Aluminium Frame Repair - Please Help!

I have recently bought a 1991 Al Mega, which was advertised as NOS, but unfortunately has a crack in the seat tube.

Luckily, the seller is a very reasonable guy, and we are currently working together to try to get something sorted out. He has told me that he was unaware of the crack and, given his honesty and good communication up until now, I am happy to give him the benefit of the doubt provided we can get it sorted out.

I have said that I would get a few quotes for a repair & refinish to the damaged area.

I should say now that I will not be subjecting the bike to heavy use. It will mainly be a "fair weather" bike, used for the occasional bit of light off-roading. For this reason I am quite happy for the crack to be repaired and for me to use it.

I wondered if there was anyone on this forum who would either be able to repair (TIG-Weld and smooth, then re-spray the area) the frame, or point me in the direction of someone/somewhere who can. If you are able to help, could you please pm me

I'm aware of Argos Cycles, and I will contact them today for a quote.

For reference, here are a few pictures of the crack in the seat tube:

Is the alu cracked or could it just be the paint? If it is nos, I can't see how it would have cracked the alu, as that's a way down the tube and protected from storage type damage.

ishaw":1w630pcj said:

Is the alu cracked or could it just be the paint? If it is nos, I can't see how it would have cracked the alu, as that's a way down the tube and protected from storage type damage.

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The trouble is, 1991 Al Megas are notorious for cracking, and specifically on the seat tube and under the head tube, which is why I immediately thought the worst!

The seller described the bike as "virtually NOS". It's definitely been used, but I'd say only a handful of times at the most. The only signs of use are the marks on the seatpost from where it's been adjusted, and the chain marks on the chainrings.

I'm going to sand the paint back around the damaged area (gulp!) at the weekend, so I'll be able to see for certain whether it's paint or metal damage. Hopefully the former, but if it's a crack in the frame then I'd like to get a few repair options together, so that I can present them to the seller.

I wouldn't fancy any one would be able to neatly fix that. It's mid tube where the wall sections are very thin. Welding directly would likely make it worse not to mention the issues with heating and cooling aluminium. I'm not an expert but I don't see it being a simple, neat, strong or cost effective repair.

JeRkY":3nyyyyju said:

I wouldn't fancy any one would be able to neatly fix that. It's mid tube where the wall sections are very thin. Welding directly would likely make it worse not to mention the issues with heating and cooling aluminium. I'm not an expert but I don't see it being a simple, neat, strong or cost effective repair.

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That's one of the little niggling concerns in the back of my mind

I'd be happy with an ugly repair (welded plate?) as it's not in a prominent area on the frame, and it means I can still use it occasionally so it wouldn't become an ornament.

You never know - perhaps I'll get lucky and strip the paint back to find out that the metal underneath is uncracked. Fingers crossed!

Regarding stripping the paint back:

Nitromors and fine wire wool?

I'm going to bet its just cracked paint.

Get someone with a boreoscope to have a look down in there.

shogun":9emnt3fr said:

I'm going to bet its just cracked paint.

Get someone with a boreoscope to have a look down in there.

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A what now?! Who would have one of them?

Sounds painful!

in my totally uninformed opinion I would say it is paint rather than a crack, rather than sand down and then potentially feck the paint- why not just ride it with a long post in and watch to see if it gets worse- if it is going to be a bike you are going to ride infrequently then you should be fine, non?

clockworkgazz":znh924lr said:

in my totally uninformed opinion I would say it is paint rather than a crack, rather than sand down and then potentially feck the paint- why not just ride it with a long post in and watch to see if it gets worse- if it is going to be a bike you are going to ride infrequently then you should be fine, non?

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This is true. But if it is a crack in the metal, then I may as well get it repaired if I'm able to, especially as the seller has offered to pay for it to be done.