Re: [CR]how much to repair a dinged top tube?

(Example: Framebuilders:Tony Beek)

Date: Sun, 11 Mar 2001 01:21:34 -0500
From: "gregparker1" <GregParker1@compuserve.com>
Subject: Re: [CR]how much to repair a dinged top tube?
To: classicrendezvous <classicrendezvous@bikelist.org>


I'm surprised no one has mentioned the hydraulic method of top tube repair. I've been told (can't remember the exact builder that did / does it) that there's a framebuilder who plugs the vent hole at the seat tube (if there is one; if not, just insert a seat post), then has a contraption that fills the top tube with hydraulic fluid, and applies enough pressure that the tube becomes round again.

Has anyone heard this story and is it true?

Greg Parker

-------------Forwarded Message-----------------

From: Sheldon Brown, INTERNET:CaptBike@sheldonbrown.com To: , INTERNET:m.battley@irl.cri.nz , INTERNET:tomwitkop@juno.com

CC: , INTERNET:classicrendezvous@bikelist.org

Date: 3/10/2001 11:24 PM

RE: Re: [CR]how much to repair a dinged top tube?

Tom Witkop wrote:
>I never tried this was a bicycle but did do it with a motorcycle gas tank
>with reasonable results. Fill the top tube with water, plug the ends and
>leave it outside to freeze. The expanding water may push out the dent.

One of the many biographies of the Wright brothers I read told of on of their first financial successes, as adolescents:

At the time, the U.S. government had a large supply of mortar shells left over from the War of the Rebellion. These were hollow steel (or maybe iron?) spheres full of gunpowder with a hole for a fuse. They were obsolete, and the explosives were no longer reliable but still dangerous. The metal had real value as scrap, but only if somebody could figure a way to get the powder out without causing an explosion. The need was for a way to crack the shells open without risking causing a spark.

The Wright brothers came up with the solution: they filled the shells with water, and fitted a plug to the fuse hole, held on with wire. They left the water filled shells out on cold Ohio winter nights, and in the morning the cracked-open shells could have the gunpowder safely scraped out, and the metal could be re-cycled!

As to dented top tubes, I've never tried this, but I've often wondered about the possibility of clamping the tube in a form, sort of like elongated frame clamp blocks, and setting off a firecracker inside...any volunteers?

Sheldon "Expansion" Brown
Newtonville, Massachusetts
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