Bare Metal question

[NHCharger]

I'm currently working on a 68 and have been using my body guy (Don) as a sounding board. Don did all the bodywork and paint on my 71. The plan was for me to do all the bodywork on the 68 and prime it and Don would do the paint/clear. Don came over last summer after I had replaced the floor pans and trunk floor and was ready to start bodywork. He told me to strip the car to bare metal, do the body work, then epoxy prime with a product called max fill that he gets from his paint supplier. I was concerned with leaving the metal exposed for a long period of time. With my work schedule I'm happy to get 10 hours a week on the car. Don said the conditions in my shop (extremely dry) presented no problem with leaving the metal exposed for 5-6 months.

I decided to only strip the metal when needed. Plan was to do the back half of the car which needed the most work, then prime it. Then work on the doors, fenders, hood and trunk lid which need minimal work. I stripped the driver side quarter the first of November. The passenger quarter in January, roof in February. I need to do another 2-3 hours of sanding and I'm ready for primer.

After reading some other threads here it's obvious that Don is old school and I should have stripped the car, done the welding,primed it, then apply the filler. It appears I should now spend some time with a flexable sanding board and sand down all the bare metal with 80 then 180. Would that be good enough to remove any rust? There is not a hint of any rust on the panels. Still confused on what to use for a first coat, I've ready so many different opinions. Epoxy primer first, followed by Evercoat Slick Sand or Feather Fill G2??

Any advice would be greatly appreciated.

[1BAD68]

I'm in the same boat sort of. There seems to be as many different ways to do this as there are people doing it. Not to mention as many different products to use.
I decided I'm taking the advice of my local paint shop, that way if there is problem this guy will actually come over and walk me through it.
Sorry i can't help you other than say good luck.

[b5blue]

  Same boat for me only high humidity and heat under a carport! Some epoxy primers have acid in them to bite into the bare steel. (SPI brand is one, Kirker has none.) I'm using OSPO as a rust convertor (Like Picklex) so I must NOT use an epoxy primer that has acid.
  I posted a topic on this and everyone insisted to base prime with epoxy primer first, so that is what I'll do. It can be used as a sealer also over other sound/stable coatings (Kirker's) so some areas need not be bare steel if they are OK.
  My main advice is to check the web sight's Tech section and be certain of compatibility for products and procedures for all products used! 
 

[Silver R/T]

work on it panel by panel. As you strip one panel epoxy it with good epoxy primer like SPI

[HOTROD]

I Finley found something that works and my car sits outside ,Green Dupli-color self-Etching primer from your local parts store !!

[Silver R/T]

I Finley found something that works and my car sits outside ,Green Dupli-color self-Etching primer from your local parts store !!

Throw that away, it's not meant to protect metal and you'll just have problems with it down the road

[NHCharger]

work on it panel by panel. As you strip one panel epoxy it with good epoxy primer like SPI

Silver. I found a guy that will media blast my doors, fenders, hood, trunk lid for 80-90 per piece which I thought was a fair price AND will knock about 40 hours of work off my plate. So I plan on having him do all of them at once and i will prime them ASAP.

My main concern is what to do with the current bare metal and filler on the car and the best way to primer/seal it and continue forward. I should be ready for primer by next week end.

[Silver R/T]

work on it panel by panel. As you strip one panel epoxy it with good epoxy primer like SPI

Silver. I found a guy that will media blast my doors, fenders, hood, trunk lid for 80-90 per piece which I thought was a fair price AND will knock about 40 hours of work off my plate. So I plan on having him do all of them at once and i will prime them ASAP.

My main concern is what to do with the current bare metal and filler on the car and the best way to primer/seal it and continue forward. I should be ready for primer by next week end.

Which media is he going to use? If it's soda, make sure you neutralize it and get it all off the panel before priming.
Epoxy primer it. It will seal it off and you can work on it when you are ready. You can use PPG or SPI for less than 1/2 cost of the PPG.

[Chatt69chgr]

I talked to Southern Polyurethanes, Inc. about my intended procedure.  I'm planning on having the car media blasted.  The shop I will use employs crushed glass.  I'm not real sure what the surface finish will end up like but Barry at SPI said I could apply his epoxy primer after the car is blasted and wiped down with his water based grease and wax remover  (no laquer thinner).  He wants me to sand the outer panels with a 80 grit DA first but the trunk, inside, engine compartment and underneath don't need this step.  He said that the epoxy will stick to the bare metal just fine but the sanding step adds a extra mechanical bond to help against chipping.  After that, I have a 7 day window to apply the Evercoat Slick Sand my body man likes to use for blocking without sanding the epoxy.  After that, I would have to sand the epoxy before the Slick Sand is applied------Barry was OK with using the Slick Sand on top of his exoxy.   I plan on using Evercoat Rage Gold for any filler work.  The shop that's going to paint the car will then sand everything lightly and apply a Sherwin Williams 2K urethane sealer before base coat/clear coat.  I'm probably going to use Sherwin Williams premium product (I think it's Ultra 7000) for this.

Note that you have to get all the rust off before the epoxy is applied.  The only way to get it off in the depths of pits is by blasting.  And Barry was quick to say that applying acid type metal treatments is an invitation to not getting a good bond of the epoxy to the bare metal and potential future delamination. 

I have worked on the unibody myself ahead of time removing rusted surfaces here and there, undercoating, and body seam sealer.  Exposed metal was sprayed with cheap rattle can primer to stop rusting.  The media blasting will remove this. 

[73rallye440magnum]

  Everything we blast with silica we DA sand with 80 grit before spraying with epoxy primer. We use Sikkens and Dupont undercoats.

Also, if you can avoid burn throughs on your final sanding it is to your benefit to not spray a sealer. No sealer equals less solvents trapped beneath your clear, and less wobble on your panels.

If the rep and your body man say it's okay, go ahead and put filler over epoxy without scuffing. I sleep better at night knowing my epoxy was scuffed before filler was applied though, for the same reasons you mentioned in your post. Chemical and mechanical adhesion.

I'm not trying to shake your tree, just sharing information and my opinion. 

[superbirdtom]

over bare metal use  PPG epoxy sealer . its not called primer. all metal work sandblasting should be done before youseal the entire car.  make sure to get rust pits out with kleen blast.  or what ever removes rust pits. .  if you let your sealer set awhile just scuff up with red scotchbrite pad and wipe down with some mILD wax and grease remover  then a tack rag.  crystal brand tack rags are the best I have found. ( i do this stuff every day . ) like kleanz ez from napa.  tou could recoat with the ppg sealer or just do your bodywork.  bondo sticks better to sealed surface better than bare metal.   then reseal where you break through to metal again in places,.....dplf - 50 ppg grey is what I like for sealer. I actually once sealed a bare metal car then used some k-36 hih build primer . and it set outside for 2 years and rain didn't affect it at all. the primer is practically waterproof as long as it has not been touched with sandpaper.  i know  it lasted as the 73 road runner was brought back into the shop 2 years later and looks good to this day.  no bubbles or anything. that was 7 years ago.
                                                It sat outside as the guy ran out of money usually  its not a good idea.  but was an interesting forced experiment.