[Bluepen]

OK, Rookie question here folks. Got the last of my original trim parts needed for my '46 Chevy Panel yesterday after a couple of months of looking for them. The truck was in a field about 6 miles from home, who would ever have thought that would happen. Well anyway the parts are usable just rust pitted. Now the question, got them home and went to work cleaned all the rust off to bare metal, applied a couple of coats of etch primer for protection. Now do I apply glaze over the primer to fill the pits or take the primer back off and glaze then prime. I know that someone will tell me to use filler but I don't think the pits are that bad or big enough for the filler, I'm hoping to get away with just the glaze.

Thanks folks
David

 

[BarryK]

You cannot use a polyester over an "acid etch primer"

If it was epoxy, its ok.

 

[MARTINSR]

I would think polyester primer may be a good choice here. If these mouldings are the typical mouldings that I am thinking of, spreading a filler of some sort ("Bondo" or polyester spot putty, DON'T USE "GLazing putty from a tube!,that is junk) will be a tremendous amount of work. A few coats of polyester primer will more than enough fill rust pits. And MUCH, MUCH easier to surface nicely by sanding.

You can shoot some polyester primer over etch primer, read the tech sheets. PCL for instance has a recommendation for etch.

 

[mrcleanr6]

it was to my understanding that you cant use polyesters over acid etch primers because the acid neutralizes the benzoyl peroxide catalyst causing a thin layer of uncured material which causes it to not bond. does this only apply to the benzoyl peroxide catalyst and not the mekp type???

 

[BarryK]

it was to my understanding that you cant use polyesters over acid etch primers because the acid neutralizes the benzoyl peroxide catalyst causing a thin layer of uncured material which causes it to not bond. does this only apply to the benzoyl peroxide catalyst and not the mekp type???

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You are 100% right-
and on top of what you said, the acetone in the polyester melts the acid etch.
BUT
There are a couple of spray fillers now that say OK to spray over acid etch.
The MEK and Acetone are still there so how they can say this, I don't know!

bwk

 

[MARTINSR]

Barry, you are so right. When Sherwin got the polyester primer from Evercoat we were preached to that you COULD NOT put polyester primer over etch primer for the reasons you express.
Then all of a sudden we got a polyester primer for the "value line" and it had a recommedation in the tech sheet to use an etch under it!

I had heard horror stories from reps about the Evercoat (of course it didn't have Evercoat on the label) being applyed over etch primer, even problems with galvanized metal. Now we got this new polyester primer and it recommends it!

The "new" primer was made by PCL, and I actually like it a lot. It is a little thinner viscosity and sprays much nicer. I have only applied it over etch primer and had no ill effects.


All I can say is READ THE TECH SHEETS

 

[Bluepen]

OK, now that I'm not much of a painter I will admit I'm confused.
First the primer I used is Sherwin/Williams GBP #988 Self eching primer. Is this the primer I can use the polyester primer over?? And the glaze I was or might use is the good two part Evercoat glaze. I can't find on the primer can label any info that will help me figure this out.
Can somebody clear this up for me??

David

 

[MARTINSR]

That is a 1k aerosol and not very good at all. I don't know what to tell you. I would sand it all off and start over. A real etch like E2G980 and then PCL polyester primer. Or, Epoxy primer and then any polyester will work.