I don’t know where to start, but I’ve been wanting to do something like this for awhile for other newbies out there. Sure…there’s a ton of info out there on the message boards but trying to find some of the info is really not easy in my experience. I also think many framebuilders keep their experience to themselves because of various reasons. All choices, such as tubing brand and diameters, are part of what makes their frames their frames and unique…so when you buy a Brand X frame, you know what you’re gonna get in a sense. I understand and respect this, but I hope to share through my experiences (good and bad) here on this blog so one day people can learn from my mistakes and triumphs.
I see in my “stats” section of WordPress what people search in Google in order to find my site. One of the latest was, “how to pulse tig weld steel.” This is something I’m no expert at but in the searching I’ve done there is much variation in this technique. It seems to me that most framebuilders will say that pulsing is “cheating” (and a way for beginners to make it look like they are good welders) but they end up doing it on their frames they sell. That’s because using a pulser serves a purpose – it works the same every time. It enables uniform heat control and consistent penetration that results in a clean finished looking weld. Sure, with enough experience you can use the foot pedal to mimic what a pulser does, or just keep constant amps and pause the motion of the torch enough while dipping the rod to create a stacked coin appearance…but in my opinion is OK to use a pulser to do that too. Moots, Soulcraft, and others can’t be wrong.
Below are some of the pulser settings I’ve found online. The first example was from a builder that did a pass without any filler rod first, and then did the ‘cosmetic’ finish weld with the pulser:
- Peak Amps @ 100
- Pulse set at 2 Hz
- 20 Amps background
- Peaktime Amps @ 65%
- Argon Preflow on steel @ 2-seconds
- Argon Postflow on steel @ 6-seconds
- Argon flow from regulator to torch @ 30 CFH
The biggest thing I’ve learned is to try all these settings in practice welds. It’s really different to use 2Hz than 1Hz, especially if you keep all other settings constant. I find that if I want to dip the rod into the puddle, i personally just cannot do it with this frequency. I find 1Hz to be much easier and I can see what is happening much easier. Maybe with more practice that will change. What I ended up doing with the 2Hz was just laying the rod (not dipping) along the miter and slowly moving the torch to create the bead. With the 1Hz I was able to actually dip the rod at the peak amperage while moving on slowly around the tube. I found the below settings from a few other builders that worked a bit better for me, even with 2Hz:
- 90-105 Peak Amps,
- Pulse set at 2 Hz.
- 13 background amps,
- 22% PTA
- 80 amps peak,
- Pulse set at 2 Hz,
- 45% PTA,
- 10 background amps
- 75 amps,
- (22 background amps – this was not given by builder but I’ve found higher background amps keeps the puddle going better with a slower pulse freq.)
- Pulse set at 1Hz,
- 20-25 cfh of argon on the torch
The last one is the one I like to use. I’m sure the first one is the best IF you can pull off doing a clean first pass without using filler rod. Good luck with that, the miters need to be absolutely PERFECT with no gaps for that one.
Coping (mitering) tubes:
At first, when using the Paterek method of centering the tube on the vertical mill, I wasn’t getting good centered cuts until i started physically measuring the tube i was going to cut and the hole saw itself with calipers. The equation to get it centered, (in inches if that’s what your mill’s table is calibrated at) is (diameter of tube/2) + (diameter of hole saw/2) = amount table will have to be moved from the edge of where the tube barely touches the side of the hole saw. Don’t take the measurements of the hole saw or tube at face value, do it yourself.
The best hole saws I’ve found are HERE. The next best place I found, that has Starrett saws is HERE. The Ultra’s (first link) have the finest tooth pattern and are constant pitch. The yellow Starrett hole saws are pretty frequently used since they’re one of (if not the only) company to offer constant pitch saws but their tooth/inch count is still less than the Ultra’s. Also, I’ve had Starrett’s teeth break off completely from the body even when using cutting fluid. Just my opinion, but i like the Ultra’s the best so far.
Please comment if you have anything to say on the above…i am always up for learning from other people’s experience!