Using compressed air to remove dents from pipe?

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#1
I have just one small dent right on the side of my pipe from where the bike slid over. I wanna try to remove it with compressed air and a propane torch, but I don't know what I shoudl use for plugs and how to inject air into the pipe and keep it in there. Can anyone explain?
 
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#2
Arghh not again! It is dangerous!

Air method really dangerous as air compresses so what you are making is a grenade. Oh sure it’ll work most of the time but. . .
Don’t do it. I use this method to check for leaks but only at a handful of PSI.

The approved method is compressed water which some companies may have access to. Failing that you can drill a decent size hole in the other side & carefully punch it out against something the approximate shape then replug the hole. For smaller dents -heat it up & time-consumingly tap around the dent which tends to bring it back to it’s original shape before stretched.

Anomalous expansion of water is the freezing method. Water will expand a set amount when it freezes (and only at freezing point so it’s all or nothing, you can’t get it a little frozen). If you trust the dent to be the weakest point for it to expand into & that the volume it will expand just the right amount it could work. Then again you could leave it under your pillow & trust the tooth fairy is a good welder.

Should be lots of firms around that will tackle pipe repair, I believe if you look in the back adds of MXA or whatever you’ll find a few.
 

SndyRds

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#3
I agree, that it is dangerous. I plugged both ends of the pipe, with the rubber type freeze plugs, I put a schrader valve on the bigger plug. I then wrapped multiple wraps of wire over the plugs and hose clamped the wire to the pipe in such a way as it could not pull off. I NEVER put more than 10 psi, plus the expansion of the torch, AND BLEW THE PLUG OFF THE END!!!
I was smart enough to be wearing safety glasses and a faceshield and made sure to point both ends away from myself, I was able to attempt it a second time with no air pressure and took about thirty minutes with the torch, heating it to red. But consider this, inside of your pipe is filled with carbon, fuel and the by products of combustion, if by chance you melt a hole in the pipe, you will have a compressed, molton, fuel fed bomb going off directly at you. Next time I would use one of the pipe repairing services. About $40.00, cheap insurance and alot less risky. If the dent is small, I wouldn't worry about it. If your racing competitivly get a new pipe, If you don't have the bucks, send it out to a pipe repair shop, They can be found in the back of the Moto mags, good luck. Remember when you ask for advice, and ignore it, what's the point. I think safety is a bigger issue. I'd feel pretty stupid explaining to my friends why I can't ride because I injured myself, live to ride another day.
 
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#4
Do "we" worry about pipe dents because they are ugly and we're pissed or because perfomance is compromised?
 
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#5
Both, but in this case it's mostly because it's ugly. My bike looks spoless otherwise, and this darn dent is really annoying and obvious.
 
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#6
Yeah I was lucky we have a local company that makes the header section for several models inc my kdx so all I had to do was saw the old section off at the right place & weld the new section on. Cost was ~ the equivalent of $25 USD. Mine was rust damaged to hard to weld without going through it.
 
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#7
I have carefully tried the freezing method, and split the pipe both times. I don't recommend it.
 
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#8
Originally posted by David Trustrum
Anomalous expansion of water is the freezing method. Water will expand a set amount when it freezes (and only at freezing point so it’s all or nothing, you can’t get it a little frozen). If you trust the dent to be the weakest point for it to expand into & that the volume it will expand just the right amount it could work.
Filling the pipe with water and freezing it usually only succeeds in bursting the seams open on the pipe.

Check out www.piperepair.com to get some info on repairing smashed or dented pipes. They charge $40.
 
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#9
Yes I think the important part you left out in my quote concerned the tooth fairy & the likelihood of this method working.

What I wanna know is how many people have this much room in their freezer that they can chuck a chamber in it?? :confused:
 
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#10
What about that other idea that another dude suggested in another thread? The one with dry ice and stuff? That seemed easy enough, but maybe it just worked for small dents. Who knows...
 
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#11
Most chest type deep freezers have plenty of room for a pipe. Couldn't figure out why they called them "chest freezers" until my wife was leaned over it for a while one time sorting thru stuff.
 
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#12
Originally posted by JediRye
What about that other idea that another dude suggested in another thread? The one with dry ice and stuff? That seemed easy enough, but maybe it just worked for small dents. Who knows...
Whats this dry ice method? My dent is only about an inch and a half wide, but it's right smack dab on the side of the pipe. I'm interested!
 
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#13
Auto detailers and refinishers use dry ice to pop out small dings and hail damage. Simply rub the dry ice in a circular motion around the circumference of the ding. It will cause the metal to contract slightly, popping the ding out. It will only work if the ding is small, and there is no crease in the metal. Caution, wear gloves when handling dry ice, it will cause severe frostbite.:eek:
 
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#14
And weren't you suppose to run the bike to get the pipe hot and then do what he said? I don't want to give out wrong information so someone please correct me if I'm wrong.