Brompton Frame Rust - nbd, requires repair, or junk? (nbd = no big deal)
 

I've come across a Brompton for sale, but have questions about the degree of rust. Except for the chain, the "outside" of the bike is rust free. The only sections with rust are by the hinges and inside the frame tubes - Please see the attached pics.

As far as can be told from the pics, is this bike likely: safe to ride as is (assuming I always wipe it dry henceforth if gets wet), in need of repair to be safe (Is there a repair? Sanding off the rust and then a coat of something?), or too damaged to ever be safe?

Your opinions appreciated.

Apologies for defining the acronym "nbd" in post title :) I'm an old timer and often have no clue what acronyms mean...

to me that just looks like surface rust to me and for the inside tubes just give it a spray of rust protection oil and roll it around the inside of the tubes and they would probably be good. Or get a long metal scrub brush for pipes in the plumbing sections of stores and give is a good scrub inside before spraying it down with oil. I don't see anything deep and structural deficiencies here.

Nbd

Agree, NBD. I have a brompton and have some surface rust in the interior tubing due to a high humidity location I visited for 6 weeks. The rust on the inner portions of the hinge flange are from the paint rubbing off and being bare metal.

My advice is buy the bike and use a large cleaning brush with some rust preventative on it and scrub the interior of the tubes. Most of it will disappear and prevent surface rust in the future.

It's normal, the steel is untreated on the inside and the tubing is thick.

you could pour in a rust inhibitor and then pour it back out , and a coating will remain.

whole assembled bike may be a bit heavy , maybe a repair stand will help as you invert the tube .

stripping it down may be too much work , you choose..

Thank you everyone for the helpful information.

My 2006 Brompton has much less rust in the frame tubes, than on this picture of IRideISmile. Could I pour in metal paint? Or is rust inhibitor better, or just lubricating oil?

I have been using Boeshield for years and also WD40. These are vegetable based spray lubes that dry and harden inside the frame to act as a moisture barrier. Spray a bunch in and rotate the bike so all surfaces are coated. I apply to chainstays, forks etc, anywhere the lube spray tube will go. Leave the bike as open as possible so the air can get in there to dry the lube, maybe for a few days. Putting it in a car trunk on a hot day will also speed this up. I've heard boiled linseed oil is also good for this purpose. There are commercial products like Weigl frame saver but I've had good results with the above.

I'm totally bowled over to read that WD-40 and Boeshield are vegetable based. 😇

nbd,, Just add some oil mate. This is exactly why I had my new bike rust coated at the shop before even picking it up.

Best way to get a cheap Brompton I would imagine. Looks awful but in reality is just minor surface rust that can easily be treated and doesn't effect the strength of the frame.