I have shot gallons and gallons of etch primer including Variprime. Most etches have strict warnings about applying filler OVER it. And as I remember Variprime tech sheets say DO NOT APPLY IT OVER FILLE. HOWEVER, the Sherwin Williams etch primer that is similar to Variprime there are recommendations for applying it over "cured" plastic body filler. "Cured" being at least 12 hours old.

Now, I know you are not "suppose to" apply filler over etch, but if you can apply etch "cured" filler, why can't you apply filler over flashed etch (acid has left). I have met someone who has been doing motorcycle frames for years where he etched them then applied filler, never had a problem. Not that you should do this, but it appears it isn't the end of the world if you did.


I say, scuff it with a red scuff pad and apply the epoxy (as long as there is a recommendation to do so with the epoxy you are shooting). Then apply any filler needed and a urethane primer over that for surfacing.

Brian

 

Not to contradict you Brian, but I remember some epoxies specifically recommending that self-etching primer NOT be used underneath them. I could be wrong, but it's worth investigating. I don't know if extended flash times remove this prohibition or not, though. Hmm.

Evercoat's G2 is recommended for applying over acid-etch primers, you may want to look into it. I've used it, and it seems to stick really good, as good as anything I've used, and filler application is highly compatible with polyester primer, though sanding will be necessary.

 

I say, scuff it with a red scuff pad and apply the epoxy (as long as there is a recommendation to do so with the epoxy you are shooting). Then apply any filler needed and a urethane primer over that for surfacing.

Brian

That is why I said as long as there is a recommendation. But there is nothing wrong with driving it home, I should have made that much more clear.

Brian

 

Well, in tech school in early 90's I remember that Icar was saying metal prep the baremetal or use a self etch primer, then epoxy, then urethane for fill. Most people were applying filler right over bare ground metal, but then started switching to applying it over the epoxy. Definately enough to keep up on with between different companys products. Most of the products and names back then are still around, and lot has stayed the same, but always some things being changed or replaced. At one time everyone was applying lacquer primer right over baremetal, and that was okay (okay I know, better ways of doing things were developed). You really have to study the product sheets before you jump into anything, even products you have used often, one day they can up and change it on you. I suppose could always grind where it needs fill then prime, but I will just make sure that the epoxy says etch is acceptable to apply it over. Dupont is about the only one that recommends etch so much, what is duponts epoxy primer? I can't remember if I seen epoxy on the list of primers to use over it when I looked at the sheet. I'll also think about polyester primer crash. Then you wouldn't really need epoxy I don't imagine, since it will have good fill and also can use the bondo over it. Don't remember if I ever even used it or not. But how much time till you can sand it to apply your filler?

 

I wouldn't put bodyfiller over that variprime, bodyfiller will melt that variprime. For the best answer to these questions I'd ask a DuPont paint rep who has probably seen this product used and abused in just about every way possible. I agree you could spray some Featherfill G2 over it but be prepared for some really slow dry times, I've tried G2 over self etch and was less than satisfied. Solvent from the G2 goes into the self etch and takes a good long time for all to come back out. My gut feeling is that you would be fine to sand it down with 180 and spray two good coats of epoxy and let it fully cure, then come back and scuff it for filler work. Ket words: epoxy/fully cured. If you didn't let the epoxy completely cure then your solvents from any filler work would go through and wet the variprime making a mess. Whichever way you do it plan on spending more than a day IMO. It probably wouldn't take long to sand the Variprime off, or you could sand down the filler areas and do your filler over bare metal. Variprime sure has been around for a long time... Bob

 

That is why I said as long as there is a recommendation. But there is nothing wrong with driving it home, I should have made that much more clear.

Brian

Well gee, if I would bother to READ!!! :embarrass

 

Kenneth,

I'm very familiar with the Variprime as years ago I made an acid etch and it was a cross between Etch-loc and Variprime.

The answer to your question is simple.
NEVER.

Acid etch, I don't care who's it is is nothing more than a "hybrid Lacquer"
They can call it all the names they want but a duck is a duck.

 

thanks guys. That was my gut feeling, the acid etch on there would be a problem with the time. Dawned on me today, duh, they use imron at work and asked one of the painters if they used variprime at all. He said we are suppose to, ha ha. He too said not to put bodyfiller over it. But thinking back at two different industrial jobs, not dupont paint though. One place we didn't do mud work on the parts, but they were wash primed, let sit a half hour, epoxy primed then painted all in one day. Another place we used an etch on sanded bare aluminum, followed by I want to say it was urethane primer, been awhile, don't remember what it was exactly, some generic company though. Then the next day bodywork was done over the primer with epoxy filler, and after that it was primed more. I am pretty sure I've used variprime at times at one of my early jobs that sprayed chromabase, but can't remember exactly what was done after it and time frames, but I know we didn't apply bodyfiller over it. Think it was ground, bodywork done and the variprime was shot on bare, but just to where there was filler. I've shot epoxy on baremetal and applyed filler over this without letting the epoxy fully cure, and no problems, but never had etch as a base when doing it. I don't really want to risk something messing up. but really wouldn't be able to let epoxy sit a few days to fully cure because like said before it over 2 hours away, and only have a weekend if that. Guess have some thinking to do, If he doesn't want to let the epoxy sit, may just sand it off where doing body work, and when done get the car in epoxy primer, then it can sit in that, and be scuffed later for urethane primer and blocking out. Thanks again for all the responses.

 

I wouldnt do it. The problem i see is etch prime is not catalyzed. You can wipe it with thinner and it will come off. Epoxy and urethane is catalyzed which makes it stable enough to put filler over. You may not have a problem but on a resto job i wouldnt chance it.If it was on the rocker of an Accord maybe. But id sure hate to have it go bad and have to redo the whole car.

 

I'm a DuPont rep and as Martin sr said no you cannot apply body filler over etch, acids and polyesters can never be together without have a coheasion failure ( seperating of layers) the best way would be Metal loc 250S followed by a good epoxy like corlar 934 or 2540. Also, etch, at least DuPont is NOT a hybrid laquer, whatever that is, etch is vinyl resin supporting an acid.
Frank

 

Also, etch, at least DuPont is NOT a hybrid lacquer, whatever that is, etch is vinyl resin supporting an acid.
Frank[/QUOTE]

Vinyl acetate?
Many chemical names for each chemical.
MSDS sheets are filled with them to throw people off.

If its not a lacquer, is it air dried enamel? Moisture cured urethane?
UV cured?
Its something with out a catalyst.

Time to call your chemist at Dupont and bone up on the facts.
I don't believe your a rep for Dupont at all.
For that one post on the other forum you did not give a state, this time you did so it would be easy to find out.

I read your post a while back on another forum quoiting tech sheets on Vari prime and stating "how epoxy bonds would be way to complicated to explain".

Also it does not support an acid, the acid is in the reducer that is why that part is in a non-metal can.

 

Yeah, I have to tell you Frank, off the record the R&D department told me the etch was "lacquer based". Now being I am not a chemist I have no idea of what that really means. Could it be like a Corvette is "just a Chevy", I don't know. I personally have had great success with etch primers.

And I was told the same thing about applying a polyester product like polyester primer over etch was a no no because the "polyester resins don't like the acid". Well, I was told that, it is in BOLD PRINT in the tech sheets for the S-W polyester primer (relabeled buy out) DO NOT APPLY OVER ACID ECTH PRIMERS. I was told over and over by the tech dept. how critical this was.

Then we started carrying another polyester primer (another company relabeled, different than the first one) and low and behold there in the tech sheets a recommendation to spray it over an etch primer "for added adhesion and corrosion resistance".

Evercoats "G II" Featherfill have a recommendation for application over an etch for instance.

Like I said, S-W etch (one of them) has a recommendation to spray it over "cured" polyester body filler. While, as I remember DuPont has a warning not to with Variprime. I don't think it is an issue other than a cover your ars issue. S-W is going out on a limb with the recommendation knowing full well some knucklehead is going to spray it over an hour old polyester filler and the uncured resin is attacked by the acid. Now,knowing how conservative S-W, I am surprised while DuPont would really protect themselves when they are a way more liberal company who takes more chances (I mean that as a compliment being they get product to the street and beat the compitition).

But if you CAN apply an etch over a "cured" filler, then why couldn't you apply the filler over a cured and flashed etch? I am just asking the question. I am not saying one should, I am just posing the question.

Brian

 

Beleive whatever you like, I don't remember you mentioning your credentials? It's maniacs like you that ruin these forums for others. Please don't respond to this post as I have no intention to debate you, I learned long ago that you can't argue with an idiot.
Feel free to check up on me.

 

My last post was directed to Barry NOT martinSR

 

Like I said, S-W etch (one of them) has a recommendation to spray it over "cured" polyester body filler. While, as I remember DuPont has a warning not to with Variprime. I don't think it is an issue other than a cover your ars issue. S-W is going out on a limb with the recommendation knowing full well some knucklehead is going to spray it over an hour old polyester filler and the uncured resin is attacked by the acid. Now,knowing how conservative S-W, I am surprised while DuPont would really protect themselves when they are a way more liberal company who takes more chances (I mean that as a compliment being they get product to the street and beat the compitition).



Brian

I think you're right about Dupont recomending not putting variprime over fillers but in one of the Dupont shops I worked in this was done on a regular basis without any problems. One thing for sure using variprime- you definately need to seal it with something before you apply BC or you're opening the door for delamination down the road. Variprime sucks up solvent just like old lacquer primer then later releases it seperating the clear from the base.

 

Yeah Bob, I too have used it over filler just like the S-W product. From reading and talking to Barry, I don't feel comfortable as I did using it. I would now say, epoxy. But I have to tell you, I did see a BIG differece when I started using etch over none at all with urethane primer over bare metal. When I sanded the urethane with say, 120, when I hit the metal there would be scratches, you could see where the metal was bare and the sides of the scratches looked very defined. They looked like little minature versions of a keyed car where the primer was breaking off the metal at the scratch. When I started using an etch I never saw that, the primer looked like it was adhering MUCH better.

I sold THOUSANDS of gallons of etch when I was a rep. It was without a doubt the biggest seller of any paint or primer part number by far. I had a few customers who sprayed it on bare metal and then a SS urethane over it, worked like a champ. Had one of my fellow reps who had a huge account with a company making service boxes for pickups. They sprayed thousands upon thousands of gallons of the stuff.

But you won't find me recommending it anymore, I just don't feel as confident about it as I once did.

Brian

 

I'd never disagree on the adhesion etch primer provides (it bites) but a good epoxy adheres just fine if the substrate is properly prepped, offers more durability, solvent resistance, and is compatible with more products. Epoxy just works better IMO.

OH no! not another epoxy vs. etch debate...

 

Honestly this is one of those deals that gives me nite sweats when painters mix various products..But given that and the fact that this project has been apparently setting around for a long time the variprime is quite likely really well cured by now and waaay outside its recoat window ..Sooo give it a good sanding and proceed with what ever you are used to using and are comfortable with..

Once it is sanded ...knock on wood ..kiss the lucky rabbits foot..run on a seal coat and go for it..hopefully there is not much bondo to be done or if there is a thin coat will do whatcha gotta do..that or a high build sanding primer..

Good luck send pics when done..

OMT

 

you definately need to seal it with something before you apply BC or you're opening the door for delamination down the road.

What would you recommend Bob for this?

Epoxy? Or just a good sealer?

While we are on this etch primer,
I know most of what little I've used has the reducer in a plastic gallon jug,but I got a freebie can of CrossFire etch and the reducer came in a METAL gallon can. Is this a true etch as the reducer has phosporic acid (?) listed on the reducer contents.

 

While we are on this etch primer,
I know most of what little I've used has the reducer in a plastic gallon jug,but I got a freebie can of CrossFire etch and the reducer came in a METAL gallon can. Is this a true etch as the reducer has phosporic acid (?) listed on the reducer contents.[/QUOTE]

Yes there is a small amount of acid in the reducer part, that is why they normally come in glass or plastic containers.

Its possible they are buying a Lined can for the product.
With sales of this type product going down every year its possible that paying more for a lined can is cheaper than ordering a bunch of plastic jugs.
It seems to me another company started doing the same thing but just can't think of what one right now. Old age.

 

Crossfire/ Econobody etching reducer is the only crossfire component (aside from a 5 gallon jug of thinner) that I have used that comes with a plastic spout on the can. All other crossfire reducers/ thinnners/ hardeners have metal spouts. Not sure if the can lining is different. OH, never mind. I just remembered, You can't see this.