bikes

The oxide occurred during the welding process. Given the fact that this oxide has not shown up during my previous batch of practice welds, I think what happened was that the jig made it difficult for me to angle the torch towards the metal I was trying to weld. I suspect this resulted in small eddy currents in the argon shielding gas that brought in some contaminants. In this case the weld appears to be be clean enough that the welds are not compromised, but the problem of torch angle will need to be resolved before I can attempt an aluminum frame. Aluminum is much more vulnerable to contaminants than chromoly steel.

Quote from: ThePedalMan998 on March 23, 2025, 09:27:46 am

That is indeed a clever way of trying to open the master link on a chain. Do you like mountain biking?

I use to a lot more, but I don't really anymore

I recently saw someone riding one of these near where I live. Apparently a trend briefly entered the mountain bike world with the downtube being replaced with a cable under tension. Do you remember seeing any of these Fishme?

The top tube is now tacked in and the front triangle is now taking shape.

This video demonstrates the importance of drilling relief holes in the bike frame prior to welding it.

This video demonstrates the importance of drilling relief holes in the bike frame prior to welding it.

Where did you learn to weld? I need to learn to weld this year

I took welding lessons at a local makerspace using a rented TIG welder.

Managed to get the front triangle welded together and the rear triangle tacked together. The bike is nearly ready to remove from the jig.

Managed to get the front triangle welded together and the rear triangle tacked together. The bike is nearly ready to remove from the jig.

Wow it's starting to look like a real bicycle!! That's awesome. I like the jig made out of aluminum extrusions

Quote from: ThePedalMan998 on April 28, 2025, 11:05:16 pm

Managed to get the front triangle welded together and the rear triangle tacked together. The bike is nearly ready to remove from the jig.

Wow it's starting to look like a real bicycle!! That's awesome. I like the jig made out of aluminum extrusions

Thanks Rachel, it was a lot of work to get this far. Anyway, in order to get the welding lessons I did, I went to a local makerspace that offered classes with a rentable welding machine capable of TIG welding. If you would like to take welding classes I highly recommend looking at a local makerspace or a local community college.

I finally finished the welds on the rear triangle last night. I decided that with the main structural welds complete the frame is now safe to remove from the jig. I also tested the frame and made sure that the rear forks where still spaced as needed to accommodate the rear wheel, which still fits and does not rub on the frame. Whew, I am so relieved to have gotten this far without any major hiccups. The last major steps are to weld in the brake bridge and to install all the parts, such as pedals and front fork.







 

Completed some more work on the frame to accommodate parts needed for riding. Some of the parts like the bottom bracket shell, the part that holds the bearings for pedals, warp slightly during welding. Overcoming this warp requires specialized tools for thread chasing and facing of the bottom bracket to restore it to its original dimensions.



I also cut the rear brake bridge, which holds the rear brake calipers next to the wheel.

I finally finished the welds on the rear triangle last night. I decided that with the main structural welds complete the frame is now safe to remove from the jig. I also tested the frame and made sure that the rear forks where still spaced as needed to accommodate the rear wheel, which still fits and does not rub on the frame. Whew, I am so relieved to have gotten this far without any major hiccups. The last major steps are to weld in the brake bridge and to install all the parts, such as pedals and front fork.

Looking good! Once you finish welding everything are you going to polish it and paint the frame?

My current plans are to just give the bike a clear coat of paint for corrosion protection, then label each tube with its respective name in bicycle nomenclature, i.e top tube, down tube, seat tube, etc.

I welded in the brake bridge today, which represents the final welding that needs to be done on the bicycle frame. The bridge seems a little far from the tire, but it looks like it is not so far that calibers only touch the tire rather than the rim. I think this is perfectly adequate for the first frame. Honestly, I just feel grateful to have been able to reach this point.

I welded in the brake bridge today, which represents the final welding that needs to be done on the bicycle frame. The bridge seems a little far from the tire, but it looks like it is not so far that calibers only touch the tire rather than the rim. I think this is perfectly adequate for the first frame. Honestly, I just feel grateful to have been able to reach this point.

Does this mean that the brakes will wear the tire and potentially damage it over time compared to the brake pressing entirely on the rim?