I finished welding frame #2 yesterday in the midst of yet another spring snowstorm. We awoke to around 5 heavy inches of snow! I hear from our local nutty forecaster that we’re on route to a record May in the foothills in terms of moisture. The last time it was this wet in May was in 1995 where I remember it raining nearly every day while I lived on 6th and Marine in Boulder. I remember it because I was in the midst of my first year as a semi-pro MTB racer and was midly stressing out at how I wasn’t wanting to spend all day outside in the rain getting the miles in on the bike like a good racer should! Ahh…how nice not to care how fit I am anymore!
The welding of the frame went better than my first frame, but funnily, I majorly f’d up the ‘easier’ joints (headtube/TT/DT) and did much better on the harder joints (BB cluster and Seatstays). I guess I got complacent on the headtube, partially because I was just using too much amperage without any type of heatsink. I used a makeshift heatsink last frame and it does help a lot.
But on the good side, the super thin (for me) seatstays came out really well and i didn’t burn any holes anywhere, nor in the bottom bracket! The BB cluster went really well, one pass, no pulser, and i’m leaving it as is.
Some random notes mostly for myself (this is somewhat a journal for me to keep a record of what my mind will forget…).
I first welded the driveside of the BB cluster, starting from the back of the seat tube. Then I finished the rest of the seat tube weld (and ST/DT) before moving on to the downtube weld. Before going onto the chainstays, I welded the headtube joints. I first welded the middle of the driveside of the HT joints (between tacks) since the frame was about a millimeter out of alignment and needed to be pulled driveside. The machine was set to around 54amps but I was maybe using 46 amps for these welds. After finishing the HT, I checked on the alignment table and it was still out. This must be due to my miters not being perfectly tight on my downtube (I knew they weren’t PERFECT, but they were close enough – could see light through the mitered joint. No more of that, I gotta make them 100% from now on). I did a slight adjustment to get the front triangle straight and then went back to the welding table.
Next, I went to the chainstays. Pretty smooth for me. The Paragon heat sink was in there with an argon backpurge hose at 5 cfh. I did the whole BB cluster welds – except for the ST/DT junction – with the welder at 64amps, but not full pedal. I’m guessing I was around 56amps for these welds (hard to look at the machine while welding). After welding the chainstays, I took the frame again to the alignment table and checked the rear triangle alignment. It was pulling to the driveside. It’s scary how easy it is to coldset the rear triangle. Gotta watch out not to push too hard on the stays and do it bit by bit. The $25 fork/frame fixture I got from Alex Wetmore rocks by the way. Super fast and easy to check alignment of seat tube to head tube then to rear dropout spacing. I’ll get a picture of the alignment process that I am learning as I go, later, but click those links to check out the tool.
After correcting the rear dropout spacing, I almost starting welding up the seatstays. Into hour 3 of welding, I decided to just STOP, and pick it up the next day. I was getting tired and needed a pint.
The next day I had more confidence and started out on the hardest joints of the bike in my opinion – the seatstays/seat tube junction. It’s the thinnest tubing on this bike at about 0.6mm, and the steep angle of the stays on the seat tube make for some hard welding angles. The tungsten electrode has to be pretty far out of the torch even using a #5 cup (the red thing at the end of the torch that funnels the argon gas at the weld so oxygen doesn’t contaminate the weld). I used about 34 amps at the machine and was almost full pedal at times so about 32amps for the seat stay welds. No burn throughs, the stays went pretty fast and so did the seat stay bridge. Awesome.
Next, back to the alignment table to see how I fared. The front triangle stayed in alignment just fine, but the rear triangle was again pulled to the driveside a few mm’s. Darn. Not sure why, must be a bigger gap on the driveside miters than on the non-driveside (?)…or i just added just a little more heat on the driveside…or my welding sequence pulled it that way…or all three (1mm per error…?). I have no idea right now, just gotta keep trying and I’ll figure it all out one day. I have heard that one should build at least 25 frames before even considering selling them to anybody. I heard another consider the number to be more like 50 frames. I think it depends on how the process goes, and how fast/slow one progresses. If you are confident in your welds and your 5th frame is coming out the same good quality and alignment as your 15th frame, you are probably good to go. If each frame is in itself a new struggle and new issues arise, then maybe it’s best to keep practicing and learning before even letting a friend borrow your frame to test out. The one thing I know is that you can’t be in a hurry. Becoming good at something new takes time…and if you rush it, you’ll only get frustrated and possibly sloppy. Just like everything in life, gotta stay focused on the end result but the majority of time is spent in the process. And if you don’t enjoy the process, why keep doing it? I hope to always marvel at the bare tubes becoming a bike frame or fork. Nothing into something that YOU created! I’ve got a LONG way to go…but I’m enjoying the ride for sure.