I also need to add this: Someone can show up here and render my post incorrect, because anti corrosion painting is so complex, and there are no absolute answers. No one knows not even Du Pont what is the best anti corrosion solution. They have something new called conductive polymers. It is like a pre treatment mixed into a primer, and then you epoxy over it and it has shown to outperform Zinc Chromate of the old era. So as you can see direct to metal primer and epoxy over it is a valid solution. Never ending ****, because one solution can be missing what the other has and vice verse. You have to do what you do best and stick to that.

First a Zinc rich epoxy's are used, Yes depends on application and use.

I for one have NEVER heard of any Etching primer epoxy or other wise that does not have Acid in it. Their is a Huge difference between Etching primers and Zinc rich Primers. Do not confuse the two and do not be confused by cleaver advertising.

Dupont Axalta and PPG do have a "Cold Galvanizing" Metal treatment product that produces a uniform zinc phosphate coating on steel and galvanized steel
surfaces. The zinc phosphate coating formed on the metal surface offers the best possible
substrate for paint system adhesion and corrosion resistance!!!!!!
I my self treat all my Restorations with these products BEFORE 2K Epoxy.

Check out this restoration guide made by PPG
https://assets-eu-01.kc-usercontent.com ... -guide.pdf

Pay particular attention to page 33 step #2 !!!!!!

I have used the products Made by Dupont Axalta and PPG they are all 3 the same.

5717s & 5718s first made by Dupont now made by Axalta are fantastic! they must be used together,

DSX579 / SX520 made by PPG is also great! and again are designed to be used together.

5717S cleans and etches the metal after rinsing the metal does flash rust this is good.

5718S protects the metal putting Zinc Phosphate on the metal This pic shows the metal after rinsing and its is drying in 110 degree weather note the meat is both shown wet and drying with NO flash rusting! note the water under the body.

After its dry you just spray it with Epoxy OR Zinc Epoxy OR you could just prime it and paint it

Doright wrote:After its dry you just spray it with Epoxy OR Zinc Epoxy OR you could just prime it and paint it

You are not correct, and I was trying to write this all out in a guide here but I'm bad at communicating, so it's hard to explain a super difficult subject for me, especially when people create confusion.

Doright wrote:I for one have NEVER heard of any Etching primer epoxy or other wise that does not have Acid in it.

Anti Corrosion pigments do not have to be acidic. And often they are not, but they still either prevent corrosion, or simply etch well. It's all from pigment character. Titanium dioxide used everywhere does not have to be acidic in paint at all, but it can be. Etch means glue, not acid.

You personally would learn the most by READING, and not by "strongly believing" in what you learned so far. It's not fully correct. Wanna verify your sentence I just quoted above? Go to Tamco, click DTA Epoxy, go to TDS sheet, and scroll down to page 3: "Do not use any metal prep conditioners, converters or any rust removers under this
product. They can cause failure." There is like maybe 5% chance you will align metal pretreatment chemical behavior with epoxy/primer. You would be better off painting it with Axalta VS3000 Etching Primer, that is "etching" in the name only. Pure Acetone and epoxy resin. Wont' hurt you.

"Their is a Huge difference between Etching primers and Zinc rich Primers." - This is the reason why I want you to slow down a bit with following me on this forum and trying to reply to me and sound smart. I have doubts you understand this. I produce these paints for myself now and I know their composition/history/effects and overall behavior including chemical for the most part. I'm trying to bridge the gap between big painting companies and average joe like me, but you're a bit in a way. Zinc is the "etching". Or one of them, so your strongly pointing these things out gives away your shallow understanding of it.

There are about 4 ways of metal preparation for top coats. They are: Conversion Coatings, Wash Primers, Electrocoating (OEM), Main Primers and Epoxies.

Those "Main Primers and Epoxies" that's mostly us now. You prepare the metal by injecting corrosion inhibitors and anti-corrosion pigments and that takes care of everything. As of right now you can do this with an epoxy or primer. Both of those things can be in that coating and any other metal pre treatment as done by Ford, DuPont, PPG or anybody else is the old way, and not required. I'm not saying it's worse, but there is no proof that it's better. The epoxy or primer like that does what pre treatment did in the past.

"The zinc phosphate coating formed on the metal surface offers the best possible
substrate" - this is incorrect. Zinc Phosphate coating is the current most used way of pre treating, and it is possible it's the best NOW, because stronger binders were eliminated due to hazard. Zinc Chromate and even Lead were much better but they got phased out. And even Zinc Phosphate is also being phased out. Zinc Chromate is Pigment Yellow 36 (the famous primers from back in a day) Zinc Phosphate is Pigment White 32. You can research them. They produce pigments now and inject characteristics into them and you can find some good stuff, but it's mostly in China and surprisingly Iran. We are way behind now.

Anyway, this is a complex subject. There is no right or wrong approach to this, because there is no proof one is better than the other. If you need to epoxy or etch primer over chemical pre treatment, you must use something from a known manufacturer that says this Pre Treatment chemical goes with this epoxy or primer. And hopefully they are correct. Tamco plays it safe and says you can't even do this, because the chemical chances of getting that right are low.

DuPont List of Conditioners to PreTreatments:

DuPont list of main anti corrosion pigments in their famous primers:

Whatever guy, I been Painting aircraft and cars for close to 40 years I am Federally certified aircraft mechanic. Careful who you say is incorrect, I know what I am talking about. Cromax IS Axalta ALL of Duponts Paint was Taken over by Axalta aka Cromax!

Their are always more than one way to do things and their will always be different products to use so don't be saying I am incorrect or wrong! I have done my research I am sold on the products that I use, IF you wish to use different products that's your choice. BUT till I see real SALT WATER SPAY TEST RESULTS on your suggested Products I could care less!

The US Navy literately spends Millions on Corrosion protection every year and does real Salt water spray testing on all of the products they use. all the Manufactures that present Bids to the Government have to have these test if they want to sell their products to the Government mainly the US Navy.

My research pointed me to the products that I use after researching the Salt water spray testing results by each manufacture, if they had them and were available.
Any legitimate corrosion preventive compound will have Salt water spray testing done. Now if they don't want to show you those results or they haven't done those tests theirs a reason!

As far as the info I provided its sound and correct, I have spoken to Chemical Engineers at DUPONT on how to properly use that stuff on Metal and aluminum.
PPG backs up what I am saying in their Instructions as well with their own products of the same chemical make up.

We are talking about entry level automotive body repair here and entry level auto restorations That provide repetitive Hi quality results their is no need for a Pissing Match.

Sorry, I left out the most important thing. DuPont had ONLY the following etch primers and epoxies listed as the only once you can spray over metal pre treatment:

22880S™ Low VOC Etch Primer
2580CR™ / 2510S™ / 2540S™ / 2570S™ LF Epoxy DTM Primer
V-2910S™ / V-2940S™ / V-2970S™ LF DTM Epoxy Primer
VariPrime® 615S™ Self-Etching Primer

And out of those above, only 2 of them: 615S and 2580CR have anti rust Chromate. And both of these are Suggested to be Replaced. The others are not really anything, but Acetone with Titanium DiOxide.

This does not mean that other epoxies or etch primers will not work with metal pre treatment, but this is their "System" and other epoxies simply say not to paint pre treatment with their stuff, or omit that and put the blame on you.

Also, there is an ultimate simple test how good each primer, epoxy, system, coating holds onto metal: Buy exact plates of metal. Prep them, paint them and let them cure. Put them into sandblaster with super fine media like stainless steal shot and observe how it peals. If it peals hard and into fine dust, it's super good, if it starts flaking a bit it's weaker.

I personally know a Chemical engineer who owns and operates his own successful Automotive Paint manufacturing company they have a web sight and sell very good products that I use to this day.
We have spoken at great length about using The metal treatment made by Dupont/ Axalta and PPG and while his web sight strongly says not to use them under his epoxy he admitted to me that He uses it under his Epoxy!
He went on to say the only reason his web sight says not to use it is BECAUSE people don't follow the instructions for the products!
Its just easier and cheaper for him to say they are not compatible and they don't recommend their use BUT Privately he says yes absolutely do it if you know how to do it correctly. I think that most manufactures have moved in the same direction Its just cheaper for them to say No don't Metal treat.

I also reached out to another well known Paint mfg who said the exact same thing Privately they admit yes you can use Metal treatments under their epoxy BUT due to the amount of failures by people not using and performing the treatment correctly their web sight and recommendations given on the phone say its use will cause paint failure and not to use them.

Is your friend TAMCO?

schabiazabi wrote:Also, there is an ultimate simple test how good each primer, epoxy, system, coating holds onto metal: Buy exact plates of metal. Prep them, paint them and let them cure. Put them into sandblaster with super fine media like stainless steal shot and observe how it peals. If it peals hard and into fine dust, it's super good, if it starts flaking a bit it's weaker.

NO! your wrong and your giving out poor information.
The Ultimate test is a "Salt spray test!" and recording how many hours before it fails and they all eventually fail That's the Ultimate test of how good a coating is at protecting materials.


Here is a company web sight that does Salt spray testing the page briefly describes the test process.
https://www.metengr.com/testing-service ... g/salt-fog


Here is a Salt spray test results of a product by a MFG that I very highly respect 15000 hrs Now that's REAL rust protection.
https://superiorcoatingsolutions.com/ru ... astm-b117/

You really need to chill. Did you read what I wrote and what your salt fog testing actually tests for?

This is my last post on the subject. This is stupid. Waist of time.