pretty tired from working and cooking most of the day.
we got a late start, i did some more TIG practice on square tube. it's especially hard (i think intentionally) because i'm welding pretty thin square tube (1/8"?) to 3/16" plate. chris says this is good training for BB shell and dropout welds. focusing the heat on the thick part is a little harder with TIG because the torch cone gets in the way a bit, whereas with brazing the torch tip is by comparison quite thin. adapting to using TIG as a heat source wasn't as hard as i expected though. it's like a super hot brazing tip.
th most annoying part is the electrode. every time i touch it to the rod or the metal i'm welding, it gets dirty and doesn't work as well. Chris has a supply of maybe 20 electrodes, so i can just switch to a new clean one, but eventually i have to stop and sand down the whole batch. if i'm trying to do nice welds i go through the batch in a day of welding, which is really more like 3 or 4 hours of actual welding.
then we went to the grocery to get food, and i asked Chris a lot more questions about what tubes to use. he said to call Lon at Nova tomorrow to order. OX Plat is offered in thick gauges, but only in mountain-sized diameters (duh) which he recommended for my dad's frame. my mom is about 5'5" and 135 lbs, so she'll get a ~52 cm frame in road OS size (28.6/31.8), probably .7/.4 gauge. Dad gets something bigger and stiffer, but i'll decide on the phone with Nova.
he has a couple Paragon BBs and Salsa stainless rear dropouts that i'll buy.
he said yesterday that there's a local powdercoater who'll do a bike frame and fork for under $80, 1 week turnaround. that's awesome since i was told $200 and 2 weeks turnaround at a place an hour outside DC.
i asked about seat tube angles. he said the following: general rule of thumb is 73º ST angle. good runners and spinners need a steeper angle, 73.5º. big gear pushers and bad runners get a 72.5º. the half degree actually makes a pretty big difference, because it translates to about an inch over 50+ cm of length.
re: chainstays he uses 412 mm on a typical 700c racing bike. sport tourers up to 420mm. after reading a lot of Rivendell propaganda i find this appallingly short. i think i'll go for about 440 mm on these frames.