I'm just not sure I'm approaching this project correctly. I don't have the space or the resources to have the ENTIRE body done at once and I don't want to completely dis***emble for soda blasting or dipping. I doing the body work in segments - i.e.: This inner and outer fender first, then the hood, then that fender, this door, etc... I figured I'd get one stripped, etch primed, bodywork and build primer, sealer/primer and then my final coat...whatever that may be. I haven't finished any panels yet, but am working on a fender and the hood right now. I've stripped both down to bare metal but have run into black oxide rust once I've sanded out the red oxide dust. So, do I treat the whole panel with RustMort or MarHyde, or will the self etching primer be good enough to seal the rust and inhibit it from cropping up? And I also have the outside of the hood primed with self etch but need to strip the inside. I was going to chemical strip or lightly sandblast it (has heavy rust scale, but no cancer) and was going to try to get a rust inhibitor into the ribs so it stops the rust under the skin where I can't get to with any tools or blasting, but I'm afraid I'll destroy the self etching primer. The reason I sprayed primer before I attacked the backside is because I didn't want the outside to flash rust overnight. Am I just approaching this all wrong? Please help...
first remember that if you dont get all the stripper off it will come back later on and realy be a pain to deal with. i would sand blast all areas that i could not get to with a da sander and then use the self etch primer if you primer over the black rust it will just come back from underneith and bubble over time or the paint,primer will just flake off.and as far as the outside primer you may have to resand and reprime due to being scratched while working on the inside of the panel and even if it rusts over night it will still be easy to sand off when your ready to prime you should start from the inside out it may save you more time and money in the long run just my .2 cents
I have good results using OSPHO or similar phosphate treating products on newly blasted metal and primed with PPG DP epoxy primer. OSPHO is reportedly not compatible with etching primers tho'.
Do etching primers serve a real purpose then? If there isn't any rust inhibiting benefit then what is the point of using them? Is it that primer won't adhere well to bare metal? Is OSPHO better for going over old rusted areas? Of course I've removed all of the loose red oxide, but the black rust "pocks" are still there. I just don't want those to pop back up. I've been told that RustMort will turn rusted metal black and that you can paint right over it once it has dried/cured. Anyone had any experience with that stuff? The main deal here is that I have old panels that are straight, but have areas that were bare metal exposed over the years...
Self-etching primer is for painting areas of new bare or partially bare metal that you can't get into to sand. As far as I know, it has no rust-killing properties. Rust-mort, naval jelly and the like contain nitric acid which chemically reacts with iron oxide (rust) and changes it to a black, crystalline substance. The problem with it (or any other chemical treatment) is that it only reacts with the rust that it touches. If you put it on over thick rust, it will react with the surface, but won't keep the metal from rusting underneath. The best luck I've had is using products like POR-15 after sanding off as much rust as possible. I let the POR-15 harden for several days, then sand it smooth and cover it with whatever primer the maker of the topcoat I'm using recommends. I'm sure others will have had different results, but this is what's worked for me.
If the parts are kept indoors I doubt you would get an overnight flash, however depending on the humidity it could be an issue. I would plan to strip, neutralize and then etch prime each side of your part in that order. Or if your sand/media blasting you should be in a good position to blast, clean and then etch prime right away. If your dealing with large scale imo I would proceed directly to blasting. POR 15, eastwoods rust converter and such are advertised to go right over heavy scale, but in or on a panel that you would want a cleaner look I would think the only option is to blast. I have tried the eastward rust converter with good results on floor pans etc. The PPG DP products, as I have been told, are not a full coverage bare metal product. The PPG rep tells me that areas about the size of a fist are ok, but for full coverage of bare metal an etch primer is a better undercoat. The DPLF products are very nice and if you choose the right color can also be used as a sealer when reduced. The offer black, gray, green-gray, red oxide and blue. However they do not offer any rust preventer or neutralizer properties that I'm aware of.
There's a lot of controversy, and hence, a lot of different opinions concerning rust, here on board. First, I would tend to follow the guys with real experience, rather than ones who have built one or 2 cars, or had a cousin, who's neighbor once fixed up a rusty car. I build cars in Jersey, where we put together stuff Cali guys would have thrown out decades ago! Guys in the Midwest also have to deal with this stuff in a big way. I would deal with the problem in 2 parts. Exterior rust removal, and prep for paint, oan interior panels, that aren't as critical, unless you're building a show car. Exterior: sand or strip to bare metal. If there are rust pits, where it is still dark in the pitted area, either spot blast them clean, to "white metal", or use a rust DISSOLVING product to reomove all traces of rust. You can use Metal Etch, like Dupont 5717 S, and scrub it (with Scotch Brite or steel wool) until it's "white metal", or use Phosphoric acid (carefully!), vinegar, or Picklex. The point is to get it all out. Then clean the residue or neutralize the acid, and primer ASAP. It's true that etch primer is not recommended over an acid treated surface. Epoxy had great adhesion, so it is a good first product. You will need to use a surfacer primer to fill in the pits, though, unless you use an epoxy that fills, like HOK's KP-2 epoxy. Etch primer is good for clean metal, and has good adhesion properties, but does not fill, either. Underpanels, if you're not very fussy, you can use a rust converter, I wouldn't trust them under nice paint, though. Clean off the panels, wire wheel the loose rust off, and treat with your choice of converters. I prefer POR-15, but if you are going to topcoat it, with a paint, undercoat, or trunk paint, you need to so it after the second coat, while it is just lightly tacky. If it dries, almost nothing sticks to it, unless you really sand it well, and it is hard as a rock!
So it sounds like I will be needing more than just a few products. From what I've read I will need a rust converter in many cases, an epoxy primer, a self etching primer, a building primer and a sealer before top coat/color coat. Damn... that's a lot of swapping paint cups! I can see why the ones who can afford it go out and buy new panels...
You're going to have to weed out the junk in some threads, don't listen to them all. You definately cannot use all the products suggested. For example, most epoxy primers recommend NOT using etch under them. Options: 1. etch primer, with high build urethane over it. 2. epoxy primer, with high build urethane over it. 3. House of Kolor epoxy...primer, high build and sealer all in one. The first 2 options you can use an epoxy or any other sealer over your high build, if needed. Depends on your paint type and brand. Follow the manufacturers recommendations for the best results. Try to stick to one brand if possible, at least for hardeners and reducers. I see primers and paints as separate steps. Any brand primer system, cured and sanded, will accept any brand paint system. But stick to one make within each step for all products. Also, you only need a high build primer, if you are correcting problems, such as rust pitting, or perfecting bodywork (pinholes, sandscratches) or blocking a body to perfection. Any panels not requiring filling/sanding, you really don't need it. You can use it as a base for final sanding for paint, but you really dont' HAVE to use it on perfect metal. This is not gospel, different painters use different techniques, brands, and steps. And they are successful. This is what I have found that works for me, over the past 30+ years.
great thread guys, I have been thinking a lot about this reacently as well as my merc has some pitting in it and I want to paint it and not have it fail in a couple of years so chopolds, do you think I would be good to media blast the rust, epoxy primer, then high fill, block then we are ready for paint? that is what I am getting out of it and I want to make sure I am on the right track! and I trust your opinions as you have built cars not only from jersey rust but have also built cars (or trucks) that are amazing in quality
Media (plastic particles) blasting will not remove real rust. Maybe light flash rust, but that's it, no matter what the media guys tell you. To get rid of rust, a more agressive "media" is needed. Gl*** beads, crushed gl***, alum. oxide, sand, Black Beauty. The gl*** media is gentler, but slower in getting the rust out. A real good media blaster will use his plastic to remove all paint and such, but will switch to another grit to get the rust out, hopefully only spot blasting the bad stuff. The more agressive stuff can be damaging in the wrong hands, either warping the metal, with high pressure, or staying in place too long, or just attacking the good metal, for the same reasons. When you get the car back, be sure all the pits are white metal, no dark spots in them. That is still rust, no matter what some of the lazier blasters tell you! Or you can treat it at home, but those acids are a bit nasty to work with. You are right, one of the options is epoxy, then high build. Block, perhaps re-primer the bare spots, then sealer (option) and paint. I prefer HOK KP-2 all the way from bare metal to paint, but that's personal preference. Again, with so many paint systems, lacquer, enamel, urethane, base/clear, and even more manufacturers, please read the "tech sheets" your local supplier can give you to direct you how to use their paints. There are many variations, even naming the same types of products. Thanks for the compliment!
I wonder how norcal compares to NJ? and Arizona? We can get away with a lot less work and paint jobs survive for years....decades even
It ain't the paint, squirrel! It's the salt they use on the road in winter to melt the snow, as well as the damper climate. If you splash mud, leaves, and junk up into rockers, between fender skins and supports, even inside doors....the trapped junk stays moist, and the salt spikes up the corrosion a LOT. Cars that come from the seashore area are REALLY bad. Just from the moist salty air. Our cars rot from the inside, I've even seen roofs rotted out! Our paint probably lasts longer than yours in your area, as I'm sure the hot sun really does a number on paint. But what the paint is on tends to go away quickly here.
Kinda what I figured...we can get away without doing hardly any prep work on the backside of panels, we can leave black rust under primer/paint, etc. We do have to worry about dirt getting into the crevices between panels, such as the bottom of front fenders, and getting wet and staying wet during rainy season. As long as we open up drain holes, and clean out all the dirt, they'll last a long time.
okay so if I get all the dark spots out and I have all white metal, spray epoxy, then high fill, then block, then high fill again? or sealer? you said sealer was an option, does it have a needed use? so If I do a last coat in sealer and then wetblock one last time I am good for paint after that right? and the HOK KP-2 that is a sealer and a high build all together? still need and epoxy underneath though right? I just want this paint to be as bullet proof as I can make it with out having to take a second mortgage out speaking of which is there any other brand that makes anything comprable to the HOK KP-2 that may be more affordable? generally if it says HOK its cha-chingy$$$
hotdamn, it really depends on what paint system you are using, if you need a sealer, if it needs to be sanded before paint, or used "non-sanding". The type and color of the paint would also be a factor, though that is based more on experience, than scientific fact. Colors that don't hide well, could use a coat of sealer under them, esp. if the sealer can be close to the same color, or at least, the same shading (white/lite grey under white or yellow paint, med. grey under red, dark under black/dark colors) Some colors, such as Pearl whites, can also be sensitive to a bleeding effect of body filler hardeners, so a sealer is a great way to prevent that. I tend to use a sealer if painting over an existing paint job, or if the car has lots of bodywork, or under light colors. Esp. with base/clears. Acrylic enamels, single stage urethanes, not as important to use a sealer, as they cover well, color-wise, and are relatively thick. HOK is good, as it's a one product does all, adhesion, high build, and sealer. It is also relatively inexpensive, you can probably get a 2 gallon kit for a bit over 200. Unless you go with economy paints like Southern Urethane, I think HOK is the same, or less than most major brand epoxy/urethane primers.
oh thats cool, I guess I just always ***umed that it was super pricey. so I guess really since the KP-2 is a one stop shop I would actually come out better than buying it all seperate. as for the sealer I guessing it is kind of like a color tinted Kilz for cars? I know these questions are probably pretty elementry but I am green at this. I do appreciate you taking time to explain all of this! so do my blasting and get my white metal, spray it the HOK KP-2, block, sealer then paint? jeeze I'll get this right sooner or later
Some great info here. What bothers me most is the paint counter "experts" who all give me info that contradicts the counter person I dealt with yesterday or will deal with tomorrow... and then they give you slack when you want to return the product they misinformed you about. One of my buddies is an HOK rep, so I'm going to keep the $80 in primer I bought last week and shelve it and use the HOK system exclusively. One last question: if I already have some panels self etched and some in epoxy, is there a single product I can spray over those various dissimilar bases to get to the point where I can then spray ALL panels with the KP-2?
A list of good rust removal threads from another board to keep everybody busy. There is some good info and techniques for properly removing rust and preparing for priming. http://www.hotrodders.com/forum/gse...ric-acid-based-rust-dissolver-59237.html#1286
Hey, Both chopolds & overspray have given ya some solid advice to follow, and I'd like to add a couple of points that may/not be helpful.......... Today, thanks to the "Tree Hugger Faction" you can not buy primers/undercoaters that contain heavy metals like lead, cadminum & zinc for automotive use These metals are very dense by nature and would serve to protect & shield the metal beneith them from moisture, they also had great build! Now we're left with primers that are betting on the resins contained in them to protect the metal beneith them. DP 90 & DuPont's "Yellow Death" were great products before the ''Nanny-State / Mrs. Cravits' known as the EPA stuck their snouts inta our business Urethane resins are a tighter interlocking technology than epoxy resins. On the other hand, I've four fingers and a thumb & as Mark mentioned, HOK's epoxy primers can be used as a primer & as a sealer if overreduced a little. A tinted sealer is cheap insurance against many paint ills " Humpty Dumpty was pushed "
Hey, I'd DA back the self-etch, then wash & re wash with acetone & clean shop rags. Dust coat your first coat of KP-2 & inspect for any reaction before a second coat. And, didn't ya know ALL paint counter jockeys are "highly trained'' automotive refinish experts?..............jus' ask them " Do not reach greedily for the Kool-Aid ''
I didn't have a problem shooting black nitro lacquer over it, about 25 years ago, the car looks good today, except for the usual lacquer cracking in a couple areas. HOK used to sell lacquer custom paints, and and said it was OK. It's tough to find a good counter guy. Hell, if they were good body/paint guys, they would be working, making 3 X what a counter guy makes! Though sometimes you DO find an old bodyman who works the counter. These guys are like gold!
so chopolds what kind of paint would you suggest for durability on a daily driver that still has a traditional look to it. I have seen a lot of base/clear jobs that are a good color but it still just looked like a "new" style paint job and I imagine that laquer paint would most likely not fair so well on a daily?
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