Well the body is OFF!! What a balancing trick with a convertible and rusted floors.

OK, here is the question. The shop that is going to media blast the body says I should have them etch primer (about $450.00) the car before I bring it home. I need to do the floors, trunk and some other body work. I want to do the underside, insides, hidden areas and all that with the POR-15. Should I just have them spray the "color coat" areas of the body or leave it all bare? It is going to be worked on in my garage and it may take eons before I get to all the places that need work. So far you guys have been right on the money with advice and answers..

Keep those cards and letters coming.

Thanks
Mike

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http://hotred66ss.homestead.com

If you have them prime it, I would make sure the primer they use is compatible with the finish paint system that you're going to use. You don't want to mix different paint brands, otherwise you're asking for problems. Stay with one topcoat mfg. Also ask questions about how they prep the surface before they spray. This is the most important stage of your paint job!

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70' El Camino SS 396 in pieces! Astro blue, black stripes someday.

I'm going through the same process as you are chief, for $700 they are blasting my shell and then shooting it in DP90LF to prevent flash rusting and to seal the metal.
I recommend sealing the metal with epoxy primer or etch primer if you don't you will have problems with rust forming on your shell once blasted.
Chuck

Our media blaster does not seem to charge that much for prime, we have it done with PPG's DX1791-1792, which is a translucent primer, and keeps it from rusting. Its fairly cheap also. You may want to inquire about this. Check out the 72 Trans am on my website to see what it looks like when its striped and sprayed with this stuff. It still looks like bare metal, which is nice to work with to start off.

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Micky Hale Restorations
69 L-89 Chevelle
68 Biscayne 427/425
34 Plymouth Drag Car
ACES #134 www.mickyhale.com (http://www.mickyhale.com)

[This message has been edited by micky69396 (edited 09-17-2000).]

I used to be part owner in a media-blast operation. This will be somewhat controversial: I don't believe you need to have it primered. Media blasting is supposed to leave the etch. I have a fender that was media-blasted several years ago. In Houston (can you say high humidity?), there's not any surface rust.

If you want it primered, that's a different story.

You are correct, a PLASTIC media will not rust fast at all. I would get it in primer in a day or two though. On a body typically there is also touch up with aluminum oxide (rust areas) which will flash if it is not covered soon. Our humidity may have something to do with it also. I have also seen any spots that are not primed, that anywhere you touch there will be a flash rust within a couple days. Chief, it sounds like you have rust areas, it will have some oxide blasting done, I would at the least do the DX if you can.

[This message has been edited by micky69396 (edited 09-17-2000).]

The etching primer is a good idea and you can do bodywork right over the top of it. That's right, you can put body filler on top of the etching primer and do bodywork without problems.
This info is according to the May issue of Super Chevy;
DP LF primers are available in different colors and you should choose one based on the color you plan to paint the car.
DP 40 LF is gray green
48 is white
50 is gray
60 is light blue
74 is red oxide
90 is black
The info in that article is consistent with what I've been told by full time body men and the folks who run my local body shop supply store.

I don't know all the brands, but I am absolutely sure that Sikkens self etching primer (wash primer) cannot be covered with polyesther filler. You should spray epoxy primer first and let it cure.

By the way. If you start with self etching primer you can spray epoxy primer on top of this within 24 hours without sanding (wet on wet).

Chief,

I am at the same stage with my 1969 Chevelle. I am not an expert but I have very good friends who are. They work at a company that manufactures Concept Vehicles forthe auto shoes and this is what they told me.

If you want to be absolutely sure that the vehicle will never rust again than "chemically stripping" the car is a sure guarantee (I found a place that will chemically strip the entire body for $350.00 and thay are close to our hometown).

Once the body is stripped it should be dipped in e-coat or completely covered in DP 90-PPG Epoxy primer. They suggest dipping becuase this insures that you are leaving no exposed metal anywhere on the car. This is espicially important for cars that are being restored in non-climate controlled buildings (like our garages). After that you can take your time with the body work because the car will no longer be rusting.

DA the epoxy primer off with 80-grit paper in the area you are working and once the work is complete, shoot it with DP-90 PPG Epoxy Primer (both sides of metal).

Then once your body work is complete on the whole cat. DA the entire surface to remove all primer and cover the whole car with 4 to 5 coats of Sikkens Poly Surfacer. Block sand the crap out of the car with 80 grit(they suggest shooting the car with some Dupont 3939 Enamel Reducer here to check the highlights in case you need to do some touch up work) and 150 grit to achieve the proper surface finish. Cover the entire car with K36 PPG Primer. Block sand the entire car with 320 grit and finally wet sand it with 400 grit. You are now ready for paint.

Hope that helps.

They must not care about mixing brands of materials. No manufacturer will stand behind their paint with that blending of systems. Stick with one brand only. Also, chemically stripping is not the best way to go. We have had 2 cars come in that were terrible on all the seams where the chemicals started to come back out, flaked the paint right off the car.

Micky,

I have heard about some negative as well as positive experiences with chemical stripping. I am hesitant about this with my own car but it doesn't appear that I have a choice. I have rust in some areas that it doesn't appear a media blaster will be able to get at. Do you have a recommendation for getting rust out of some tough to reach spots before etch coating the car? Any suggestion would be greatly appreciated.

Thanks

There probably are positives to the chemical stripping, I have not had it done although like I said we did redo a couple car that were. Where exactly is your rust? In a body brace? Thats the only downfall to the media, it cant get inside everything.

That is exactly where my rust is. I have a few spots where there are braces welded to the body and also some areas where the floor pan meets the side sill and creates a really narrow and steep trough. It hasn't eaten through the metal. It's mainly surface rust but I can't get in there with a wire wheel or any media blasting and I hate to cut perfectly good metal which is why I was looking at chemically stripping the whole car and then having it dipped in etch coat.

Thanks for the input. It's good to have a place where we can bounce these things around and get other ideas before we dive in head first.

Bill

1969Sleeper:

Who in our area (Eastside?) does the chemical stripping? I'm considering starting a frame-off on my '68 this winter.

Glenn Humphries
Warren, MI

Glen,

The name of the company is International Paint Stripping. They are located on the SW corner of 275 & Eureka. They quoted me a price of $350.00 for the body on my 1969 Chevelle. Their number is (734) 942-0500.

I am still searching for a place that can dip the entire body in E-coat. I have heard of a place in Grand Blanc called Meticoat but I haven't called yet.

Bill Presley
Macomb, MI

I am concerned about the comments on putting body filler over etching primer. Most manufactures don't recommend this. The polyester resin in plastic filler and the acid in etching primer just don't get along. If you insist on putting some primer down before doing bodywork, make it an epoxy. And 1969sleeper, the idea of priming the car and then doing the body work and then DAing ALL the primer off boggles my mind! Why would you do that? If you prime the whole car in epoxy primer, and do the body filler over the primer and then reprime those spots..you are done. Just go ahead and prepair the car for paint. What in the world would make you want to remove that primer to lay down more? And the reason plastic media blasting leaves a rust resistant surface is because it dosn't remove the factory protection like sand or chemicals do. And one last question for all you guys...why do you need to remove EVERY bit of rust on a car anyway? I know in some parts of the country with rust being so viscous it's a loosing battle. But most of the time, if there is some rust inside a panel or in the interior or trunk...if you can't remove it, it may have to stay. If the "reason" the rust is there is eliminated..than it won't rust anymore (at least not very fast) In the trunk for instance, if the rear window is fixed and the trunk seal is good, that rust deep down inside of the seams is going to stay dormant, you need moister and oxygen for the rust to keep growing. If you cover that surface rust with etching primer or epoxy primer and those water leaks are fixed..that rust will leave you alone. I know I am in sunny Califionia and I don't know diddly about RUST but I have repaired rust for decades and I have found these things to have worked for me. I have seen more troubles with chemical dipping and I just think that it is used WAY to often and should be resurved for a select few projects.

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T

[This message has been edited by MARTINSR (edited 09-21-2000).]

Whoops!! Another double, and after all these years! http://www.chevelles.com/forum/redface.gif

[This message has been edited by Randy Mosier (edited 09-21-2000).]

MARTIN, the humidity levels in other parts of the country just won't let you leave rusted parts alone like you described. Even if you think it's sealed, even if you think the source of water leaks are fixed, it always seems to creep back. That's been my experience, since I have had to go back and redo rust repairs that I thought were treated, sealed, and would last forever. Rust never sleeps, just like it says in the article in the tech reference pages elsewhere on this sight.
I thought the PPG DP LF primers were self etching, epoxy type primers and that was the reason you could put filler over the top of them. I threw that out there because I, like you, couldn't see the reason for priming, sanding off the primer to do the bodywork, and then re-priming. There are primers that will hold filler with no problems.
And last, according to one of the articles by the late Skip Cain, he doesn't recommend dipping an entire body. Front clips are OK, but not the back half of the car. The reason he gave is that the acid cleans out everything, including seam sealer. There are areas in the body that are almost impossible to reseal once the old sealer is cooked out. Thirty year old sealer is better than no sealer, he reasons.

I agree with Randy. The rust never sleeps. Especially in a vehicle that will spend the rest of it's life in a state like Michigan. Even stored through the winters the cars in our state will see violent humidity cycles.

I also agree that chemical stripping is not for everyone and that you should really evaluate what you are trying to do. The vehicle I am working on has had a lot of previous bodywork on it done and done poorly. There is a lot of rust trapped in areas that media blasting will not get to (the car came from the SouthEast Coast where it was subject to 30 years of saltwater air and humidity). The chem stripping is the only way I can be sure I have killed all the rust demons and it is true that I will have to replace all of the seam sealer. However, since I will have to unstitch some major panels for replacement this is a benefit in my case.

So chem stripping may not be for you unless you are willing to take a long time with the details and spend a significant amount of money on the body of your car. In some instances (and that is up to you to decide for your own project) the benefits outweigh the negatives.

[This message has been edited by 1969sleeper (edited 09-22-2000).]

This is the article I was referring to:
http://www.chevelles.com/shop/resto_3.html

Hi Mike.

Blast-cleaning a body-shell is by far the best option for any old car, especially on pre-1980's cars when many manufacturers strated using reduced section panels (some went from 1.2mm down to 0.8mm in thickness).
Blast-cleaning not only removes visible rust, but it also removes hidden road-salts and other residues that sit around doing othing most of the time but start eating at you metal when they become wet from rai of puddle splashes.
And please don't use chemical strippers. You are merely introducing more chemicals and more potential problems into the equation.
Apart from that, you can also introduce health hazards to yourself. The methylene-chloride used in paint strippers can permanently damage an eye in a single splash.

Regards etch-primers, be careful there. Etch-primers are designed to go on very thinly (around 12um thick) and in a single sprayed coat.
They are to provide a high degree of adhesion onto aluminium and certain plastics etc and are meant to be coated with a 'build-coat' sealer before any topcoats are applied.
When you blast-clean car bodies, the blast-profile in the surface of the metal can vary between 25um and 50um in depth depending on the grade of blast-media. This means that you will always end up with a fair amount of 'blast-peaks' protruding through the top of the etch-primer layer.
This results in 'measles', which is a rust-rash all over the bodywork.
The 'measles' can appear within 30 minutes in humid areas or during the winter months.
Remember, etch-primers react with the metal surface and they form a layer of ferrous phosphate, which is an anti-corrosive layer.
The prblem is, at such a low film-build if you apply a filler over an etch-primer there will be so little shear-strength from the primer-coat that I wouldn't take a bet on the life of either the primer or the filler.

A better choice is using automotive epoxy primers. Epoxy primers are designed to go onto both plain and galvanised bodywork panels, and they are tough and vibration-resistant. They take fillers with no problems and with no reactions whatsoever and, very importantly, they fill the blast-profile and seal the newly-blasted metal. There is no danger of 'measles'.
Some folks will say that there is no point in removing all coatings from the metal, but if you are not sure what has been treated and what hasn't, you may have a problem depending on what coatings you are using.
If the surfaces are cleaned completely, it's like working with brand-new body-parts.

A third choice (and the absolute best possible remedy for a cherished classic car) is to 'zinganise' your body parts.
After they have been sand-blasted you, can apply the Zinga coating in exactly the same way as you apply a normal paint.
The main difference here is that Zinga is a one-pack material (no mixing with other chemicals = no potential problems) and it merely needs to be thinned as usual and sprayed through a normal spraygun.
The zinc will be dried within 15 minutes, and after that time your body-parts are actually fully galvanised. The car can be left out in the rain for months and even years with no problems whatsoever.
Whenever you are ready, the zinc is then sprayed with a standard 2K primer and then topcoated.

I have helped guys from many countries over the past 25 years with this system when doing up old Volkswagen camper-vans and street-rods etc and have helped another classic car fan with a 1966 Ferrari.
The bodywork can sustain heavy stone damage but it will never rust.
Even SUVs used for launching boats in the sea will not rust when they've been zinganised.

I hope that this helps shed some light on alternatives to etch-priming

I have gotten away from etching primers and now use NASON epoxy primer, $150 a gallon. One good medium coat, let it dry for 1 hour and then put 2-3 medium coats of Trans-star 2k sandable primer for blocking.

What about an etching epoxy primer?