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

> 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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