure the etch primer was a good choice under the Imron as it was as much work as doing a normal acid etch/alodyne treatment.

I am still using the etch primer on interior areas that will not be top coated.

Deene
 
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