BoilermakerFan
Well-known member
As per the above, the biggest impetuous for my own purging in my steel bikes is actually what happens POST weld. I have to chase the threads in the bottom bracket, then face the shell and face/chase the inside of the seat tube and head tube all with tools that are really expensive. Any oxidation on the backs of those welds really shortens these tools lifespan. It also makes those tough jobs even tougher as they're all done by hand. So the biggest reason for me from the outset was from a process approach where maintaining tolerances were super critical. Then there are all the small benefits with regards to weld integrity with chromoly/4130 aircraft tubing. Small gains, but critical in a product that really see's a lot of abuse and cycles over time.
But to the welder just starting out with 4130 or steel? It's completely not necessary. You really need to focus your efforts on cleanliness. I can't stress this enough. Both sides of the work piece and/or inside/outside of the work. No dirt, mill finishes, oil, not even a finger print. All of that can lead to contamination. Your work space also should be clean where you're welding too. So if you don't have a routine, get into one and make sure things are tidy. From there it's all heat input, pace, and experience with the torch, tungsten, filler and pedal. And practice.
Practice would be 2nd most important factor.
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Anyone reading this can do this weld. And I'm not joking. It just takes practice and a level of familiarity with the process where it becomes intuitive and that intuition, that one where you don't think and you're just reacting and acting? That's practice. Just know that the learning curve can be steep at times but being persistent, dedicated and putting focused time into that skill will make you better. I still learn new things every time I weld. I actually picked up the torch yesterday after welding up another Ti prototype and already I could feel and see I'd learned more just from welding a different material.
Just to be clear: The NH service provider refused to drop in a 2nd service and bring 3 phase over. So I'm stuck with 110v at the shop and things are on phase converters while my welder (Miller Dynasty 200 DX) recognizes both single and three phase. Everyone I know who runs three phase into their shop here in the US, depending on material thickness have similar high amperage settings. An Amp is an Amp. Reference paragraph 2 titled under constant current in this article.
However, what made me change my settings was penetration and how the weld was wetting out. Instead of relying on the percentage of power at the peak of the arc (which is why my amps were low originally, with a high peak percentage), I flipped it: So now I have higher amperage settings with a lower percentage of power at it's peak. Example using this weld junction which is unique on a bicycle frame:
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But my settings for that junction are:
115 Amps
30% Peak
9% Background
1.3 PPS (pulses per second)
15-20 SCFH at torch
10-15 seconds post flow
5-10 SCFH for purge
.035" Filler Weldmold 880 (basically 312)
1/16 2% Lanthanated Tungsten
No. 10 Alumina Nozzle with Matching 1/16 gas lens.
No secrets there really. It's all in the technique.
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And for those who want to know what's new: TITANIUM!
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In the shop now: Dedicated Single Speed
Can't thank you enough for all the advice. I'm sure a lot of it will carry over to the steel motorcycle frame mods I'll be doing in the future.
Do you purge with Argon, and blend, or is straight CO2 sufficient for purge?
I'm not surprised you're utility wouldn't bring in 3phase. If you're towards the end of a line of just single phase residential, that's a lot of required equipment upgrades on their line.
But, you should have been able to pull 240V single phase to your shop? An amp is an amp, but 240V provides the same power at half the amp draw so you can use smaller wire size for the same power delivery. 20A at 240 would put 10A on each leg so the wire is smaller, 20A on a 120V circuit is all 20A on one wire...
I rewired my house when we bought it in 2000. I upgraded to a 200A service. At the time I had a Jenn-Air in the kitchen that required a dedicated 60A circuit so I pulled a single 90A feed from the main panel and set a sub-pannel under my kitchen. I fed a close coupled 60A sub-panel for all lighting loads in the house and ran another 60A feed to the garage. My garage panel was a MLO (main lugs only) so I had to backfeed a local 60A breaker in the garage sub-panel. I'm going to buy a new 60A main breaker panel to replace it so I can add another 30A 240V circuit for the welder since my panel is out of provision spaces. I'll have (2) 30A circuits, a 20A circuit and 3 or 4 20A 120V circuits but the main panel can only draw a max of 60A. At any given time the maximum current draw would be 50A if I had my heater, welder, and lighting maxed out, but in reality, it's much lower than that.
You could even have your utility upgrade your service to 400A and put a large disconnect outside, then feed 200A to shop and 200A to the house. If you have gas heat, gas furnace, and gas stove you can easily get by with a 100A service in the house. In hind sight, I should have pulled wire sized to handle a 100A sub-panel in the garage but limited it to 60A while we had the Jenn-Air. Changing to LED light bulbs has also dropped my lighting load considerably so I would have no problem handling a 100A feed to the garage with damn near everything on and the AC on in the house in the summer.
That SS looks awesome!
