[81Chevrolet]

Ok, I plan on swapping out my front end on my 81' stepside with an older pre 80' and need to repaint the truck since the nose won't match and the current paint is a quicky black respray that is chipping off.
My question is if I sand down the doors for example, can I just apply filler, then prime over? If so, what is the best primer to use to avoid potential rust issues? Thanks!

[boatbob2]

Hi,sand to bare metal,spray 2 (or 3) coats of 2K epoxy primer,bondo on TOP of primer. ALWAYS...

[mitmaks]

You can apply filler right over metal nowadays. Body fillers have gone up in quality since they came out and will stuck to pretty much anything as long as it's prepped/sanded.

[NEW INTERIORS]

Mr. bob.. You are right.. I ''NEVER'' put filler on bare metal.. I shoot epoxy primer first,,And most of the time I will put a 2K high build primer right on as soon as I can after the epoxy.. Then do my filler work.. This topic has been beaten to death so many times here.. Everyone has their own way.. I just don't like filler on bare metal..

[302 Z28]

Putting filler directly to bare metal is old school. The better adhesion is accomplished by first applying a good coat of epoxy primer then do filler on top of that. If you sand through to bare metal just apply another coat of epoxy primer then finish off with a quality 2K primer/surfacer.

Vince

[mitmaks]

http://www.evercoat.com/faq.aspx
Q. Can Evercoat fillers be applied over bare metal? Can they be applied over paint?
A. Our fillers are designed to work over bare, properly prepared substrates such as: steel, aluminum, galvanized, stainless steel, fiberglass, and SMC. Some people prefer applying an epoxy primer over bare substrates to enhance corrosion protection. Our products don’t need to be applied over an epoxy for corrosion protection as long as the bare surface area is clean and no surface rust or contamination is present. However, some auto manufacturers do require body technicians to coat the bare metal surface with an epoxy before applying fillers. If you are performing warranty work, you should consult the manufacturer of the automobile for the recommended procedure. Fillers and putties will normally work OK over properly sanded (80-180 grit) cured OEM paint. However, with so many different types of aftermarket paint available (lacquer, enamel, urethane, water-based). We recommend that all paint be removed where filler is to be applied.

[oldBodyman]

"My question is if I sand down the doors for example, can I just apply filler, then prime over? If so, what is the best primer to use to avoid potential rust issues? Thanks!"

Now I'll rain on everyone's parade:

It does not matter if you are applying primer or filler, first you have to heat the panel 20*F over room temperature to dry the water out of the pores of the metal. Primer and filler are petroleum base and float on top of the water.

Prove it to yourself.
Go out in the shop and dry any piece with air and a paper towel till DRY.
Now take a propane torch, fire it up and paint the flame over the panel. Start at the bottom and keep it moving, DO NOT over-heat anything.
Watch the water sweat out of the COMPLETELY DRY metal, EVERYTIME.

[NEW INTERIORS]

Originally Posted by mitmaks

http://www.evercoat.com/faq.aspx
Q. Can Evercoat fillers be applied over bare metal? Can they be applied over paint?
A. Our fillers are designed to work over bare, properly prepared substrates such as: steel, aluminum, galvanized, stainless steel, fiberglass, and SMC.

You are right it can be done.. But some of us been doing this for way too long to know what work's and what should and shouldn't be done.. I will stand by what I have learned over the ''years of doing custom cars.. you can bring a horse to water, But you can't make him drink... All we do here is post first hand,, and hands on ''EVERYDAY''.. Go ahead and keep putting your filler on your bare metal.. Good luck.. This isn't even worth it..

[jeremyb]

Filler over clean bare metal is common practice in collision work, and IMO that's the only reason why evercoat states that. I never put filler over a whole panel that is bare metal. It's common practice in restoration work to go over epoxy. Fillers have come a long way in the past 10-20 years.

[atichargr]

I shot a couple coats of SPI epoxy over the metal, and in some spots filler went right on the metal after prep and degreaser... I have had now problems... I also used no high build primers... just the SPI sanded easy , and if you need to seal you can reduce and use as a sealer, but the SPI should be sufficient. hope that helps, by the way I am no expert by any means but I did learn from one!

[NEW INTERIORS]

Originally Posted by jeremyb

Filler over clean bare metal is common practice in collision work, and IMO that's the only reason why evercoat states that. I never put filler over a whole panel that is bare metal. It's common practice in restoration work to go over epoxy. Fillers have come a long way in the past 10-20 years.

Collision work, And Restoration work,, is two different things in my book.. Most people doing Collision work can care less if your car rot's out in five year's are not.. And do take the easy way out most of the time.. In and out as fast as we can..

[MARTINSR]

We have beat this to death and every time it comes up people make this mile difference between applying filler over bare metal and epoxy primer. People make statements that would lead the unknowing into believing that on a scale of 1-100 putting filler on bare metal is at 2.5 along with painting without washing the car and epoxy over the bare metal at 100 as the ONLY way.

That is HOGWASH, WAY, WAY, WAY more cars are repaired across America with filler over bare metal than over epoxy. There is realistically probably, LITERALLY 10 million to one repairs being done with filler over bare metal as opposed to epoxy.

That doesn't make it better but it sure shows that your car isn't going to rust away before your next birthday if you do like a lot of people express.

I have talked to the Evercoat techs and R&D dept about this.

There are WAY more variables than people think about.

1. They can't say "use epoxy" every time because of all the different "epoxies" and what some people CALL "epoxy". I am still amazed at the "pros" who don't know the difference between an epoxy and a urethane!!!!! I have spoken with "pros" who are doing this stuff every day who when told to apply an epoxy walk over and grab a urethane primer! How about different quality epoxies? Evercoat can't say "use an epoxy" without a brand name and part number. If they just say "use an epoxy" someone will grab some crap cheapo epoxy made in China and it will fail and Evercoat will be paying out a warranty. They can't put a brand name and number because that would alienate all the stores who carry other paint lines from their distribution. So they have to walk a thin line with that.

2. All "bare metal" isn't created equal. What is "bare metal", for the last number of decades EVERY CAR made be it American, Japanese or European is totally coated in Zinc. Every single piece of the car is galvanized. So, what exactly is "bare metal", maybe when a guy takes a grinder to strip paint like in 1970 he strips it all off. But in todays world in the collision industry if you remove the paint properly, leaving the zinc on the metal and then use the proper filler and seal it under a urethane surfacing primer your filler isn't going to fall off from rust for God's sake.

I have cars that I painted in the seventies with filler over bare metal and then primed in lacquer primer and paint that are still looking good. Hell, I have stuff that sits out my back yard that I did decades ago that is still sitting there with the filler not falling off.

NOW, today with what we know, damn tootin applying epoxy is the way to go. It is WAY better, as long as we are talking a quality epoxy, it is WAY, WAY WAY better than applying it over bare metal on your restoration. But if you happened to have done some without it, it isn't the end of the world. It is done EVERYDAY on hundreds of thousands of cars across America. Because epoxy is WAY better doesn't make it being done without it hack or junk or anything. It is just stepping it up big time to use the epoxy.

Brian

[mitmaks]

Originally Posted by oldBodyman

" Most people doing Collision work can care less if your car rot's out in five year's are not."

Exactly what kind of crack are you smoking on?

Every bodyshop I know of extends a LIFETIME warranty on ALL of their work.

I would have to agree. Most reputable shops in area guarantee their work.

[lets cut it up]

Well, I have been sitting back reading all this stuff and I feel I will chime in this time. I don't come here very often anymore because of all of the bickering,BUT, I thought because of my background I would try to do my best to tell what I think is the way to do filler work.
I have over 20 years in the collision industry and more than that in the restoration side of things(I do both kinds of work) In no way can collision work be compared to or even put in the same class with restoration work. Collision work is done as fast as possible with speed and quality as the goal. A lifetime ownership warranty was always given. The restoration side of things is not based on speed but quality mostly. I wont go into the different stuff done like rates, rust removal and such that is another whole thread.
It is not cost effective to do body work over epoxy in a collision setting. Putting filler over properly prepared bare metal is just fine as long as it is primed the same day in my opinion. A collision customer wants his or her car back yesterday and does not want to have to wait any longer than they have to for their vehicle. Filler over metal will last a very long time if done PROPERLY.
On a restoration, where the car is going to be open bare metal for a long time epoxy is a must to prevent rust on the metal. All of the cars I do that fit the restoration definition get epoxy on the metal before body work every time. On collision work , its filler over PROPERLY prepare bare metal. The reason that rust forms under filler on the metal is because it was left exposed to long to the air and moisture.
Never put filler over self etch, It will have poor adhesion and may peel off. I know this from experience.
I know this is my opinion and I am sure other people will feel differently about this but this is how I do things, And have made living for a long time doing it. If I have forgot something...sorry I have not had my coffee yet this morning. Tim

[lilgreenjeepyj]

Wow, not to open a can, but what about those of us not in a restoration or collision circumstance? I just want my car straight, but can't spray epoxy at the moment due to where Im located. I would love to be able to setup a gun and mix 2k primer, but that isn't an option at the moment, and Id rather learn/do the work myself than take it to a shop.