Framebuilders - Stupid mistake - final soak too hot, surface rust - help me treat it?

Sorry for the length. I'd appreciate help.

The problem:
I just finished a frame building course, and soaked the frame to get rid of some big hunks of flux, and the water was too hot. Now, there are little wisps of rust all over the down tube and bottom bracket. :(

It's coming off easily with 220 grit, but I'm worried about the inside tubing, where the tubes were prepped for brazing. I'll have it painted in a few weeks, they can probably take care of it, but I want to stop the tiny bit of rust now if I can.

My plan:
I picked up some 'Krud Kutter - The Must For Rust' at the hardware store. (It was a choice between this and Naval Jelly, and since I'm trying to treat the insides of tubes I figured the more liquid, flowing stuff would work better.)

I'll sand off most of the outer rust, and then treat some place inconspicuous - i.e. the inside of a chainstay - to see how this stuff works. Then, get set up with a big bin and a big water bottle with some sort of thin nozzle, spray a bunch of the Krud Kutter into a tubes, wait a decent amount of time, then rinse the snot out of it with room temperature water - through the water bottle braze-ons / bottom bracket drain holes. Probably do one tube at a time.

Will this work?
Anyone have better advice? Thanks in advance.

don't panic, happens all the time. I wouldn't even mess with it. If you're really worried, get some metal prep. Just tell the painter what you've done.

Ok, cool. Thanks. I'll stop stressing and just work on smoothing out the brazes. LOTS of bronze I can focus on there instead. :D

Any brand of metal prep stand out for you, or is it all the same?

there are many brands, get some that is meant to be painted. I have never bought any.

Personally, I wouldn't worry about it, the frame should get media blasted on the outside before painting, and then just use some frame saver on those tubes that aren't sealed after you get it back from paint.

With that said, soaking the entire frame is a bit excessive, I just use the hot water from the spray nozzle on my kitchen faucet to wash the flux off, hitting it with a brass brush, and that does the trick. It also helps me avoid getting too much water inside the frame...some is normal, especially in the BB.

Pete

I have a large bowl that I fill with hot water, saves a lot of energy
Brass flux takes some soaking in very hot water to remove.

I will admit to running the hot water when I am in a hurry though.

i was looking at Engin Cycles' pictures, and I found this (http://farm5.static.flickr.com/4034/4525566941_2ff994214b.jpg)
I'd rather it not happen just because it means more cleanup, but it happens to the best of us.

With that said, soaking the entire frame is a bit excessive, I just use the hot water from the spray nozzle on my kitchen faucet to wash the flux off, hitting it with a brass brush, and that does the trick. It also helps me avoid getting too much water inside the frame...some is normal, especially in the BB.

I was just following Mr. Yamaguchi's advice.:o

I will admit to running the hot water when I am in a hurry though.

i was looking at Engin Cycles' pictures, and I found this (http://farm5.static.flickr.com/4034/4525566941_2ff994214b.jpg)
I'd rather it not happen just because it means more cleanup, but it happens to the best of us.

Oh man that's super excessive. I think I'd faint if I ever saw that.

Nope, this is just a dusting. Like a pinch of talcum powder here and there.

Sorry for the length. I'd appreciate help.

Anyone have better advice? Thanks in advance.

Yes, I do.

STOP using abrasive means to remove it at all.

Go to your local health food store, or such and buy a tin of blackstrap molasses. Dissolve the contents of the tin in nine times as much water and soak the whole frame in it.

I know it sounds a little bizarre, but basically, there are a number of complex acids in molasses that chelate iron (ii) and (ii) ions, and will eat the rust off the frame, all the tubes, inside and out but because the sound metal underneath isn't penetrated or pitted, won't cause crevice corrosion or cause the rest of the sound metal to corrode.

On an object bike-frame sized, you'd need a large vessel, big enough to submerge the whole frame. and then some, so that you can agitate the water and ensure none of the solution becomes stagnant inside the tubes.

If you want a practical demonstration, the find a couple of rust bolts or nuts and treat them in a jam jar with the same strength of solution - 9:1.

That sounds awesome. Thanks.

FWIW I'm leaving the rust alone and focusing on sanding down the joint brazes. I'm calling the painter later on today (funny enough, Yamaguchi's main painter is local to me in San Diego) and ask their advice. If they want me to treat it before I bring it in, I'll give that method a shot.