Hey everyone, this may not be the place to post this, but I see that a lot of people here like to try new things. I found this 80s Schwinn world sport in the garbage and took it home so that I could do a road bike build but the obvious issue is that it’s huge. Looks like a 58 cm or a 60 cm size so because this frame was free to me and I already have others like it I thought it would be fun to try and remove the brazing on all of the joints and cut down the tubes to size and re-braze it. however, the issue that I’m having is, I don’t have an oxy acetylene torch kit and I was going to try and do it with propane, but I couldn’t get either of the seams to budge despite having brought it up to cherry red on both pieces that I heated up with a propane torch. let me know what you guys think and what I can do to take this apart without buying an oxy acetylene torch kit, thanks!
by vufgew
11 Comments
I’d go no further than chopping out the top tube and re-brazing it into a step through. Like the idea of giving an old giant frame a second life as a step through with nice swept back bars like a large Rivendell Platypus type vibe (unchanged wheelbase and all other massive differences acknowledged of course).
I’ve wondered if you could cut it out real close to the seat tube and head tube if you could file down the remaining upper head tube lug so that you could fillet braze to the lug remnant and then braze on a reinforcing bit of tube onto the seat tube where the tube will connect and then fillet braze to that.
Edit: you need something hotter than just propane. It’s almost certainly brass brazed. My thoughts above aren’t really compatible with the equipment you have on hand, just a fun thing I’d considered to make a large frame rideable for a wider range of heights.
Resizing a frame is harder than building a frame from scratch. You’d need oxy-propane at least, not just a regular propane torch. Oxy propane torches are more expensive than oxy-acetylene torches for whatever reason, and while some components are interchangeable, the hoses and the actual torch isn’t.
All the joints are going to be brazed with brass, so need to get past about 1500 degrees F, and keep the whole joint that temp to slip the tubes out of the lugs. Good luck messing around with it though, that’s how a lot of us started. Check out r/Framebuilding as well.
I suppose you’ll have to shorten each tube a proportional amount or the lug angles will be wrong
Have fun with it and post the results
The medical bill will make this project less worth while.
The tubes are butted at the ends to make the joints stronger, and are thinner elsewhere. By cutting the tubes short and rejoining them, the “new” frame will be weaker and prone to failure.
These frames are a dime a dozen, way to much work, just find one that fits and scrap this
This is a bad idea.
If you wanted a fun project, make a tall bike or some crazy contraption with another free frame. Most bikes have butted tubes that are thicker at the points they attach to the lugs, so the frame is likely going to be weaker if you shorten the tubes.
Thank you all for the quick feedback
Also a problem you could have is that in some lugged frames some pegs where added to hold the lugging and frame together.
I would add that this would be like building a frame from scratch, which includes muttering all tubes to fit the tubes they attach to. Also if the frame is buttered then you may not have enough buttered length left to cut and re-attach. I would say bad idea just not worth it.
Check out r/framebuilding