Do you guys do your bodywork first or over the primer?on metal that IS NOT MEDIA BLASTED, metal should be sanded with 80 grit? That is what is on the can,or I use a purple 3M stripping wheel? Can I put the primer down first, then the 2 PART seam sealer? I have done body work for 30 years but always used varprime then the 2k uro prime. Just trying something new and want to learn from guys that have done it. Any info is good. I USE DUPONT we do not have a PPG outlet anywhere near. Let me know what you guys use and had good luck with. ON some tractor parts I used some DTM SEM brand and it seemed to BITE real good. Sorry for being long winded.

I prefer filler on bare, roughed-up steel. Then epoxy. I know a lot of others that prefer to prime first.

For 30 years I always have used a 3 inch 24 grit grinding pad to rough up the metal then filler,but then you read guys say do it over epoxy primer.

I teach autobody at the Venango Tech Center in Oil City, Pa and here is our procedure:

Sandblast steel or 80 grit DA

WASH steel with water and Dawn dish detergent (I will discuss this later)

Clean steel with a water based wax and grease remover, then with solvent based wax and grease remover.

Allow to flash off and spray epoxy ( I like SPI Epoxy)

After 12-24 hrs, apply filler and block sand as normal. It is not necessary to sand the epoxy first as epoxy and filler will have a death grip on each other as long as the epoxy has not cured too long.

After filler work is complete, re-epoxy to sandwich your filler from both sides. Now you can use primer filler and block sand until the panel is ready.


*Sandblasting and washing*

Most sand used for blasting has contaminants- you are forcing those contaminants onto the surface of your car when blasting. Some dawn detergent followed by a waterborne wax and grease remover is a great way to really have CLEAN bare steel.

I know that it seems counter intuitive but when done the correct way excellent results are achieved.

As far as epoxy I am also a DuPont guy but I have to say that SPI epoxy is the best I have used, you also have a full 7 days to do your filler work and re coat with epoxy before you have to sand the original coat of epoxy.

Any questions let me know.

Here is an easy way to explain it:

Collision shops are all about speed- grind, fill, etch, prime, seal, color, clear.

Resto shops are all about longevity- Blast, clean, epoxy, fill, epoxy again, prime, seal, color, clear.

Collsion shops hate epoxy because it is waaay to slow for them.

I personally believe epoxy is best for restoration work.

A video for you to watch:

This video runs a little long but it shows how well epoxy sticks to steel, and how well filler sticks to epoxy.

On the first test, the steel was treated with acid and not properly cleaned- the results speak for themselves. The other tests show how good the system can be.

https://www.youtube.com/watch?v=-yA8q4K-_Bo

When you say "flash off" are you referring to the solvent based wax and grease remover evaporating?
I like that you are suggesting redundancy in de-greasing.
I have adopted the process that areas being blasted or sanded are washed with dawn and wiped down with solvent based wax and grease remover, and then again after blasting or sanding.
Another thing is to keep hands off any panels that are being worked on.
Also worth mentioning is to make sure that your top-coats are compatible with primers/sealers used.

If I'm using Epoxy Primer/sealer (I usually prefer acid etchant eg. Dupont's Vari Prime) sandblast the vehicle's metal usually with coal slag/Black Beauty, vacuum/blow off dust, wipe down with a solvent, usually acetone, perform the necessary metal work/filler in a timely fashion, then epoxy prime/seal or acid etchant, then prime block sand, prime, block sand, prime, block sand until the surface is flat/straight, then prime and block sand the primer base down to approx 600 grit finish, then top coat whether it be single stage or BC/CC, then colorsand down to 2000/3000 grit finish/polish

Mike

Isn't the 2k Primer by dupont an epoxy primer? I know it is a two part system. Any input?

Does Nason offer an epoxy system?

Thanks for the info I will look into it.

x's 2 on the SPI Epoxy.

Though not a student of his, I follow Hudsons procedure to a "T" and it has always yielded great results.

I use SPI also, have been for a few years now... way better than PPG which everyone seems to love. Only part I don't like is in the cold months, it's hard to keep my garage above 65 degrees as long as they recommend for spraying it. I've used their universal clear also, nice stuff too

Quote:

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Clean steel with a water based wax and grease remover, then with solvent based wax and grease remover.

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What product(s) are you using for the water based wax and grease remover?

Thanks

I touched on something to be careful of but thought I should offer a little more insight on the compatibility issue. I've seen failure of paint because of top-coats eating into lower paint substrate, especially at panel edges. After doing all the prime and bodywork and sealing do make sure the final sealer is not sanded through (if not promptly top coated) exposing non solvent resistant materials to be exposed to the color and clear solvents.
I like to hit edges of panels at least twice with sealer whether or not I plan to sand.
Bottom line is to plan your paint system completely before you start. Mixing it up could result in bad finish.

Not a pro but have plenty of projects under my belt that have turned out well.

One way to answer the epoxy question depends on how you work your project. If you have the car stripped, blasted whatever, something should go on the bare metal ASAP. Epoxy is a good answer. Then you can take the car panel by panel and work it over on any time table.

I don't get caught up in the window time of epoxy recoat/cure. To me that's for the guys doing stuff very quickly.

After the epoxy has been sprayed it might be weeks, months or years before I get to the specific part. In which case, I will block the epoxy with 80grit, add light filler on top in spots where needed. Areas needing heavy filler I will abrade the surface with a grinder. After filler use a polyester primer like slick sand or if you don't need that kind of fill, a 2K urethane primer surfacer. Each will stick well to the 80grit sand scratches in the epoxy. Small bare metal break throughs say the size of a golf ball don't bother me. Most primers can stick to bare metal like that without another product.

I have been using cheaper primers as of late with good success. The Eastwood/Kirker epoxy is nice stuff, lays down well, is cheap and very sandable after cure. With 2K I've used the Eastwood/Kirker 2K Urethane primer (Perfect Prime). Add a sealer on top and use the paint brand of your choice.

Follow the tech sheets for the product you use, if there are questions, call/email the tech department for the brand you're using. Where a lot of people have issues is pushing the recoat or curing envelope with incompatible products.