gas purification

[gastafalo_bob]

I am new to this forum and have searched all the keywords I can think of for this question. I am purchasing a tig machine soon and a going to be piecing together a gas purification system. I know nanotech makes one but it is $$$. I was going to use a aeronex filter with swagelok SS valves and high purity flow gauge. Has anyone used similar type setups. I was at a guys shop in MA that had a nanotech system and he said that he could weld almost any material with Ar that was filtered. Is that a true statement. Sorry for the rambling....

[BCarlucci]

I just have one question on this matter, why would you want to Filter your AR to Tig weld? I'm just curious because i use normal AR from my company to tig weld everything from SS to Alum to Steel. So i'm not really sure why you'd want to filter it, unless the guy has gotten a few bottles that weren't AR orginally and the supplier didn't purge the cylinder completely. That's the only thing i can think of, but if you could let me know why you'd need your Ar filtered i might be able to help.

[GARAGEGADGETS]

Gas Purification

Are you sure it was not a gas mixer or blender where you can mix a variety of different gases such as helium or nitrogen with argon for special welding applications?

[gastafalo_bob]

Most inert gas you buy from the welding store is quite dirty. They have a high ppm of hydrocarbons and other trash in it. The hydrocarbons are introduced from lubricants in the pumps. Things like regulator diaphrams, gas hoses, flow regulators, and brass fittings all generate particles in the purge gas. From the studies I have read it can make a big difference in eliminating pits and splatter in metals like Al, Ti, and Copper. Filtration also reduces the need for blended gas.

[BCarlucci]

Hmmmm Maybe we can get some advice from Hawk, he seems to be the best source of Information. So hopefully he checks this one out.

[sparx]

why filter

If the purity is an issue with your welding grade argon, you could order a higher grade. something like ICP grade, or Zero Air argon, or whatever your supplier calls their spec. gas. I am assuming that the cost to build a special filter system doesn't outweigh the extra cost for higher purity shielding gas.
just my .02 worth.

[GARAGEGADGETS]

Filter

Why couldn't a good quailty compressor filter such as motorguard be used on the outlet side of the regulator? The pressure is way lower than what the filter is rated at.

[GTA/SPEC]

Are you going to filter your argon just to pump it through the junk hose and $20 solenoid valve in the tig welder? How about the quality of the tig torch? You better address these issues if you think that you need higher quality gas.

Also high quality argon does not replace various mixes. Example: Helium is added to up the ionizing voltage of the gas creating a thinner, more intense bell shaped corona from the electrode to the work.

If you still feel that your gas is not clean enough after you inspect you machine and torch hoses, then you should look at a Zero grade argon or UHP argon, both are avaliable in a 300 size from Airgas. Liquid argon has a very high purity level, taht my be another option.

[gastafalo_bob]

I know about having to use external solenoids and stainless tubing for the plumbing Pre-torch. As for the torch you have to run teflon hose or similar. As for the UHP argon I have no idea what that costs compared to normal stuff. Like was said it would not make any sense to run UHP through the welder with out all the fancy valves and such. like I stated earlier I am new to tig welding and work in a industry where all the welders use UHP inergt gas setups. I just did not know exactly how many other people use it.

[GTA/SPEC]

check this pic out, it deals with different manufacturers of tubing, same spec of tubing. I have alot of this tube in stock because of one of my customers needs is high purity.

[GTA/SPEC]

Here it is:

[gastafalo_bob]

did you also supply the UHP regulators and such? I have been looking for a supplier for that stuff. I have access to all the swagelok and VCR fittings but not the valving. I have not completly decided on doing a UHP setup. I have seen what a difference one of these setups can do when welding Al and Cu. Does your shop do mail order for equipment?

[GTA/SPEC]

We can supply everything related to specialty and high purity gas delivery that you may require. You would need a low pressure regulator and a couple of stand alone flowmeters, designed to be used with UHP gases. I have a similar set up on my GTA / Plasma welder. One UHP regulator, 3 flowmeters for the GTA and purging, and 3 for the Plasma unit. You should use SS tube for all rigid connections, SS braided for the high pressure to the cylinder, and PolyFlo to the torch. If you need any of these, contact me through the board.