Project Car Rust Prevention

[racer8432955]

I'd like the advice of some of the auto body / restoration experts here, shade tree guys like me please advise what works for you as well.......

When working on a long term car project how, (or do?) do you coat the repaired areas as you go? For example; say you just finished welding / grinding the new cab corners, but are going to do repair work on multiple areas of the truck, what do you do for rust prevention before getting around to the next area. The timeline for all repair to be completed is approx. 1yr. At some point the vehicle will be taken to professional shop for complete paint and primer work.

Advance thanks for advice.

 

[MP&C]

I'd say your best bet is to find a good epoxy primer as it's something you won't have to sand back off when it comes time to get into final painting. Spray bomb primers from your hardware store aren't really suitable for automotive paints.. As long as your shop is warm enough for painting, even with small areas you can put it on with a brush or tight nap roller. Spraying will give a smoother coat, but it's going to need blocking regardless. So your primary goal of rust prevention is accomplished....

 

[countryroad82]

I feel a little more elaboration is needed. Is the vehicle going to be driven? Or will it stay in the garage? I agree with MP&C to stay away from rattle can primer. I try to stray away from most lacquer products. I don't use epoxy primer myself, I'm stuck on 2K urethane. Never had a problem so why change? Anyway I like to scuff the EDP coating off the front and back of my patch panel paint the backside along with weld through primer. After I get the panel welded in I etch prime then prime with 2K.

 

[racer8432955]

I feel a little more elaboration is needed. Is the vehicle going to be driven? Or will it stay in the garage? I agree with MP&C to stay away from rattle can primer. I try to stray away from most lacquer products. I don't use epoxy primer myself, I'm stuck on 2K urethane. Never had a problem so why change? Anyway I like to scuff the EDP coating off the front and back of my patch panel paint the backside along with weld through primer. After I get the panel welded in I etch prime then prime with 2K.

Car will be kept in garage until completed.

 

[Bsj04]

I'm Interseted in this also. I'm about to start a project that will take somete to complete.

What is etch prime? And do you have to do that with epoxy too or just 2k primer?

 

[73surffisher]

Ditto on the epoxy primer, , this is a great reference, no bs, site SPIuserforum.com
Take a look at some of the restorations, top notch IMHO

 

[MP&C]

I'm Interseted in this also. I'm about to start a project that will take somete to complete.

What is etch prime? And do you have to do that with epoxy too or just 2k primer?

Typically (this means check your prospective products to verify) epoxy primers are a direct to metal primer, so etch is not really needed in those instances. Etch is slightly acidic to promote adhesion, which in some cases will cause adhesion issues (delamination) if used with an epoxy that is not compatible with such subtances. Etch is used primarily as an substrate to high build / 2K primers, as many of the high builds are not a direct to metal.

And the final comparison, Epoxies have a much longer flash time, fully curing in anywhere from 24 hours to one week, depending on brand. This makes them less suitable for the collision industry, where car repairs may be in and out the door in about 3 days +/- , and more in line with a restoration shop, where something may be sitting a bit longer. Etch primers and high builds have a much faster flash time as they are intended for the collision industry and the time constraints driven by the insurance companies. So for those who may have a long term project, epoxy may be the better choice, and it also should give better protection from moisture intrusion to the panel if left un-topcoated during this timeframe.

 

[ng8264723]

Try southern polyurethane. They have awesome service and products. I love their expoxy primer

 

[HMCFab9]

If you will not be driving the vehicle, your work area is kept at a fairly consistent temperature (no condensation) & there is little moisture in the air, you really don't need to coat everything immediately.
You can do most, if not all of your metal work & prime everything at once. If a little surface rust would happen to start, just D.A. the area. Everything being primed should be sanded before priming anyway.
Use a good quality epoxy primer. PPG DP line is good stuff. You can do body / filler work right over the epoxy. If you use an etch primer, many of them do not recommend doing bodywork directly over that. (which defeats the purpose of the etching primer)
There are also "conversion coatings" or acid wash products available that will clean the metal before applying any other coatings.

 

[Deskmechanic]

You can roll epoxy primer on. Use the flat foam rollers. I did a few small areas when I was restoring my truck. I used SPI epoxy primer (cheap and good). I had someone else do the priming/painting of the whole truck, but he just scuffed up those areas since the recoat window passed. Three years later not a problem.

 

[IndyGarage]

I feel a little more elaboration is needed. Is the vehicle going to be driven? Or will it stay in the garage? I agree with MP&C to stay away from rattle can primer. I try to stray away from most lacquer products. I don't use epoxy primer myself, I'm stuck on 2K urethane. Never had a problem so why change? Anyway I like to scuff the EDP coating off the front and back of my patch panel paint the backside along with weld through primer. After I get the panel welded in I etch prime then prime with 2K.

I may be opening myself to riducule from a paint guru, but isn't 2 part urethane another name for Epoxy?

I've used the Southern Polyurethanes epoxy primer and I agree with the others that it's good.

 

[countryroad82]

Epoxy is a different animal. Epoxy can be sprayed straight over bare metal and it will adhere, whereas 2K primer will eventually let go as it requires something to etch into the bare metal. I have used epoxy in the past, I don't have any complaints, I have gotten so used to using 2K that it is hard to go to anything else. Epoxy also dries a little slower which is another reason as to why I'm not a fan, whereas I can be sanding and getting ready to paint in 2 hours with 2K. But I'm in more for production type work, I have pretty much cut out resto work in my shop, I still do it, just not as much.

 

[rsanter]

I'm in CA. If it's in the garage, not outside, not getting wet, not driven. Don't do anything.
Other parts of the country....you got to prime it

Bob

 

[Blake150]

Havent heard anybody mention body wax.after doing panel work the weld will burn any corrosion protect applied in the weld zone.a good application of body wax will ensure it foesnt corrode from inside out

 

[toomanytoyzz]

I've never heard of epoxy taking a week to fully cure. It has a pot life as to when you will need to scuff if you plan on top coating with a 2k primer, but it dries within a day all the years I've used it.

I have used PPG's DP series (the original stuff aka not Lead Free) and it's probably been the best, but the newer stuff is good. I also have had good success with BASF's R/M line of epoxy primer which is the EP series. Also try Montana/Big Sky epoxy. The best part of that product is the mixture. At 1:1 you get two gallons of product from one kit. Most of the others are 4:1 or at best 2:1.

You can also use epoxy as a seal coat before applying base coat using urethane reducer. Follow the tech sheet for amounts. Most of the ones I've used requires 10% reducer to use as a seal coat.

 

[MP&C]

Perhaps I used a bad example, as it is no longer made. House of Kolor's EP-2 used to take about 48 hours to cure enough for sanding, and about a week to fully cure. Curing so slowly left it extremely flexible, making it ideal for carbon fiber, plastics, fiberglass, other flexible panels, and yet still a good choice for steel or aluminum. It contained zinc chromate, so obviously the epa folks had a hand in removing it from the marketplace.. Too bad, it was about the best you could use..

 

[Chad M]

Picklex 20 has worked very well for a couple friends of mine... years in a garage in a northern climate. You spritz it on bare metal with a regular spray bottle. I believe you can spray primer right over it when it comes time. Expensive but apparently worth it.

 

[Jetfixr320]

This was recommended to me by the paint and body guy that was helping me last year. He swears by it.


http://picklex20.com/

 

[MP&C]

Taking a recommendation from a paint and body guy may not always be a safe bet unless you are using the exact same products start to finish. Seldom do P&B guys use epoxy for the reasons I mentioned above, and some epoxy primers are not compatible with the rust converters, Picklex, Ospho, etc. Best bet is to check the tech sheets for whatever primer you plan on using for compatibility prior to using the rust converters. Very likely your P&B guy never mentioned this compatibility issue as he's not had the experience of using epoxy primers to be familiar with it..

 

[Kevin54]

If it were me, and I did it when I was working on my truck, at the end of each day, I'd take some wax and grease remover, wipe the areas down, and mix up a little 2K and prime the spots that I had worked on. Then I'd roll the truck out, wash the garage out, then pull the truck back in. It sounds a little extreme, but I was going to have to paint in the same area I was doing body work, so I didn't want dust on everything.

Get yourself a cheap HF Purple gun, of a green TSC gun, the smaller one, and use that as a dedicated spot primer gun. Go to your paint jobber and get some lacquer thinner to clean your gun. And have an empty can to put your waste thinner in.

BTW.....if you go to a paint jobber to get lacquer thinner, buy a 5 gallon can of it. It's only about $5 or $6 dollars more than a 1 gallon can, or at least it was.

 

[toomanytoyzz]

BTW.....if you go to a paint jobber to get lacquer thinner, buy a 5 gallon can of it. It's only about $5 or $6 dollars more than a 1 gallon can, or at least it was.

Couldn't agree more. If you are painting a car 1 gallon of lacquer thinner is about as useful as a shot of beer on St. Patty's Day. Price difference is also minimal.

Happy St. Patty's Day!!!

 

[arrowhead]

Another vote for epoxy prime. Stay away from the rust converters and encapsulates, if you have clean bare metal there is no need for them. Also, regular 2k primers can breath and moisture can still cause rust whereas an epoxy will give you an air tight barrier.

Follow this the best you can and you won't go wrong.

http://www.southernpolyurethanes.com/perfect paint.htm

 

[roblouvasz]

I've always sprayed two coats of epoxy primer-PPG'S Omni Line, over bare metal and bodywork and sprayed two coats of 2K surfacer primer on top of the epoxy within an hour or so with out scuffing the epoxy and never had any issues. Most epoxies have a "window" of time where you can apply different coatings on top of them without scuffing them. "pot life" refers to the amount of time you have to use the catalyzed epoxy before it goes bad. I would definitely be using epoxy as you go. Rolling it on should be ok, But I would recommend it only if you don't have spray equipment. As for buying a cheap Harbor Freight gun, make sure you dissasemble the whole thing and clean it out with laquer thinner before you use it! They are loaded with oil. Try to get one that uses some sort of packing for the needle in stead of an "O" ring, they will leak(ask me how I know!). Anyway, I wouldn't worry about getting the 2K surfacer primer on at this stage, just the epoxy. Because of the time it's going to sit, You're going to have to scuff all of the epoxy you've put on over the course of the year in order for an overall coat of epoxy to be applied before you apply 2K surfacer.