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Help with metal bashing please

Hi group,

My son has a motor cross bike and after last weekend crash the expansion chamber now has some rather large dents in it. I made two blanking plugs for the ends of the pipe. One blanking plug has an air valve in it so that I can pressurise the pipe. I put 30 pounds pressure in the pipe. Heated the dents with my blowtorch until nearly red hot and started tapping around the edge of the dents with a hammer. Most of the dents comes out but not as good as the motor cross shop could do. Each dent is about a quarter of the size it was originally but I can't seem to get them any better. Is it that I need more pressure in the pipe or do I need to get the metal hotter? Any thoughts please.

Regards, Martin Perry

Reply to
Martin Perry
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I'd say you need more pressure than just 30 psi, but if you overheat the metal it could blow out.

So for safety's sake, let's change methods and go with hydraulic, rather than pneumatic pressurization. No heat with that method. But the area has been annealed, so it'll be softer than the surround.

Either way, sounds like you're proceeding carefully. Should be able to get some nice results. Consider also, heating from outside and tapping from inside with a hammer made from steel just for this one job.

Yours,

Doug Goncz, Replikon Research, Seven Corners, VA Unequal distribution of apoptotic factors regulates embryonic neuronal stem cell proliferation

Reply to
Doug Goncz

Doug Goncz wrote: (clip) Consider also, heating from outside and tapping from inside with a hammer (clip) ^^^^^^^^^^^^^^^^^ Wouldn't one of those slide-impact dent pullers be the easiest way, and the weld up the screw hole afterwards?

Reply to
Leo Lichtman

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