Best way to prep and paint rusty frame.

[Bondovw]

I am having good luck with mastercoat

 

[DerekTheGreat]

LOL, Gm has skimped in a lot of places over the years, and paint manufactures have put out products that haven't worked so well. The dp was a better product as opposed to lead free dplf. But yeah depending on the brand they want other prep. Some claim better UV resistance, I don't know, but most call for a topcoat of some sort for long time exposure. Most epoxies I've used have a window where sanding is not necessary. I find the 1 week on the TDS you posted excessive. Sanding epoxy is a PITA so whether I put 2k primer or paint over it I get it done within the flash/recoat window. Gm was telling us the issue was the base, so we stripped them, metal prep, etch primed, epoxy primed, and an 1 hr later fresh base was going on. One time through the booth.

Yeah, I've painted over other products which said sanding was necessary without issues (so far.) Depending on the application & visibility, I may not care as much.

LoL well I didn't write the TDS, the supplier did. I'm inclined to take their suggestions depending on my mood.

And you believed GM? I'm sure their litigators spend a lot of time & money to make the BS which comes from their press desks look & sound great. None of the OEM's seem to admit exact root cause failure or someone's poor decision unless a third party/whistleblower does it for them. Years ago when I first started here I was talking with one of the old timers who used to work for PPG. IIRC, he said that PPG convinced GM that with their paint system, primer sealer wasn't necessary as you could tint their Ecoat or something like that. So of course to save some bux PPG was chosen as the supplier. So if you believe that (like I'm inclined to) it's technically PPG's fault.

 

[Hipster]

Double

 

[Dd1994]

I think I'm just going to do the acid wash and then use the cans of bedliner I have and coat it with krown and see how it holds up.

 

[Hipster]

@ Derek I know the PPG put the TDS together. It's probably perfectly fine at a week out to recoat without sanding but at a week I would probably at least scuff it.

Gm reps were telling us it was a basecoat issue but directing us to strip to metal. However you want to interpret that. PPG paint reps made a very noticeable presence at the dealer looking at these cars during this time frame. PPG stands behind there product if you use it from the metal up so it wouldn't surprise me if there was some reimbursements or something taking place. I can't see Gm intentionally misusing a product or skipping a step and creating this size of warranty issue but you never really know.

There have been quite a few products unleashed. PPG very quietly pulled K200 primer off the market for issues with it cracking so they do like to hide their problems. I worked at a new shop where they put in Sikkens. Sikkens had a sealer where according to the tech sheets you prep-sol the factory ecoat on crash parts and apply the sealer with no other prep. Six moths later that turned into one wholly hell of a disaster with comebacks. Sikkens would not stand behind the product so out the door they went. Many shops that transitioned into waterborn are now transitioning into low Voc solvent base with an activator in areas where they can. Water will remove the basecoat so it will pull out of rock chips, scratches , and other type of clearcoat damage. We are back to seeing cars come in with 100's of pock marks in the front with the underlayment exposed.

Even on the bodyshop level there are deals made to lock in paint contracts. They'll help you with whatever you need to help them get their product in the door. Paint booths and other equipment are not unheard of.

 

[DerekTheGreat]

@ Derek I know the PPG put the TDS together. It's probably perfectly fine at a week out to recoat without sanding but at a week I would probably at least scuff it.

Gm reps were telling us it was a basecoat issue but directing us to strip to metal. However you want to interpret that. PPG paint reps made a very noticeable presence at the dealer looking at these cars during this time frame. PPG stands behind there product if you use it from the metal up so it wouldn't surprise me if there was some reimbursements or something taking place. I can't see Gm intentionally misusing a product but you never really know.

PPG very quietly pulled K200 primer off the market for issues with it cracking.I worked at a new shop where they put in Sikkens. Sikkens had a sealer where according to the tech sheets you prep-sol the factory ecoat on crash parts and apply the sealer with no other prep. Six moths later that turned into one wholly hell of a disaster with comebacks. Sikkens would not stand behind the product so out the door they went.

Even on the bodyshop level there are deals made to lock in paint contracts. They'll help you with whatever you need to help them get their product in the door. Paint booths, and other equipment are not unheard of.

You could always do that ASTM D3359 ADHA or B adhesion test on some test panels. Get some coupons, prepare and paint them identically with D90. Paint one with topcoat immediately but have one painted a week later. Test both after topcoat cure and see if there is a difference in adhesion between the paint layers..

That suggests the Ecoat was suspect to me. GM used the stuff as intended but they were misinformed by PPG. I'm guessing GM did make them pay for the repairs and that could explain why they were at dealers collecting information.

I've been told by the old timers here that the problem with refinish is the lack of ASTM or OEM standards to pass. So while the color & gloss may match in the end, what say GM gets and you the paint shop get aren't exactly the same. I wouldn't be surprised if at the dealer/paint shop level that when claims are made against paint suppliers, they try instead to blame the application process or some part of it rather than own up to a terrible batch or product.

 

[Hipster]

You could always do that ASTM D3359 ADHA or B adhesion test on some test panels. Get some coupons, prepare and paint them identically with D90. Paint one with topcoat immediately but have one painted a week later. Test both after topcoat cure and see if there is a difference in adhesion between the paint layers..

That suggests the Ecoat was suspect to me. GM used the stuff as intended but they were misinformed by PPG. I'm guessing GM did make them pay for the repairs and that could explain why they were at dealers collecting information.

I've been told by the old timers here that the problem with refinish is the lack of ASTM or OEM standards to pass. So while the color & gloss may match in the end, what say GM gets and you the paint shop get aren't exactly the same. I wouldn't be surprised if at the dealer/paint shop level that when claims are made against paint suppliers, they try instead to blame the application process or some part of it rather than own up to a terrible batch or product.

We never really get into the actual testing or dig into it too deep.

If you are referring to the Sikkens and ecoat issue. This happened at an independent shop I was at where we did predominately high end European cars across multiple makes based on referrals from the respective dealers. BMW, Benz, Porsche, Land Rover, Jaguar etc. Most of these dealers operated under one corporate label. The problem was across multiple makes and multiple ecoat formulations but by the time we knew there was a problem we had this stuff on a bunch of cars using this no sand method from the paint manufacturer. Peeling in sheets back down to the ecoat. It was ugly and there was lots of it.

The bigger problem was when you put affluent and prominent people in the community that drive $200k Benz's, 7 series IL's, and the like in an Enterprise rent-a-car because you jacked up their ride they're just not happy …...at all.

It difficult to get them to warranty it. PPG is better about it maybe because they don't want the publicity again IDK. Same with the adhesives out there. They all want batch mumbers, date codes, when the package was opened, the job Ro#, next of kin, etc. The common denominator is "stale product" It's been open or on the shelf too long.

What gets me is If I was to go into a shop where I was unfamiliar with the paint, a rep is a phone call away. PPG, Dupont, Sikkens, and many others will send a rep to train you on their products and work with you 3 days to a week to make sure you're using the products correctly. When there's an issue they forget your name.

 

[David89gmc]

Try Corroseal, but it'$ expen$ive...

 

[DerekTheGreat]

We never really get into the actual testing or dig into it too deep.

If you are referring to the Sikkens and ecoat issue. This happened at an independent shop I was at where we did predominately high end European cars across multiple makes based on referrals from the respective dealers. BMW, Benz, Porsche, Land Rover, Jaguar etc. Most of these dealers operated under one corporate label. The problem was across multiple makes and multiple ecoat formulations but by the time we knew there was a problem we had this stuff on a bunch of cars using this no sand method from the paint manufacturer. Peeling in sheets back down to the ecoat. It was ugly and there was lots of it.

The bigger problem was when you put affluent and prominent people in the community that drive $200k Benz's, 7 series IL's, and the like in an Enterprise rent-a-car because you jacked up their ride they're just not happy …...at all.

It difficult to get them to warranty it. PPG is better about it maybe because they don't want the publicity again IDK. Same with the adhesives out there. They all want batch mumbers, date codes, when the package was opened, the job Ro#, next of kin, etc. The common denominator is "stale product" It's been open or on the shelf too long.

What gets me is If I was to go into a shop where I was unfamiliar with the paint, a rep is a phone call away. PPG, Dupont, Sikkens, and many others will send a rep to train you on their products and work with you 3 days to a week to make sure you're using the products correctly. When there's an issue they forget your name.

I was talking about paint suppliers in general. Annd yep, that sounds like the usual BS they try to use to exonerate themselves of liability. That also sounds too familiar; they're all too eager to sell you a product but to warranty it, nahh. They know that to take them to court is too much money for a small business to risk. Justice is not blind. OEM's have the capital to fight back, and that is often why at a major plant there will be a paint rep on hand or one that makes monthly rounds at the least. Damage control.

 

[94_Z71]

I went with POR-15 for my frame and undercarriage. I put it on over four years ago and it's still holding strong. My frame was about in the same shape yours is. (I found the truck in Nebraska where they salt the roads in the winter.) The POR-15 is about $100 a gallon and you also need the metal prep POR-15 makes, as well. If there's a better product on the market, I don't know what it is. But if that's what you decide to go with, just make absolutely sure you don't get it on your skin. Because once it's on there, it will not come off for about a week.