Wildwood 

I put a bare frame in about 2" of an oxalic acid solution, left it overnight. It was sitting in the solution so that only the BB area, slightly into DT & ST and chainstays were submersed. Solution was 2 tablespoons of pure OA powder per gallon.

Without the story = after draining the OA from frame, and before the rinse I was called away and did not get back to the frame to rinse it. Early 70s Holdsworth Pro (R531). It has been almost 12 hours sitting outside in sun. Must I rinse now, or just leave it?

TIA

edit: There was no external rust, but some internal around bb tube joins and in chainstays. I had previously brass brushed inside tubes and 'rust dust' and a few small rusted bits were present. Head tube was rust free, seat tube looked un-rusted as far down as I could see from seat lug.

ollo_ollo

Rinse to remove crystals that have reformed

Wildwood 

When I towel wiped inside the bb, there were no 'crystals'. And none on the exterior chromed chain stays. Just a thin yellowish 'film' of residue. Not sure what is in tubes beyond what can easily be seen.

(cannot find that old small dental mirror I used to have)

davester

In a situation like this, I always default to "What could possibly go wrong?" The problem as I see it is that you have an acidic residue coating the frame, whether you can see crystals or not. That could definitely cause problems with the ensuing coats of paint. I vote for rinse.

merziac

Yes, rinse and dry thoroughly straight away. I also treat with PB or T9 so the rust doesn't start right back up which it will, starts as tarnish and goes from there.

Think micro level, hard to see but it often will be there.

Wildwood 

OK, rinse and dry.
I will use boiled linseed oil in the chain stays after drying. And a little bit in the tubes near the bb.

thanks for fast - and unanimous - answers.

obrentharris 

I go a step farther. First bathe it in solution of baking soda and water to neutralize the acid, then rinse with clean water. Might be overkill but it's easy.
Brent

Wildwood 

Rinsed with a baking soda solution, flushed well with water and drying in the sun. I think a few drops of linseed oil in each chain stay is a good idea, what I can see in the main tubes looks pretty clean. The frame is orange and much of what I thought was rust is orange paint and grime. The Holdsworthy paint shop in 1972 must have been a busy place.

My first OA bath, even tho' only part of the frame is complete. Maybe it wasn't really necessary, but the experience was good and I feel better for having done it.

thanks again to all.

Classtime 

My only concern would be the OA left in the tubes somehow making their way to aluminum bits and pieces and that is not a good combination. But you took care of that with the neutralizing rinse.