crack on road bicyle frame

conrad101
conrad101 Posts: 18
edited October 2013 in Workshop
Hi,

I have a Giant Defy 0 frame in bright white Team rabobank markings, the frame is made of an aluxx 6000 material. The rest of my bicycle is very ordinary but the frame is very attractive and a country mile better than any of the other components.

I had an accident a year and a half ago, I stupidly came off my bike at decent speed - there was no other object or vehicle involved, the left hand side of the saddle hit the ground with force. As a result of this a crack of about 1 cm length, formed near the join between the horizontal bar and the part of the frame in which the saddle post sits. Photos are attached.

The crack has not changed or increased in size since the accident but I am aware that cracks around this area are considered really not good.

I will not consider scrapping the frame as I have doted on it for the past 3 years and moreover I would not be able to afford a decent replacement. Therefore I am looking to mitigate this damage as far as I possibly can.

I am aware that it is practically impossible to turn back time to before the accident but would be most interested if there any unobtrusive ways in which the crack can be strengthened and any damage mitigated. I was wondering whether a translucent epoxy resin could be worthwhile in strengthening the area.

Any advice would be appreciated!

Comments

  • robbo2011
    robbo2011 Posts: 1,017
    If the crack is in the aluminium and not just the paint, my advice would be to scrap the frame. Your life is worth more than a bike frame, isn't it? I hope so..
  • conrad101
    conrad101 Posts: 18
    Thanks robbo!

    I am not certain if it is a hairline crack in the paintwork or a hairline crack in the alluminium, I assumed it was a crack in the alluxx 6000 but am not absolutely sure. In that there has been no further expansion of the crack in 1.5 years of regular use since the accident and I have doted on the frame since getting it, I don't feel I can scrap it.
  • robbo2011
    robbo2011 Posts: 1,017
    I don't think it is possible to fix aluminium frames, but someone else may know better. Let's hope its the paint and not anything more.

    Personally, I think you'd be extremely foolish to keep riding it if is a crack in the aluminium. Still, it sounds like you mind is made up about that.
  • Barbarossa
    Barbarossa Posts: 248
    If the crack hasn't grown in a year and a half, it probably isn't going to - keep an eye on it, mark the ends of the crack with a marker pen to see if it is growing. Epoxy on its own will do nothing.
  • me-109
    me-109 Posts: 1,915
    It's not necessarily scrap as a fab shop or machine shop could weld the aluminium. You would be needing a respray afterwards.
  • conrad101
    conrad101 Posts: 18
    How can you tell if it is a crack in the paint as opposed to a crack in the aluminium?
  • desweller
    desweller Posts: 5,175
    If you know anyone who regularly works on pressure vessels then they could let you have some fluorescent leak solution; but it's not as effective if you can't generate a pressure difference across the crack.

    The only reliable way to tell visually would be to strip the paint back in that area and examine the frame with a magnifier.
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  • TheBigBean
    TheBigBean Posts: 21,618
    I've cracked lots of non-carbon frames. You usually know about it by sound or feel a long time before you see it. I'd just keep an eye on it.

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