Brand New Rusty Steel Split frame Bike

[Gastrobuskus]

Hi all, I'm new to the forums here, so sorry for any etiquette mistakes.

I recently bought a new belt drive bike and after getting it built, I noticed that the frame split was quite rusty. I was told it was just surface rust and to just sand it and paint it with the provided touch up paint.

I decided to get inside there and take a look and found the entire surface to be quite rusty. I sent photos to the company, they agreed it was unacceptable and offered to ship a replacement and an issue like this wouldn't happen again. Sceptical, I asked for pictures of new the bike before it was sent to me and here's what I got.

They offered to sand, paint and clear coat the affected area, but should I trust this? I understand steel bikes rust, I was a bike mech for 3 years and have 2 steel frames.

[Jesper]

Welcome @Grastobuskus

NO RUST is acceptable on a new bike. It indicates poor anti-corrosion measures. On new bikes made nowadays the interior of tubes should be treated, and even if they were not treated it indicates poor storage conditions (high humidity), and/or stored for a long period of time. I suspect that the company you got the bike from would have that issue with every frame in their inventory. If they were smart (like me?), they would remove any rust and treat the area(s) before even showing you another example; certainly before shipping another bike out to you.

[jeffg]

If this bike were mine, the action to take is grease the connection and go ride. The surface rust is not going to evolve into an issue if you seal it well with grease. In no instance will I sand and paint without proper surface treatment before paint.
I have a weird hobby of experimenting with rustproofing (live in the rust belt) for automobiles and can tell you how effective grease can be, especially on a bicycle that does not see nearly the torturous environment that autos experience.
If you want to coat the inside of the frame tubes do it with motor oil slightly thinned with mineral spirits to help make flow easier. Don't be shy about using too much! The more the better.
From my experience of commuting in all weather year round, I have never rusted out a frame. Of course I sealed the weep holes in the seat and chain stays along with the ones in the forks. I also have never felt the need to treat the inside of the frame tubes to prevent rust. My main commuter for 10 years straight only had light surface rust in the tubes. It remained in service for another 10 years, then served as a fair weather fitness bike up until this past year. Still no real rust to worry about.

FWIW, I rustproof my vehicles with a mixture of tacky grease, paraffin wax, and oil. 2009 Ford Ranger with zero rust on the underside and fenders along with rear bumper. I only wash the vehicle once a year in the spring. I know grease works.

[Pete b]

Im more concerned at the shocking welding on the lower pic!
Looking the way it is,this is a cheap as chips bike

[jeffg]

Yes, those welds look like they came out of a toothpaste tube. When price is king, this is what you get.

[Jesper]

I'm glad someone else mentioned the welding. I figured rust on a new bike was bad enough without going there. When instructing about electronics soldering we had a saying; "the bigger the gob, the better the job" due to the amateurs using too much solder on one component.
I agree with @jeffg about lubing those connections. I generally use a little something on all mating surfaces and exposed/bare surfaces. I haven't had a frame rust through, but I do like to treat the tube interior just to prevent corrosion through the decades (and hopefully centuries) since I would hope my frames will still be rolling long after I'm not. I have may be picking up a 20s/30s Automoto bike this week which will certainly get treated if I indeed take ownership of it. It also becomes a little bit of a buying point for another collector when I sell frames.