I'm sure this has been addressed before, but I couldn't find anything in the 'search' function about it. Anyway, I eagerly sanded my car down to bare metal before the Memorial day Paso show this year, with the intent of putting it in paint beore the show. Well, that didn't happen and one thing lead to another and... TADA! it still isn't painted. I shot it down with WD-40 before Paso & am now a little scared of the prep that will probably be involved. In recent months it has developed LIGHT surface rust. Now it MUST get at least a sealer coat on it before winter or I'll really screw myself. What steps would you take to A) Get rid of the WD-40 residue, B) remove the surface rust, C) Prep for paint? Any thoughts appreciated. -r
A) Get rid of the WD-40 residue - --laquer thinner, do one quick cleaning coat to remove most of the dirty residue. Then wipe it down two or three more times untill the rag is clean.. be carefull around seams.. it hides there.. you might want to flush seams and hard to reach areas clean with some aresol carb cleaner... B) remove the surface rust --I typically mechanically clean the surface.. if is lightly rusted i'll hand or DA sand with a 100 or 120 grit or even course scotch bright.. of course you need to be careful not to remove any significant metal or for heat which will warp the panel.. if the thing is pretty rusty i would have it media blasted... there are some chemical coctails that work pretty well... i haven't personally used em but i know some folks that have, check eastwood and local autobody places.. C) Prep for paint? --this is the tricky part.. you really need to treat the metal right away after cleaning.. even leaving the car bare metal for a day or so is a no-no since rust will already start forming... be ready to prime as soon as you are done sanding... I haven't used DP yet and use kinda an old school approach to prep: 1. scuff entire car with course scotch brite 2. wipe car down with prepsol once or twice 3. prime "dirty" or hard to reach areas with oil based or stops rust primer.. 4. etch primer car for one or two coats 5. two coats of sandable surface primer/sealer.. 6. FLAT BLACK!! I hope that helps.. Any thoughts appreciated. -r[/QUOTE]
Prep Sol or Paint Prep #5900 by Autobody Master to get rid of the WD-40, Dupont Metal Conditioner 5717S to kill the surface rust and prep for primer. Just follow the directions. No need to be afraid of a little rust. Like the old timers say, "If you can't push your thumb through it, it's good to go." pigpen
Hey Randy, The least expensive solvent, that will cut the WD40, is going ta be mineral sprits (paint thinner), plan on usin a lot of it to clean the surfaces of your vehicle. Sprits takes a much longer time to evapor- ate vs lacquer thinner, giving ya a longer window ta sop up all that oil on the surface with clean rags, before ya push it back into the pores of that raw steel. Use as many clean rags as it takes, untill nothing comes off on a clean rag, probably two-three times all around the vehicle. Plow dry with compressed air, again wiped with clean rags. Next, use metal conditioner (diluted phosporic acid) and course steel wool to scrub those rusted areas. Wipe those areas again, until you get nothing on a clean , soked with metal conditioner, rag. Treat all of the bare metal areas with the metal conditioner following the direc- tions on the container. Ya didn't say anything 'bout what kinda finish you want ta top coat with, poly, epoxy, lacquer etc. Not all paint products can be successfully sprayed over one another. Be advised that primer, and or sealer are not waterproof, and will not stop rust from forming on the steel beneath them, ya know the stuff ya worked so hard ta clean up to begin with. A bad paint job is better than no paint job when it comes ta holdin off rust.
Maybe somebody that has some scientific knowledge of how liquids behave can explain something to me. I was told by a Tech Guy that a liquid can travel inside a small crevice, like a spot weld seam.( straight up even...) I guess it has something to do with the surface tension of the liquid, or something like that... We were discussing a certain early French unibody Car, and the Liquid was Water ( with road salt in it ). I can see how Water would evaporate in time ( leaving the salt to do its nasty work ), but what would happen if a seam filled itself with a oil product? Would a penitrating oil react the same way? ( I guess it would, thats what its supposed to do, right? ), and if so, you couldn't get it out, because the way it was explained to me a liquid will do that only if the seam is dry. Is any of this true? If so, would having some oily residue in a seam be anything to worry about? ( like after the Car is painted ) Or was the guy I talked to full of ****?
Orange Blast Greased ligntning, at Wal Mart in the auto section will clean off the WD-40 and the car will be ready to paint, I think It is only a couple bucks per spray bottle.... LUKESTER
It's called "capillary action." http://en.wikipedia.org/wiki/Capillary_action It's the same principle that causes a lit candle's melting wax to travel up the wick, also against gravity. --Matt
I can tell you that what you describe in re to liquids "creeping" in small gaps is correct - I believe the scientific term for liquids that have this property is "thixotropic" (sp?), and it is indeed a function of the liquid's surface tension (actually "capillary attraction" which is combined effect of surface tension, viscosity, etc.) Unless I am mistaken, WD-40 was designed specifically to be a highly thixotropic material - WD stands for "water displacement" the stuff was originally designed to displace water in electrical circuits (I think) - in addition to being thixotropic it is also "hydrphobic" being mostly silicone which displaces water. Many other lubricants are thixotropic - a good thing if what you want is a substance that will get-into small cracks in a wear surface to produce a lunbricating film. Of course this is a bad thing if you are subsequently going to want to clean the surfaces and remove all the material - I am not a painter but I am surprised nobody mentioned the concern with "fish-eye" effects that is usually the reason painters do not want silicone-based materials around their shops! When you have thixotropic WD-40 hiding in cracks and seams it will likely cause big-time "fish-eye" problems with any paint applied to the areas! I observed some "fish-eye" problems when painting my '55 Chevy a few years ago and invested in a "fish-eye eliminator" product to try to prevent it. It worked pretty well but is very expensive - don't know the chemical make-up, but I doubt it would help much if liquid WD-40 hiding in a seam was leeched-out into liquid paint on the surface - I imagine it would be a real mess!
That is what I suspected... Thanks for the info Deuce Rails and mr5by5. I will keep my Roadster in bare Metal, just like it has been. When its time to get it Painted I know I can take care of surface rust...
Not that this will help you now, but for others doing the bare metal thing this stuff is supposed to be great, and creates no paint problems. I wanna try some soon, its called Gibbs, heres a link with info: http://www.roadsters.com/gibbs/
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