Shielding Gas Bath

[eSCHEn]

I've been mulling this one over for a wee while but is there any reason other than cost and safety why you wouldn't use a gas bath to weld complicated items? Specifically thinking about TIG here but principle would apply for MIG as well.

Something like this:

You'd save on gas and get full purge coverage. The gas wouldn't react as it's only there to displace the oxygen in the air.

Am I right in my thinking?

Ps no stealing my amazing art :P

 

[BrokenBiker]

I would assume that although the shielding gas is heavier than air and would sit in the container quite happily, as soon as you put your hands along with tig torch and so on and make movements, the gas would become agitated and move about, flowing over the edges of the container, drawing oxygen in.

by all means give it a go though and see what happens.

are you considering this as a replacement to gas flow through the torch as im sure the tungsten requires a flow of gas rather than just a puddle of gas

 

[eSCHEn]

No, nothing more than a thought experiment that's been occupying me on the netty for the last week

 

[TechnicAl]

If your looking for a top quality weld it doesnt work. Hot gas rises and drags in air. Ive seen something similar tried inside a cabinet and even that didnt work. The shielding gas has to be higher pressure than the surrounding gas.
I suppose there is a chance that you might get a weld that looks OK but it will contain oxides.

No doubt you will try it just to prove me wrong

 

[brightspark]

If your looking for a top quality weld it doesnt work. Hot gas rises and drags in air. Ive seen something similar tried inside a cabinet and even that didnt work. The shielding gas has to be higher pressure than the surrounding gas.
I suppose there is a chance that you might get a weld that looks OK but it will contain oxides.

No doubt you will try it just to prove me wrong

only if he has nothing better to do than waste his time

 

[eSCHEn]

Lol no way - argon's too expensive!

No it was just a "I wonder why you don't hear about this" idea I had.

 

[premmington]

Convection would remove the gas out of a bath.

Yes we purge things with argon and keep pressure on (and waste gas) to weld up some pipe work!

Nitrogen is used for this purpose, not in the UK much, but when working overseas they seem to not mind wasting loads of nitrogen.

 

[Freddy0309]

could you not use a something like a blast cabinet so it contained? manipulation maybe be a problem unless ypu could replace em with thinner gauntlets

 

[MattH]

Wouldn't a sealed glove box work? Thinking along the lines of a media blasting cabinet. If the lid was sealed air tight and the welding cables bought through with IP65 cable glands you could flush it through with argon and then do the whole job with it inside.

Edit, Freddy beat me too it.

 

[premmington]

could you not use a something like a blast cabinet so it contained? manipulation maybe be a problem unless ypu could replace em with thinner gauntlets

I have thought about this concept! Would it work! YES... Would it be practical in use.... NO....

 

[backpurge]

You can buy a glove box for welding off the shelf, been around as long as I can remember. They are commonplace in the aerospace industry

 

[pedrobedro]

When I have gas in the bath it always rises

 

[eSCHEn]

When I have gas in the bath it always rises

Yes but does it shield your weld?

Actually if you're welding in the bath then you've got more problems to contend with than porosity

 

[eSCHEn]

You can buy a glove box for welding off the shelf, been around as long as I can remember. They are commonplace in the aerospace industry

Glove box, fantastic thanks @backpurge - that's the term I was missing in my searches

You're right indeed, loads of images of it when you have the correct terminology. This one is very space age looking!

 

[lotus 30]

Could you pull a vacuum in a sealed tank then tig as normal.

 

[ibrooks]

You wouldn't get an arc in a hard vacuum - the arc actually travels along a tunnel of ionised gas. No gas - no current flow.

I've seen this proposed method used when welding magnesium alloy parts but it's not a home setup by any stretch of the imagination.

Iain

 

[hotrodder]

You don't need a glove box to weld magnesium, it's VERY difficult to set a large chunk of the stuff on fire and easier (though you still have to try) to start a fire while machining it than welding. Mag used to be gas welded, the origional patent for TIG (known as heliarc back then) was about welding mag without the need for corrosive fluxes
Titanium is pyrophoric too and commercially pure Ti swarf burns a lot more easily than many mag alloys although obviously you need to go nuts with argon when welding Ti anyway to avoid embrittling it

A shielding gas bath is useful for some jobs provided you have argon flowing into it constantly. http://www.weldingtipsandtricks.com/gas-shielding.html
I call 'em a purge tray, yes on the face of it it's more wasteful than a glovebox but to knock up a few small widgets that are difficult to purge it's a LOT cheaper than filling a glove box. I don't use 'em much now i've made an electrolytic weld cleaner as i can just hang a bunch of small components in a bath to clean and passivate them while i get on something else but in the past i preferred to use a little more argon instead of having to reach for pickling paste

 

[premmington]

You wouldn't get an arc in a hard vacuum - the arc actually travels along a tunnel of ionised gas. No gas - no current flow.

I've seen this proposed method used when welding magnesium alloy parts but it's not a home setup by any stretch of the imagination.

Iain

Very correct....

 

[langy]

I was working somewhere the other day and they have a Argon room with an entry airlock !!!

 

[eSCHEn]

I was working somewhere the other day and they have a Argon room with an entry airlock !!!

That must be a weird room to work in. Knowing you can't see, taste or smell it but take the BA off and you're dead...

Pretty cool though