Soooooo... a friend of mine gave me a track frame with a substantial crack in the BB shell that he had sitting in his basement. The BB shell had basically cracked around the base of the seat tube. I've been riding fixed for a while and I'm interested in getting a real track frame, so I figured I could build up this trashed one to see if the geometry/ride/etc are agreeable before dropping the money on a frame. In any case, I took the frame to a welding shop that specializes in car framework but also does a lot of bike repairs (nice guys who did a bunch of work on my old band's van) and got the BB shell welded back together. It is now solid as all get go, and I'm itching to find a fork for it and build it up. The downside is that the $10 repair job ain't so easy on the eyes and I'm finding it very hard to resist the temptation to take a file to the weld and clean it up. My mind says that I should leave the lump for the sake of structural integrity, but my keen aesthetic eye is saying "file! file!" To whom shall I listen?

I'm scrawny (5'9", 130) and not a messenger, so I don't really see myself putting the kinds of stress on the bike that my friend did in order to crack it in the first place. Does anyone think that me cleaning this blob of metal up a bit is going to substantially - or even significantly - reduce strength of the weld? Is it a bad idea to tidy it up?

-Michael

ianam/e (i am not a metallurgist/engineer) but my instincts say leave it.

Could you smooth it over with bondo or jb eld?

I don't think filing around the weld will weaken it substantially. Obviously if you file down to the crack or the material of the frame, then your have a problem. I'd say file it, but it isn't my frame.

file! file!

Leave the lump. It's character.

im guessing the frame is not yet built? because when it is, i doubt you'll notice the bottom of a BB much for it to bother you

Argh!! Read the effing first post!! !@#$%^

Depends on the lump and what you expect the weld to look like, but it is typical to file or grind welds smooth. If it is really an ugly weld, it may be not very strong (pretty weld=stong weld).

Look at a lot of higher end frames. Their welds are filed down.

I would guess you'd be safe in cleaning up the welds. Maybe you can ask the shop what they recommend?

Excess material from the weld is not making it stronger. If it's a good quality weld, filing it will only make it pretty, not weaker at all. If it's such a poor weld that filing it (or chasing it) will weaken it, then it's about to break already.

The fact is filing and chasing takes more time than welding, so for ten bucks you get it fixed-- if you want it pretty, it's your job to file.

But the bottom line is: If you trust the weld, file away. If you're that concerned, go back by the welding shop and ask them for filing tips.

if the weld was done properly, the external glob doesn't really do anything for strength. the idea of a good weld is that proper penetration of the metal to be welded is achieved. so, if the weld was done properly, you may file away and your frame will not be weakened. was it a heat treated frame? welding messes up the heat treating and makes it weaker unless you re-heat treat it.

comprende?

why don't you call up the shop that did the welding and ask them? A welder should be able to give you trustowrthy answer. It's there a$$ on the line if they don't. If they say it won't hurt to file it then there ya go!

I was a welder in a shop for a while, and I've never left a weld undressed for the sake of reputation. it shows a lack of pride in your work to leave an ugly weld.
FILE IT, if it breaks, then the weld was crap to begin with. ask the welder why he didn't clean it up for you...

you assumed incorrectly...
crack's on the top...

regardless, i can't imagine caring enough to file the weld... especially if you're only intending to ride the frame for a little while and then buy a new one...

I think random stangers on the internet always provide the best advice

Who you calling stange!

send it to a good frame builder to get it fixed. It nmay not seperate but don't take the chance.

S/F,
CEYA!

Before I give my advice I will give you a background story to my knowledge in this subject...I am a certified welder, I used to own a custom car and motorcycle shop building wild lowrider trucks and motorcycles two of those lowrider trucks have been on the cover of DUB magazine. I have welded aluminum, steel, stainless, I have also welded automotive frames so that they could be strong enough to take the abuse of hydraulics and the fun that goes with that sort of setup.

Now on to my answer.....The weld was obviously done by a professional if they do chassis welding on automobiles, not to mention that they have to be certified welders to be doing that sort of work, so that would lead me to believe that the weld was done correctly. It is perfectly safe to file it down to match the contour of the surrounding metal.