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PostPosted: Thu May 16, 2013 4:16 pm 
Gold Trader
Gold Trader

Joined: Tue Jan 19, 2010 7:53 pm
Posts: 3068
Location: Northumberland
Hey, I'm just wondering if it is at all possible to remove dents from a frame? I'm starting to restore a 94 Zasker LE and it has quite a nasty one on the side and two very small ones on the down tube. Thing is its the ball burnished finish so I cant just fill and paint over. Is there any what of pulling them out? Cheers Rob


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PostPosted: Thu May 16, 2013 5:13 pm 
Dirt Disciple

Joined: Mon Feb 04, 2013 3:25 pm
Posts: 40
It can be done, weld a bolt to the middle of the dent, heat the surrounding area up and pull the bolt, its rough but works, bike factories just fill the dent with braze and sand it down


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PostPosted: Thu May 16, 2013 6:52 pm 
retrobike rider / Gold Trader
retrobike rider / Gold Trader
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Joined: Sun Nov 23, 2008 10:44 pm
Posts: 3267
Location: Rushden......ish
winchman wrote:
It can be done, weld a bolt to the middle of the dent, heat the surrounding area up and pull the bolt, its rough but works, bike factories just fill the dent with braze and sand it down


Problem is its alloy so you need to find someone to Tig an alloy bolt to do it.

I had this prob on my easton tubed Kona U'hu. It was going to be too much hassle & expense ( frame was Karma'd to me)to send to a frame builder so i filled them with metal filler and had it sprayed.

It may not be as it left the factory but it looks great :)


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PostPosted: Thu May 16, 2013 7:01 pm 
Old School Hero

Joined: Thu Jun 10, 2010 4:46 pm
Posts: 159
Location: Salt Lake City Utah USA
You can use water, Yes water, fill the tube that need to be fix with water, seal the entry points so it can hold pressure and place it on a big freezer, the water will expand when becomes ice and find the point of less resistance (the dent) but be careful if you leave it for to long the tube can burst..


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PostPosted: Thu May 16, 2013 7:08 pm 
Dirt Disciple

Joined: Mon Feb 04, 2013 3:25 pm
Posts: 40
Gruff wrote:
winchman wrote:
It can be done, weld a bolt to the middle of the dent, heat the surrounding area up and pull the bolt, its rough but works, bike factories just fill the dent with braze and sand it down


Problem is its alloy so you need to find someone to Tig an alloy bolt to do it.

I had this prob on my easton tubed Kona U'hu. It was going to be too much hassle & expense ( frame was Karma'd to me)to send to a frame builder so i filled them with metal filler and had it sprayed.

It may not be as it left the factory but it looks great :)


I dont think it would work with alloy its very difficult to get the correct amount of heat as its too close to the Oh Shit moment when you melt the tube.
Best bet is to fill it and paint.
Never seen the water method used, I dont think it would work but I might be compleatly wrong.


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PostPosted: Thu May 16, 2013 7:42 pm 
retrobike rider / Gold Trader
retrobike rider / Gold Trader
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Joined: Sun Nov 23, 2008 10:44 pm
Posts: 3267
Location: Rushden......ish
winchman wrote:
Gruff wrote:
winchman wrote:
It can be done, weld a bolt to the middle of the dent, heat the surrounding area up and pull the bolt, its rough but works, bike factories just fill the dent with braze and sand it down


Problem is its alloy so you need to find someone to Tig an alloy bolt to do it.

I had this prob on my easton tubed Kona U'hu. It was going to be too much hassle & expense ( frame was Karma'd to me)to send to a frame builder so i filled them with metal filler and had it sprayed.

It may not be as it left the factory but it looks great :)


I dont think it would work with alloy its very difficult to get the correct amount of heat as its too close to the Oh Shit moment when you melt the tube.
Best bet is to fill it and paint.
Never seen the water method used, I dont think it would work but I might be compleatly wrong.



That's why i filled & painted mine :wink:

I did once see a very cool method for steel frames by using 2 metal blocks with slightly smaller tube profiles cut out of each one & then clamped around the damaged tube and then rotated round and round which slowly forces the tube back to its original profile.

Sorry if that doesn't make much sense but i know what i mean :mrgreen:


**Edit** here you go:
http://chuck.kichline.com/bikes/Framedents/default.htm

Obviously you couldn't use this method on an ally frame though :roll:


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PostPosted: Thu May 16, 2013 8:16 pm 
Retro Guru
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Joined: Wed Feb 20, 2013 12:35 am
Posts: 1006
Location: mostly in my backgarden building my shed
ooh now that is trick, I likes that.... And the water method hmm.


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PostPosted: Thu May 16, 2013 10:43 pm 
Old School Hero

Joined: Thu Jun 10, 2010 4:46 pm
Posts: 159
Location: Salt Lake City Utah USA
Oh the water works, in fact it works so well it burst my Klein forks after only 2 hours in the cold.
Image

Well at least the dent on the other side got fixed.
Image


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PostPosted: Thu May 16, 2013 11:26 pm 
Dirt Disciple

Joined: Mon Feb 04, 2013 3:25 pm
Posts: 40
Thats the bit that bothers me I am not convinced the dent will be the weakest point so it may burst in another place before the dent pops out, but again I havent tried it


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PostPosted: Fri May 17, 2013 12:40 am 
Old School Hero

Joined: Thu Jun 10, 2010 4:46 pm
Posts: 159
Location: Salt Lake City Utah USA
winchman wrote:
Thats the bit that bothers me I am not convinced the dent will be the weakest point so it may burst in another place before the dent pops out, but again I havent tried it

The pressure will go first to the "Path of less resistance" usually the dent, for example a friend of mine makes motorcycle exhaust pipes (expansion chambers for 2stroke engines) out of two flat pieces of steel welded together using the same principle with great success..
Image


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