Natural gas for TIG welding

Helium is an excellent shielding gas for tig. Especially good for steel. It increases arc penetration for the same current.

helium bagpipes is quite a thought, a high pitched racket

And also makes the weld lighter which is why NASA uses it so much.

Hi, seriously, I've been thinking of a TIG machine for Sifbronze welding of steel. Apparently the process works very well. Has anyone any experience of this using these cheap chinese welders? The Aliexpress one looks quite a good deal. abut £112. You can also get German ones on Amazon for less than £200. The argon can be got by putting a deposit on a bottle of around £60, which is not time limited [ you can keep it for as long as you like] and if you return it you get the deposit back less 20%. The refill costs around £35 for 10cu m.

John you really should consider the helium bagpipe solution i suggested back in early april.

I understand that specialist vacuum components such as parts for microwave tubes and electron microscopes may be induction brazed in a hydrogen atmosphere. H2 is highly reducing so the process inhibits oxidation. Apparently the process sometimes uses an inverted-U tube open at the bottom and filled with the gas, with the work supported in the tube and the induction coil around the outside of the tube. It sounds scary but because the whole thing is at atmospheric pressure throughout and vented, if the gas does ignite at the interface at the open bottom it just produces a flame and a loud "whoop" sound. I guess if the gas is trickled in at the bottom and the hot work is supported well above then the chances of ignition can be controlled.

Hi, I just bought 80 sifbronze rods 330mm long on eBay for £11. I was wondering if I could use it with borax flux and propane for brazing small bits of steel.

Should do, sifbronze is just bordinary spelter as I understand it and curly used to use it for everything with a petrol blowtorch (ow!)

Your rods will melt roughly when the steel turns red at 800 ish degrees so if you can get to that stage all stould be well.

Thanks , I'll give it a try. I was looking for something that would do as an alternative to silver solder on steel for small fabrications. I know Curly used it for everything although he favoured using oxy acetylene. I have read somewhere that you can use and ordinary arc welder and a carbon rod to strike an arc to get the heat. Apparently it was in the old books on brazing but has now been superseded by TIg. I used to be a bagpipe maker so the bagpipe idea maybe isn't such a bad one. I could pump the gas into the bag with the bellows under my right arm and squeeze the bag with my left while manipulating the brazing rod and torch with my hands!

Sif bronze melts at about 885 C which is a lot hotter than the silver solder most of us use. Let us know how you get on, as I've got a bundle of Sifbronze rods somewhere

Hi Duncan, the sifbronze works well on small pieces of copper using propane. You have to get it to bright orange heat. On steel I found it didn't work well. The steel does not conduct the heat right through so the sifbronze did not flow into the joint. I was using borax as flux.

Hi Wout,

this is what happens if you use a flammable gas incorrectly!

**LINK**

A Darwin Event.

Neil

What a horrific tale.

The crux of it all: "...he was excited to tell O'Neill he'd managed to store two components of oxy-fuel, oxygen and acetylene, into one LPG bottle."

Hi, yes Acetylene is the most explosive gas there is. This **LINK** is what everyone needs to know about Acetylene and storage of, who feels they wish to experiment with it.

Regards Nick.

I got rid of my Acetylene bottles when I got my TIG welder as you only need it for welding steel or ali.

I think he would have got a similar result from mixing propane and oxygen into one bottle then striking a light to a hose and torch connected to it through an open valve. Maybe not as bad but bad enough, you would think. Probably the worst home workshop idea ever. The mind boggles.

Hi Hopper, the big difference is that Acetylene becomes unstable at high pressure, and that is why it is dissolved in Acetone in a porous material. So the explosion could have taken place without the slightest spark, as even a knock on the cylinder could have detonated it.

Regards Nick.