Cleaning and painting body cavities

[Andy Somogyi]

I’m getting ready to clean and paint the various frame cavities like the inner fenders and suspension pan.

I’ve ran a bore scope through them, and they look pretty decent, albeit rather dirty. The inside of the front suspension pan seems to be decent, though there might be some surface rust, but it’s hard to tell with the bore scope. It looks like most of the cavities are painted with a black primer.

Let me know what you think of my plan:

I’ve got the whole front disassembled now, and I’ve pried open one of the access flaps to the suspension pan.

1) clean the insides of all the cavities with POR15 Cleaner & Degreaser. This looks like an organic solvent combined with a base and some surfactants. Seems like it would make an excellent cleaner with no residue. I’ll be spraying with an undercoat gun and wand extension, letting it sit moist then rinsing with water.

2) spray with EvapoRust to make sure any rust is gone, and keep the EvapoRust moist by reapplying it every so often. Water rinse.

3) clean again with POR15 metal prep. This is a phosphoric acid based phosphating solution that should remove any remaining rust, and leave a layer of zinc phosphate covering everything. I don’t think it will harm the existing black primer. Water rinse.

4) spray with Eastwood interior chassis paint. This is a very low surface tension paint that also has a phosphoric acid based etcher, and is designed to creep into every little crack and seam, and designed to seal any existing rust.

Yes, I know I still have some more prep to do, and I’m going to hit the sloppy MIG welds with a TIG to smooth them out.





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[Andy Somogyi]

I took some bore scope images of under the battery tray and inside suspension pan. There looks like a bit of surface rust right where the battery tray is closest to the gas tank lip, underneath the tray.



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[Dpmulvan]

That's not gonna solve your rust problems, it may slow it down a bit but that's about it. Only way to get rid of rust is sandblast, cut, or grind then apply a good two part etching or epoxy primer. I might use those products on a plow truck but not on a 911.

[Andy Somogyi]

Originally Posted by Dpmulvan

That's not gonna solve your rust problems, it may slow it down a bit but that's about it. Only way to get rid of rust is sandblast, cut, or grind then apply a good two part etching or epoxy primer. I might use those products on a plow truck but not on a 911.

There doesn't seem to be any rust problems other than what looks like a few specs of surface rust. The bottom of the suspension pan on the inside looks almost perfect.

What I'm trying to do is clean the insides off as much as possible, and protect them.

Right now, the galvanizing is protecting the insides. If I cut the top of the suspension pan off, sandblast and weld it back on, I destroy much of the galvanizing.

I think what I'll do is first clean the insides really well with the POR15 cleaner & degreaser, then run the bore scope through it again to see how it looks.

One of my main concerns is I don't want to harm the existing galvanizing and black primer. They've done a good job of protecting the car for the past 40 years.

[wayner]

How about just using wax oil or something similar instead?

[safe]

Originally Posted by wayner

How about just using wax oil or something similar instead?

+1

Some liquid cavaty vax, something that creeps/wicks (or what it is called in english) into seams.

[Iciclehead]

I used the Eastwood Internal Frame coating on mine...about 6 cans. It is a paint, looks a lot like the green stuff that is on the inside of aircraft

It comes with a neat little hose/spray tip arrangement that lets you stick it into the cavity and then spray to your hearts content. From what I can tell it creeps well and is very liquid so ought to soak into the various crevices.

Allegedly it contains zinc phosphate and a bunch of resins that **should** work. I used it mainly in areas where I had done welding and this was the way to protect the backside/inside of the cavities.

I will also follow up with Waxoyl or similar when my paint work is done.

Tell you in 10 years whether it works or not...

Dennis

Originally Posted by Andy Somogyi

It's a boy!