Silver Case

First Half of the Day: T-fillets

Middle Part of the Day: Luke, Lee, Woei, Ling, Nini, Ling’s mom, Australian Cherries.

Last Half of the Day: Cordura Applique on waxed canvas

At 39amps full-pedal, the heat is not a problem.

Practiced welding mitered thinwall cromoly today. Not ready to put a frame together yet, but the results were further along than I feared they might be. Was a big aid to change my grip on the TIG torch.

An erratic weld, but is improving with practice.

I got in some good, purposeful practice welding thinwall cromoly steel this weekend.

Ready to provide constant current

…but sadly not enough

My welder has power now, but I couldn’t give it Argon shielding gas because the pony-sized bottle of argon we have has the wrong side valving. Thus it cannot connect to my welder and my Harris 355 flowmeter cannot connect to the bottle. Tomorrow I’ll go buy two full-sized jugs.

Shop sporting a new 30amp outlet.

Only so many times I can pick through shipping remnants hoping to find 20 pounds of missing metal.

Butt Welds II
Lap Welds
Destructive Forensics

Welding went ok last night. My big breakthrough was kicking the stool away, squatting down, and holding the TIG torch like a pencil. Why does that all help? Because then I can really see the luminescent green arc cone hitting the material and to see how the weld pool is behaving. In some ways, it feels very similar to oxy-acetylene brazing.

I did lots of butt joints then got bored so I started lap joints. The first two were harrowing disasters. On the third I consulted my Miller TIG handbook which explained the angles to hold the torch and rod. That made all the difference in the world and I laid down several laps with minimal scalloping or undercutting of the upper plate. For fun I also welded a couple mitered, thick aluminum tubes. That was a lot of material to heat up and the cleaning action seemed to be boiling off unlimited quantities of garbage from the plate.

Don’t ask about the corner joint I tried to weld.

I brought my welds to the workshop today to do some destructive forensics on them… to see how deep the welds penetrated, how strong they were, etc. Aside from the strength test of the lap joint (I had to do some substantial pounding of a wedge to break the weld), I couldn’t determine anything. The aluminum filler rod (er5356) must be identical or very close to the aluminum plate because it was absolutely impossible for me to see where the weld stopped and the base material began. It was nothing like the welding textbook photos.

I’d upload all my photos, but I forgot the camera at Straits Dispatch, so I’ll have to do it later. I won’t be in the workshop much tomorrow or this weekend because Ling will be away having a solo mother’s vacation in Kuala Lumpur. She hasn’t spent a night away from Luke in very-close to five years (he turns five in June!!!). So this is a big deal, but mostly to Ling. Luke doesn’t seem to care (although tonight I think he was testing how much he could get away with while Ling was out for the evening) and I’m ok with it. Ling has left me a large schedule and agenda for Luke’s Friday, Saturday, and Sunday. It’s written in a thick magic marker as if it were for a five year old to read. Perhaps she thinks Luke will be able to cross-check me?

My Juki sewing machine has really pissed me off. It was sewing great, then some thread caught, and ever since its tensioning will not work properly. The thread behaves as if the top thread tension is too low. I can tighten that and loosen the bobbin tension and it didn’t help, in fact it made it worse. (the bobbin thread lies flat along the wrong side, the top thread makes big hoops on the wrong side and as I fussed with the tension more and more, eventually was making soft loops on the right side as well). It feels like something is out of adjustment beyond just the tension adjusters, and I know I have threaded everything properly, so I am going to have them send a technician over and sort this out. Very irritating.

The 9Velos are approaching completion. The main frames are totally done and right now I’m working on the forks. As soon as those two are done, I’ll clean the whole lot up and send the frames and forks for powder-coating. I screwed up yesterday and made fork blades to the wrong dimensions. Fortunately they are perfect for another bike project I have scheduled next so I didn’t have to scrap them, but it set me behind a day. Fingers crossed, I should have both frames finished on Monday. (I doubt I’ll get to the shop this weekend)

This welder has all sorts of cool functionality. I can’t wait to work with it. I think I’ll order a bunch of 22 or 23 gauge (~0.7-0.8mm) 4130 tubing from Spruce Aircraft supply and then chop those into lots of mitered pieces that I can practice on. It’s the same metal, and same thickness as the tubing I make bicycles out of. They even sell scraps for welding practice.

Here are some more welding analysis photographs I took:

And here was the tungsten that was responsible….

Spent all evening working on TIG welding aluminum butt joints. I did all sorts of experiments trying to work out how to do it according to spec. I really wish I had a teacher who knew something, but he doesn’t. I tried to discuss the AC Balance control with him and it was clear how little he understands. He somehow thought this was connected to the gas pre- and post-flow slopes. Clown.

So instead, i did my own tests and kept detailed photo notes, so hopefully I’ll be able to get some help on an online welding forum.

Top of a butt joint looks ok, but the pentration isn’t sufficient (apparently)

Was too tired to look long, but I did find this short explanation last night which makes sense:

the idea is to balance heat and travel to carry the puddle- almost at the point of blowing a hole. the filler additions help prevent the puddle running away too as they’re constantly cooling it. only small pedal adjustments should be necessary to compensate for the part heating up. cap appearance comes from filler additions NOT pulsing the arc

watch the puddle (don’t add filler and move as soon as it forms), wait for it get VERY shiney and begin to sink before adding filler and moving. ‘wait’ in this instance is relative- maybe the blink of an eye. if the amps are right you’ll be able to move along at a comfortable pace without pausing. the weld can be done slow or fast, as long as the heat/travel/filler are all balanced. from a mechanical point of view faster is better as the overall heat input will be lower- one thing at a time though, go at a comfortable pace and adjust heat to suits

One of dad’s friends is an experienced professional welder and he asked him to look at this photo. Here’s his feedback:

Harry was impressed with your early work being so good. The weld looks good because it is consistant (stack of nickles) puddles, straight, and consistant width (like railroad track) The bead is pretty well tied into the base metal looking like solder fillets along the edges except in the middle where it looks like the bead is sitting on top of the plate.

Harry noted the weld looks better (shiny) from the half way point due to the base metal plate coming up to temperature. If you preheat the alum plate to 150-200 F the bead will be better. There are temperature sensing wax crayons that melt at specific temps you can get “temple sticks” is what I heard them called years ago. Put marks on the plate with 150 stick and 200 stick then heat the plate up with a torch to whree the 150 melts but the 200 doesnt then weld.

The black deposits in the weld are dirt from not cleaning the plate one inch both sides of weld. You need to scotch brite the aluminum to remove the dirt and oxide till it is shiny. You could do it by hand or with a flapper wheel on a drill. Any method you use must not leave deposits in scratches on the plate.

The end of the weld shows a crater caused by stopping without keeping the cover gas in place until the metal freezes and caused by not “tailing off” the weld current. The start of the weld shows not enough filler wire added at the start of the puddle. You might cut a 7 inch piece of wire and handle it all day for practice. Practice rolling the wire between fingers and thumb while moving the wire end to end in and out. Like your inserting and retracting it from the puddle with rolling finger motion rather than arm or wrist motion.

Your doing great learning on your own and the pix you showed was OK’d by several guys that know welding as a pretty darn good aluminum weld. There is more that I am forgetting. Preheat the aluminum and as you have discovered controling the duty cycle of + to – controls the penetration. Practice, practice practice straigth constant width railroad tracks with consistant shaped and even height bead puddles.

This is why I wish I had a teacher in my TIG class, not just an attendance-taker. I was amazed he spotted the “bead sitting on the top of the plate” — that was one of my two pre-weld tacks. If I don’t take the aluminum plates, it’s a disaster. Inevitable one side of the butt becomes hotter and it start pulling away, warping up, then the whole joint it shot to hell. I wonder if I should have penetrated the tack more in the first place or have tried to melt it down more during my real welding pass?

And yeah, I don’t do any cleaning at all of this stuff. The welding shop is so starved of equipment, there is nothing to clean with and a single pair of pliers to go around the rooom for tightening the screws on the brass welding plate clamps.

Finishing the welds is tricky, as I don’t have a current-adjust pedal. So I try to pull the electrode away and feed a last bit of rod in. I guess that’s the wrong way to do it, as I lose shield gas. Instead I guess I should try to shove in more filler rod to cool the puddle off?

I have read a bunch about welding safety and I’m confused why i never see anything about electrical safety. You’ve got the electrode and then the workpiece as the other side of the connection. I would have thought there would be electrocution potential here, but it’s never discussed as far as I’ve read. And I DID manage to shock myself wednesday night while AC welding. Somehow I zapped my left forearm. Maybe my sweaty leather gloves and cotton coat were enough to conduct better?

Miller has a lot of online education material. I found a short four-part beginner’s guide to welding aluminum just today.

A trouble-shooting table as well as a visual guide to troubleshooting welding problems and quite central to my welding needs: how to weld 4130 Cromoly Tubing.

I have lots more welding result photographs. Perhaps I will add them to a big flickr set. I’m sure everyone will be amazingly interested in them………….

Had my second practical TIG session last night. I did lots of stringer beads and then switched to welding butt joints.

I tried out a tight-fitting rubberized glove so that I could feed the rod more smoothly. That worked for about one minute before I started smelling burning rubber, so I switched back to the baggy leather glove. Somehow I finally got the hang of using that glove and could feed sufficiently ok. I could add probably a half-meter of aluminum filler rod to a 10cm stringer bead, which gives some sense of how smoothly and quickly I need to be able to feed the filler.

My butt welds were not too bad. The top bead looks good but I am getting only partial penetration of the joint. I tried multiple permutations of feeding more filler rod into the pool as well as lingering the arc longer over each pool, but neither improved the result satisfactorily. I increased the amperage (I thought slightly) but that produced way too much heat and gave me a flat, pooled bead and still didn’t penetrate that well.

This is where the class annoys me… I see the issue and want to solve it, but:

1) The teacher knows essentially nothing about welding. He can offer no useful advice. He’s not a welder, he’s an airplane ground engineer.

My school TIG Welder

2) There is no manual for the stupid DYNA TIG 201AC/DC machine I’m using, so I am guessing at how to control the machine. The controls are sparsely labelled. I looked for an online manual but didn’t find much more than an information flyer.

Plus the machine is a piece of shit, the machine keeps overheating on me. Miller has a useful online reference book. It says AC machines need a big bank of resistors to help get rid of some sort of DC flow that builds up in the circuit (current flow when the electrode is positive is not so good I think). I suppose these resistors are what’s overheating. Why can’t the cooling fans be sufficient to work? The machine is claimed to have a 60% duty cycle. I think that’s a joke.

Anyway, this is giving me practice, and I am doing my own independent practice. I’ll be looking forward to better education at Lincoln in June.

In retrospect, instead of increasing amperage, I should have adjusted the balance control to increase the Electrode Negative percentage, so that I get more penetration and less cleaning action. Duh. Shit, wish I had realized it at the time. I thought my cleaning zone was already fairly small.

DO NOT WELD GALVANIZED STEEL. Galvanized steel contains a zinc coating that produces carcinogenic and poisonous gas when it is burned. Exposure to the stuff can result in heavy metal poisoning (welding shivers) – flu like symptoms that can persist for a few days, but that can also cause permanent damage.

Sulaiman at work with his problematic machine

Today was our first practical session of the TIG welding class we’re taking at ITE. It went way better than I’d feared. I’ve heard so much about how difficult it is to TIG weld that I was planning for the worst. There is a piece of TIG-testing metal in Sulaiman’s shop that looks like it had been involved in an IED attack in Fallujah. I figured that’s what my welds were going to look like. But in fact, I could make somewhat even fish scale fillets on a sheet.   

Biggest surprise? The arc is much more manageable than I’d feared. It is sort of like brazing without the hysteresis. In fact, I jumped ahead a lesson near the end of class and tried to do some butt joints on old scrap. The top side looked pretty ok, but the penetration wasn’t sufficient. That’s saying that I actually need to linger over the metal longer than I did. I came into class fearing I’d be “blowing holes” into metal left-and-right.

Biggest problem? I was wearing these horrible, horrible China-made gloves. The finger lengths are absurd. Against all odds, my thumb is actually not as long as my middle finger. Consequently it was quite hard to feed the filler rod smoothly, the largest impediment to beautiful fillets. I’ll have to buy some proper welding gloves before our next class. I have a pair of marvelous workshop gloves that fit perfectly, but they have some non-leather parts and I’m scared of melting a molten glove on my hand — the heat is quite intense, particularly when I’m running low on filler rod (or doing a bad job of feeding it, ending up with my hand close to the arc)

(*) As a side note, I love the “Mechanix” (size L) gloves I bought at Blug Lug in Tokyo. The fit is unbelievably perfect. Somehow they don’t make my hands sweat, either. I wear them almost constantly in the workshop. They’re comfortable, prevent my acidic (and copious) sweat from rusting my frame tubes, and allow me to touch quite hot tubes while I’m brazing, giving me better positioning. I’d give them 5 stars and declare them perfect if I hadn’t managed to make a small slice in one of the thumbs somehow. I hope they are durable and this was just a lucky razor-cut on a bit of flashing or something.

Other problem: I think I managed to blind myself a tiny bit. I never looked at anyones’ welding, but I did notice a few times that I could see white light bouncing off my leather apron up into my mask. Perhaps I didn’t have it closed down sufficiently. Oops. Well, I’m not seeing spots, my eyes are just tired, so lesson learned. Perhaps I should dig up all those nice turtlenecks I used to wear in high school.

Anyway, I’m quite enthused by this class and I’m looking forward to my full-on training at Lincoln in June.