After reading this board for 2 months or so, I'm losing my courage to tackle my '39 Sedan. :( The technology has evolved so much in the last 20 years, that I'm scared that all the work I put into the car will be a waste of time. Even full time painters are doing stuff wrong. (Supra White 66 - blotchy) I can easily handle the metalwork as far as rust removal, panel replacement, dent removal, etc.
Where I'm getting nervous is this:
Because this is a hobby, I will be taking one body panel or area at a time. I won't be able to do everything over a weekend. (And it gets colder that heck here-so I run the heaters)
I sand down the one panel to bare metal, replace the bad section. Do I metal prep, then etch prime and seal prime, or is it right to just do the metal prep and etchprime? Does etch prime still absorb water? Now, after I have the body close with the metal work, I have to seal prime the whole car before applying any bondo or filler, right? And when blocking the car out, I have to reshoot seal prime anywhere I sand through ? After final blocking, do I shoot the whole car again? Then I can send it to a real painter for the color coats.
Before I even start this, though,I should find out the product line that my painter uses, and use his brand for the etch, and sealer, right?
OK, I got my 66 questions in... Thanks guys!

Help?

If you want to use filler over primer you have to use special primer just for that application. I did my 72 and I'm doing my 70 a panel/section at a time. Strip it, fix it, bondo it, acid it (171/172) if its bare metal, not good over the bondo they say. Then K36 high build primmer. Then move on to the next panel. When I had all the body work done. I blocked the car and reprimmed where needed. I used a high quality paint from PPG so I didn't need a sealer, but could have used one. I then disassembled the car, painted/cleared the jambs, inside of the fenders, inside of trunk and under the hood. Then I moved the car to a buddy's paint boths, reinstalled the fenders/doors then shot the body, fenders etc. After everything dried I reassembled the rest of the car (hood trunk lid, valance, fender extensions, etc. After several days we wet sanded and bufffed it out.

First if you have the entire car in primer surfacer there is NO NEED WHAT SO EVER for sealer. What are you planning on gaining from sealer? First off it adds unneeded orange peel to the surface, 2nd film build up.

Ive always thought that someone who HAD to shoot sealer over primer surfacer was covering something up. Now I do know YES there are times when sealing is needed but always?

You can apply filler in two ways, the first is the OLD school method of filler on bare metal. The other method is appling filler over epoxy primer and ONLY EPOXY PRIMER. The only time Ive done the filler over epoxy is when Ive welded something up and shoot a coat of epoxy over the weld seem to give me that warm fuzzy feeling inside. Is filler over epoxy the way to go, I dont really believe so in EVERY CASE but its a good thing to be abel to do.

On bare metal Id go with an etch primer, some say epoxy primer. Etch is the only way to go when dealing with bare metal its the best route to go for fighting rust. Do a search you'll find tons of info dealing with etch primer.

So basically if you wanted to go with the filler over bare metal method, do your mud work first. Once straight apply one coat of etch, PPG DX1791, dupont's variprime, or S-W EGB980.

NEVER EVER APPLY BODY FILLER OVER ETCH PRIMER you can apply etch over filler thou. The chemical reaction that the filler goes throu WILL loosen the etch causing it to lift.

Once you got your etch primer on you can apply the primer surfacer(the primer you sand til level). I like PPG K38, builds nice sands nice, better primer then k36 in my book.

Now if you wanted to go with the filler over primer method then apply your etch primer first then apply 2 coats of epoxy primer like PPG dplf90. Now remember ONLY epoxy primer can be used under filler. Allow 2 days for the epoxy to cure then scuff lightly with 80 grit then apply filler. Once done sand entire part then apply primer surfacer.

Also NEVER use a metal prep and etch primer. The acids in the different products will react and cause problems later down the road if not right away. Also no paint company that I know even recommends the use of metal preps anymore its all etch primer...Eric

Eric,
if you go bare metal and then filler, is there really an advantage to applying etch before the K38? Only reason I ask is because the most likely place for rust to form would be on the welded seams which are under the filler. If the seam is 100% with no pinholes wouldnt it be simpler to apply the K38 over the bare metal or wont it stick?

2nd question..if you have the whole car in K38, let it cure a couple weeks and then block with wet/dry 400 do you normally spray the color coat right over the K38 or do you use a sealer coat?

Dave, yes there is an advantage to using etch after the filler.

A primer surfacer is not meant to be used on bare metal, althou it does state for use on clean sanded metal. Just saying if you have a sand throu or two then primer surfacer would be fine over metal but NOT something like an entire fender or door.

Etch is the best base for a solid foundation in my book, am not a believer in epoxy on BARE metal. The etch primer also aids in adhesion, if you look on any PPG tech, the primer surfacers all call for a etch to achieve MAX performance even the so called DTM(diret to metal)primers like the NCP series of primers.

Etch has proven its self to me time after time for being the best base agaist rust and adhesion. All the info writting the tech sheets be it PPG, dupont, S-W, and I recently got Spies Hecker sheets all call for a etch primer to be used as the first product on bare metal.

Now on ALL welded seems do I do the filler over epoxy...NO. About the only times I really do filler over epoxy is when I feel that moisture could some how get in there. Say if you did a patch patch on the rear bottom quarter, kinda an area exposed to more water or dirt then the rest of the car. Another example when I restored my father's 45 John Deere B tractor, the area where the muffler comes throu the hood is also near a water pipe. I welded in a patch around the muffler did the etch, epoxy then filler as that area gets lots of condension(sp?) so I wanted that barrier of etch and epoxy on the metal.

As for the 2nd question, I use NO sealer, I feel there is NO NEED for that product. You really dont have any better base for paint then sanded primer surfacer. Like mentioned before sealer can add un wanted orange peel in the finish. Now dont quote on this but I do believe that all of PPG sealers are converted primer surfacers, K36,k93,ncp272. Now the only time a sealer is needed on any primer surfacer in the PPG line is when you are appling DBC BLACK basecoat. Why that is I have no idea, something Ive be meaning to ask the rep but keep forgeting.

You are also right in the thiking of allowing the K38 or whatever surfacer you choose some cure time. I like to allow 1 week inbetween blockings to allow the surfacer time to shrink down. Last winter I did some testing on the K36 primer and found it shrunk down almost 12-13%. :eek: I have not done any on k38 but still prefer it over k36 as it fills much better also its a higher solid then k36 so shrinkage would be less.

So NO I dont spray sealer on a car with sanded primer surfacer. I know to some painters that step is a most have but to me its unneeded...Eric

graemlins/hurray.gif Awesome thread. Eric, you rock. That was VERY informative for a beginner such as myself with clear cut examples. Dont get no better then that , bud. right on. graemlins/thumbsup.gif

Eric-
Let me just regurgitate your info so I'm 100% clear..
Sand to bare metal, weld/patch, wipe down w/ tack rag -no solvents, ETCH prime, 2 coats Epoxy Prime PPG DPLF90,let cure, scuff w/ 80 grit, body filler, K38 Surfacer/primer, move to next area, do the same until I'm happy with everything, block car out, send to painter, get drunk and relax.

Did I get it all right?

Thanks !!!!!!!

I liked the filler over epoxy method, so I had less "exposed" time. Too nervous, I guess.

Yes you are right on the steps.

The ONLY thing I would add to that is right before you apply ANY type of product to the metal you should blow it off with compressed air, then wipe down with a wax grease remover. Oils from your hands can remain on the metal which can ruin a paint job. Will paint start flaking off if you touch bare metal NO, but its just good practice to wipe the metal clean. A paint job is only as good as the FIRST step.

I like PPG products because thats what I learned to paint with and feel most COMFORTABLE with. I KNOW what I can and cant do with the products. Ive used Dupont, S-W each have good and bad points about them. On this project chevelle am starting on am gonna try some Spies Hecker, which is a HIGH END euro paint. Ive heard nothing but great reviews about Spies and am the type of person that believes if something out there works better then I wanna try it.

Anyway a PPG wax and grease remover would be DX330 or 440. Id stick with 330. Also when you get ready to apply the k38 or whatever type of primer surfacer you choose, Id wipe the entire area once more with the grease remover. You'll be amazed by the amount of sanding sludge that still remains even after blowing off with air.

To apply this cleaner you can do it 2 ways. the first is take a clean dry towel fold it in 4ths then pour some cleaner on the rag. Wipe the area, continue to fold over the rag so you arnt wiping the entire area with that same side. Once you got the door or fender wiped then take another DRY CLEAN rag and wipe that part dry. You dont want to allow that cleaner time to dry on the part which can cause fish eyes. So you want to wipe the part dry after wiping it clean.

The second method of appling the cleaner is pouring some into a squirt bottle like an old windex bottle, I use a small portable sprayer used to spray horses to rid them of horse flies. Anyway you squirt the cleaner on the area just enough to dampen the surface no need to hose it on, then take your DRY CLEAN TOWEL and wipe dry.

So the steps would be sand to bare metal, weld patches, do hammer dolly work. Blow off with air wipe surface clean with grease remover, apply ONE coat of etch, two coats of epoxy. Allow say 2 days for curing, scuff sand with 80 grit just enough to yo give the filler(Id go with Evercoat's Rage or rage gold) some tooth to bite to, apply filler, sand til smooth. blow off with air, apply cleaner, apply primer surfacer.

Sorry to be so long winded and not get straight to the point smile.gif ...Eric...one ticked off Cubs fan graemlins/angry.gif

Eric,
Thanks a TON !!! I feel like a 4200# Chevy has been lifted off my shoulders ! Reading all the "nightmares" had me pretty skiddish. I'll be ordering the replacement panels in the near future. (As soon as I get the shop cleaned out again.) graemlins/beers.gif

Thanks again !!

Jeff

I've been doing the filler over epoxy deal for about 10 years now and believe me it makes a great deal of difference. The epoxy is a moisture barrier and also an excellent substrate for filler to adhere to. I also epoxy over the filler work for an additional moisture barrier before primer surfacer application. You will not see this technique used in high production collision shops because it almost doubles the in garage time for the repair. Another quick note on filler application-don't just slap the stuff on like frosting on a cake. Polyester filler is loaded with small air pockets that you don't want. Apply a quick coat of filler with pressure and quickly scrape it back off then reapply the filler. The scrape off is to eliminate any chances of an air bubble contacting the substrate and compromising adhesion or worse yet providing oxygen to start corrosion---and again this is where the epoxy barrier helps big time. Ever see old filler repairs with bubbles not from metal pinholes but from actual surface rust under the filler?-I guarantee the rust started when the filler began taking in moisture or air bubbles were trapped between the filler and bare metal. I truthfully think a job done right with today's materials can actually last 30plus years with good maintanence. Corrosion protection is simply a matter of keeping oxygen away from steel period. Do the job panel by panel, take your time and do it right and the rewards will be worth every minute. graemlins/beers.gif

I have read your thread here and need to ask a question...Here goes.....
I stripped and sanded my 66 down to bare metal and fixed all the dents and rust with new steel & body filler on bare metal.Before ever coat of filler I blew off with compressed air & wiped off with Laquer thinner the area I was working on, then applied anougther coat of filler.
I have not primed anything so far. I have been working on this in my garage all summer.
Do you think there is rust under the filler now?
:confused: :confused: :confused:

If the rest of the bare metal areas show no sign of corrosion then the area under your filler is fine. But I'd get primer on it asap before any starts.

Good advice from everyone. Maybe it has touched on and I missed it: in between skim coats of body filler I've always found it good to run a wire brush over the hardened layer of filler as an adhesion test - sometimes more than I expected comes off. Better to find out the bond isn't good before you get paint on the filler.

Thomas

You guys make it sound to easy. If I keep reading I will have convinced myself to do some of my own bodywork smile.gif

Caleb