Best way to prep and paint rusty frame.

[Dd1994]

Most companies do not recommend color directly over etch primer. Epoxy would be a better product on a frame vs. etch. Epoxy is used in many industrial applications requiring corrosion resistance. Etch is used in collision repair because of it's speed, it is not a substitute for epoxy in all cases.
The Ecoat talked about on fenders is not epoxy it is a different product. Epoxy will not fade for years under a vehicle, I have some I have done at least 25 years ago. Direct sunlight will fade it and break it down.
And the cars peeled because of lack of clear, which is the UV protection. With proper mils of clear no UV gets below.
A catalyzed bedliner applied properly will be better than an acrylic enamel. It will give a little better chip resistance.
I wouldn't use any products that do not have a hardener. The chemical crosslinking the hardener initiates yields a far superior product.
Rustoleum isn't even a consideration

I'm now thoroughly confused. I have used 2 part epoxy on my boat, for fiberglass repair but never as a paint.

 

[Supercharged111]

Why would a UV vulnerable paint be bad for a frame that never sees sunlight?

 

[Hipster]

Most companies do not recommend color directly over etch primer. Epoxy would be a better product on a frame vs. etch. Epoxy is used in many industrial applications requiring corrosion resistance. Etch is used in collision repair because of it's speed, it is not a substitute for epoxy in all cases.
The Ecoat talked about on fenders is not epoxy it is a different product. Epoxy will not fade for years under a vehicle, I have some I have done at least 25 years ago. Direct sunlight will fade it and break it down.
And the cars peeled because of lack of clear, which is the UV protection. With proper mils of clear no UV gets below.
A catalyzed bedliner applied properly will be better than an acrylic enamel. It will give a little better chip resistance.
I wouldn't use any products that do not have a hardener. The chemical crosslinking the hardener initiates yields a far superior product.
Rustoleum isn't even a consideration

x2 Whatever the e coat is that comes on crash parts is it's definitely not epoxy. I have used DP90 epoxy on partially done cars and the stuff has sat outside for a few years without issue.

 

[Hipster]

I'm now thoroughly confused. I have used 2 part epoxy on my boat, for fiberglass repair but never as a paint.

There are epoxy paints and there are epoxy repair materials for marine and auto. Epoxy is generally waterproof. You didn't say what you used but an example is West Systems epoxy. They have several additives to create different repair compunds for different uses, but it is not paint. We body and paint guys say epoxy , but it is an epoxy based primer/sealer paint we're referring to. Some automotive epoxies call for an etch prime underneath and some are direct to metal(DTM). A lot of automotive epoxies mix 1:1 with a catalyst to be used as a primer with an additional reduction ratio if it is to be used as a sealer. There are also automotive epoxy based adhesives and seam sealers.

 

[ole paint]

with this ospho can you paint right over it

 

[DerekTheGreat]

Why would a UV vulnerable paint be bad for a frame that never sees sunlight?

Because not all rays which hit the ground are absorbed by it, some get reflected up. The frame on my 2011 Colorado was starting to go chalky by the time I sold it in 2014. It wasn't terrible but I could tell it wasn't deep black as it had started life.

Most companies do not recommend color directly over etch primer. Epoxy would be a better product on a frame vs. etch. Epoxy is used in many industrial applications requiring corrosion resistance. Etch is used in collision repair because of it's speed, it is not a substitute for epoxy in all cases.
The Ecoat talked about on fenders is not epoxy it is a different product. Epoxy will not fade for years under a vehicle, I have some I have done at least 25 years ago. Direct sunlight will fade it and break it down.
And the cars peeled because of lack of clear, which is the UV protection. With proper mils of clear no UV gets below.
A catalyzed bedliner applied properly will be better than an acrylic enamel. It will give a little better chip resistance.
I wouldn't use any products that do not have a hardener. The chemical crosslinking the hardener initiates yields a far superior product.
Rustoleum isn't even a consideration

Ecoat has epoxy in it, it's part of the formulation and that's what breaks down. Show me one that was used in the late 80's and through the '90's which didn't incorporate it.

The stuff used on fenders isn't a different product. If the metal replacement part has a coating on it, it's ecoat of some sort, just black instead of a gray shade as to identify it being aftermarket.

I do not agree, epoxy isn't a good choice in my opinion for a frame or anywhere where UV exposure is possible. If it is protected by enough topcoat & clearcoat to decrease UV transmission to "acceptable" levels then you can use it. But if a dude or dudette intends to leave their epoxy or epoxy based paint layer exposed, it will not hold up over time and that's not what I recommend.

I don't know what basis you have for your conclusions but again, I've been in the anti corrosion industry for over 10 years. I've worked directly with OEM's at testing our pretreatment in tandem with other suppliers' coatings against their specs for approval. Above all things, cleanliness/surface prep is key. Without proper adhesion (test against ASTM 3359 ADHA or AHDB or humidity adhesion is even better- ASTM D2247, followed with either adhesion test) any coating you apply over your surface will fail. Rubberized coatings trap moisture, as do coatings in general. Which is why I don't recommend them, not to mention when you start spraying that stuff over bolts & connectors, good luck with disassembly in the future.

If it's a show car, do whatever makes you happy. But if it's going to see salt, I wouldn't do anything other than what I've previously suggested.

x2 Whatever the e coat is that comes on crash parts is it's definitely not epoxy. I have used DP90 epoxy on partially done cars and the stuff has sat outside for a few years without issue.

A few years ye say? About how long did it take for those ill fated GM products of the early to mid 90's to start shedding their topcoat in sheets? Somewhere close to ten. It's not immediate, the damage is over time.

 

[Hipster]

A few years ye say? About how long did it take for those ill fated GM products of the early to mid 90's to start shedding their topcoat in sheets? Somewhere close to ten. It's not immediate, the damage is over time.[/QUOTE]

Gm's paint issue back then was the clearcoat delaminating and GM wasn't the only one that had issues. I stripped and painted enough from 88-95 under warranty at a GM dealer to know the color codes were called out as WA#xxxx Lac. Indicating lacquer base. Yes, enamel clears on lacquer base. Urethane BC/CC systems were in there infancy at that time. Some of the adhesion problems continued, and it was also at a time when the EPA was hammering the paint co's to change their products. The problem was in the adhesion of clearcoat to basecoat and not basecoat adhesion to the underlayments or a total paint system failure. With the clear gone moisture could penetrate the basecoat. The paints we can walk in the jobber and purchase are not the same paints used at the oem level. Even with current aftermarket urethane paints the life expectancy is about 7-10 yrs depending on the quality of paint unless it sits inside.

yes, I have used dp 90 epoxy and left cars outside for 2 to 3 years. Yes, they chalked up but they still remained protected. Alkyd enamels enamals also fall short on Uv protection, lose gloss, and chalk up but it's on water towers, park benches, fire hydrants, and equipment everywhere. Yes it's need to be repainted every few years but I'm not getting the because it suffers from some UV degradation it affords zero protection.

In the OP's case his methods are a long exercise to get halfway there. Clean it up, treat it, put something on the areas you attempted to clean. Spray the Krown, used motor oil, Wd-40, or whatever makes you happy, but do continue to keep an eye on it.

 

[Larry-Cleveland]

Everything I have is rusty living in Northern Ohio. They mine the salt from under Lake Erie so it is all over the place.

Yes, epoxy is the best on a surface prepared for it and you can afford it (i never get it that clean).

Acid changers and most paints did nothing for me, with the exception of Zero-Rust (the internet says it is like any paint BS) but it has worked very well for me. ($75 to $100 USD).

Transmission fluid works the best if you are an oil sprayer. I have a long hose and funnel that I use to get oil down to the bottom of the doors a few times a year.

Krown T40 or Fluid Film are good top coaters on top of the Zero Rust or epoxy primers as your not getting paint everywhere.


Best of luck in this never-ending battel!!!

 

[DerekTheGreat]

Gm's paint issue back then was the clearcoat delaminating and GM wasn't the only one that had issues. I stripped and painted enough from 88-95 under warranty at a GM dealer to know the color codes were called out as WA#xxxx Lac. Indicating lacquer base. Yes, enamel clears on lacquer base. Urethane BC/CC systems were in there infancy at that time. Some of the adhesion problems continued, and it was also at a time when the EPA was hammering the paint co's to change their products. The problem was in the adhesion of clearcoat to basecoat and not basecoat adhesion to the underlayments or a total paint system failure. With the clear gone moisture could penetrate the basecoat. The paints we can walk in the jobber and purchase are not the same paints used at the oem level. Even with current aftermarket urethane paints the life expectancy is about 7-10 yrs depending on the quality of paint unless it sits inside.

yes, I have used dp 90 epoxy and left cars outside for 2 to 3 years. Yes, they chalked up but they still remained protected. Alkyd enamels enamals also fall short on Uv protection, lose gloss, and chalk up but it's on water towers, park benches, fire hydrants, and equipment everywhere. Yes it's need to be repainted every few years but I'm not getting the because it suffers from some UV degradation it affords zero protection.

In the OP's case his methods are a long exercise to get halfway there. Clean it up, treat it, put something on the areas you attempted to clean. Spray the Krown, used motor oil, Wd-40, or whatever makes you happy, but do continue to keep an eye on it.

Yeah, that was a different issue though. My '94 Grand Am was single stage white, the paint was flaking off on the decklid & surrounding areas back in '06 or so. Like I mentioned in a previous post, GM skimped on their primer sealer which was another layer which served to protect against UV transmission.

Clearcoat serves multiple purposes but a big one is to block/reduce UV transmission. Whatever the chemistry supplied to GM at the time was, the bottom line is it failed, leaving just the basecoat behind which really wasn't formulated for UV transmission resistance. So once the clear peeled, the paint failures related to ecoat chalking would expedite.

I never said epoxy based chemistry weren't durable, just that they'll chalk if exposed to UV or not protected by yet another paint layer.. If a person doesn't mind that, then by all means. However, just epoxy paint on it's own will fail eventually and since I don't like the chalked appearance and properly cleaning the surface is tough, I stand behind oiling over paint. If a person was to use this DP90 stuff from PPG and wanted to topcoat it, they'd have to sand it down per TDS. (https://www.myrv14.com/buildlog/20160510/p-196_dplf_epoxy_primer-9-13.pdf). Not to mention the TDS stresses the importance of metal prep & it says it requires the use of a metal conditioner, probably at least something comparable to Bonderite 1455W wipes, which are in no way a replacement to true zinc phosphate like B958. Paint is paint, it'll chip and perform weaker over welded areas. Where it chips it'll of course rust and now you're back at square one. I'd rather just oil my cars annually instead.

 

[Hipster]

Yeah, that was a different issue though. My '94 Grand Am was single stage white, the paint was flaking off on the decklid & surrounding areas back in '06 or so. Like I mentioned in a previous post, GM skimped on their primer sealer which was another layer which served to protect against UV transmission.

Clearcoat serves multiple purposes but a big one is to block/reduce UV transmission. Whatever the chemistry supplied to GM at the time was, the bottom line is it failed, leaving just the basecoat behind which really wasn't formulated for UV transmission resistance. So once the clear peeled, the paint failures related to ecoat chalking would expedite.

I never said epoxy based chemistry weren't durable, just that they'll chalk if exposed to UV or not protected by yet another paint layer.. If a person doesn't mind that, then by all means. However, just epoxy paint on it's own will fail eventually and since I don't like the chalked appearance and properly cleaning the surface is tough, I stand behind oiling over paint. If a person was to use this DP90 stuff from PPG and wanted to topcoat it, they'd have to sand it down per TDS. (https://www.myrv14.com/buildlog/20160510/p-196_dplf_epoxy_primer-9-13.pdf). Not to mention the TDS stresses the importance of metal prep & it says it requires the use of a metal conditioner, probably at least something comparable to Bonderite 1455W wipes, which are in no way a replacement to true zinc phosphate like B958. Paint is paint, it'll chip and perform weaker over welded areas. Where it chips it'll of course rust and now you're back at square one. I'd rather just oil my cars annually instead.

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.