Today, in my infinite wisdom, I managed to dent a frame I was working on, first time I have ever dent a frame and I wasn’t even riding it.
Long story short, I am modifying this steel frame with some internal cable routing, new dropouts and removing the tens of cable guides that were all over, I have removed all of the ones that I needed to successfully by heating them up with a torch and pulling them out once the bronze is soft, I thought of removing them mechanically but this way seemed safer to me… Up until I dented the top tube smack in the center by being too aggressive with the pliers…
The area of the tube was red-ish when I left my mark, there is no visible bulging that I can notice.
See pic. It’s a small dent but it does bother me because of how it happened.
Is there a way to fix this?
I have thought about using a tig rod and weld it there to pull-out the dent but thought about asking before making it worse. I could also simply fill the dent via tig or silver (I don’t have bronze with me but I do have silicon bronze rods to tig-braze)
Smoosh down the high spot and fill the dent with sliver, then file away excess. It’s easier on a round tube with no braze-ons in the way, because you can use a paragon tube block.
Right after I made the dent, I measured it out with calipers and took notes. Theory being, after a few rides I could make sure it wasn’t getting any larger, as a sign of the tube buckling.
I think that it would take more than a year of serious riding for a dent like that to cause a tube failure, if it were going to at all.
I built a lugged frame with a .7-.4-.7 TT and dented the frame the second time I rode it. It looked much like the dent in your picture, I pressed it out with a paragon tube block and some paper towel as a soft jaw and then filled it with silver, being very careful not to remove any steel when I cleaned it up.
I broke the top tube when I got the front wheel stuck in a ditch and I went OTB. The tube failed just behind the TT/HT butt, a good five inches from the dent.
IMO, filling a dent like that with silver doesn’t do any harm.
Are you using flux when heating those up? I would make sure you are to protect the toobs.
If it were me I would take off that other guide as well and then try rolling out the dent with a tube block as best I could. Then I might fill and sand whatever mark is lift there. It looks big enough now that filling/sanding could eat into the tube enough to make it sketchy.
Seems unlikely to yield a desirable result. Edit 2: I put a dent in a tube and looked at it for a good minute. I think you stretched the tube while hot, rather than denting it and have to either silver or bronze braze or leave it alone. A gusset os unnecessary, imo. Make one if a crack develops.
There’s no need to direct any heat into the tube when removing braze-ons.
Paul Brodie does this in this first video removing canti-mounts:
In the downtube replacement video he has, he also uses a wirebrush to get rid of some of the braze. I just used this method to remove all of the guides on a frame and it worked quite nicely and needed only a quick cleanup with emery to get it smooth again. I figured I would have had to do a lot more filing if I went the hack saw route.
Use flux, orient frame so braze-on will fall, and dump heat into the braze-on without heating the tube. It will get hot, braze will melt and it will fall off.
other cable guides are very close, i could have removed them but didn’t wanted to mess anything more
the tube is not round and it transitions from round to oval exactly where the dent was…
I have also learned a few things:
Think before doing anything, once decided, think again.
I was using a MAPP torch instead of my oxy torch because i still don’t have my tanks, mapp is good for quick brazing tasks but it’s not precise and it’s too “forceful”. Very error prone!
Ive had good success on some pretty devastating looking dents by rolling the dent between some tube blocks. Yup, clamp those tube blocks onto the dent, say goodbye to some paint, clamp it in a vise and start rotating. Fill in what’s left with silver. Pro tip: don’t use a tube block you care about.
With that paint job, you probably wouldn’t have even noticed the dent 