It’s been a pretty frustrating week in the shop. Not a lot of time, and the time in there was usually undoing/redoing my mistakes from the previous day. Groundhog day for the last week or so. It’s weird, i just can’t get out of this rut! I know I’m still a newb, but I feel like i just started welding again. It’s like my brain and body took a hiatus and left this stupid dude that just stares at stuff clueless to why anything is going wrong!
Tig welding is the most awesome and frustrating thing I’ve ever learned. I’d been putting off welding up the front triangle of Jim’s cross frame until I felt more back to ‘normal.’ Today I went after it, and even though I had some not-so-pretty results around ‘tongs’ of the counter miter of the BB/ST/DT (the hardest part to weld IMO), it’s done, and it’s all pretty good. I haven’t checked the alignment yet (I got caught up starting to make my own seatstay fixture…more on that fun later!) after spending an hour welding up the front triangle and chainstays.
“If you put 10 framebuilders in a room and ask them how to weld up a frame, there will be 12 different answers.” – Don Ferris.
“Keep your process exactly the same for each frame so you can see what works and what doesn’t in terms of frame alignment.” – Carl Strong.
(Ok, so I’m paraphrasing those quotes, but they are more or less what I heard and read, respectively, from those two builders. A newb has trouble fixing their alignment issues if they don’t change their process, so I’ve basically thrown Carl’s advice out the shop door (I don’t have a window). I’m not getting Carl’s whole point across in that paraphrase => he was saying that if you change too many things at once, you’ll never know what is working and what isn’t…so leave at least the welding sequence constant and any variation that results in frame alignment will be easier to discern where it came from…or something like that.)
Another rather large tip I got from Mr. Ferris was to only tack-weld the frame in the fixture in the vertical plane ONLY. This definitely runs counter to how I learned from Mr. Kopp, and what I’ve interpreted on the online forums. I’m not sure I’ll stick with it but it does seem to make sense to me. I thought I had heard him wrong at first, but I’m pretty sure this is what he was recommending. (Who knows, maybe he’s totally f’ing with me.) Regardless, I gave it a try. The one problem is that he recommended welding the acute 1/4’s in the fixture FIRST (10-2 on the top tube, 4-8 on the downtube), then the obtuse angles before taking it out of the fixture and welding the rest on the stand. This was confusing to me because I’ve always heard to weld the obtuse angles first, then the acute angles since the steeper angles tend to draw together more than the obtuse angles. The reason behind welding the acute angles first in the vertical plane is exactly that though – because doing so securely draws-in the head tube to the TT & DT. I do tack weld the obtuse angles first and acute second though.
Also, don’t stay on one tube for the whole welding sequence…split it up so that the tubes on that particular joint don’t build up heat and start acting differently under the same amperage. I’ve noticed this, once hotter, tubes act differently. Move to the top tube/head tube before finishing off the down tube/head tube joint. Once the vertical 10-2/4-8 welds are done, then weld up the sides. Weld in 1/4’s if you can, but honestly, I can’t…i weld in 1/6’s.
So, I followed these recommendations for the most part – except for welding at all in the fixture – because I like to use heat sinks to minimize ovalizing/distortion to the head tube and BB (and save my reaming/facing tools). It’d be easy to weld the vertical planes on the joints in the fixture, but I know that I’d have more distortion than I’d want, so after tacking I took the frame out of the fixture and welded in the bike stand attachment on my welding table. It’s just SO much easier to flip flop it around to get the right position and sighting on the joints that way. The heat sinks and the backpurging are the main reasons my welded tubes don’t have much discoloration even though I’m at around 64amps floored most the time. (It seems each machine has a different 60 amps though…and maybe air vs. water cooled torches make a difference too…i don’t know. But I do know that I learned on a huge fat Miller Synchrowave 200 and was burning through at 32 amps. My little inverter 185 seems ‘cooler’ at the same amperages. I’m probably high on argon so maybe that’s totally wrong…)