Removing Dent in Thin Steel Top Tube

[ratbane]

I'm looking to repair a ding in my dedachai Kona Explosif top tube.

The steel is extremely thin at this point, and I was wondering if there are any techniques for pulling the dent out, as opposed to filling it.

Anyone got any good/bad experience?

 

[Neil]

I wonder if those tools that paintless dent repair outfits use on cars would be of any use, here?

 

[legrandefromage]

there was a post concerning hydraulic dent pulling - sealing the tubes and filling with oil until the pressure pooped the dent out.

 

[ratbane]

...

I wonder if those tools that paintless dent repair outfits use on cars would be of any use, here?

That's sort of what I was thinking.

Pics attached. No crease, so blunt trauma caused it. :?

 

[FMJ]

My KTM dealer does a similar thing with dented expansion chambers. Seals both ends (one with a schrader valve), fills the pipe with 35 PSI, then heats the affected area.

POP.

Sand and paint.

 

[john]

Apaprently you can remove or lessen such dents using wooden / alloy block which fit around the tube. A quick google will reveal all.

 

[Pogo]

Guy I know tried this on his motorcycle tank and confirms it worked for him,
maybe worth a go...

http://www.metacafe.com/watch/501379/remove_car_dent_with_airduster/

 

[biglev]

tube blocks here:
http://paragonmachineworks.com/storenam ... 68650.aspx

you can then fill any space with silver solder/ braze does

 

[NickD]

Tube blocks are the best idea.

You could also fill the tube with water then freeze it, but that runs the risk of splitting the metal if there is too much water.

 

[Andy R]

I've copied and pasted this from Fairfax Pat's reply to similar question last year. I've used much the same method (not on a bike frame, but on another welded tube structure) and can confirm that it does, of course , work.
Obviously you need the machining facilities.

Joined: 08 Oct 2007
Posts: 608
Location: Fairfax, California
Posted: Wed Jun 24, 2009 8:21 pm Post subject:

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I posted this fix last year to a similar question-- A long time ago I had a chrome plated Eddie Soens track bike frame with a large dent in the top tube. Joe Breeze fixed it for me. He had a fitting he had made which was a solid plug to insert in the head tube. This plug had an L shaped hole through it that went from the top (when inserted in the head tube) to a right angle turn to come out at the middle of the top tube. The hole in the plug had a relief cut and an O-ring inserted for a seal on the inside hole and was drilled and tapped for an automotive grease fitting on the outside of the top hole. With a drill he made a hole inside the head tube into the top tube and lined up the fitting with it. Then he filled the top tube of the frame with oil, re-inserted the fitting and used a grease gun full of grease on the other end of the fitting (the outside top) and pumped up the pressure until the dent popped out! All that was left was to drain the oil out of the top tube and reassemble the now perfect bike-even the chrome was perfect!

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