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getting a dent out of alu frame

pilsburypiepilsburypie Posts: 891
edited November 2008 in MTB workshop & tech
hi all

need to rack your brains as mine have been racked and come up with a few ideas that may or may not work and are not ideal.....

I have a aluminium caffine frame (Cannondale F1) with a fair dent approx 6 inches up from the bottom bracket on the downtube. This dent is about 1/4 inch deep caused by my roof mounted bike carrier gripping arm as I drove under a height restricted barrier with bike on roof!

How can I get this dent out? My thoughts so far revolve around gaining access to the rear of the dent and carefully bashing it out. But access is the problem.

My ideas:

1. drill a 1/2 inch hole on the underside of the downtube and knock the dent out, then fill hole
2. drill a small hole on the dent, self tap a screw in and try and pull dent out
3, as above but with a slide hammer on a self tapper.

How else can I access the inside of the dent or how could I remove it?

Any other ideas?

Cheers in advance

Mark

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    leave it.
    trying to fix it will make it worse.

    If you are that worried about the looks buy a new frame.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • yeah plus 1 for leaving it. if your really bothered u could filler it and respray that area :D
    Go big or go home!!

    dmr exalt
    fitbike team park bmx
    both my custom jobbys :D:D
    http://www.pinkbike.com/photo/2915789/
  • nicklousenicklouse Posts: 81,520 Lives Here
    yeah plus 1 for leaving it. if your really bothered u could filler it and respray that area :D

    but as the frame flexes with use it will not stay there.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • I take your advice chaps - I have to get over my need for perfection..... just wondering how much the structural strength and integrity will be affected...... how long is a piece of string?!!!
  • I'm no expert, but I think the integrity etc. would be more adversely affected by drilling it for acces or self tappers, look upon it as a battle scar!!
    ' From the sharks in the penthouse,
    to the rats in the basement,
    its not that far '
  • there is a kit that you can get for getting dent out for cars, so it maybe work for bike too..? never try but just an idea.

    can get it from Halfords for £18(ish).
    "It is not impossible, its just improbable"

    Specialized Rockhopper Pro Disc 08
  • nicklousenicklouse Posts: 81,520 Lives Here
    I take your advice chaps - I have to get over my need for perfection..... just wondering how much the structural strength and integrity will be affected...... how long is a piece of string?!!!

    for that we will need to see it.

    Pictures.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • call me stupid, but how do you add a pic to your post?! :oops:
  • nicklousenicklouse Posts: 81,520 Lives Here
    read the forumFAQ's in the bikeradar area.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • You can see the main dent on the topside of the downtube and just about the smaller dent on the underside..

    Mark
    DSC00026.jpg
  • nicklousenicklouse Posts: 81,520 Lives Here
    How did you do that!

    Sorry I would scrap it.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Personally, I wouldn't ride that again

    Edit - Damn, nick beat me to it
    Scott Scale Custom
    http://img.photobucket.com/albums/v496/ ... C09729.jpg

    Kona Coilair 2007 Dark Peak Destroyer
    http://img.photobucket.com/albums/v496/ ... C09727.jpg

    "BOCD - If it aint perfect it aint good enough"
  • igaiga Posts: 155
    The correct way to repair it would be to weld a pin to the dent and pull it out with a slide hammer, but I think your seat tube would be in the way. Is it covered by insurance?
    FCN 7
    Aravis Audax, Moulton TSR
  • schweizschweiz Posts: 1,644
    I had a similarly sized dent in my top tube caused by the handle on my girlfriend's dad's snowplough!! I took it to the LBS and he said it was a write off!

    I got a new frame off my household insurance (as it included sports and leisure equipment). I plumped for frame in the previous years colour which was 1/3 of the original price and got a set of Ksyerium Elites with the difference! :lol: My friendly LBS just gave me a receipt for the cost of a new frame for the insurance and everyone went away happy.
  • Time for you to have a giggle...... I had my bike on a roof mounted carrier and drove under a height restricted barrier - the dents you see were caused by the clasp that holds it to the roof bars! Buckled the front wheel and duffed the frame, wrecked the roof bars and dented my car roof! - Was covered on my household insurance and I now have a spanking new Trek Fuel Ex 8 to show for my stupidity. :D

    Insurance company just said scrap the F1. Was just trying to thing of a way to fix it up as cheap as poss so I have this one rideable as well. Seems such a shame as it was under 6 months old - like the idea of a full susser and a hardtail! :wink:
  • nicklousenicklouse Posts: 81,520 Lives Here
    just salvage the bits you can and get a new frame.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • amt27amt27 Posts: 320
    I probably would ride it, maybe, :? , depending on if there were an stress marks around the dent and the nearest welds.

    My dad did the same thing to a Cadex many years ago, I still ride it, there was more damage to the car than the bike.
  • Just order the same bike from Halfords, when its delivered, ring them and say,"Here, dafty, me bikes dented" than demand a full refund due to lack of commercial confidence and keep the new one. :twisted:
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