Thread: Self mix Argoshield?

Hi czzer I also have the same Token tools welder and as far as the gases are concerned I don't think it would be a good idea to try and do what was done on the Tips and Tricks welding sight.
Just because they said it could be done doesn't necessarily mean that it is safe to do so ; there maybe some very good reasons why this is not safe to do so. Safety should always come first especially with welders and gases, inert gases can be just as dangerous as flammable gases.
However I do understand where you are coming from with the cost of gases and the bottle rentals.

Hi czzer,

Your question was the topic of a recent thread on this site. Unfortunately I can't find the link at the moment.
Anyway, I was faced with the same dilemma. I have a multi-process machine and was trying to decide on the most efficient strategy for the various types of gasses. I did a lot of reading and finally came to the realization that to achieve the functionality I wanted with a minimum of types of cylinders I needed a gas mixer. I picked mine up on eBay for about $500 used. It is made by Smith and is designed for mixing argon and CO₂. There is no reason that you can't use an appropriate set of welding gas hoses and a Y valve like this https://www.arc-zone.com/index.php?m...&gclid=CLibjom. Your mixing ratio is of course going to be approximate at best but the cost of the valve is much lower than a mixer. If you want a better read on your mix ratio you can use a bubble meter https://www.youtube.com/watch?v=J_vWOFJeHLM. These are easy to make with a couple of pieces of clear plastic tubing and a squeeze bulb. You don't need graduations on the tube since you are interested in the ratio of gasses. For instance, if you want 75/25 argon/CO2 you just need your argon flow rate to be three times that of the CO₂. In other words the time that it takes for the bubble to hit the mark is 1/3rd that of the CO₂. This method is more than accurate enough for welding applications.
As to mild steel, just use straight CO₂, it's cheaper and for steel you don't need argon.

Here's the link: https://www.woodworkforums.com/f160/oxygen-mig-gas-189740

Cheers,
Rob

Hi Guys,

Had the same issue as have tig and mig welders. I found after looking at it all, I have two bottles, one mix and one argon, different color hoses for the default machines they would work on. Put in two quick disconnect couplings so I can swap over as needed as I use argon and the mix on the mig welder. Works well, just have to remeber to purge each time. I think all up, cost me about $30 in tubing and couplings.

Alan

I don't see why you couldn't with the right parts just as they did on tips and tricks.

Gives the advantage of being able to run Argon, Argon/CO2 mix (not really like argoshield but more like a 75/25 mix) or straight CO2

Most of the time you could get away with just running CO2 for mig or Argon for aluminium.

I'd be very interested to hear what the effective method is for post mixing gases.

Post mixing liquids is generally done with peristaltic pumps and can be achieved very accurately.

It occurs to me to effectivly post mix gasses you would require both pressure regulation and restriction prior to the mixing for the gas mix to be stable..and yes non return valves.

There would also have to be a some sort of blending chamber at a lower pressure than both source pressures...both to ensure the gass flow from both sources was not impeeded by the other and to ensure the gasses properly blended before being passed on then flow rate regulated for use.


I don't think a couple of standard flow rate regs and a y adaptor will do it accurately or reliably.

Remember those regs with a flow rate guage are pressure regs like all other and the flow rate is a result of presuer applied to the restriction in the gear.

Thus.....if I have one reg set at 10psi and another reg set at 20 psi.....unless the hose pressure is lower than both the flow of the 20psi reg will dominate.
when the trigger is pulled the 20psi gass will predominate untill the hose pressure drops to below 10psi then they will blend....so unless you run a continuous gas flow there will be wildly varying gas mixes flowing thru the hose.

so...this is what I expect to see.....pressure regulators running well above user line pressure.....feeding thru calibrated rerstrictions into a lower pressure mixing chamber...Still well above user line pressure.....then regulated down to user pressure and flow.

Then there are complications with controlling gas flow so gas from all sources starts and stops flow at the same time..and in response to demand.

A way more complicated process than it may first appear.

cheers

Think about it this is more or less what happnens in an oxy fule hand piece...except the pressuresemain fixed and the restrictions are varied.

Say we have oxy and acetelyene both at (for arguments sake and in round figures) 10 psi......both gasses flow to the handpiece where they are presented with the regulating valves ( variable restrictions).....the remainer of the hand piece that is the mixer and the blowpipe are running at pressures way below the line pressure.

cheers

here is a link to one in the US

http://www.millerwelds.com/products/...p?model=M00281

By the time you baught one new and paid the australia tax, I recon you would not get any change out of $3G

here is another.....no price but it makes the miller one look cheap and nasty

http://www.harrisproductsgroup.com/e...s-Blender.aspx

cheers

I looked up the gas mixer that Rob mentioned...$1700ish new.
The fact that a $1700 gas mixer even exists probably means the process isn't as simple as I thought.

I think I'll grab a CO2 homebrew bottle off ebay to start with, then grab a pure argon bottle when a swap n go type place sets up near to me.

I can then keep an eye out for a second hand mixer down the track if I think straight CO2 isn't working for me.

Cheers guys!

Originally Posted by czzer

I looked up the gas mixer that Rob mentioned...$1700ish new.
The fact that a $1700 gas mixer even exists probably means the process isn't as simple as I thought.

I think I'll grab a CO2 homebrew bottle off ebay to start with, then grab a pure argon bottle when a swap n go type place sets up near to me.

I can then keep an eye out for a second hand mixer down the track if I think straight CO2 isn't working for me.

Cheers guys!

If you look around and are willing to wait you can sometimes find them for $300-$500 used. Here's a couple Chinese versions http://www.ebay.com/itm/Flowmeter-Di...item4adb27cd9e, http://www.ebay.com/itm/standard-Gas...item3a964150c2.

We're not doing gas chromatography here so perfect mixing is not necessary. There's plenty of tubing to adequately mix the gasses. Close enough is good enough in shielding gas, especially for us hobbyists.

Originally Posted by soundman

I'd be very interested to hear what the effective method is for post mixing gases.

Soundman,

Welding is not a very demanding application. We used to make gas mixers for GC-MS by using stainless steel tubing filled with stainless or glass beads. For welding you could use a piece of 50mm PVC about 300 mm long, clean it thoroughly to remove surface contamination, cap one end with an appropriate threaded adapter for your gas line and fill it with clean glass marbles then cap the other with a similar cap including fitting. The gasses, even if they segregate coming out of the Y connector up stream will be thoroughly mixed by passing around the marbles in the mixer. Certainly good enough for welding.

Cheers,
Rob

It all comes down to why bother.

If gas bottle rental was an issue....yeh may be.

But all the gasses in question are avaiable now as purchased bottles and the best economy is buying the largest bottle you can afford....bottle costs ZERO after the second year.

why even bother tyring to mix gasses when you may get a big section of one or other of the gasses filling the hose.

There are enough frustrating variables in welding without there being a variance as you weld from 100% of the dominat gass to something aproaching the correct mix...well you will never know how close you are to the correct mix because you have no way of measuring.

So you think you are running a 75% 25% mix......how close do ya recon you are.

Might as well just run CO2 for ya MIG and argon for ya TIG and be done with it.

cheers

Soundman, you asked so I gave you a solution.

A note to everyone who has this question: CO₂ works just fine for MIG welding mild steel. Don't bother with argon unless you're welding aluminum, stainless or using TIG. It's a waste of money and an enormous waste of energy. CO₂ boils at -57 ^oC and argon boils at -186 ^oC. It takes a lot more energy to liquefy argon than it does to liquefy CO₂. You pay for that energy and there is no need to do so.