went to a paint store today. they told me to use etching primer on the bare metal. first question is can i spray the bare metal with the primer and use the filler on top of it? second question is will the primer screw up the auto body shop will they need to sand it back down to bare metal? ;):beers:

Skip the etch primer is old outdated technology.

NO you can NOT apply filler over etch primer.

Use epoxy primer on bare metal, its a far superior product and you CAN apply filler on top of epoxy.

I disagree etch primer is not outdated, we give every metal car 1 coat of etch primer we use Glasurit products in the shop it is very translucent and then topcoat with epoxy primer which comes in grey-green, red oxide, white and black and they may be mixed together to make any color you like, then you can do plastic on top of the epoxy this is the ultimate protection but the epoxy will work just fine, in my shop we look for long lasting protection I get paid to do it once not when it comes back, but everyone has different opinions and that is fine. Good luck !

It depends on what brand epoxy your using. I have switched over
to Matrix and in their tech sheets for the best protection is their
etch followed by their epoxy.

Some epoxy brands don't want any etch under it. The supply house
or tech sheets will tell you.;)

Chuck

I agree with Thomas. I've also never found that I had to be in a hurry to get primer on bare steel. I had my El Camino blasted, inside and out. Right down to bare steel. Then I spent almost 2 months doing body work, before any primer was needed. I had no rust issues at all. After the plastic work was finished, I sprayed everything with 2 light coats of Sherwin-Williams etching primer. Then filler/sanding primer, for blocking. I like etch because it's thinner. Less build-up. There's enough paint with all the sanding primer, base, and clear. Thats just how I prefer to do it. It's always worked out well for me.

here's a shot, the day I did the etch.

http://www.chevelles.com/showroom/data/500/primer3.jpg

Skip the etch primer is old outdated technology.

NO you can NOT apply filler over etch primer.

Use epoxy primer on bare metal, its a far superior product and you CAN apply filler on top of epoxy.

Isn't epoxy much more toxic than etch primer? As in isocyanates? That might be more of a consideration to the hobbyist that doesn't have access to the proper safety equipment for spraying paint that is far more toxic than the alternative.

anybody use eastwood 2k epoxy primer in the spray can looks like the same stuff you would spray from a gun but in the can? just curious may try it on my quarters than finish with filler on top

Etch is nothing more than a high class laquer primer. Use epoxy if you want no problems with adhesion. You cant sand etch since its so thin. I also use glasurit and matrix and will not use etch, no way. Yes epoxy is a urethane based product and more toxic but isnt your base clear? If you arent using protection like a full suit and a fresh air respirator you dont need to do this stuff, imho. Eric is a seasoned veteran and take his advice wisely.

Epoxy does not have isocyanate in the activator.

Isn't epoxy much more toxic than etch primer? As in isocyanates? That might be more of a consideration to the hobbyist that doesn't have access to the proper safety equipment for spraying paint that is far more toxic than the alternative.


Don't be fooled into thinking lacquer based products are harmless.

There should be no alternative when it comes to your health,Id personally drive my chevelle into the crusher to get mine back, you only get 1 set of lungs!
No hobby is worth risking your life and health

Etching primer IS NOT a high class lacquer, it has anti-corrosive properties, has a hardner and reducer added to it. Some come transparent and some come where they are easy and quick to sand, why you would want to sand it you are looking for protection not flatness. 1-2 coats of etch then straight to epoxy primer 2 coats, bodywork, any sand throughs you may reapply the epoxy and then a good Hi-build 2K primer or spray-polyester. All of these products are dangerous to your health even spray cans, we spary all of our products in a Accudraft full downdraft heated spray booth and we also have a Accudraft full downdraft prepdeck, in New York if you are not using HVLP guns each non HVLP gun is a $1000.oo fine. The epoxy primer is great protection but the epoxy over the etch is the ultimate protection, like I stated above "you get paid to do the job not to repair the job".

This is a very long standing debate, etch vs epoxy.

Here are some facts:

1. A good etch is 2k, not glorified lacquer.

2. Etch is a part of every paint manufacturers lifetime warrantee, it can't be all that bad.

3. Some etches CAN'T be sanded, they are designed for a very specific application with a short recoat window and aren't very forgiving.

4. Some etches will soak up water like a sponge being they are NOT designed to be exposed.

5. Epoxies are a barrier, a shell that is MUCH more durable than etch.

6. Etches have acid in them, basically they are a sprayable metal conditioner. They ETCH into the metal.

7. Epoxy is a very sticky resin and STICKS to the metal very well.

8. Epoxy is VERY user friendly. Spray it, leave it, sand it apply filler over it, apply more epoxy or urethane primer, use it as a sealer, it is pretty universal.

9. The corrosion resistance provided by a quality etch UNDER the epoxy is hard to match.

10. The word "epoxy primer" and "etch" are technologies. The PRODUCTS that carry these technologies and words on the cans can be VERY different. One etch may not be very good and with the right epoxy primer could be skipped. While another epoxy primer is not very good and needs some etch primer under it to get full protection.

The one thing about etch is if you feel you haven't gotten all the rust out of the metal it is going to "convert" it somewhat with the acid.

But in most circomstances epoxy is sooooo user friendly it is the way to go in my opinion. You spray a part and set in in the back yard if you want to. If you epoxy it and let it set for a month, just scuff it and shoot some more or apply your filler over it. It is VERY user friendly.

It DOES NOT contain ISOs it isn't a urethane, it is an epoxy, two totally differnet animals. HOWEVER, I don't give a rats rear, PROTECT YOURSELF with EVERY product you spray.

JMO

Brian

Just like I said, just missing some fine tuning !

If you read the Matrix epoxy tech sheet for the best protection with their
epoxy they suggest their etch;)

Chuck

Don't be fooled into thinking lacquer based products are harmless.

There should be no alternative when it comes to your health,Id personally drive my chevelle into the crusher to get mine back, you only get 1 set of lungs!
No hobby is worth risking your life and health

I totally agree with you. My suggestion was that maybe there are safer (as in a respirator will cut it) products out there for hobbyists to use. I wasn't talking about not using anything, but it just isn't reasonable to think a hobbyist has a full body suit with some sort of fresh air source.

That being said, I didn't know that there were epoxy primers out there that are non-isocyanate; that's pretty cool, and I just might check them out and see if NAPA has anything in that range. Things have obviously changed in that vein of this hobby, and that's why it's great that guys like yourself, MartinSr, and others come on this board to set us "weeked warriors" straight :)

Brian....Is Etch a 2k product for real? I mean, could you spray etch on a piece of sheet etch WITHOUT the activator and have it dry like normal?


My understanding is that Etch is indeed just solvent base primer with an acid activator that makes gives it the etching action.

This debate is another example of how the Makers let us all down by not fully educating their people. I have been told two different things about the same product by two different Reps of the same Co.

I will be using Epoxy as there is no debate about Epoxy, only if Etch is as good as Epoxy. I think that should tip the scale.

When using epoxy on bare metal it's a good idea to scuff the metal to give it some "tooth" for the epoxy to grip. SPI (who makes an excellent epoxy primer BTW) recommends sanding the metal with 80 grit before priming.

When using epoxy on bare metal it's a good idea to scuff the metal to give it some "tooth" for the epoxy to grip. SPI (who makes an excellent epoxy primer BTW) recommends sanding the metal with 80 grit before priming.

One thing to remember, SPI doesn't have an etch in their line up! So, thougth the epoxy may be the cats meow, I don't know, never used it or tested it.

But when a company doesn't offer an etch, they are going to tell you etch is not needed or even inferior. It is after all about sales. :)

Brian

I totally agree with you. My suggestion was that maybe there are safer (as in a respirator will cut it) products out there for hobbyists to use. I wasn't talking about not using anything, but it just isn't reasonable to think a hobbyist has a full body suit with some sort of fresh air source.

That being said, I didn't know that there were epoxy primers out there that are non-isocyanate; that's pretty cool, and I just might check them out and see if NAPA has anything in that range. Things have obviously changed in that vein of this hobby, and that's why it's great that guys like yourself, MartinSr, and others come on this board to set us "weeked warriors" straight :)

On the 12 forums I visit I see a few questions about supplied air and it seems like some of the hobbists are using them. I'm also a hobbist and heres a picture of supplied air in action.

I use it for welding, grinding, blasting, painting, sanding, clean up, spraying my three dwarf apple trees.

If I even suspect theres any bad air, I put it on. I vacuumed my storage garage the other day, put the old supplied air on.



http://www.1969supersport.com/rest34.jpg

Man...That's quite the set up you have there! If I had a deal like that, I'd have the works too! That's nice.

Believe me..I TOTALLY understand the importance of being safe with paint and body. You can literally harm yourself for life with it. One of the reasons I used etch at one point was because the epoxy I wanted to use was extremely toxic and I flat out couldn't afford to spray it in the right way. All I could afford was the proper half mask and cartridge. That being said, it DOES look like etching primer still does have it's place, and since it isn't the most expensive stuff out there, it looks like the only thing you really lose by using it is time.

Man...That's quite the set up you have there! If I had a deal like that, I'd have the works too! That's nice.

Believe me..I TOTALLY understand the importance of being safe with paint and body. You can literally harm yourself for life with it. One of the reasons I used etch at one point was because the epoxy I wanted to use was extremely toxic and I flat out couldn't afford to spray it in the right way. All I could afford was the proper half mask and cartridge. That being said, it DOES look like etching primer still does have it's place, and since it isn't the most expensive stuff out there, it looks like the only thing you really lose by using it is time.

Thanks Buzz, heres a couple more pictures, I live in a raised ranch and its in the bottom level of an unused back bedroom, piped 7' underground out to the garage, that way I don't hear it running and the bride doesn't either in the house.

HOME (http://www.1969supersport.com/index.html)

http://www.1969supersport.com/grg026.jpg
Yeah, you're right more supplied air, we didn't need this to, but the bride left it so I'll put it up.
http://www.1969supersport.com/grg027.jpg
Supplied air pump in lower level closet in the house, I use the paper hood style, nice and light and cool.
http://www.1969supersport.com/grg028.jpg
Supplied air line going through the wall underground out to the shop
http://www.1969supersport.com/grg029.jpg

Rob, you always bring your "A" game !

Thanks, to Brian Martin for clarifying the value of the acid etching capabilities of Etch primer. I have been in the automotive paint business for 30 years and the last 16 with the largest coatings manufacturer in the world and would never strip a car to bare metal with using etch primer.
Does anyone remember the GM and Ford peelers in the 90's that body shops were over whelmed with the warranty work and some people decided to strip those to bare metal and epoxy primer over the metal only to fail again later in the form of corrosion on the metal and peeling.

Jeff

Rob, you always bring your "A" game !

Thats because I'm retired Thomas and have lots of free time.:) If I had to compete with you hard workin guys I couldn't cut it.:)

Thanks, to Brian Martin for clarifying the value of the acid etching capabilities of Etch primer. I have been in the automotive paint business for 30 years and the last 16 with the largest coatings manufacturer in the world and would never strip a car to bare metal with using etch primer.
Does anyone remember the GM and Ford peelers in the 90's that body shops were over whelmed with the warranty work and some people decided to strip those to bare metal and epoxy primer over the metal only to fail again later in the form of corrosion on the metal and peeling.

Jeff

Jeff, could you please explain this peeling in a little more detail, thanks.

Rob

Since epoxy primer has no phosphuric acid to bite into the metal it relies on mechanical adhesion only as in the sand scratches left from whatever grade paper is used. Without this acid etching capability any residue left on the metal can result in what looks like small bubbling in the paint surface over time. This leads to galvanic corrosion and ultimately an area for delamination to begin. You can at that point use a razor balde and remove the primer color and clear from the metal and you can see a grey almost powdery substance on the metal in the affected areas.

This was a common occurance in the 90s on vehicles that were stripped and then primed direct to metal with epoxy. This may not be as much of an issue in drier climates but in the deep south with high humidity the moisture in the air could attack the bare metal in the time frame between when you solvent wash the metal and begin piming it. The etch primer is an insurance policy against this and an easy way for you to not have to create extra work for your self down the road.

I also advocate finding the paint system you want to use and sticking with their full system in the case of some kind of issue you have someone to back up their products rather than a mulitude of vendors where they all point their fingers at the other. All MAJOR paint manufacturers offer their Product Data sheets and MSDS sheets online for your review.

As a testiment to the value of etching primer, I have witnessed commercial units that are repainted on a regular rotation and are stripped via media blasting. Even after media blasting you can see a slight yellow green coloration to the metal from the previously appiled etch primer. No non-acid based primer is going to bite like that.

Since epoxy primer has no phosphuric acid to bite into the metal it relies on mechanical adhesion only as in the sand scratches left from whatever grade paper is used. Without this acid etching capability any residue left on the metal can result in what looks like small bubbling in the paint surface over time. This leads to galvanic corrosion and ultimately an area for delamination to begin. You can at that point use a razor balde and remove the primer color and clear from the metal and you can see a grey almost powdery substance on the metal in the affected areas.

This was a common occurance in the 90s on vehicles that were stripped and then primed direct to metal with epoxy. This may not be as much of an issue in drier climates but in the deep south with high humidity the moisture in the air could attack the bare metal in the time frame between when you solvent wash the metal and begin piming it. The etch primer is an insurance policy against this and an easy way for you to not have to create extra work for your self down the road.

I also advocate finding the paint system you want to use and sticking with their full system in the case of some kind of issue you have someone to back up their products rather than a mulitude of vendors where they all point their fingers at the other. All MAJOR paint manufacturers offer their Product Data sheets and MSDS sheets online for your review.

As a testiment to the value of etching primer, I have witnessed commercial units that are repainted on a regular rotation and are stripped via media blasting. Even after media blasting you can see a slight yellow green coloration to the metal from the previously appiled etch primer. No non-acid based primer is going to bite like that.

Good explanation Jeff. Another question on the media used that you can still see the coloration, would this be walnut shells, I wouldn't think that sand blasting would leave any residue.

Since epoxy primer has no phosphuric acid to bite into the metal it relies on mechanical adhesion only as in the sand scratches left from whatever grade paper is used. Without this acid etching capability any residue left on the metal can result in what looks like small bubbling in the paint surface over time. This leads to galvanic corrosion and ultimately an area for delamination to begin. You can at that point use a razor balde and remove the primer color and clear from the metal and you can see a grey almost powdery substance on the metal in the affected areas.

This was a common occurance in the 90s on vehicles that were stripped and then primed direct to metal with epoxy. This may not be as much of an issue in drier climates but in the deep south with high humidity the moisture in the air could attack the bare metal in the time frame between when you solvent wash the metal and begin piming it. The etch primer is an insurance policy against this and an easy way for you to not have to create extra work for your self down the road.

I also advocate finding the paint system you want to use and sticking with their full system in the case of some kind of issue you have someone to back up their products rather than a mulitude of vendors where they all point their fingers at the other. All MAJOR paint manufacturers offer their Product Data sheets and MSDS sheets online for your review.

As a testiment to the value of etching primer, I have witnessed commercial units that are repainted on a regular rotation and are stripped via media blasting. Even after media blasting you can see a slight yellow green coloration to the metal from the previously appiled etch primer. No non-acid based primer is going to bite like that.



Impressive, very complete explanation. I do however have to critique one point. You said "when you solvent wash the metal and begin piming it".

I am sure most, if not all Epoxy makers will say NOT to solvent wash the metal before spraying Epoxy. Any contaminate at all will possibly effect the Adhesion of the Epoxy. This is usually the root cause of Epoxy failures. That is why most collision shops use the Etch, it is faster and more "mistake proof". It is fine for a daily driver, but the Classics are meant to be around a long time and need the Superior Epoxy. Let's not throw out the good stuff just because so many don't follow the P-Sheet!

Larry, there are some DTM epoxies (direct ot metal) but they are not designed for full panel strip scenarios. They are for certain amounts of bare metal only. If anyone is doing a full restoration the only best case scenario is clean bare metal, followed by etching primer with a 30 min or so flash ( depending on climate) and THEN application of Epoxy primer. Epoxy was not designed for direct to metal on fully stripped panels even under the best of cleanly circumstances. DTM epoxies were designed for new replacement panels in the collision business where you cut through the e coat primer etc. When you are doing restoration work why would anyone not use the best possible system to make sure their hard work is not in vain.

Rob, I am not sure on the media used but what I was referring is in fact a coloration of the metal not just a residue. Coca Cola is the company I was referring to on their over the road beverage trailers.

Jeff

It is hard to generalize what a proper procedure is when it comes to bare metal.Every paint manufactuer has there own way of doing things.What ppg recomends is very different than what akzo nobel(sikkens) would recomend etc.Some say etch then epoxy,some say just epoxy.My point is follow the paint manufacturers directions,they are the ones spending millions on a fool proof system.

This is a very long standing debate, etch vs epoxy.

Here are some facts:

1. A good etch is 2k, not glorified lacquer.

2. Etch is a part of every paint manufacturers lifetime warrantee, it can't be all that bad.

3. Some etches CAN'T be sanded, they are designed for a very specific application with a short recoat window and aren't very forgiving.

4. Some etches will soak up water like a sponge being they are NOT designed to be exposed.

5. Epoxies are a barrier, a shell that is MUCH more durable than etch.

6. Etches have acid in them, basically they are a sprayable metal conditioner. They ETCH into the metal.

7. Epoxy is a very sticky resin and STICKS to the metal very well.

8. Epoxy is VERY user friendly. Spray it, leave it, sand it apply filler over it, apply more epoxy or urethane primer, use it as a sealer, it is pretty universal.

9. The corrosion resistance provided by a quality etch UNDER the epoxy is hard to match.

10. The word "epoxy primer" and "etch" are technologies. The PRODUCTS that carry these technologies and words on the cans can be VERY different. One etch may not be very good and with the right epoxy primer could be skipped. While another epoxy primer is not very good and needs some etch primer under it to get full protection.

The one thing about etch is if you feel you haven't gotten all the rust out of the metal it is going to "convert" it somewhat with the acid.

But in most circomstances epoxy is sooooo user friendly it is the way to go in my opinion. You spray a part and set in in the back yard if you want to. If you epoxy it and let it set for a month, just scuff it and shoot some more or apply your filler over it. It is VERY user friendly.

It DOES NOT contain ISOs it isn't a urethane, it is an epoxy, two totally differnet animals. HOWEVER, I don't give a rats rear, PROTECT YOURSELF with EVERY product you spray.

JMO

Brian

Etching primer IS NOT a high class lacquer, it has anti-corrosive properties, has a hardner and reducer added to it. Some come transparent and some come where they are easy and quick to sand, why you would want to sand it you are looking for protection not flatness. 1-2 coats of etch then straight to epoxy primer 2 coats, bodywork, any sand throughs you may reapply the epoxy and then a good Hi-build 2K primer or spray-polyester. All of these products are dangerous to your health even spray cans, we spary all of our products in a Accudraft full downdraft heated spray booth and we also have a Accudraft full downdraft prepdeck, in New York if you are not using HVLP guns each non HVLP gun is a $1000.oo fine. The epoxy primer is great protection but the epoxy over the etch is the ultimate protection, like I stated above "you get paid to do the job not to repair the job".
Single part etch "is" a high class laquer product. The 2k stuff is better but i personally do not use the stuff because of adhesion reasons. I could get the etch to stay on body but the paint peeled on the etch. Now with that said There are many companies that do not suggest epoxy over etch. There are epoxies i do not like. PPG has an epoxy product that i hate. A laquer rag will break it down every time. Now i like there other stuff just not the epoxy. One "etch" i personally like and maybe love is Diamont. I do suggest it and it will not cause adhesion problems later. A rep for them said the acids will be present when flashed for an epoxy coat. Better adhesion. So to clarify if you use the etch in an aerosol can its junk to me.

Now here is some of thought on the whole. My family and teachers of the trade were very old school. I have seen jobs they did that involved etch and laquer. End result was beautiful. They however had a short life span because of the non-protection days. Yes non iso stuff will still kill you. I still like a laquer black paint job. That is i use single stage for my personal vehicles involving urethane because it can look like laquer when buffed.