Whoa, that's quite the change isn't it? The site have been down for a day or more and now it's like someone rearranged all the tools in the drawers. It's probably better but I'll need to figure it out.
That’s awesome that Sean lives so close that you guys can meet up and work in the garage together. I think it’s time you guys collaborate on a 2 wheel build, with or without a motor.
Well, you (and I) might get your wish. Sean is perhaps the most dedicated perfectionist I have known and I've known a few. I am drawn to these sorts of people (my friend Scott comes to mind) because I want to be more like that. I'm not but I strive to be. If I were to be honest I don't know that I would ever achieve that level but I want to be closer - always closer than where I'm at.
Hmm, I can now drag and drop photos - I'm curious how big they'll be...
Okay, Sean came over and, since we're now both double vaccinated, it was a treat to finally skip the masks and just be able to hang out. We started with coffee and chit chat. I didn't shoot quite so much because I was trying to pay attention. As if it wasn't enough that Sean had already given me some titanium tube to play with he brought another box...
This box of tube weighs less than if it were filled with packing peanuts. Titanium is shockingly light.
We started by just testing my setup. Sean adjusted my machine to match his settings which wasn't too far off my stainless settings. Despite owning my machine for... 14 years? I still don't really understand some of the settings. As a point of reference we were running 100 amps but controlling that with the pedal, our pulse was 1.8 per second which was super fast for me, our peak time started at my stainless setting 33% but we dropped it to his setting of 25% and I usually had my background amps set to 33 but we cut that in half. I was foggy on background thinking it was percentage but it's actual amps.
My diffuser cup seemed to do a decent enough job that we didn't test out the cup Sean brought. We ran a few beads and Sean gave me some tips. My method of laying the rod down in front of the puddle instead of feeding it in with dabs turns out to be a real technique. I feel better.
At this point we took a break and had some pizza for lunch - I felt it was the least I could do and also, you know, pizza. Of course.
After I really wanted to see Sean weld a real tube joint. That's the money - that's the hard thing. While you (and Sean) would think I have ever tool it quickly became apparent I do not. We tried to cut a larger diameter tube but I didn't have a good method of holding it and my small V-blocks, drill chuck holder and otherwise shoddy setup actually had Sean hiding in the back corner of the shop as the hole saw bit the material and threatened to explode. We abandoned that and moved to a smaller tube. For that I had sufficient tooling to hold both the hole saw and the material rigidly. Another valuable lesson: rigidity is key and more important with ti than any other material because of it's sticky and springy nature.
Held tightly the mill power fed the table through the hole saw with zero issues. Like butter.
Sean welded a small 3/4" tube to a 1-1/4" tube with a fusion pass to start. The fit up was super tight - no gaps. With no gaps a fusion weld is pretty easy. What I learned is that the purpose of the fusion weld first is about creating a thermal junction so that there is greater heat dissipation.
This is the fusion pass. The other thing I learned is that what I thought was clean is not clean. In fact I think there are many people welding titanium that might think they're clean and they're not. I don't think I can convey how freakishly obsessively and maniacally clean Sean is with the welds.
But I'll try. Material is cleaned with red scotchbrite (inside and out) to remove the oxide layer, then soap and water, rinsed with distilled water, then wiped down with acetone. The filler and tungstens are also scotchbrited and wiped down with acetone. Bare hands don't touch the clean material. We didn't go to those lengths for our tests - we just did scotchbrite and acetone.
This might just be my favorite photo I've take this year. Maybe longer. It's very "me" but also, come on, how cool is seeing the weld in the reflection? Very. Also, man am I happy with the choice of the Sony A7C. This was shot with the new 35 f1.4 and it's a pretty dreamy piece of glass.
This is the filler pass. Ti is very susceptible to cracking so you want a clean, smooth fillet. Almost better to be undercut than over filled. Ti flows very nicely but as a material it's sticky and wants to grab the rod when it's hot.
After Sean left I wanted to go right back to the garage and try the same weld on my own. This time I used the cold saw with a very fine blade and it cut flawlessly. I also tried machining a tube down a bit to see how ti machined and it actually cut really nicely - better than stainless.
I also tried to do a filler pass on top of the fusion welds and that wasn't going well. Coverage is key and any color past straw is basically a fail. I had a lot of fails. Sean was right; that was much harder than the tube joint.
It was the best of Ti and it was the worst of Ti. I'm not sure why my ends lose gas coverage but I'm guessing I'm not keeping the torch at a right angle.
We burned a good amount of welding rod and I contaminated a lot of tungsten.
The tube joint is much better. Sean's on the left and mine on the right. My other side isn't as good but this side was passable. Too much color but not a bad start. I feel like my journey would not be complete if I didn't get the chance to build a frame with Sean. I know there is sooooo much to learn and going through the process will teach me much more than just how to build a frame.
Hopefully it will be able to happen sooner than later but we'll see how our schedules line up. I will sell off both of my bicycles to help pay for the one new one and I'm still mulling over what it would be but I'm leaning towards something like a dirt jumper with a few gears. As simple and clean as can be.
Sean, thanks so very much. It was a real pleasure to hang out and I learned a lot.
Gregor
