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ETCHING PRIMER ON SAND BLASTED METAL??

Posted By: Moparnut426

ETCHING PRIMER ON SAND BLASTED METAL?? - 05/05/10 07:52 PM

Is it ok to use the acid etching primer on blasted bare metal? I have never heard this, and dont understand the difference in blasted metal, or ground on metal?

Just asking to clear up my head.

Kasey
Posted By: hotairballoonpilot

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/05/10 08:00 PM

NO!!!! Acid sits in the pores and then screws up the paint.

corey
Posted By: sixpackbee

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/05/10 08:36 PM

You DA it or hand sand it a bit to get the sand out of the metal that embeds itself there. After that a good cleaning with DA330 other type of wipe solvent then you are good to go.
Posted By: Moparnut426

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/05/10 10:09 PM

I have never heardthat before.

Learn something new every day...

Kasey
Posted By: 375inStroke

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/05/10 10:51 PM

Why etch? You won't gain anything. Always read the tech sheets.
Posted By: Challenger 1

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 12:55 AM

Quote:

Is it ok to use the acid etching primer on blasted bare metal? I have never heard this, and dont understand the difference in blasted metal, or ground on metal?

Just asking to clear up my head.

Kasey





wow, Yes it's ok to use etch primer first on bare metal, it's recomended.

First off I don't see any difference between blasted and sanded ground metal. it get's treated the same imo.

I have done lots of sand/media blasting and paint work over the years(25).

As soon as I'm done blasting when I have bare white metal before I even touch it, I paint it. The first coat of paint is etching primer. 1 light coat, it's translucent and provides a chemical advantage for top coats. Then within 1 hour or so the second and third coats are epoxy primer. Then at that point within 24 hours if I can, I apply the top coat without any scuffing or sanding. Like say the bottem of your car or inside the car. Wet on wet is best for best results.

Some people will say epoxy directly on bare blasted metal but using etch primer first is better.

Once your metal is blasted bare, you want to coat it fast and definety don't touch it or pre treat with anything, as it as clean as can be after blasting.

I've done entire cars and trucks with the above procedure and still own some of the trucks that I painted 15 years ago. I know what holds up.
Got lot's of pictures of my work.

My 71 has etch primer all over it.
Posted By: elitecustombody

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 01:21 AM

Quote:

Quote:

Is it ok to use the acid etching primer on blasted bare metal? I have never heard this, and dont understand the difference in blasted metal, or ground on metal?

Just asking to clear up my head.

Kasey





wow, Yes it's ok to use etch primer first on bare metal, it's recomended.

First off I don't see any difference between blasted and sanded ground metal. it get's treated the same imo.

I have done lots of sand/media blasting and paint work over the years(25).

As soon as I'm done blasting when I have bare white metal before I even touch it, I paint it. The first coat of paint is etching primer. 1 light coat, it's translucent and provides a chemical advantage for top coats. Then within 1 hour or so the second and third coats are epoxy primer. Then at that point within 24 hours if I can, I apply the top coat without any scuffing or sanding. Like say the bottem of your car or inside the car. Wet on wet is best for best results.

Some people will say epoxy directly on bare blasted metal but using etch primer first is better.

Once your metal is blasted bare, you want to coat it fast and definety don't touch it or pre treat with anything, as it as clean as can be after blasting.

I've done entire cars and trucks with the above procedure and still own some of the trucks that I painted 15 years ago. I know what holds up.
Got lot's of pictures of my work.

My 71 has etch primer all over it.




I agree with every word to the letter .

It's funny when clueless people would give advice on something they have no experience with.

Etching primer is always recommended to be applied before any other primer for ultimate adhesion,after etching primer any primer system can be used,epoxy or 2k primer-surfacer or sealer.As always, read tech sheets before use.
Posted By: Mr T2U

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 01:23 AM

PPG certified painter here.
it's not recommended to acid etch prime sand blasted metal. because the acid flows into the blasted craters and will bleed into the top coats.

with that said i etch prime sand blasted metal all of the time. just remember not to top coat it with anything for a few days and you will be fine.
Posted By: vancamp

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 01:46 AM

PPg's tech sheets says not to etch over blasted metal and do not use epoxy over etch primer. the attatchment is a tech sheet on their dpx etch primer

Attached File
Posted By: Moparnut426

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 01:47 AM



Kasey




I honestly thought the exact same thing you wrote. what is the difference if there is bead pit versus 80 grit channels? I dont think any really, both gives tooth, thats about it. My cuda project, my demon, the 65HPP d100 we did, and the charger have all been etch/acid primed from bare metal, nothing lifting off yet. I do it the same way a very light translucent coat.

I guess I just didnt go to college for body work so I couldnt say either way, It just didnt make any sence to me.

Kasey











wow, Yes it's ok to use etch primer first on bare metal, it's recomended.

First off I don't see any difference between blasted and sanded ground metal. it get's treated the same imo.

I have done lots of sand/media blasting and paint work over the years(25).

As soon as I'm done blasting when I have bare white metal before I even touch it, I paint it. The first coat of paint is etching primer. 1 light coat, it's translucent and provides a chemical advantage for top coats. Then within 1 hour or so the second and third coats are epoxy primer. Then at that point within 24 hours if I can, I apply the top coat without any scuffing or sanding. Like say the bottem of your car or inside the car. Wet on wet is best for best results.

Some people will say epoxy directly on bare blasted metal but using etch primer first is better.

Once your metal is blasted bare, you want to coat it fast and definety don't touch it or pre treat with anything, as it as clean as can be after blasting.

I've done entire cars and trucks with the above procedure and still own some of the trucks that I painted 15 years ago. I know what holds up.
Got lot's of pictures of my work.

My 71 has etch primer all over it.


Posted By: Challenger 1

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 01:47 AM

Elitecustombody

I've rebuilt and maintain tank trucks. Which includes complete paint jobs. I've sprayed gallons of etch, epoxy and old fashsioned enamel with a paint pot, hose and spray gun.

etch primer, epoxy primer and 3 colors of enamel with hardner makes for 3 long days.Many rolls of tape, fine line and masking tape. But all the paint work get's done with no sanding or scuffing which is what adds to the labor bill. Helps to avoid it by recoating within the recoat window.
Posted By: MonGoo$e

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 01:52 AM

I think the knowledgeable paint guys need to have treads like these saved in the tech section or something, I recall a year ago I put etch on my Duster after sanding it bare, put a 2k on it, and the majority told me to forget that stuff, sand it off and put epoxy on the bare. After my wondering why the etch even existed in the first place if no one was to use it, I just decided to hold off. I'll be painting car in a month or so and its say this whole time in etch/2k/sealer

This thread helped me. thanks.
Posted By: Challenger 1

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 02:01 AM

Quote:

PPg's tech sheets says not to etch over blasted metal and do not use epoxy over etch primer. the attatchment is a tech sheet on their dpx etch primer




That's not the etch primer paint I use, PPG I thinks it's DX1791 wash primer or something like that or I use Dupont Variprime which is the same thing, a little cheaper.

But your right, that etch primer advises against it, but wrong etch primer for blasted cars.
Posted By: DAYCLONA

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 02:19 AM

Quote:

Quote:

Quote:

Is it ok to use the acid etching primer on blasted bare metal? I have never heard this, and dont understand the difference in blasted metal, or ground on metal?

Just asking to clear up my head.

Kasey





wow, Yes it's ok to use etch primer first on bare metal, it's recomended.

First off I don't see any difference between blasted and sanded ground metal. it get's treated the same imo.

I have done lots of sand/media blasting and paint work over the years(25).

As soon as I'm done blasting when I have bare white metal before I even touch it, I paint it. The first coat of paint is etching primer. 1 light coat, it's translucent and provides a chemical advantage for top coats. Then within 1 hour or so the second and third coats are epoxy primer. Then at that point within 24 hours if I can, I apply the top coat without any scuffing or sanding. Like say the bottem of your car or inside the car. Wet on wet is best for best results.

Some people will say epoxy directly on bare blasted metal but using etch primer first is better.

Once your metal is blasted bare, you want to coat it fast and definety don't touch it or pre treat with anything, as it as clean as can be after blasting.

I've done entire cars and trucks with the above procedure and still own some of the trucks that I painted 15 years ago. I know what holds up.
Got lot's of pictures of my work.

My 71 has etch primer all over it.




I agree with every word to the letter .

It's funny when clueless people would give advice on something they have no experience with.

Etching primer is always recommended to be applied before any other primer for ultimate adhesion,after etching primer any primer system can be used,epoxy or 2k primer-surfacer or sealer.As always, read tech sheets before use.







...with you guys, I've been painting cars, bikes, trucks, speed boats for over 30 years now,...and I basically tried every manufacturers product or "system" over the decades,...I'm generally a consumer of Dupont products, I do prefere the high end componets,....but the base is always the same, blasted or sanded metal coated immediately with Dupont Vari-Prime, 1 flash coat followed by a good med 2nd coat, allow to dry 1-2 days, followed by a Dupont 2K primer surfacer coat, then blocked, reprimed, Euro-soft putty for small defects/shallow lows,...I generally have all the metal work, with bondo to an extreme minimum done before I apply the Etch primer,....I feel that after etching/2K priming the car should be in just the blocking stage, all major bodywork done prior to etch priming,...If you choose to use the DuPont line, AVOID the Dupont/NASON crap,...pure junk....Dupont Vari-Prime, 2K primer, and a BC/CC in Chroma Premier will result in a show quality finish that will last for years

Mike

Attached picture 5966398-mellon1234.jpg
Posted By: 375inStroke

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 03:15 AM

DPX170 and 171 say not to spray over media blasted metal, and not to topcoat with epoxy. DX1791 is not to be used over media blasted metal, either, but may be topcoated with epoxy. Why would one want to spend the money on quality products, and go against the advisement of the manufacturer? They put the resources into testing their products, but you think you know better? I'm not saying you are wrong, but I would think the manufacturer has good reasons for their recommendations, and I don't have the resources or knowledge to be able to disagree with them. Does anyone know why they recommend the opposite of what others here are doing? This is what PPG says about DP40 Epoxy Primer: Film build of 1.2–1.5 mils of DPLF is required or the surface must be treated with Metal Cleaner/Conditioner or coated with DX 1791/1792 [self etch/wash primer]. You can't do both, though. I don't have any recent experience with automotive coatings. Many here have experience, and apparently haven't had problems going against the recommendations of the manufacturers, but without knowing the reasons for their recommendations, and under what conditions you could have success deviating from them, I wouldn't.
Posted By: elitecustombody

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 04:04 AM

there are other brands besides PPG and DuPont
Posted By: Kern Dog

Re: ETCHING PRIMER ON SAND BLASTED METAL?? - 05/06/10 06:35 AM

Heres another quandry.... All PPG and Sikkens literature state that you MUST use their catalyst and reducer. I am sure that they are trying to keep the money stream flowing in their direction. I am also sure that all other higher line products want you to use their complete line of products as well. My point is: I have mixed brands several times and have yet to have any adverse affects. I dont think that I have been lucky either. I have never used Lacquer, everything has been medium to high quality enamel or urethane. I have mixed small amounts of base coat in with single stage to extend out the mix, and I never had any problems. The paint supply guys I have spoken with play the same tune as the Tech sheets, but they must know that you can use Omni reducer with PPG paint or Nason clear with PPG catalyst... and so on. I use the matching products as recommended but always have stuff left over. I have tested the interspecies mixing on spare fenders, hoods and whole cars without any wrinkling or lifting of the paint. Anyone else?
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