Thread: Phosphoric acid, anyone use it afterv bead blasting

there frame to get all the rust in the nooks and crannys?

That's an uncertain proposition. Phosphoric acid is very effective, as long as the rusty part(s) are kept wet until all of the rust has been dissolved. Degrease a gas tank with methyl ethyl ketone, then fill it with phosphoric acid solution, agitating from time-to-time with a handful of nuts & bolts inside and 24-72 hours later the inside of the tank will be down to virgin "white metal". That'd be tough to do with a frame. There's simply too much inacessable area.

The rear wheel arch seams can cleaned pretty effectively with a small blasting gun. If there's significant rust, you can gently/carfeully, pry sections of those seams open with a putty knife, media blast, then dolly the metal back into place. That won't reach everything, and the seam beneath the gas tank, along with the steering tube lugs are just plain out of reach.

You're on the right track, in my view. Chemical treatment is the only answer. Rust conversion treatment that turns rust into stable black oxide (can't remember if it's ferric or ferrous that's black) is your best bet, but you still have to seal the metal completely and keep the seams wet long enough for the process to thoroughly penetrate the seams. The anal-retentive/perfectionist method would be to media blast the seams as thoroughly as possible, followed by MEK cleaning, then an application of rust conversion primer ( a convenient and effective combination of two processes). After the frameset has been repainted, giving the seams an application of rustproofing is the perfect capper. I'm not referring the black rubberized undercoatingcommonly available in autoparts stores, but the brownish, waxy, penetrating rustproofing used inside of car doors, rocker panels, etc. It sprays on with the consistency of thick oil, then sets up like wax. Your bike will smell like a box of crayons for a few weeks, then you're home free. I've used these materials with great success over the last 20 years on cars that see lots of winter road salt. Check the Eastwood catalog for the rust stabilizing primer (formerly sold as "Corroless Rust stabilizing primer" - developed by the US Army corp of engineers) and the penetrating rust proofing (which is available in convenient aerosol cans, complete with plastic straw for the hard-to-reach seams). It's a lot of steps, but only the media blasting takes a lot of hands-on labor. "Rust never sleeps"

I plan on glass beading the frame and parts followed buy some chemical treatment (that's the part im working out) then prime and paint.

Was also looking at the Rust Guy Rust Converter product.

I used this stuff on my 75, with great results.
Evapo-Rust Rust Remover Home

You can find quart-sized bottles at AutoZone, and order larger quantities off the web site.

It takes some patience, and really requires that the part be submerged, but it does an amazing job on light to moderate rust. Best thing is, it doesn't damage any painted areas, doesn't smell much more than a mild detergent, and is non-toxic.

I was able to get it to work on the inside of the frame, by squirting from a spray bottle, and scrubbing with a wire brush. It was far from ideal, but it worked.

--Mike