[65Mark]

Just to add....

On some parts that have a heavy rust coating and hard to grind, or I just don't feel like grinding, I have used muriatic acid (Hydrochloric acid) to eat the rust then rinse with water to neutralize. Let it dry then wash with phosphoric acid to remove the little bit of flash rust that develops,or sand to remove. This is useful on frames and those hard to grind areas. It can be found at Home Depot too, or your favorite swimming pool supply store.

[PONTIAC SLEEPER]

Originally Posted by 65Mark

I was referring to POR 15 on conversion coating, among others. Phosphoric acid is a good etch, as long as you neutralize it completely.

Ah, Gottcha, my mistake... I miss under stood you... my appoligies...

Yes you are right on both counts there too. Although I have no personal experince with POR 15, If you apply it over rust or any type of similar coating that claims to neutralize it in a similar fashion, It is only a Band Aid fix at best...

Although I have no experince with POR 15, If it is So great why is not being in industrial applications like Bridges??? Especial ones in or near salt water??? I am Not saying its a Bad product just that the best way to treat rust is to completely remove it and then coat the bare metal accordingly...
Thats my worth

[Greg Reid]

Originally Posted by PONTIAC SLEEPER

Although I have no experince with POR 15, If it is So great why is not being in industrial applications like Bridges??? Especial ones in or near salt water??? I am Not saying its a Bad product just that the best way to treat rust is to completely remove it and then coat the bare metal accordingly...
Thats my worth

Here's one they used on a bridge. It's called Master Series.
http://www.masterseriesct.com/wst_page3.html

[65Mark]

Originally Posted by PONTIAC SLEEPER

Ah, Gottcha, my mistake... I miss under stood you... my appoligies...

Yes you are right on both counts there too. Although I have no personal experince with POR 15, If you apply it over rust or any type of similar coating that claims to neutralize it in a similar fashion, It is only a Band Aid fix at best...

Although I have no experince with POR 15, If it is So great why is not being in industrial applications like Bridges??? Especial ones in or near salt water??? I am Not saying its a Bad product just that the best way to treat rust is to completely remove it and then coat the bare metal accordingly...
Thats my worth

no apology needed, we both on the same track.

[Grand73Am]

Originally Posted by abefromen

After stripping my '73 Firebird here is what I found. The car sat outside for a long time and has developed surface rust under the paint. Whats the best way to remove this and treat the metal before I spray the DP90?

I suggest the PPG DX579 metal cleaner, a phosphoric acid cleaner. Follow the directions. I put some in a spray bottle, spray it on, use a wire cup brush on a drill and scrub it until the rust is gone. Reapply as necessary. It does require rinsing with water. So, it doesn't rust back, have plenty of clean, dry terry cloth towels and some clean air supply and air gun to use to dry it quickly. Once it's clean, then use DX520 metal conditioner, which is a zinc phosphate treatment that provides further rust prevention and improves adhesion too. Again follow the directions, which is to apply, allow to sit a few minutes and rinse. I like to rub it in with a scotchbrite pad while keeping the metal wet with the DX520. After a few minutes, rinse it off. Then again, be ready to dry it off quickly. The metal will be dull and splotchy looking, which is fine, since paint sticks better to dull...you don't want shiny. The DX520 is really great for preventing rust from coming back. The bare metal can sit for a long time without rusting if treated with the 520.
Once it's dry, the next step is applying your DP90LP.

[PONTIAC SLEEPER]

Originally Posted by Greg Reid

Here's one they used on a bridge. It's called Master Series.
http://www.masterseriesct.com/wst_page3.html

Yes, but again it did not "stop" the rust. It's only a preventative step from allowing it to get worse... 5% maybe good on a large object like that but eliminating it all together is a better option in the long run

[PONTIAC SLEEPER]

Originally Posted by Grand73Am

I suggest the PPG DX579 metal cleaner, a phosphoric acid cleaner. Follow the directions. I put some in a spray bottle, spray it on, use a wire cup brush on a drill and scrub it until the rust is gone. Reapply as necessary. It does require rinsing with water. So, it doesn't rust back, have plenty of clean, dry terry cloth towels and some clean air supply and air gun to use to dry it quickly. Once it's clean, then use DX520 metal conditioner, which is a zinc phosphate treatment that provides further rust prevention and improves adhesion too. Again follow the directions, which is to apply, allow to sit a few minutes and rinse. I like to rub it in with a scotchbrite pad while keeping the metal wet with the DX520. After a few minutes, rinse it off. Then again, be ready to dry it off quickly. The metal will be dull and splotchy looking, which is fine, since paint sticks better to dull...you don't want shiny. The DX520 is really great for preventing rust from coming back. The bare metal can sit for a long time without rusting if treated with the 520.
Once it's dry, the next step is applying your DP90LP.

Grand73Am,
When you do it that way does risineing with water leave a film of any kind??? what did you use besides a rag to clean the surface??? Any chemicals??? I have never used the DX520 wich may have been my problem but I always had issues until I started using acetone to neutrilze the DX579 and Red scotch brite. The red scoth brite Helped losen any contaments and also preped the metal... after that I re-cleaned until I had a Clean surface...

[fastwayfirebird400]

Here is another twist for you if you have any sandblasted panels. PPG does not recomend and advises against metal treatment on sand blasted metal. Here is some info from the site, It's in the pdf below. Does this also mean that Picklex20 as well as other should not be used ? Does any one know why ? I was going to call the tech line on Monday to ask as I'm ready to spray some DP on my panels and I have used their DX520.

[PONTIAC SLEEPER]

Originally Posted by fastwayfirebird400

Here is another twist for you if you have any sandblasted panels. PPG does not recomend and advises against metal treatment on sand blasted metal. Here is some info from the site, It's in the pdf below. Does this also mean that Picklex20 as well as other should not be used ? Does any one know why ? I was going to call the tech line on Monday to ask as I'm ready to spray some DP on my panels and I have used their DX520.

I Would imagine that it has something to do with the pitting of the metal and not being able to get into the pits to properly neutralize the products when it is roughed up from Sandblasting...

[Grand73Am]

Originally Posted by PONTIAC SLEEPER

Grand73Am,
When you do it that way does risineing with water leave a film of any kind??? what did you use besides a rag to clean the surface??? Any chemicals??? I have never used the DX520 wich may have been my problem but I always had issues until I started using acetone to neutrilze the DX579 and Red scotch brite. The red scoth brite Helped losen any contaments and also preped the metal... after that I re-cleaned until I had a Clean surface...

I've never had a film with 579, doing it the way I wrote. The water is what neutralizes the 579. Then do the 520 and the rinse and dry and the surface will be nice and clean. No need for any other chemicals, unless you let it sit around and get handled and dirty, and then you'd have to wipe it with a pre-cleaner.

A long time ago, I used a rust cleaner that left a film, maybe Ospho, and I didn't like that at all and quit using it. I wouldn't use anything that leaves a film.

[Grand73Am]

Originally Posted by fastwayfirebird400

Here is another twist for you if you have any sandblasted panels. PPG does not recomend and advises against metal treatment on sand blasted metal. Here is some info from the site, It's in the pdf below. Does this also mean that Picklex20 as well as other should not be used ? Does any one know why ? I was going to call the tech line on Monday to ask as I'm ready to spray some DP on my panels and I have used their DX520.

I did know you aren't supposed to use metal treatment if using etch or wash primers. That's one reason epoxy primer is better, since epoxy is great over acid treated metal.

I had not seen that before about not using acid treatment over sandblasted metal. It's difficult to see how it could do any harm. Doesn't make sense to me. Let us know what the tech line says if you would.

One thing is that if the metal has been sandblasted clean, you don't really need any other metal treatment. I don't metal treat my sandblasted panels. I just epoxy it as soon as I can. Sometimes if I have a rusty panel, and I use a metal cleaner on it that can not clean all the rust off, I will lightly sandblast it to remove the last of the stubborn rust. Then epoxy it.

[fodder69]

I am surprised no one mentions this stuff, safestrustremover.com. It's slow and somewhat expensive but it does a pretty awesome job of removing light rust. For lightly pitted stuff, I have found just a spray bottle of it works well. Spray it, wait a bit, wipe or rinse it off, repeat. You need to soak deeper rust and you are want to get the big stuff first of course. But it gets into the pits, doesn't leave anything but metal and occasional carbon staining and really seems to work great for what I have used it for.

Is there some other drawback on this that I don't know about? I know it is really slow and doing a lot of rust eats up the product pretty quick but for getting that last bit of rust out of pits and things it really seems perfect.

[Mr. Unbelieveable]

Originally Posted by Grand73Am

I've never had a film with 579, doing it the way I wrote. The water is what neutralizes the 579. Then do the 520 and the rinse and dry and the surface will be nice and clean. No need for any other chemicals, unless you let it sit around and get handled and dirty, and then you'd have to wipe it with a pre-cleaner.

A long time ago, I used a rust cleaner that left a film, maybe Ospho, and I didn't like that at all and quit using it. I wouldn't use anything that leaves a film.

The 520 leaves a film. It leaves a zinc phosphate coating on steel.

[Grand73Am]

Well....I don't think it's really considered a film, since I think of a film as something that sits on top of the metal...something that has some thickness to it that can be scratched off fairly easily. I have seen that kind of film from another product, that looked and felt like a waxy film on the metal, that I was able to scratch off, and thought, "that's not good" .

Whereas, 520's zinc phospate is not like that. It's very thin and etches and bonds to the metal, so it's considered a metal treatment. And this treatment provides rust protection and excellent adhesion for the epoxy primer.

[PONTIAC SLEEPER]

When I rinesd with water I would get a flash rust effect. By that I mean a light orange surface rust from using water. When trying to clean with a chemical cleaner it would kind pick it up but it did not seem like it was getting everything. I never used the 520 because I was supposed to be able to just use the 579, neautrilize it, and then epoxy it... I just wasn't happy so I started using Acetone and red scotchbrite to neautrize it. no faliures so far and I have had parts that sat out side un covered for up to 1 year...

[Mr. Unbelieveable]

Originally Posted by Grand73Am

Well....I don't think it's really considered a film, since I think of a film as something that sits on top of the metal...something that has some thickness to it that can be scratched off fairly easily. I have seen that kind of film from another product, that looked and felt like a waxy film on the metal, that I was able to scratch off, and thought, "that's not good" .

Whereas, 520's zinc phospate is not like that. It's very thin and etches and bonds to the metal, so it's considered a metal treatment. And this treatment provides rust protection and excellent adhesion for the epoxy primer.

I see what you're saying now.

[Mr. Unbelieveable]

Originally Posted by PONTIAC SLEEPER

When I rinesd with water I would get a flash rust effect. By that I mean a light orange surface rust from using water. When trying to clean with a chemical cleaner it would kind pick it up but it did not seem like it was getting everything. I never used the 520 because I was supposed to be able to just use the 579, neautrilize it, and then epoxy it... I just wasn't happy so I started using Acetone and red scotchbrite to neautrize it. no faliures so far and I have had parts that sat out side un covered for up to 1 year...

I don't think Acetone neutralizes it. But I'm really not 100% sure on that.
I've seen this too, I think the 579 will leave a coating if not washed with water, but the coating isn't suitable to paint over, it does somewhat help to keep it from rusting.

Why don't you use the 520? It's a pretty quick step and inexpensive?

[PONTIAC SLEEPER]

Originally Posted by Mr. Unbelieveable

I don't think Acetone neutralizes it. But I'm really not 100% sure on that.
I've seen this too, I think the 579 will leave a coating if not washed with water, but the coating isn't suitable to paint over, it does somewhat help to keep it from rusting.

Why don't you use the 520? It's a pretty quick step and inexpensive?

Thats the only way I knew untill I got my hands on a product tech sheet. The stupid things you learn when your young... any way the Acetone seems to neutralize it and the red scotch brite helps to remove the chemical from the surface. I reclean sevral times untill I am sure i have a clean surface...