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I’ve just finished sand blasting my front subframe and now need to decide how to paint/primer it. What is the recommended process from here? I do have some POR-15 I thought would work well. I could powder coat but prefer something I can do myself. TIA for the advice.

like you, I did something similar. Had it sandblasted - pretty ferociously - primed in a special primer and nylon powder coated. So far, so good. But the powder coat, whether it's paint of nylon, doesn't get between the spot welded layers of the steel. So I dunked the sub frame into a tank of supertrol 001 oil (there are loads of other preservative oils about) and left it there overnight so that the oil would penetrate between the layers. Did the rear sub frame like this too. Worked a treat and rust free ever since. A bit OTT but it only cost me the nylon powder coating. On the other hand, you don't have the corrosion problems that we have!

We used epoxy mastic from rust busters on the Van. Very happy with the semi gloss finish too!

I did mine in red oxide primer and POR-15 Chassis Black. Odd stuff to use and not the easiest to apply correctly. But when you get it right I do like the finish, as to how hard wearing it is time will tell.

Reading Peter's post makes me think I should put some layer of creeping cavity wax on mine prior to fitment, I have some Bilt Hamber Dynax UC that should do nicely

I would always inject a creepy-crawly type oil or wax between the spot welded layers of steel that make up the front and rear sub frame. Regardless of the paint or coating you use, once air gets between the layers, the rust WILL reform and return.leaving the little red tell tale line. That's what corrosion in the form of rust is! It is the nature of the beast.

Bilt Hamber Dynax UV .. yes brilliant stuff .

I favour a 2 coats of a zinc rich primer (normally Zinc182) and 3 coats of 2K semi gloss black.

Is rust a problem on front sub frames ? especially on a California car …..?

If its some thing you want to do yourself then I would be tempted to just etch prime and few coats of 2k semi gloss

I have an automatic rust prevention machine on my front subframe which sprays oil all round the engine bay

EDIT: just spotted you have some POR 15, not used it, but supposed to be good, not sure whether it looks authentic or not..

Exminiman wrote: ↑Sat Dec 31, 2022 9:23 am Is rust a problem on front sub frames ? especially on a California car …..?

If its some thing you want to do yourself then I would be tempted to just etch prime and few coats of 2k semi gloss

I have an automatic rust prevention machine on my front subframe which sprays oil all round the engine bay

EDIT: just spotted you have some POR 15, not used it, but supposed to be good, not sure whether it looks authentic or not..

I have an automatic rust prevention machine on my front subframe which sprays oil all round the engine bay - love it!

I have used POR 15 extensively and for many years (in the UK) quite a remarkable product in my view and with no offense to Peter would rate this over powder coating, simply that POR can be touched in should it get chipped where as PC seems to creep below unseen until it balloons out...

I’ll be using por 15 and some rust penetrating oil for the seams. Will report back, or won’t as I’ve read pretty remarkable things about it. Rust is not an issue on the subframe but the car came from Michigan, so there are other spots to be dealt with.