Removing dents from a frame
 

Is this possible? I don't have a dented frame, but wonder if there is a way to repair one (other than using bondo and paint.) A Portland c-list posting is advertising a Cinelli track bike (http://portland.craigslist.org/bik/101367165.html), but the top tube has two small dents... definitely a concern if not structural, then just asthetic. Just curious.

Bike Tools Etc sells tubing blocks that are mostly used by framebuilders.

The description in the catalog also states that they can be used for removing dents:

http://tinyurl.com/96lcu

You could make a tubing block from wood. I did it with a drilll press and a band saw.

I don't get how those could possibly remove dents.

I saw a commercial once for this product that removed dents from car sidepanels using a suction cup (it was the same guy that sells Oxyclean) but I doubt anything like that would be possible for bike tubes (different materials, different sizes, etc).

i suppose a dent causes on a very minor scale for a tube to become out of round and the blocks are perfectly round so buy working the tub back to round you kind of remove the dent that cause the un roundedness. haha. im probably wrong???

Yeah that sounds reasonable. I wonder if it really works though.

yeah it should work fine and its probably a long tedious process like auto bodywork.

But how do you get inside the tube to press it back out against the blocks?

With tig welding there are no holes into the tt and with lugs, the holes are about 1/4 inch.

its sort of like playdough in your hand, if you roll it between your two hands, it doesnt matter what shape it is in to begin with, it will eventually form a long round 'snake'. same basic premise with a metal thin walled shaped, if you bang a crooked tube from several different angles with these round blocks long enough you will get a round-crosssection tube. just like with auto body panels, you reshape the piece into what you want by banging on it, not by taking it apart flattening it, reshaping and then reattaching.

23 cents, it looks like those blocks will work for very gentle shallow dents. Dents that will "pop" back into shape. However, for sharp dents, I can't see it working.

btw: there are techniques used in the tubing related industry that uses hydraulic pressure to pop dents out from the inside of hard to reach places. so maybe if you use a hydraulic pump and the blocks.... :D

Also, there are other techniques to fill a tube w sand (or simular grain solid) or a liquid and then work it to shape to prevent kinking and other unwanted "dents". I think that some bike manufacturers are using these kind of techniques to shape tubes.

the moral of the story is to abuse your beater bikes, not your nice bikes.

so it is ok to beat your beater?

if it floats your boat (and re: beater bikes, otherwise no)

I had some scaffolding fall on my KHS a year ago and it made a pretty sizeable dent. The dent didn't affect the ride or mess anything up, it' sjust cosmetic damage. Anyway, I took it to many a bike shop here in NYC to ask their opinion. All of the bike shops said that they wouldn't mess with the dent. They could roll it out with a tibe roller, but that would just weaken the tube even more than the scaffolding falling on it......

i think you just have to hammer it from the other side to remove a dent

:eek:

are you talking about removing the dent or adding a complimentary designer dent?

As in Dent, Arthur Dent?

42

speed grooves...

the hydraulic thing doesn't work; it's been discussed at length on the cr list and it's a no-go.
if the dents bother you take it to a framebuilder and have them filled (depnding on thr tubing they can use silver or brass, or a lead-silver mix for super-thin tubing, but that stuff is toxic.

then you have to repaint anyway, so it's not a cheap solution.

i've heard of the tubing-block solution working, but it's delicate, risky, and anyone who knows how to do it is going to be expensive, and you still have to repaint because the blocks rub the paint off the tube.

back when dinasaurs ruled the earth, this was called leading, and is only toxic to the persons present when it is apllied (beathing in the fumes) or the person who is stupid enough to eat it. btw; braze and silver solder used to contain cadmium!

Understand, yes, the hyd thing does not apply to the bike tubes, but it is an industry fix for other tubing or vessel applications. It was just a piece of trivia, pardon if I did not present it as so :o

place a sticker on the dent and ride :)

ya all need to get bent.

So, the moral of the story is that it cannot be done?

debraze the offending tube, now you can shove a mandrell into the tube and push the dent out. 1st step not necessary with head or seat tubes :D

depends on how the frame was built, but in 99.9% of the cases yeah, it cannot be done.

no no no, the moral of the story is in post 10