Bending tube with a TIG torch

[IslandTractor]

Given the price difference between acetylene and propane, it seems like the long run is exactly where propane would shine, even if one had to buy the propane equipment new up-front. But I don't know for sure--for example, different flow rates and oxygen ratios may make the cost closer than it would seem just from comparing the price of propane to acetylene. The real equation should be dollars-per-inch-of-cut, or what-have-you, not dollars-per-cf-of-gas.

The other concern that I have is that, with acetylene, most of the tanks I see look pretty small, and I think are intended for welding or cutting. My impression is that heating requires higher flow rate that can quickly hit the 1/7th rule of a smaller acetylene tank. Is that right? For example, take a look at this ad: Oxy-Acetylene Tanks and Torch

Could one use that tank for the kind of heating and bending we're talking about?

If you make your living cutting up scrap 8hrs a day then propane is the way to go. For heating the sort of small metal objects like you are working on now, it would take a lifetime to see any real benefit from propane over acetylene. And, you can weld with acetylene. Propane plus oxygen can cut, solder and braze only.

 

[joshuabardwell]

Just wanted to update y'all and let you know that the "weld a U" method worked really well. The uprights on the cart are now as straight as the rest of it. I'd say I moved them a total of about 3/4" to 1" over a radius of about a foot.

Regarding TIG and overheating, I tried some welds today with a focus on going faster--getting in, getting hot, and getting out--and saw a noticeable difference. Heat-marks were much smaller, but interestingly, the ends of the welds were also neater. I was able to taper off much faster without creating a bubble or a crater. How about that?

 

[CNC Dan]

It's realy fun to see your progress.
Thanks for the update.

 

[weldermike]

Cool man! Your coming on hard and fast bud, cheers!

 

[CNC Dan]

Just saw this vid about heat straightening a shaft.
http://www.youtube.com/watch?v=0TqvEXS3f88&feature=youtube_gdata_player

 

[joshuabardwell]

Fascinating. He is dry washing like I was talking about doing. Maybe it didn't work for me because I was needing more than just a few thousandths of movement. Or maybe it's just technique.

 

[joshuabardwell]

I've got a small update for y'all. I was on a family vacation all last week, so I didn't get any work done. Now that I'm back, I finally got to work on the cart some more. One lesson I'll take from this project: when trying to heat-bend using welds, don't spray the thing down with water to speed up the process, or the entire thing will turn to rust. Sheesh. What a mess. After, literally, over an hour with the grinder and a flap disk, it's clean again.



I don't know why it looks like the lower shelf is so much shorter than the upper shelves. They're not 100% perfect, but it's not that far out if I measure with a straight-edge.



The middle shelf was the biggest challenge. The right-hand side was lower than the left-hand side (looking at it from the front) even though the two sides were exactly the same height at the back. By putting beads on the top of the right-side and front sections of tubing, I was able to pull the corner within about 1/8" of true.

By any real standards, this is pretty amateurish work, but if you knew how many hours I've put into this just to get it to this point... well, you'd think I'm an amateur. Which I am! :confused3:

PS: My house is clean because we have company coming over tomorrow. That's the only reason y'all get the kitchen instead of the basement. Enjoy!

 

[Arc weld]

Scratching the kitchen table with it... warping of your cart may be the least of your problems:laughing:

 

[joshuabardwell]

Scratching the kitchen table with it... warping of your cart may be the least of your problems:laughing:

Fortunately, she doesn't read TBN!

 

[IslandTractor]

Scratching the kitchen table with it... warping of your cart may be the least of your problems:laughing:

Yeah, in our house I'd be risking a high squeaky voice if a welding project came anywhere near a piece of furniture.