Technical Another weird bare metal before primer question

I have this 33 coupe that is in pretty good shape. It was Redi-Stripped (remember them?) years ago and left in the phosphate wash, with no primer.
It still has the grey surface color, with very light surface rust in a few areas. The pictures show the cleanup started with a Contour SCT and Scotchbrite, as well as contrast between old surface and new.
So what's the next step?
Ospho?
Metalprep?
Self etching primer?
Wipe with thinner and epoxy prime?
I know, like doctoring over the phone, but I got no experts around here.
Thanks much!!

 

Personally. I would acid etch, neutralize, DA and shoot epoxy. The rust has set back in, gotta kill it. Ensure your acid etch is compatible with your chosen epoxy, even after neutralized, theres varying opinions on using both.

Ill let the paint experts take it from here, Im not a pro painter, just dealt with a lot of rusty junk.

You can probably have it blasted again pretty reasonably, they dont have to remove mutliple paint layers, just dust it off. Shouldnt be in the booth very long. Time is money on that endeavor

 

I think the safest way would be to have the body blasted and then Epoxy primed straight away.
It looks like a good body to start with.

 

I went through the same experience about 15 years ago.
A prior owner had the car dipped and never did anything with it. Mine looked like your does.
When I primed it to keep the rust off of it I noticed that the acid leeched out from under the seams in the body and lifted the primer.
I acid washed and power washed it with hot water a few times until there as no more evidence of leeching.
I eventually stripped it back to bare metal and then coated it with DP90.
I painted it a year or so later with no problems.
The dipping process was great for fenders etc. but not so much for parts tyou could not get to to neutralize.

 

blasting it, or having it blasted will be the best/cheapest/fastest way to do it right.
tight budget? better to skimp on the paint, not on the prep.

 

Phosphate is water soluble and should be washed with water. Even in hidden areas. Wash and dry thoroughly with clean cloth and compressed air. Sand to remove surface rust. Sand the remaining metal to provide tooth for epoxy primer.
Try to do this work beginning to end in one session as the clean bare metal could flash rust depending on your humidity level.
You have witnessed the ability of phosphate products to preserve metal. For extended periods of time the surface should be examined and more phosphate applied if needed.

 

Thanks, everyone.
Do you suggest doing the interior surfaces to the level of the exterior, or just wipe and shoot epoxy?

 

Chemical striped. Blasted then 80 grit DA
Etch or epoxy is up to you. You can do body work over epoxy.

 

Interesting question. My Dad has a 34 coupe that was dipped probably 35 years ago and has sat bare since just like yours. Its amazing that the coating has protected it as well as it has.

 

Mine would have probably fared better, but a friend storing it pushed it outside to clean the shop and it got rained on! ...

Thanks for the responses so far.

 

I would blast the interior as well as long as the cost doesn't go over the top. Definitely Epoxy prime everything. This will hold moisture out a lot longer than Etch primer will while doing the body work.

 

Here is what I would do:
I would break it up into sections and do one at a time, hood, doors, trunk, inside body and outside of body.
I use rust mort or metal prep from HD, spray and lightly scrub with green scotch brite. Do this away from cement and do it outside. I keep everything wet with acid until I have gotten rid of all the rust, do not let any of the acid dry, keep it wet. I work the bad areas with 80 grit sandpaper and stainless wire brush until it stops bleeding red or rust from the rust pits. I apply and go back into the shop and work for a while then check parts re-apply, keep repeating this cycle until the rust is gone. Again the part needs to stay wet, do not apply and go to lunch, you have to stay on top of it. When I feel the rust is gone I start the soap process. I apply a good coat of soapy water, I use an electric pressure washer that has a soap tip and mix a heavy "Dawn" soap mixture to help neutralize the acid. I then take green scotch brite and lightly scrub the surface to break up the acid that is left on the surface. I then rinse the surface at least twice with high pressure tip making sure to get into the nooks and crannies to make all the acid has been rinsed off. Start the drying process by wiping down the parts with a shop towel at the same time blowing it dry with clean air. Keep blowing off until it's completely dry! Work quickly get the parts dry, rub the surface and blow until its all dry.
Once it's totally dry, the surface should have a nice phosphate coating on it ready for paint.
I also like to set the parts out into the sun "Oregon weather" if I can to make sure everything is completely dry before prime.
I use two types of epoxy primers. SPI epoxy when it bare metal and PPG CRE-X21 when I acid etch.
Both sand very well and are very good primers. Make sure that the primer being used has a statement that adhesion is improve with etching. I use the CRE-X21 because its close to the same price as SPI and much cheaper than PPG DP40.
I use gloves and safety glasses through the whole process "protect yourself"
Hope this helps

 

The interior hidden areas will need to be washed and dried at least. Primer will then prevent surface rust from starting.
Flood the crevices.

 

The rain began washing the phosphate off.

 

got to do the same thing this summer
blasted a cab about 15 years ago
been sitting in the shop and has some light surface rust in a few spots
going to have it re-blasted.
We always lightly blasted the parts/cars that were chemical stripped back in the day mainly just to etch/abrade the metal for primer
I tried some metal cleaners/prep and it did OK but I think blasting will be much faster

 

Rust Mort is a rust converter intended to convert rust to a substance that has stopped rusting not eliminate rust. Specifically what acid do you refer to and who is HD?

 

Thanks for all the input. I'm leaning toward a gentle media blast followed by epoxy prime.

Or sell it and move on...….

 

Sell it? In that case A, the first step is to send the car and title to me and we'll work out a payment plan later.
I'm glad you asked this question. I'll be dealing with bare metal soon. I've been reading about the importance of sealers...as a barrier and an adhesion enhancer.
Good lookin' coupe body.
Good luck. Have fun.

 

that would make a dang fine ride
would be hard to sell unless someone was hungry

 

Media blast does not produce the same results as water wash/rinse. Water wash/rinse is the manufacturers recommended first step for phosphate treated surfaces.
Media blast could certainly follow.
I have a feeling you are looking for an easy/fast way to deal with this rather than a sound long lasting first step in the process.

 

Nope.
Easy and fast is good at my age (72) but if I'm going to do a "last" build, it will be the RIGHT way. Hence the reason for my query.
But apparently, from the replies, there are various "right" ways. If the right, right way is wash and rinse first, I have a pressure washer. No problem.
Unfortunately Redi-Strip is not around to ask, and I can't remember. Their procedure was strip the paint, strip the rust, pressure wash, apply the phosphate, let dry. So, yes, the phosphate is in every seam and cranny.
My intent was to gather real world experience, and yours is greatly appreciated. Thanks!

BTW, I have three builder projects, so doing all of them is looking dim.
Not a Sophie's Choice, but a reality check. Or a hell of an estate sale.

 

I recall Frank Oddo and his '40 coming out of the Redi-Strip tank. Whole body...I winced when I pictured all the runs of phosphate up out of the paint at seams, hinges, etc...
There are procedures, should we bother to follow them...

 

The phosphate treatment and any residual rust/bleeding related to the acid etch is all done by this time. All things considered its holding up well. Adding water at this point, especially on the irregular interior panels and crevices, is NOT a good idea at all.

I'd hit all the folded seams and trapped areas with Gibbs and let that get in and displace any moisture and residual chemicals. While the Gibbs does its magic I'd solvent wash then lightly sand blast all interior surfaces, odd shapes, drip rails, window surrounds, firewall and under side surfaces. Hit the seems and areas you treated with Gibbs with brake clean or lacquer thinner and shoot all those areas you blasted with DP90 (or the color of choice...74, 40, etc).

All exterior surfaces get worked over with your DA with 80 Grit and your fancy surface prep tool. Once all exterior panels are clean hit them with a solvent wipe down and DP those surfaces. Do all your bodywork on top if the DP epoxy primer.

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I've had a 356 Porsche Speedster body and a 356 convertible D body dipped. One in Rochelle Illinois and one in Minneapolis. They both left the facility with phosphate coating and instructions to wash/rinse with water.
My recommendations are based on experience.

 

Hey John, my recommendations are from experience as well....I've been restoring cars for 40 years. When you took delivery of your freshly dipped bodies the wash - rinse w/water instructions were to remove residual chemicals that may be still reactive. The OP indicates that his dip was done many years ago...in that time frame any residual acids and other reagents left behind have since been used up. Soaking down hard to reach areas and folded/welded body/panel edge seams with water runs a high risk of causing problems.....even if there is access to an oven to bake out the body shell. If it were mine I'd avoid adding moisture to these vulnerable areas at all costs.

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A place in Mississippi is baking bodies. Would be curious to find out what a bake would cost.
They do a factory dip style e- coat. A friend of mine had a cuda done. Looked like a fresh OE body. But was not cheap.

 

BigChief--- I'm pretty sure all the chemicals would have been rinsed out before the phosphate was applied. Seems to me that regardless of the time frame phosphate still remains through out the body and if water was recommended initially than it is still best at this late date. Using anything but water first will contaminate the body phosphate and add to the uncertainty.
It's not that difficult to completely dry a body flooded with water. If water can penetrate closed areas compressed air can as well. I made a simple 24" or so wand out if copper tubing that attaches to an air gun and reaches into cavities and can easily be bent to go around corners or whatever.
I also did all the metal work to primer on a dipped Hemi Charger body.
Each to his own I guess.

 

Yup. Theres more than one way to skin a cat.....LOL.

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Sorry for the delay
HD is Home Depot and the product is Klean Strip phosphoric prep and etch.
I prefer Rust Mort and its based on phosphoric acid like prep and etch but its more expensive than prep and etch . I agree with the statement that it's a product to convert rust.
I convert the rust, then remove the conversion coating with a wire brush or scotch-brite, re apply and convert the rust again. I do this over and over again until there is no more rust to convert. I will never let it dry on the surface, I have seen paint failure in the areas that had a white film after drying at a buddies body shop, his helper did what the instructions said to do.
I have been doing this process for about 25 years with great results.
https://www.homedepot.com/p/Klean-Strip-1-gal-Phosphoric-Prep-and-Etch-GKPA30220/100406369

 

I mis-stated above that Redi-Strip was no longer. Wrong!
Search showed them still in business in Jackson, MS. Surprise, surprise!
I'll call them, get their input, and report back so you others facing the same issue can weigh their response.