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Are 1/4" fittings different for welding gas cylinders than for air lines?

JimGnitecki

Active Member
Are 1/4" fittings different for welding gas cylinders than for air lines? I'm asking because I have been using my Argon gas cylinder to feed my TIG welder, and today tried to hook the same "gas" line to my plasma cutter instead. The female fitting on the end of the line from the gas cylinder would not attach to the male fitting on the plasma cutter.

The outer ring on the air fitting on the plasma cutter, which accepts the same airline from my compressor as does my Bostitch air nailer, appears to be larger than the outer ring on the back of my tIG welder, even though both lines are casually referred to as "1/4" (I think).

So, are welding gas line fittings different than air line fittings for safety, or other reasons?

Jim G
 

ShawnR

Ultra Member
Premium Member
Are 1/4" fittings different for welding gas cylinders than for air lines? I'm asking because I have been using my Argon gas cylinder to feed my TIG welder, and today tried to hook the same "gas" line to my plasma cutter instead. The female fitting on the end of the line from the gas cylinder would not attach to the male fitting on the plasma cutter.

The outer ring on the air fitting on the plasma cutter, which accepts the same airline from my compressor as does my Bostitch air nailer, appears to be larger than the outer ring on the back of my tIG welder, even though both lines are casually referred to as "1/4" (I think).

So, are welding gas line fittings different than air line fittings for safety, or other reasons?

Jim G
Can you post some photos?
 

Aliva

Super User
I think only fuel fittings are left hand. Gas, air, oxygen are right hand. But that's just an observation.
I know acetylene fittings are left hand threads for safety reasons. They have a cut mark or notch on the fitting so you don't get confused. Not sure about other gases.
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
I know acetylene fittings are left hand threads for safety reasons. They have a cut mark or notch on the fitting so you don't get confused. Not sure about other gases.

Yes, all of mine are like that too. Your note reminds me that I want to buy or make some hose plugs so spiders don't build nests inside my unused hose.

Thank you!
 
Combustible gas fittings are typically LH thread. Acetylene, propane etc.
Non-combustible gases (CO2, O2, Argon, Nitrogen etc) should be RH thread.

Some threads are tapered NPT. They seal with the aid of thread sealant (Teflon tape, thread sealant). Other threads can be straight cut and usually require some kind of o-ring or gasket.
In small diameters, I find it can hard to tell them apart without looking carefully.
Then there’s the whole metric-SAE issue.
 

JimGnitecki

Active Member
Ok, here are photos of the 2 obviously different fittings:

Normal quarter inch air male fitting, as found on my plasma cutter and my finish nailer:

Normal quarter inch male air fitting - 1.jpeg



The Argon gas line male fitting on my Canaweld TIG welder that accepts the Argon gas line female Quick disconnect from my Argon cylinder:

Argon gas line male air fitting - 1.jpeg

Does anyone make an adaptor of some sort, that would enable me to feed Argon gas, instead of compressed air, to my plasma cutter??

A local church buddy who is a welder says he THINKS that there ARE adaptors available at welding supply places.

Jim G
 

ShawnR

Ultra Member
Premium Member
I would change the fitting on the tig welder so they are all the same...not recommended in industry but if you want options in your shop, .... Or make an adapting whip.

Why do you want to run expensive argon through the plasma cutter? Is it for special metals or ...?
 

ShawnR

Ultra Member
Premium Member
I googled my question....

Sounds like you will need another fitting as well and tee or blending valve

Argon​

Argon is a rare, inert gas, making it relatively expensive but unreactive with the metals it's cutting. Using argon gas improves the stability of the arc and prevents atmospheric contamination of welding pools. While its high kinetic energy makes it an effective gas for plasma cutting, it can't work alone because of its low conductivity. As a result, argon must be paired with an appropriate secondary gas.
 

JimGnitecki

Active Member
Well the last 2 postings give me pause. I was considering using Argon instead of a BIGGER and much costlier compressor than I already have for long plasma cuts cuts where my current compressor cannot handle the combinaiton of psi, CFM, and duration required.

But ShawnR states that Argon cannot be used alone without another gas mixed in, due to its lower conductivity. I am pretty sure that I have read in multiple places that Argon WAS used for plasma cutting in the past, but was replaced by an Argon + helium mix, or other specific mixes for certain plasma cutting tasks, because it improved productivity or quality. ShawnR, are you SURE that Argon alone cannot be used as the propellant in plasma cutting where the productivity or quality issues don't exist?

The cost of using Argon from an Argon 80 cu ft cylinder is relatively high, but for my anticipated usage only when needed for long or thick cuts, it's MUCH cheaper than buying a new, high capacity air compressor!

Jim G
 

JimGnitecki

Active Member
Found the answer to my Argon question at:


In the quote below, the red font emphasis was by me:

"
Argon hardly reacts with any metal at high temperature, and the argon CNC plasma cutting machine is very stable. Moreover, the nozzles and electrodes used have a higher service life. However, the voltage of the argon plasma arc is low, the enthalpy value is not high, and the cutting ability is limited. Compared with air cutting, the cutting thickness will be reduced by about 25%. Also, in an argon atmosphere, the surface tension of molten metal is relatively large, which is about 30% higher than in a nitrogen atmosphere, so there will be more slagging problems. Even cutting with a mixture of argon and other gases will tend to stick to slag. Therefore, it is rare to use pure argon alone for plasma cutting.
"

Jim G
 

JimGnitecki

Active Member
i mean you have been told this more than once already
No, I was told that you can't use Argon alone. It is different to say that you CAN use it, but it will cause more slag AND will reduce your cutting capacity by 25%, and that this 25% reduction added to the 25% reduction already caused by cutting aluminum versus steel, would cut your cutting thickness capability in half! THAT's why you CAN use Argon but probably won't WANT to! :) I just like to know specifically WHY something can't or shouldn't be done.

Jim G
 

phaxtris

(Ryan)
Premium Member
Premium Member
yes and that is why it is said you cant use argon alone....

im still not sure how your math factors out that it is cheaper to burn up 100$ bottles of argon for 16 minutes of "air", factoring in pre/post flow you probably only end up with 8 minutes of cutting time, its not going to take long at that rate to pay off a compressor, not even factoring in other uses of the compressor
 

trevj

Ultra Member
Y'know Jim, you remind me of some of the apprentices I had in the Machine Shop.

They would spend, quite seriously, hours, looking for an 'easier way', to avoid just doing the few minutes work it took to grind a tool, and just getting on with the job at hand. Usually, those hours spent, should have seen them done the job at hand, and the job or jobs that followed...

Really, the "Easy" way, is to follow the accepted standard practices, and leave the experimenting and looking for new dodges, to guys that already understand the process, inside out, and sideways.

If you need more compressor, get more compressor. Or change up your cut plan, to allow for some time for the compressor to get caught up with the usage.

And yes, the fittings are made different on purpose, so you don't fry your TIG torch, by feeding it Air, instead of the gas it is supposed to have.
 

JimGnitecki

Active Member
Yeah, I hear you trevj. You are right about the proven easy way versus the experimental way. For example:

I tried cutting my 3/16" thick by 3" wide aluminum flat bar using a Bosch jigsaw with a Bosch blade designed for aluminum, and got 3 decent 3" cuts and then the portion of the blade in contact with the aluminum plugged up with aluminum that would not dislodge from it.

A couple of forum members had advised me to use my wood bandsaw with its woodcutting blade, but I had not wanted to create an area-wide aluminum dust coating, nor did I want to hurt the bandsaw blade because changing it is a pain. But, after the jigsaw effort failed, I went ahead and starting cutting on the bandsaw. Like the experienced forum members had said, it worked fine. No loading up of the bandsaw blade (presumably because it stayed cool with its long length compared to the jigsaw blade). And, it was FAST - I did 7 pieces as fast as I could pick them up and feed them through the bandsaw. I did have to vacuum the exterior AND interior of the bandsaw, plus the floor all around it, but it was still the best and fastest solution by far. Not even noisy compared to the jigsaw or what a circular saw would be like (scream city).

So yes, I am listening.

I am realizing that the cost of getting into plasma cutting is not just the cost of the plasma cutter and a consumables supply, but also a larger air compressor that costs way more than the plasma cutter.

But the 10" bandsaw can't do curved cuts on really large pieces, and can't do INSIDE curved cuts at all. The plasma cutter can.

Jim G
 

Tom O

Ultra Member
I’d just get a cheap bandsaw off kijiji, I use one for aluminum and never had a problem. There is always a scrollsaw for the insides.
 
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