On the rear triangle of the latest frame, my new super fat rotundcycle, I test-drove the pulser on the ThermalArc 185. I started trying it when I had poor line-of-sight on the elevated chainstay bridge and I thought it’d help with heat control on those tight spots. But after I got done with the bridge I just kept going. I always have done ‘straight amps’ but wanted to see if I could get more consistent looking beads and less heat distortion by using the pulser. Also, I realized on the last few frames that I was foot-pulsing more than normal, mostly in the acute angles – under the downtube, countermiter of downtube/seat tube. I was also finding myself not dabbing the filler road and just laying the wire in there for the high part of the foot pulse to “absorb” into the bead. Laying the wire in there with tension (pushing it in there) also acts to close or block those small miter gaps that you just didn’t feel like filing any longer to get water-tight. So when using the pulser previously I felt like I was losing control but something has clicked in my brain recently. The pulse heats/cools so you should get less ovalization/heat distortion and it also gives more control over how the bead looks aesthetically. I could also lay longer passes and minimize my starts/stops, and my welding isn’t as affected by tired hands and arms which would make me more shaky when using straight amps and dabbing the filler.
I didn’t take many pictures of the frame welds other than of the E-stay junction. I set the peak amps to 100, the ‘background current’ to 25 amps, the frequency at 1.7pps, and the pulse width at 45%. I used the foot pedal to regulate the amps based on the tube wall thickness instead of futzing with the pulser settings for each joint. I could weld the BB with a heatsink to the seat tube with these settings as well as the hooded dropouts to the stays. Unless I was going to be using something less than 0.7mm wall tubing, I may just stay with those pulser settings. I’m using the next frame, a new geared cross bike for me, for further experimentation with the pulser to get it dialed in before taking on friend’s bikes.
I also used the pulser on my first stem. The steerer clamp and bar clamp/front plate are Paragon’s sweet Machine Works. I just mitered the 1.125 x 0.049″ tube to make this a 90mm x 8 degree rise stem and welded if up in the fixture that has been too long a really expensive paperweight till now. These are so quick to make using the Paragon parts, but they are super expensive. Really no need to make stems, but it is a nice touch to a custom frame and pretty sweet looking in my opinion.