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-   -   Prepping (http://www.hotrodders.com/forum/prepping-39192.html)

SJU 05-10-2004 02:20 PM

Prepping
 
I have stripped the car to bare metal. I was told to put an etching primer on the bare metal then do body filling etc. then prime with a different primer.
I have since been told that I cant put filler over the etching primer because the acid neutralizes the hardener in the filler. So now I have part of the car with etching primer and part of the car with bare metal and no body work done. I was told to put epoxy primer over the etching primer and then the fill work then more epoxy primer. But what about the part that is still bare metal. can I go straight to an epoxy primer, or start with an etching primer on that as well. Help, I am a first timer and I'm determined to do this. Is there a good web site with step by step instructions?
Totally confused.
Thanks

BarryK 05-10-2004 04:39 PM

Spray epoxy over the bare metal and over the acid etch, than you can put the bodyfiller over the epoxy. DON'T acid etch the rest of it as the acid etch will be the weakest part of the paint job.

Centerline 05-10-2004 05:49 PM

Re: Prepping
 
Quote:

Originally posted by SJU
I have since been told that I cant put filler over the etching primer because the acid neutralizes the hardener in the filler.
I don't know who told you that but they're flat wrong! There is no reason you can't use body filler over etching primer. Professional body shops do it all the time.

Centerline

BarryK 05-10-2004 07:43 PM

Sorry, its outdated technology.
Rarely do you find a full time restorer acid etch all you have to do is one come back and thats it. The sales for acid etch are mostly
warranty work for dealerships and back yarders.

Spray some, let it dry a week and wash it off with lacquer thinner.
What do you think urethane reducer will do to it?

It was great under enamel and lacquer.
And will be your weakest link under a base/clear system.

You can NEVER use body filler over acid etch! Call any body filler manufacturer! The acid will react with the filler and effect adhesion and curing of the peroxide.
Its pure suicide!

SJU 05-11-2004 05:37 AM

prepping
 
Thanks for the help. I know its the old way, but I may use acrylic enamel paint. Does that make any difference? Should I remove the etching primer? If so what is the best way? Is it better to do the filler work on bare metal? I think I have something called evercoat glaze.
I need step by step instructions as I'm confused at this point. It seems like different places tell you different things or leave something important out.
SJU

BarryK 05-11-2004 05:58 AM

If your using enamel just let it be. The epoxy over it will make it a lot stronger. Its the urethanes that cause the melting problems.
If you were to take it off 80grit on da will remove acid etch in no time.

you can put the glaz or bodyfiller over bare metal or epoxy, your choice

Centerline 05-11-2004 08:12 AM

Quote:

Originally posted by BarryK
you can put the glaz or bodyfiller over bare metal or epoxy, your choice
I disagree. Using body filler over bare metal promotes rust. The filler is porous and it can and will trap moisture under the filler which will allow the surface to rust over time. This is the exact reason for using either a self etching primer or epoxy primer over the bare surface prior to doing bodywork.

Centerline

SJU 05-11-2004 08:51 AM

prepping
 
I think what I'll do is finish spraying the car with the etch primer then spray with an epoxy primer do the fill work, sand and spray with a primer surfacer/sealer?
I appreciate the quick responses.

BarryK 05-11-2004 01:35 PM

Quote:

Originally posted by Centerline
I disagree. Using body filler over bare metal promotes rust. The filler is porous and it can and will trap moisture under the filler which will allow the surface to rust over time. This is the exact reason for using either a self etching primer or epoxy primer over the bare surface prior to doing bodywork.

Centerline

Your right the best idea is always put body filler over epoxy but in his case (learning it really don't matter. Long term 10-15 years it will. Most body shops still put filler over the bare metal for everyday production work. I always spray epoxy first but only thing I do anymore is show or restoration.

But you need to educate yourself on the acid etch primer as far as putting body fuller over it. Do it yourself but don't give that advice to other people as that is a major problem waiting to happen both short term and long term.

Centerline 05-11-2004 04:58 PM

Quote:

Originally posted by BarryK
But you need to educate yourself on the acid etch primer as far as putting body fuller over it. Do it yourself but don't give that advice to other people as that is a major problem waiting to happen both short term and long term.
I still disagree. When I worked in the industry we did it every day and I've never had a problem with filler over self etching primer. I will admit that there could be a problem if the primer isn't fully cured which can happen if the tech is in too much of a hurry but in 99% of the cases it works just fine.

Centerline

troy-curt 05-12-2004 08:06 AM

Anything you apply to bare metal to seal it will trap moisture, if it is present at the time of application.

Of all the thousands of gallons of filler that I have used, I have never had any problems with moisture or rust underneath it when applied over bare metal.

If you have moisture problems, you need to use some kind of humidity control.

Troy

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Centerline 05-12-2004 09:16 AM

Quote:

Originally posted by troy-curt
Anything you apply to bare metal to seal it will trap moisture, if it is present at the time of application.

Of all the thousands of gallons of filler that I have used, I have never had any problems with moisture or rust underneath it when applied over bare metal.

If you have moisture problems, you need to use some kind of humidity control.

I agree, however a lot of shade-trees wind up doing bodywork over several weeks (or even months) and the surface never gets protected until the car is totally ready for its first overall coat of primer. These are the people that need to be concerned about body filler over bare metal. :cool:

Centerline

Blowing on Flames 05-12-2004 09:35 PM

SJU, PRIME OR NOT TO PRIME??? If you are using acid you should never put polyester products over it. Even fully cured (if you want to call it that or gassed out is the proper term) it will push that ploy off eventually. I have come across some non poly based fillers that can (so they say) go over acid. You need to read the tech sheets or call the product manufacturer if you are in doubt. I would never recommend filler over acid.
I prefer to put filler over bare metal (as troy has said). However, if the project is going to sit bare for more than a day or two (as Centerline mentioned). I use acid then I prime before my filler. I have totally given up on epoxy
after they removed the lead. I don't care what anybody says... It is not the same stuff without it. There are much better ways to go these days.
SJU... I would make a few phone calls to get all the tech info on the products you are using before going forward. They are the people that will write the warranty check if their products fail using their procedures. If you need help with contact names and numbers..PM me anytime.........Good luck...... Bryan

mitmaks 05-12-2004 10:52 PM

the proper way to do it is to fill/do bondo work on bare metal then spray where metal shows with self-etching primer, not spraying on bondo, then spray with primer-filler, then sealer and base coat/clear

BarryK 05-14-2004 09:20 AM

Quote:

Originally posted by mitmaks
the proper way to do it is to fill/do bondo work on bare metal then spray where metal shows with self-etching primer, not spraying on bondo, then spray with primer-filler, then sealer and base coat/clear
Really!

Thanks !!!


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