Factory primer in 67?

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dustya_383

dustya_383

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Hey guys been a while since I've been on the site. Been pretty busy as of late but anyways, I started doing the body work on my 67 fb cuda. Car was repainted by previous owner some 30ish years ago , so I used aircraft stripper to get car down to metal to start fresh , I got down through most of the layers but now I'm down to this red layer which I'm guessing is a corrosion protectant of some sort or an etch possibly an etch??.. So it has factory paint coat , a primer coat ,Then this red coat which I don't know what it is and then that's on top of the bare metal.......

So my questions are ... What is this coating?? And since my car does not have any rust on it .... Is it ok to leave that red coat on the car and lay my epoxy primer over it ?... What I'm trying to do is save my self from sanding off if it can actually benefit me and provide more protection ...

I'll try to post a pic see if it comes up but you can see all the coats in this picture
The dark blue which last owner sprayed,then a primer under that , then the factory color which is a blue/sliver , then another primer coat , the red coat and then bare metal


Thank you all in advance sorry if it's a little confusing trying to describe best way possible
 

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The primer surfacers used in the 70's we nothing special. The Big 3 paint manufacturers (PPG, BASF, Dupont) knew it was a good way to use up off-spec resins and misc. intermediates. In other words use up scrap materials.

The backbone resin system was a polyester base material. The cross linking (curing) mechanism was a thermo-set catalyst. The curing temperatures were around 425 degrees F and the dwell time in the ovens were normally 30 minutes at the desired temperature. There was usually a 20 minute ramp to temperature and a 30 minute cool down period. Bodies coming out of the ovens were normally too hot to touch for about a half hour.

Batch quantities were usually around 5000 gals on average. From what I remember you could get various shades a brick red or a medium grey colour. Again, colour dependent based on what "scrap materials " the manufacturers were trying to use up.

As far as durability goes with thermo-set polyester primers, sometimes you get a good primer and sometimes you get a great primer. It all depends what off-spec materials were used or not used during the batch formulation process. Today's primer surfacers have vastly improved in durability and corrosion resistance from the old polyester material.

Rust resistance was fair at best, mainly because of the pre-treatment products used. Chip resistance was actually very good for such a in-flexable product (surface hardness). Solvent resistance was good also, thus explaining why your stripper wouldn`t move the material.

Yes, you could leave the original primer on the vehicle but there may be hidden problems that you can`t see with the naked eye. If it were my car I`d remove the material mechanically, metal prep it, and put on a good 2K polyester high build primer. Use DP primer first if there is bodywork involved. This DP primer will seal the metal surface. Flash rust takes very little time to develop.

I hope this helps. Good luck with your project.


If you need further advise PM me and I`ll do my best to help you out.

All the best!

:glasses7:
 
sscuda said:
The primer surfacers used in the 70's we nothing special. The Big 3 paint manufacturers (PPG, BASF, Dupont) knew it was a good way to use up off-spec resins and misc. intermediates. In other words use up scrap materials.

The backbone resin system was a polyester base material. The cross linking (curing) mechanism was a thermo-set catalyst. The curing temperatures were around 425 degrees F and the dwell time in the ovens were normally 30 minutes at the desired temperature. There was usually a 20 minute ramp to temperature and a 30 minute cool down period. Bodies coming out of the ovens were normally too hot to touch for about a half hour.

Batch quantities were usually around 5000 gals on average. From what I remember you could get various shades a brick red or a medium grey colour. Again, colour dependent based on what "scrap materials " the manufacturers were trying to use up.

As far as durability goes with thermo-set polyester primers, sometimes you get a good primer and sometimes you get a great primer. It all depends what off-spec materials were used or not used during the batch formulation process. Today's primer surfacers have vastly improved in durability and corrosion resistance from the old polyester material.

Rust resistance was fair at best, mainly because of the pre-treatment products used. Chip resistance was actually very good for such a in-flexable product (surface hardness). Solvent resistance was good also, thus explaining why your stripper wouldn`t move the material.

Yes, you could leave the original primer on the vehicle but there may be hidden problems that you can`t see with the naked eye. If it were my car I`d remove the material mechanically, metal prep it, and put on a good 2K polyester high build primer. Use DP primer first if there is bodywork involved. This DP primer will seal the metal surface. Flash rust takes very little time to develop.

I hope this helps. Good luck with your project.


If you need further advise PM me and I`ll do my best to help you out.

All the best!

:glasses7:
Click to expand...

Great info thank you so much it's greatly appreciated... with all that said I think I'll go ahead and take it all the way down to metal .... Stuff is tough to get off for sure , I'm using a 60 -80 paper on DA To get through heavy stuff and then going over the top of that with 150-180 grit .is this an ok finish for the metal before I spray my epoxy ?
 
Red oxide primer had a lot of lead in it. Back when I worked plant maint' in the textile mill it was called "red lead". I imagine the grey waste paint mix had lead in it too. Don't breathe the dust.
 
my dad called it "red lead" 60 yrs ago. he swore when they took lead out of paint it went down the toilet!

taking it to bare metal is no doubt the safe and correct way. that stuff is tough, the 67 Bel i'm working on now, I used some stripper ( hate the stuff), and D A ed it bare metal where it might not be totally perfect metal,... where the metal was good I left the original primer. it is STUCK on there good! I've used that method before with no problem, years later. anything coarser than 80 grit will leave bad scratches. even 80 is harsh, but ya would never get it off with anything smoother!!!

my deal is where I d a off the primer/paint and find the surface with small rusty spots where it is obviously rusted into the metal, is kill the rust with an acid. body guys I talk with do not like the rust convertor products.

pro paint stores sell this acid product but cost is high, i use a phosphoric acid called Ospho. works well for me. I was turned on to it by FABO. they are many ways to skin a cat. members.
 
It had paint stripper on it. Take it all off to make sure there is no residuals left.
 
i have been talking to different experienced painters lately and all claim modern 2k primers are fine over bare metal and epoxy primers are not required.
..but most believe only epoxy primer will work?
 
if you talk to 10 bodymen, you can get 7 different answers.

I have to do my own work so I ask any that will give me a few minutes. only way to learn. but you cannot use everything you are told!

you have several things to keep in mind. you take it to bare metal,.... apply epoxy primer, and let it sit long enough in the company of moisture which is always in air, O2... and you will eventually see it getting some oxidation. so is that epoxy primer really sealing???? used as sealer, it says to add reducer, as final seal......so...... ....BUT, it will stick bout anything and well/.......

polyetsrer primer is a high build sorta like shooting filler. has some great properties, you can get it too thick no doubt, seems to have good sealing properties.....

aircraft stripper, nasty stuff... takes several coats to get off all layers of paint/primer.... keep it covered with plastic so not to dry out to quick and work better....... ( have the wife do the stripper part!?).....generally. you better neutralize it ALL, best to keep it out of cracks!

when I pick up materials from the pro paint store, I always have a couple of questions I like to ask,,, I f nothin else, I get another answer to an old questin!?????

I was just on FBBO reading how this guy has to spend $10,000 for his quality paint job!!!! if I had an extra 10 grand, I danged sure would NOT spend it on paint!!!!!!!!!!!!!!! just me..
 
dustya_383 said:
Great info thank you so much it's greatly appreciated... with all that said I think I'll go ahead and take it all the way down to metal .... Stuff is tough to get off for sure , I'm using a 60 -80 paper on DA To get through heavy stuff and then going over the top of that with 150-180 grit .is this an ok finish for the metal before I spray my epoxy ?
Click to expand...

The grit sequence is OK. There is no need for epoxy primer the body first but I strongly suggest wipe the car down with Metal Prep before you shoot the 2K urethane primer on.
 
barbee6043 said:
my dad called it "red lead" 60 yrs ago. he swore when they took lead out of paint it went down the toilet!

taking it to bare metal is no doubt the safe and correct way. that stuff is tough, the 67 Bel i'm working on now, I used some stripper ( hate the stuff), and D A ed it bare metal where it might not be totally perfect metal,... where the metal was good I left the original primer. it is STUCK on there good! I've used that method before with no problem, years later. anything coarser than 80 grit will leave bad scratches. even 80 is harsh, but ya would never get it off with anything smoother!!!

my deal is where I d a off the primer/paint and find the surface with small rusty spots where it is obviously rusted into the metal, is kill the rust with an acid. body guys I talk with do not like the rust convertor products.

pro paint stores sell this acid product but cost is high, i use a phosphoric acid called Ospho. works well for me. I was turned on to it by FABO. they are many ways to skin a cat. members.
Click to expand...

Lead was used only to control colour quality in pigments , nothing more. Paint technology has only improved with time. mainly driven by government mandated corrosion warranties.
 
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