Looking great! Looks loke I need to assess my grinds vs. arc.
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Day 21- Another day in the books.
The joint pulled apart on the backside when tacking. Made for a pretty bad fit up and a tough joint.
Good reminder to get enough tacks.
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Now’s a great time to start taking notes on how things pull when they’re heated up and then cool. It’s minor info now but it’ll help you make educated guesses when you build your frames.
Something I wish I had thought of (or had been told) when I was starting. I’m really, really bad about taking notes . . .and its made my learning curve much longer.
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I wrote down how to set up my jig last week so that’s all the documentation I’ll be doing this year 
I tacked this at 2 o’clock and 7 o’clock then started welding from 2-5. This caused 11 o’clock position to lift 2mm.
Big lesson in tack welds. Especially with the limited access my fixture provides.
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Consider tacking in 4 places and tack the way you’d tighten lug nuts.
10:00 then 4:00
8:00 then 2:00
If you’re able to move fast and don’t push a lot of heat into the tacks you’ll get minimal distortion/pull.
From there you can start develop a weld sequence. As you’re developing that sequence remember that the metals first expand and then contract more than they expanded – and that contraction follows the the weld. So if you’re first weld is 4:00 → 8:00 the tube is ultimately going to pull toward 8:00. To counteract that you might run your next weld from 10:00 → 2:00.
If you’re still having problems consider using 6 tacks but always tack in a sequence that counteracts that shrink/pulling.
You probably figured some of this out already but I posted for the folks that come behind you.
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Day 22- I got a few more welds in. They are getting more consistent but still look weird compared to other 4130 welds.
Looking at my past results the ripples showed up when I switched from 2% Ceriated to 2% lanthanated tungsten.
It looks like most people use lanthanated for 4130. What do you all prefer?
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Looking good. I’d be happy with those beads, especially after a coat of paint! lol.
I’ve always used Lanthinated. What I used to read was that Thoriated was considered the best, but radiation concerns bumped it off the preferred list and off many suppliers shelves. Cerriated seems OK too, pure Tungsten has some issues with durability, I think. ¯_(ツ)_/¯. I’ve no dog in the fight nor the chemistry/welding knowledge to back anything up, just internet word-of-mouth.
Keep up the good practice!
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It looks really good! I would ride that headtube off a picnic table!
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Haha that is good encouragement but I am sure everyone here sent a wal-mart bike off something reckless as a kid
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