There is a point of contention as to wether we want sealer on the metal before any filler or after? Bueller?
On Big Olds sealer was applied right before the shiny paint..... or at least it was on the pieces that I actually painted
on a big job where there is alot of metal work and body work I will do all the metal work then sent the body to be sandblasted when it comes back i prime the inside and out with one coat of acid etching prime then 2 coats of an epoxy filling prime that body work can be done on top of.
I'm going to use DP90 epoxy primer. If that makes a difference. And she won't leave the shop until she's shiney...
For me, I go in this order: Clean bare metal / Epoxy sealer / Filler / High build sanding primer / Sealer again. I sure hope that's right...I'd hate to have to go back and do it all over again
Sometimes cir***stances dictate dofferently. but I usually go with clean metal/epoxy primer/bondo/epoxy primer/high build primer (if needed)/evercoat 408 finishing putty (if need in low spots)/epoxy primer/base coat/ clear coat. Nothing like epoxy to make things stick to each other. Also, I apply another coat of epoxy after the bodo work 'cause you inevitably hit bare metal around the bondo) plus it's a good thing to have over the bondo anyway). BTW I've been building customs/show cars for 30+ years. HTH, ~ Paul aka "Tha Driver" There is no problem that cannot be solved with the right application of high explosives.
When people talk about sealer they can ussually mean 2 things. You can use an epoxy primer as a sealer on the bare metal to inhibit rust. then after you have done the body work and used the filler primer you use a primer sealer before paint. least thats what I use. HotRob
here are my 2 cents...I do all metal work. then bondo on bare metal,spot putty to take care of pin holes. and if there is only light or no visible surface rust I use a metal cleaner with a scotch brite pad,then a metal etcher/conditioner , then epoxy primer. then filler/primer. and once all block sanding and pin holes/sand scratches are done redo all bare metal up to the filler/primer step, then seal the whole thing,wet sand and paint....note;if you ask a hundred body man you probably will get a hundred ways of doing it and they all will swear their way is the right one.
The reason people put epoxy down on the bare metal is because polyester products(bondo) have NO corrosion protection, and any moisture that got on the metal durring the bodywork process will continue to rust the metal under the bondo, causing delamination down the road. If you spray epoxy on immediatley after you strip it you keep the moisture exposure to a minimum. And as a tip, polyester must NEVER be applied over etch, if you etch the metal then epoxy it, dont sand through it then put bondo on it, it will fall off. I accidentley put Polyester surfacer over etch once, and it came off in sheets within a week. And yes, everybody has there own way of doing things. I say if its straight and shiny, you did it right!
The last car I did was in the early eighties, so I am WAY out of the loop on current prep.paint technology. I've been reading and learning a lot from you guys. Thank you!!! The OTHER question I have is (not meaning to hijack the thread!!).... How long does way you do the application LAST? An awful lot of VERY GOOD body/paint guys never see thier work 2-3 years or more later. Which methode INSURES that I won't have to repaint my baby again in 5 years??? Do we have any history with the newer products? Thanks for being patient. Glenn
What I learned was to always put a coat of etch on bare metal. I don't like to use bondo because not only is there no protection sometimes it can hold moisture. But the car I have now has a load of it on there and it's quick and cheap, so... I suppose I can figure something out.
How long does way you do the application LAST? What? I can't even read that sentence without getting a headache. Please clarify.
My instinct, and what I've been taught in the past is to hit with the epoxy before any filler, so that's what I think I'll do... It makes sense to me and it seems to be split as to what to do.... so the truck cab is almost stripped completely.... the rest tomorrow..
If you can afford it, try using epoxy primer before you start with the bondo. You'll be surprised how it sticks & how much better it feathers! My jobs will last for a minimum of 20 years, if left out in the weather. I'd say at least 50 kept inside. My deceased mothers' Cordoba's paint job still looks good after 20 years; spent most of it's time in a carport & the last 8 years parked in the woods (thanks to my stupid brother & his daughter). There is rust coming through in a few places from the inside, which always happens if you let leaves & debri pile up around the trunk & such for 8 years, but the paint itself still looks great. ~ Paul aka "Tha Driver" It's been so long since I've had ***, I can't remember who gets tied up.
My PPG guy quoted the Co saying mud before primer or sealer. Evercoat products adhear and feather killer if you prep the metal with a Black Scotchbrite or 80g DA. Also, if it is RAW blasted steel, stay away from Etching primer, the acids collect in the pores and CREATE corrosion over time. Again, from the company, not me. But Z, like you said, it is 50/50 when you ask around!?
http://www.jalopyjournal.com/forum/showthread.php?t=8318 LONG READ--I don't think I could type it again. overspray
Zman- Slag's method (reply #3) seems to be the most used. I have used the same method with both PPG and RM with good results. We have a paint rep who does a lot of custom work, he also does the same. Good Luck
No question, this is the right way,stay with the same brand,PPG,Dupont whatever all the way. What would Scooby Do ? -------------------------------------------------------------------
well,I was with Tman going on a local rep's info which led me to believe that bondo/putty would not stick to primered surfaces.so I though it was a wasted step.I just finished reading overspray's post on the subject and this is what I got from it; before bondo ;epoxy- good etching-bad in a controlled environment my way would be fine, but in real life epoxy on bare metal is the way to go. p.s. I'm already working on my shading techniques
Please check with a chemist (not the sales rep) for the company whose epoxy or etch primer you use together. The phosphoric acid used in etch primers can affect the activator of some epoxies, possibly not letting the epoxy primer fully cure. Most epoxy primers should NOT be used over etch primers for this reason. Good quality urethane primers can be applied (wet on wet) over etch primers. Check with the system the manufacturer reccommends and get as much information as you can. The BIG keys to putting filler over primer are: 1-the primer needs to be cured with all solvents evaporated before filler is applied-and then scuffed for mechanical adhesion of the filler. 2-the primer film should be dense enough that styrene (the solvent in filler/polyester resin) will not soak into the primer and cause a separation problem later. overspray
I've started doing my Capri and the gal at Ben's paint shop told me to use DP over bare metal, no etching primer and apply body filler over it. I've almost finished my trunk, by golly did it have some hidden rust, it's all fixed ready to be primed. Factory red primer is some tough **** to strip. This car will have to be stripped to bare metal, there's no way around it. This time I'm using only top of the line paint and I'm not buying anything from Central Paint And Body Supply anymore, they ****.
Epoxy is the ONLY primer - only THING - you can bondo over other than bare metal or fibergl***. Never bondo over anything else. As stated before, bondo can absorb mosture, & with the epoxy under it you eliminate the possibility of that causing rust. That combined with the fact that it sticks better & feathers better is the reason I (almost) always use epoxy under bondo. As I said before sometimes cir***stances dictate jumping into the bondo first, but that rarely happens. You may want to invest in a trim gun for shading - if you haven't already. The big guns work OK, but a trim gun makes the job a little eaiser (plus you have the different colors in different guns in case you need it). HTH, ~ Paul aka "Tha Driver" Since I gave up hope I feel much better.
Epoxy primers come in different varieties and today's formulas are usually lead-free (LF) or chromate free. The absence of lead and zinc chromate in the filler materials used in epoxy and other primers is safer but lessens the effectiveness of the sealing capability and moisture/rust inhibiting quality of the product. There are still some good protective epoxies with good solids content available-but most of these are found in industrial or aircraft finishing products. If anyone has some good high solids epoxy primer information that they have good experience with, please add the name and company to this post. Todays DP epoxy primers/sealers are lead free and sometimes chromate free and low in solids. They don't have the sealing and rust inhibiting qualities that were available in the original formulas of 20 to 30 years ago. 20 years ago PPG had better high solids epoxies in their aircraft line-DPU35 for one, and another I can't remember the part number for. These time frames are when putting body filler over epoxy primer started to evolve as a technique that was still not thouroughly proven as a surefire effective method of corrosion control for bare metal under filler. Also it was reccommended in the tech sheets for most epoxy primers, that bare metal be prepped with metal conditioner/treatment and cleaned prior to the epoxy being applied. Epoxy does not nuetralize rust. It will work to put filler over epoxy primer and also most 2 part high solids catalyzed primers as long as the primer film has cured and released the solvents/thinners in it and is not affected by the styrene in the filler. Most of todays fillers/bondo have new resin technology that gives the adhesion a level comparable to epoxy glue. The phosphoric acid in etching primers can drastically slow the cure of body filler/polyester resin so this is not reccommended for use under filler. Phosphoric acid will also affect the activator/hardner of some epoxies. Etch primers are very good for what they were designed for and come in different application varieties. Always consult the manufacturers tech sheets. When using metal etch products (acid based) always use caution concerning the possibility of acid residues left in the film before applying something on top that could be affected by the acids such as:epoxy activator/hardner or polyester/fibergl*** resins. Sealers for application between the undercoats/primer and the topcoats/paint are usually limited in how effective they are at stopping solvent penetration, especially when the paint is applied wet on wet to the sealer. If you can take a rag with solvent from the paint and wipe off the fresh sealer coat even after 30 to 60 minutes, how effective are they at sealing. Most of these are really "tie coats" that help bond the 2 layers together. Most basecoat paints are actually better "sealers" when it comes to solvent penetration due to the parafin used to orient the metallics and pigments, but these will still let solvents thru. The best "sealing" is accomplished by good quality 2 part high solids primers or fully cured 2 part paint finishes. Tie coat sealers or epoxy sealers/primers are still a good part of a complete refinish system. overspray
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