Learn me: Welding Gas

So, I need to get a gas bottle for my metal glue gun (https://grassrootsmotorsports.com/forum/grm/anyone-familiar-with-clarke-welders/179896/page1/), but I have been told that it isn't necessarily as simple as just grabbing a bottle of argon and hooking it up.

I've got a regulator, and I'm only planning on doing mild steel and aluminum with this.  What do I need to know?  What do I need to plan for?

You need co2 for steel, or a mix gas that mainly contains co2.

You need argon for aluminum.

So the regulator typically attaches to the bottle and there is a little plastic seal in there.  Make sure it is present or all of your gas will just disappear!

Your best bet is to take your regular with you to the welding supply place and tell them what you are gonna be welding.  They can recommend the best shield gas for that application.  They will also help you figure out how to connect it (some regulators require an adapter).

also if you have been using your MIG with flux core wire and no gas, you might have to flip the polarity inside the machine. There will be instructions under the cover by the wire spool. 

So I definitely need two bottles.  That's mildly frustrating.

Yeah, you need two bottles for sure. I would suggest 100% argon for aluminum, and 75/25 argon and CO2 for steel. You'll see different recommendations from different people on the best choice for steel, though.

If I may piggy-back on the question a bit....  Let's say I've got my regulator and all that and I've found a place that sells welding gas.  Do I just walk in and come back out with a bottle (or bottles) full of gas the same way I get my propane?  Or do I need to go buy a cylinder first and then have them fill it for me? 

In reply to wae :

I looked briefly at my local Airgas requirements.  You have to fill out an application for safe handling of gas bottles or something.  With them I think that you can buy or rent a bottle

Most places will only exchange bottles, meaning you need to bring one or buy one from them on your first trip. Sometimes you can rent the bottles, too, but that's more geared towards businesses.

wae said:

If I may piggy-back on the question a bit....  Let's say I've got my regulator and all that and I've found a place that sells welding gas.  Do I just walk in and come back out with a bottle (or bottles) full of gas the same way I get my propane?  Or do I need to go buy a cylinder first and then have them fill it for me? 

At my place they don't fill for you, they exchange tanks. So it works just like propane. Bring tank and exchange for some money or bring no tank and buy full tank and gas for much more money. 

I think they fill for commercial customers, but the tank exchange is easy and quick. 

Generally speaking you should regulate flow for  a MIG welder.  So, you need a flow regulator not a pressure regulator.  You also need a CO2/Argon mix (sometimes called Stargon) for steel and straight Argon for aluminum. There's a good artical here -> https://weldguru.com/mig-welding-with-100-argon/ that describes why.

You can buy a used bottle in CL or marketplace then use that to exchange at the welding gas store.  

Mr_Asa said:

In reply to wae :

I looked briefly at my local Airgas requirements.  You have to fill out an application for safe handling of gas bottles or something.  With them I think that you can buy or rent a bottle

Go anywhere but Airgas as a hobbyist/home shop weldor. Their prices are insane and they are more interested in leasing tanks than selling; they cater to businesses with commercial accounts.

Find a local gas supplier, they will sell you a full tank with the gas fill and cylinder itself listed as different line items. Then when you come back with an empty they will likely just exchange it for a full one, but you still own the cylinder. Don't lease a tank.

You can save some money by picking a smaller cylinder for the pure argon for aluminum welding, assuming that you will be welding aluminum much less often than mild steel.

The above chart gives you some idea of the recommended gases four different materials the upper part shows you the weld bead that you get on Steel using the various gases. You can weld steel with straight argon however you can get undercut if you're not cautious.  75% argon 25% CO2 works best for mild Steel

I forgot to add those charts are for the short circuit transfer process which is what most people use when they mig weld

Can we talk about the psi gauge (range)that administers said gas to the welder?

759NRNG (Forum Partidario) said:

Can we talk about the psi gauge (range)that administers said gas to the welder?

Go for it, I've got what I need

Two types of flow meter

TSC, Tractor Supply Company, does bottle exchanges.  FYI. An alternative to AirGas.

I highly recommend this textbook it was available on Amazon for $10 the $20 usually. That is a used book new is a different addition and they run well over a hundred

pilotbraden said:

 

Two types of flow meter

Thank you pilot B

In reply to 759NRNG (Forum Partidario) :

That information is included with the electrode wire on the settings chart or available online from the manufacturer . usually 20 to 30 cry using 75/25 Ar co2.

Sonic said:

You can buy a used bottle in CL or marketplace then use that to exchange at the welding gas store.  

Most of the welding supply stores around here will only exchange their own bottles, which are stamped as such. 

The following chart show the different models and the different types of gases that can be used on each of them and their advantagesup

Sonic said:

You can buy a used bottle in CL or marketplace then use that to exchange at the welding gas store.  

Careful with that.  There are marking on the tanks that need to be up to date showing the tank has been pressure tested and certified.  Nobody will fill an out of date tank that I am aware of.  Risk is WAY too high.

Nobody has ever so much as glanced at the bottle I've brought them at either Airgas or Praxair.  I leave it on the dock and get a slip from the dock worker, bring it inside, pay, leave with a different bottle that is full.