Sprint Frame sending to sandblast- original finish

[74Twincam]

Hi all-
After starting to troubleshoot a sump gasket leak, I ended up taking all the drivetrain out, and then subsequently decided to strip the entire chassis/suspension/drivetrain from the car.
Anyhow, it?s been stripped and I?ve been working on the bits that attach to the frame, and today the frame was delivered to the soda blaster for stripping. I have seen a lot of questions and discussion about how an original Sprint frame was finished, mine?s a ?72 car original to the States, so here?s a few pictures to offer up. Red oxide primer with the black (bitumen?) tar-like coating. The pictures are after power washing all the oil and grease off.
I wanted to keep the car original, but after seeing the corrosion starting and all the rubber needing replacing, I decided to be proactive and refinish the frame to protect it so I can keep the original frame underneath it.

[elanfan1]

Have you considered getting it zinc sprayed i.e super heated zinc wire sprayed on as a liquid (not zinc heavy paint) I found shot blasting shops tend to do this. It effectively galvanises the chassis. Once done you can etch prime it and paint it red oxide or black (or lime green with pink polka dots) if you like. Doubt it would need attention for another 50 years!

[nmauduit]

the rubber perishing over 50 years of use and time is one thing, but is the corrosion affecting the red oxide? on the photo I only see a bit on studs that were not painted... it seems that this chassis was quite well preserved (I would keep it, esp. considering I don't take my elan when it's wet if possible, and certainly not on salted roads).

[Grizzly]

As Steve says hot spraying zinc is the very good but beware just life spraying with paint it's difficult to get inside boxes (like the front uprights) usually you would want to paint or powder coat on top (we tend to epoxy powder coat on top and i'd like to think it will see me out)

This is a shop i know that did a quick video of them applying it. https://www.youtube.com/watch?v=xig7puE2j80

[The Veg]

Looks like my frame. I always wondered of the black coating was original or something the first owner had had done, not a bad idea since after a year in the UK he took the car to the Gulf coast of Florida!

[74Twincam]

Well,
The chassis is back from sandblasting, with mixed results. Great news is that the front box section, uprights, all mounting, etc. seem solid. Only a few small dings to straighten out here and there, but I was pleasantly surprised.
The only issue is with the lower, right-hand face and flange immediately behind the suspension. This is the only real corrosion spot, and it's obvious by looking at the cakes of crud still stuck to the underside of the body in this area as to why.

I'm considering repair methods, from consulting with an expert welder to cut/replace, to welding on a type of over-lay plate- I'd bend a piece of sheet to the L-shape and weld it to laminate over this section, then use seam sealer... Not sure yet. Has anyone else done repairs to their chassis for issues like this? Given the condition of the rest of the chassis, and it's originality, I'm not convinced I want to replace it yet, but maybe that's being stubborn.

[gjz30075]

Easily repairable. I had the same rust, a little further back, and welded in new sheet metal. Don't forget
that the vertical metal is spot welded to the horizontal section. Drill out the spot welds.

[74Twincam]

Thanks Greg,
On my chassis in this area, forward of the center tunnel, it is just a folded section so no spot welds to contend with. Just need to get my courage up to take the saw to it for the first couple of passes, then as they say- no looking back!