View Full Version : GMAW stainless shielding gases

11-20-2015, 10:31 AM
Hard wire, all position, what's your preference?

I'm building a 5'x5'x12' ice builder tank (sweet water in our dairy plant) and would prefer not to tig weld the whole thing. My choices are 98%Ar/2%O2 and Tri-mix 90%He/7.5%Ar/2.5%CO2 for mig shiedling gas. The 304 plates are all 3/16".

11-20-2015, 11:02 PM
Hmmmmmm don't quote me but pretty sure 316 would be the choice for a food product container?

11-20-2015, 11:10 PM
Sweet water is not a food product. I don't even know why it's called that. We use a two stage plate cooler (heat exchanger) to take our pasteurized product (145-165F) to 38F almost instantly. Well water does the first part and ice water (the sweet water) does the second part.

It should never come in contact with the food product. If the plate cooler fails, then there would be some bad commingling.

All of our dairy piping is 304, so maybe the regs are different where you live.

I'm planning on building something similar to ice builders made by Chester-Jensen (http://www.chester-jensen.com/#!ice-builder/c1lsm). I'm not going to use a steel tank and coils though, mine will be stainless.

11-21-2015, 07:52 AM
I have used both tri-mix and 98% argon/2%co2 not o2 to me I could not tell the difference. But my lws does not have a 98/2 that they stock so they custom fill one of my

If I have a big job like that I just rent a 330 size and the tank is back before a months rent is on it. I have exchanged more than one tank within the same month as tri-mix
goes fast.

And you are right almost all stainless steel in the dairy industry is 304

Are you going to us a glyol solution with this or just water.

11-21-2015, 08:26 AM
We just use water right now. We have a very small setup (<1.5 million lbs through the plant PER YEAR), so I end up repairing a lot of old equipment. We looked at falling film chillers briefly, but they are all way too oversized for our needs. Do the gases have any influence on appearance after pickling?

11-21-2015, 09:41 AM
I did by a weld cleaner set up from I think walter from my lws but the process takes to long so we went back to using ss wire brushes and scotch bright wheels.

When Madero came and built the rotary milking parlor they brought a acid alone for pickling the welds.

Instead of using tri-mix I would look at using Esab shield-bright 308l and 75/25 gas its a gas-shielded flux core wire it comes is a .045 wire size and lays down a nice weld
and the slag peels right off and it is a all position wire and goes on in a spray transfer. I had talked to Bob Rivers at Esab in PA before we started building the rotary and he
recommended this product and shield-bright 309l for stainless to mild steel. I see that you have 250 amp mig which you need to run this wire as the min voltage is 25v. I
tried it with my TA-181i and the voltage was to low.

I remember looking at pictures of your milking parlor rebuild very nice job. I worked for and was a Boumatic dealer for 30 years.

11-21-2015, 10:16 AM
Is the flux residue a problem for food grade applications? Does it add much to finishing time?

I use what Airgas calls Stainmix Gold, which is 97% Ar / 3% CO2. 308LSi wire.


11-21-2015, 11:48 AM
Is the flux residue a problem for food grade applications? Does it add much to finishing time?

I use what Airgas calls Stainmix Gold, which is 97% Ar / 3% CO2. 308LSi wire.


This is not a food grade application as the vast majority of this type of equipment is built with black iron pipe.

How do the welds look when you're done? Do you pickle or passivate these welds?

11-22-2015, 10:24 AM
The oxides are fairly dark but they are easy to remove. I am not doing food grade welds and I usually just wire brush them.