Primer? Bare metal-after soda blasting

[Wicked72]

I come to you guys for you wealth of knowledge and experience. I have done a bunch of paint jobs myself and I can spray a car great but I have never done the home work on different primers and paint combos. My grandfather did all that so I missed out a bit so i could use come help and heres what I got.

I am about to strip the car down to the metal so I am going to pick up a soda blaster and get messy. I was wondering what kind of primer I should/can apply after and if I can bondo to that bare surface after I soda blast or should I bondo after I primer? Also I have a gallon of Evertcoat Uro-fill acrylic urethane primer (high build) that I was going to use after. I could use some advice on this one, any suggestions are welcome. Thanks guys

[jpsycoboy5]

I am by no means qualified to answer this I've just read basically every thread about it the general consensus is epoxy primer, bondo, sealer, high build primer, sealer, paint in that order hope that helps

[Wicked72]

Ive never gone over an entire bare metal car before. normally I went over existing paint or primer. So I would bondo over paint then primer sealer..etc. I just want to do this car as good as possible. thanks for the input! I had been told a long time ago that there can be an issue with using either epoxy or etching primer after soda blasting. Anyone have info on that?

[Patronus]

some start with a sealer coat, then 2 coats primer, then body work...

[FLG]

Southern polyurethanes epoxy primer (exellent primer) body work on top of it.

[Charger-Bodie]

If you want to use Epoxy primer over soda blasted steel you will need to sand the metal for adhesion. The soda actually polishes the metal and the Primer will not stick with out sanding.

[Wicked72]

Ok Ill DA the body some after I blow the paint off and throw an epoxy primer on it then on to body work. Ill take a look into that epoxy primer as well. Thanks alot guys!

[jaak]

From what I understand, you have to neutralize the body after soda blasting, even Barry at Southern Polyurethane emphazies this on the tech sheet for his epoxy primer.... contact him before spraying his epoxy on soda blasted vehicles.

Southern Polyurethane Epoxy Primer tech sheet...
http://www.southernpolyurethanes.com/tech%20sheets%20new/2010revised/Expoxy_primer.pdf

I'm no expert, but I would find out for the primer you would be using,
Jason

[Wicked72]

YES! Thats what I heard about it, I totally couldn't think of it.Thanks for that info!

[elitecustombody]

Yep, neutralizing is a must after sodablasting, otherwise you'll have all your paint and bodywork coming off in sheets. After metal is clean, shoot few coats of good epoxy ,then filler followed by high-build primer and you know the rest.

[NGC414]

You might also want to note that the epoxy primer needs to be covered in a certain window of time or it needs to be rescuffed and re-epoxied. I shot my epoxy then followed with my 2k high build.
I did most of my body and filler work directly on the bare metal then shot the epoxy and 2k and started block sanding the car.
Im no expert, but got all my info from the experts on a autobody forum.

[FLG]

The thing with body work on bare metal is bondo breathes. Epoxy primer seals the surface and leaves an exellent surface for filler to adhere to.

[jaak]

The thing with body work on bare metal is bondo breathes. Epoxy primer seals the surface and leaves an exellent surface for filler to adhere to.

I agree, I like to 'sandwich' filler in between coats of epoxy.

Jason

[Wicked72]

How long can i leave epoxy primer sit on before I body filler and high build? Because Ill need time to go over the car with filler and I may not have time to throw another coat on after im done with filler for a little while.

[NGC414]

The thing with body work on bare metal is bondo breathes. Epoxy primer seals the surface and leaves an exellent surface for filler to adhere to.

I agree and thought the same thing, but when I posted the question on the auto body forums the majority of guys said to apply fillers directly on the metal. If the car was epoxied already they reccomended sanding off the opoxy in the area and applying the filler. I still think that is open to debate. I imagine its fine to put filler over epoxy as long as its within the set up time window. I ended up taking there advise since most guys on that site either own shops or are product distributers with 30 plus years experence. Here is one of the responces I got in reguards to epoxy primer and filler.:

"Sounds like there is some confusion. Epoxy's main claim to fame is it's adhesion. It acts like contact cement, gluing your primers and finish materials to the bare metal. It has what's called a re coat window. Just like contact cement, you shoot it on, wait for the solvents to evaporate, then shoot your next coat, usually your 2k high build primer. Again, just like contact cement, if you let it dry too long nothing will stick to it. Every epoxy has a different or specific time in which you can topcoat. The one I use is 3 days.

Once you have missed your re coat window you have a couple of options. Most manufactures recommend that you scuff the epoxy thoroughly, apply another coat of epoxy and then your next layer, now within the new re coat window. This provides that chemical bond that we talked about previously.

The other option is to sand thoroughly with the grit recommended by the manufacturer of the next product. IE, if you're going to apply a 2k primer and the manufacturer of that 2k says it needs a 180-220 grit substrate that's what you would sand your epoxy with then shoot your 2k directly onto that. This foregos the chemical bond and relies on a mechanical bond.

As to the filler question, there are a couple of different schools of thought. The epoxy manufacturers say it's okay to apply filler over their epoxy, but the filler manufacturer's want the filler on bare metal. If you're going to put filler over epoxy it would be advisable to do it within the re coat window. But that's not how I would do it.

I would hit only the areas I want to fill with 40-80 grit, do my filler work, scuff the whole thing, apply a coat of epoxy then my 2k high build.

To save time and money on materials read your tech sheets before you begin and follow your re coat times. Saves on elbow grease, sandpaper and epoxy.
"

[Troy]

Or you could work the metal until it's totally straight (no filler), then epoxy, then filler primer, then paint.

I am not a professional but I take an interest in these things and I have read both sides of the argument. People have had success doing it both ways. I personally would prefer to have epoxy against the metal purely for the rust prevention capability (most fillers absorb water). More importantly, I would concentrate more on doing things correctly down either path as being sloppy/haphazard with any procedure will likely ruin the end result. For example, don't stress about the order of things but then mix with the wrong ratio or in the wrong environment.

Troy

[Wicked72]

The filler holding moisture to bare metal is what I worry about, so really if you epoxy first then it just hold that moisture in the between the layers and wont rust. I think I may try to epoxy then filler where needed. However I am cutting out my driver quarter panel so i would Imagine Im going to have to run some filler with that. Also I have dents right in the center of my roof, any advice on how I can fix that being that its so flexible. I used a heat gun and a keyboard duster can to help pop some of it out but I didnt go crazy...

[Patronus]

If you're doing a qp you'll be using lead... Its pretty easy to work with and really cuts down on the filler. Im looking forward to more experience/projects with it.
http://www.eastwood.com/autobody/leading-body-solder.html

[Wicked72]

That looks awsome. I think I may look into it. But Im concerned about the heat needed to use it. I wonder if it will warp the panels bad

[Patronus]

theres some products that keep the heat localized. Some brush/wipe-on paste product. Its crazy the feather edge you get with lead, with todays high build primer you could fill in any finer filing marks, never sand it. The video the kit comes with has them doing some custom work like small inner radiuses, pretty cool.

[Wicked72]

I see there is a tub of some round blobs that you can put around the spot to keep the heat under control. And the fact that they have a lead free one looks even better and you can use a DA on it! A bit more expensive but it seems well worth it. I do not need any more health issues lol. Btw I gotta ask again. anyone have advice on fixing my roof dents with out cutting it off and welding a new one? maybe the lead will do the job?

[Wicked72]

How about the temp being 50degrees F out? how would that effect the paint. I figure it would take a lot longer to do it and I would have to be careful. what kind of issues would I run into at that temp? My brother inlaw just wrecked his car so Im about to get working on it very soon. I have to replace a quarter panel on it and a fender etc.. then going to primer and paint it.