Those rust holes...

[critcritter]

I would like to ask for advice regarding diagnosing rust damage and options for treating / repairing an otherwise nice and light Univega Alpina 504 frame.
One chain stay, the chain stay bridge and to some extent the bottom of the main triangle are affected (see attached photos). Presumably removing the paint from the affected area should be the first step to diagnose the extent of the under paint rust.

Is this frame safe to ride without chain stay replacement?
Does the bottom of the main triangle look worrisome?
Do you have a suggestion how to check the insides of the tubes without specialized tools (like pipe camera)?
Do you have general suggestions for mitigating the damage?

Thanks a lot!

 

[pictonroad]

ooh, I don't like the look of that hole in the stay. I wouldn't ride that because it's a waste of time to build up a frame that clearly has terminal rust issues. Is it safe, short answer, no, not really, we have no idea how big you are, how many potholes you'll hit etc. Long answer, it's unlikely to be a massive issue if it snaps there. It's more the fact that you'd be better off putting energy into a worthwhile project.

As for solutions, it's a steel frame, it can be fixed if you're prepared to spend enough. I'd suggest that some judicious poking with a sharp implement will probably reveal other nasties though and the bill would go up rather than down...

 

[Ippikin]

^^Agreed, am afraid to say that the hole proves that rot has taken hold, I'd be poking at that (with a screwdriver) to investigate. Rust can be treated but rot requires repair which is probably not financially viable.

 

[legrandefromage]

'Ucked

shame as they're nice ridin' iron

 

[Ippikin]

Happy to explain! More a term used by owners of 'mature' cars where the rusting is so severe that it has rotted the steel with the only repair possible being to cut out the rot and weld in a piece of new steel. Bikes are not immune and usually caused by storing the bike wet or sweat damage from indoor turbo trainer use. With bikes the repair it would involve tube replacement.

 

[Stressed]

Side note- this was an issue with Univega because those parts of the chain stays were the lowest point on the frame- hence water/ moisture gathered there and did it's thang!

 

[mullinino]

Whoops! Nevermind, good luck to all involved

 

[doctor-bond]

Must … resis …..

 

[TheRadioGuyUK]

Have agree with it needing investigating, even if just remove paint in affecting areas and try to determine the depth and actual extent.

Lesson you learn, the hard way but hopefully not the dangerous way, is visible corrosion is often only half the story, and it’s the hidden damage that’s potentially structurally dangerous or heading that way. When you’ve experienced seeing structural compromised steel catastrophic fail it’s a wake up call you never forget and the instance I’m thinking of was a benched frame pressure/torsional stress tested in a workshop.

And, if you do attempt to patch or replace tube sections and weld, assume the worst and take due precautions in case the steel is galvanised as the fumes are very toxic.

But a quick way to gauge an idea is to tap the frame each side of the corrosion visible. If it don’t resonate as you’d expect and gets dull around/near the corrosion visible - odds are, you’re in trouble.

Remember the golden rule - know when to quit and if the doubts are like an inner voice screaming it’s lungs out, walk away very quick and call it a dead loss. But regardless of what I have written or that of anyone else - get a second IRL opinion from someone who’s got experience with welding and repairing steel and can actually assess the situation in the ‘flesh’.

Which would be shame, but every frame eventually hits a critical stage where it either needs refurbishing and sectional replacement (and welding) and you can be pretty sure it’ll cost more to restore than source a better condition substitute frame.

My experience, since no doubt there will demands from certain circles to cite supporting evidence behind my reasoning :-

1. A full bare metal restoration of a early year one production Mini, which had subframes that were so perforated it probably was divine intervention that prevented catastrophic failure up to that point. Where the metal were subframes mounted to were barely any better - as thinned, after removing the rot, to cigarette paper thickness. To cut a long story short - it was even worse in the less critical places. It got stripped of refurbishable parts, and the rest scrapped. That was a classic case of bullishly determining to succeed whilst my inner voice was screaming ‘run like hell’.

2. Various steel motorcycle frames from 60s, 70’s and 80’s - each were rot monsters, thankfully they were donated or from trades i dropped the ball on.

3. Restoring a CBX1000 as part of building a group project replica of the SDM from the movie. My job was the frame and the custom bodywork.