I'm doing my car's body as time and most importantly $Money$ allows me. There's a lot to do so I have to work on one small aria then on to the next and there will be time spacing the repairs. For some reason rust seems to be real bad in this aria it might just be my yard but rust seems to form as I'm watching, its really ridiculous. What I'm looking for is a primer that will seal the metal to keep the rust off but I can still come back to it an add some filler if I need to do more work on it and if its possible the kind of primer that helps fill pin holes and scratches. Is there a product that combines these properties? Keep in mind that I am a novice so I'll be coming back to do repairs on the same spot over and over again before I get things right. Thanks
First of all, the undercoats you use must be compatible with the topcoats you plan to use. Too often people cheap out on primers/sealers then wonder why their expensive, incompatible topcoat ends up looking horrible, or worse yet, falling off. I'm a few years behind on the latest technology, but the primer you describe that is best for coating steel and then applying filler over the primer is a low-build, two-part epoxy primer, which unfortunately is not cheap and requires robust safety equipment to keep you healthy. It's awesome stuff though, I have a hood that was chemically dipped in '86 and immediately covered in PPG DP-40, and it's been sitting in an unheated garage since then and shows no evidence of rust, even through 26 years of climate and humidity changes. After epoxy primer and body filler, you can add a layer of high-build primer which can further help you fill very minor pinholes and scratches. Keep in mind though that epoxy primer has a narrow window of working time in which it's ok to topcoat with filler or a different primer. If you wait too long, the epoxy primer has to be scuffed and another coat of epoxy should be applied so that further topcoats are applied inside the window of working time, adding time and cost. Hope that gets you started with the project. Cross your fingers, there may be more low-cost products available now that will serve you better than what I described. Devon
Thanks for the fast response Devon I hope there is a less expensive rout to go, my money tree has taken a beating lately and I think it's dead. Is the PPG DP-40 the epoxy primer your recommending? I know what you mean about the prime coat having to be compatible with the final coats of paint, the foundation pretty much determines the final out come of the finish. That epoxy prime can take about any final paint can't it?
That I don't know, Pete. I don't even know if PPG sells that line of epoxy primer anymore. With luck, there's a high quality equivalent that costs less and less harmful for your health. Speaking with your paint shop would be a good bet regardless of what line of materials they carry, then let us know what they had to say. Devon
Epoxy is your best bet, it is spendy though and PPG is probably the high end. I'd still use PPG or another good name over the no name stuff because it just works. Make sure to do all the proper prep first though. Also talk to whoever sells you the stuff as some doesn't stop water or rust as well.
If you are trying to save some $ then another high quality primer line is Southern Polyurethanes (SPI)....they manufacture and sell a high quality line of epoxies, etc and prices are excellent. You should give their products serious consideration. They also have excellent tech support, an online tech forum, etc. Worth your time and $.
Looking at the SPI primer .pdf sheet I see it says " Precautions: NEVER use SPI Epoxy over a Soda Blasted vehicle, Acid Etch/Wash Primer, Rust Converter or other Metal Treatments. NEVER!" I wonder why? It gives no reason, or alternate method. Anyone know?
Thanks I definitely need something that is sandable as I'm sure I'll have to come back to it and do it again, its like I said I'm quite inexperienced at body work but I am picky so I'll go over the same thing dozens of times whether it needs it or not. I'll get it right eventually. Thanks ---------- Post added at 11:38 AM ---------- Previous post was at 11:29 AM ---------- Thats a tough one I guess they want bare metal I'll have to read up on that. The only thing I've used on that list is the rust converter but I hate that stuff black fingers and all so no problem cutting that out, still it seem awfully picky for a primer.
I have no experience with SPI, but there's a ton of information and discussion for you to look into here: http://www.spiuserforum.com/forumdisplay.php?25-SPI-Product-Specific-Discussions Devon
SEM and 5 Star both have a high build epoxy primer that is sandable and can be used as a direct to metal primer , a high build primer, and a sealer just by adjusting the thinner ratio and cost a litlle bit over $125 per gallon......i have used these primers on past and present projects with very good results....the only problem is that the primer takes a little more effort to sand than urethane primers but is as hard as nails when cured
Here you go! Not real expensive. I used this on many cars years ago when working in a shop. We sprayed Dupont over it an had no issues. We would spray this and then block it with 180 grit and them reprimed it and finished it wil 400 grit prior to painting. This stuff didn't shrink even when baklng it in the booth when it was actually being painted and clear coated. We didn't bake the primer to dry it we had it sit in the prep station over night. Any products you use wear protective gear. Chemicals will kill you...................sometimes a slow death. http://www.tptools.com/p/3183,201_Clausen-Z-CHROME%E2%84%A2-RUST-DEFENDER%E2%84%A2-Sprayable-Primer-Filler-Sealer.html] http://www.clausenautobody.com/library/Rust_Defender/Rust_Defender_Handling_Instruction.pdf
Thanks for the tip that does look cover most of my concerns I'm really flying blind here so any help is appreciated
I've been using dupont 2850 dtm direct to metal for years ,works great ,really user friendly. Can be used as sealer also. Strip to metal, prime and do the body work as you have time. But make sure you use a respirator it's bad stuff.
One of the best products we have ran across to clean the metal prior to epoxy priming is Glasurit 360-4 Metal Cleaner. It's potent stuff, you really need to wear a respirator when using it. Regular wax and grease removers do alright, but if you first clean it with one of those, then go over it with the Glasurit, the towels will turn dark gray from all of the surface contamination it picks up. The adhesion of any primer will only be as good as the cleaning of the surface. The Glasurit products are pretty much top of the line, and no more expensive than PPG or DuPont but better quality. We have also had good results with the R-M EP 569 epoxy primer. R-M is made by the same manufacturer as Glasurit. ---------- Post added at 11:46 PM ---------- Previous post was at 11:34 PM ---------- Soda blasting leaves a film that primer will not ahere to. To prep a soda blasted surface, it works good to scrub thoroughly with Comet and scotch brite and rinse extremely well with water and dry as quickly as possible. You never want to use epoxy primers over an acid etch or wash primer as they are not at all compatible. The acid will interfere with the curing of the epoxy. The rust converters and metal treatments leave a phosphate coating on the surface that will interfere with the zinc phosphate or zinc chromate in the epoxy primer, possibly causing a loss of adhesion. Not all epoxies have either of these ingredients, such as the PPG DP 40, as they actually recommend a metal treatment.
