308 stainless question

[81Malibu]

Hi all,

I was wondering if my Miller 175 MIG would be able to weld this with the right wire and gas and if my machine could do it what would the correct wire and gas be to do it? I work on a dairy farm and this is for milk pipeline, my boss wants to put in a milk cooler before it goes to the bulk tank and was wondering if my machine could do it. Any help is appreciated.

[tigman]

We would need to know the thickness of the material to answer your question

[Hotfoot]

Yup, we need to know more. It'll weld that stainless just fine, and you'll need the right wire to keep the welds from rusting. Your regular wire and gas will weld the stainless, but the weld will rust. I actually fine stainless welds a little nicer than regular mild steel, but I use the regular wire.

[81Malibu]

I'm not sure on the thickness off the top of my head but ill check tomorrow and see. And so your sayin i can use my regular wire and C25 gas for stainless???? i didnt think that was right but it wouldnt be the first time ive been wrong.

[OldSparks]

I'm not a wire feed person but I think you are misinterpating what Hotfoot stated. The way I see it, yes you can weld stainless up to the limits of your machine with regular wire and C25 but it will rust. If you are talking food industry...no rust allowed...then you need stainless wire. When you use stainless wire you need or should have tri-mix gas. Like I said, I'm not into wire feed but don't make any plans until you get a few more responses.

[joebass]

308 Lsi wire and Tri mix gas. You will need to back purge with argon, and only wire brush with a stainless brush.

[Engloid]

No offense, but if you have to ask this question, you most likely don't have the ability, skill and experience to make this weld in a way that would be acceptable by FDA reglations.

In other words, the weld should not have any lack of fusion on the inside of the pipe, no porosity, or anything.. if you swipe the weld with a cotton ball on the inside, it should not snag anywhere. Achieving this with a mig weld will be very difficult, even with a lot of practice. Personally, I'd not even attempt it unless it was just a test peice to see how good I could do it.

It should look something like this on the inside:


Any microscopic crevices or pores will collect bacteria and can create big problems for you in the future....and cost you big money, as you may not know where the problem is till you've spent tons of cash.

[TOMWELDS]

Engloid, is that a Mig weld? Very nice. When welding on the outside of the pipe, i cant imagine making a weld that wont catch cotton on the inside. Id love to learn these techniques.

[Engloid]

No, that was TIG. The root was actually more even than the pic showed. It was hard to get the pic, and I guess the lighting made it look deformed. One guy, that obviously knew a lot about photography, told me some big term for what it was that happened, but I forgot it.

I couldn't see anybody being able to get a "food grade" acceptable weld with mig either.

[BillC]

I couldn't see anybody being able to get a "food grade" acceptable weld with mig either.

Good call on the cleanliness, Engloid. Dan probably has a wealth of knowledge, as he welds on food-related equipment. Its kind of scary to think how easily our food can be unintentionally contaminated. The dairy owner should know better than that. Probably does and just wants to save money...

Edit:
81Malibu is from Canada. Maybe things are different there. Also, maybe he already knows about pickling and flushing the tubing to remove contaminants. And I am not in the milk business. Maybe all of this is SOP. Maybe we don't want to know where our food comes from. It wasn't too long ago that milk and orange juice traveled in tanker trucks one way, and gasoline or chemicals were carried in the same tankers on the return trip.

[enlpck]

Engloid is on the mark for Canada as well, according to the speaker at the AWS meeting last fall. Subject was sanitary welding, and focused on orbital (the speaker was fom an orbital contractor), but opened with the regs for sanitary in the US, Canada, and other NAFTA countries... all about the same as Engliod described. He also made the implication (which may not be correct) that wire feed is not suitable for this work out of position at any time, and is a specialist job using a positioner. TIG is pretty much it in practice.

[James D. Clark]

.

Edit:
It wasn't too long ago that milk and orange juice traveled in tanker trucks one way, and gasoline or chemicals were carried in the same tankers on the return trip.

Where did they do that? I worked for a trucking company 50 years ago that had trailers specific for the product. Food trailers, chemicals and petroleum were not interchangable. Gasoline, diesel and fuel oil where hauled in the same tankers. Alcohol was hauled in it's own trailers, sealed and subject to federal law inforcement tracking. Acid was in acid trailers and caustics in caustics trailers. We didn't haul milk but milk was only hauled in milk tankers. Bulk food products like high fructose corn syrup are carried in stainless steel tankers with all the valves, hoses and fittings sealed in plastic and the tanker is secured with tamper proof safety seals.

[BillC]

Where did they do that? I worked for a trucking company 50 years ago that had trailers specific for the product. Food trailers, chemicals and petroleum were not interchangable. Gasoline, diesel and fuel oil where hauled in the same tankers. Alcohol was hauled in it's own trailers, sealed and subject to federal law inforcement tracking. Acid was in acid trailers and caustics in caustics trailers. We didn't haul milk but milk was only hauled in milk tankers. Bulk food products like high fructose corn syrup are carried in stainless steel tankers with all the valves, hoses and fittings sealed in plastic and the tanker is secured with tamper proof safety seals.

Jim,
It sounds like the company you worked for was ahead of its time. Congress passed the Sanitary Food Transportation Act of 1990 to combat the mixing of food with hazardous materials. It was common (although not legal) to carry food one way and garbage on the return trip. Indian River Trucking Co. in Florida has been in trouble as recently as 2004 for carying wastewater in tankers that were meant for food only. The term is backhauling. Here is an excerpt from: http://tuberose.com/Chemicals_in_Food.html. I can't vouch for the content, but it gives you an idea of the problem. Google some of the examples cited to verify them...

Backhauling
Out of 3.5 million truck drivers, four from the Northwest broke a code of silence in the industry, and told members of a House Public Works and Transportation Subcommittee in July, 1989 that it is common practice to use the same refrigerated trailers to haul food and garbage. The truckers described how loads of food are taken from farm states to Eastern cities and then exchanged for loads of urban waste that are "back-hauled" to landfills in the South and Midwest. Then the process is repeated, with the trucks again hauling food eastward. "It actually pays more to haul garbage than food," testified one trucker. For example, Indian River, a nationally recognized Florida tank company that regularly hauls liquid foods, with a fleet of more than 300 tank trucks, was regularly hauling a non-food-grade chemical for Nyacol Products, of Ashland, Mass. The substance is colloidal antimony, a pentoxide used as a flame proofing agent in textiles and plastics (shown to cause acute congestion of the heart, liver and kidneys, according to the American Conference of Governmental Industrial Hygienists). One of the tankers, owned by a nationally known carrier with a large fleet of tankers, had previously carried ethylene glycol (also known as antifreeze; it is in the family of solvents, and also is used as hydraulic fluid and as a chemical intermediate in the production of polyesters), then carried cooking oil. Another Midwest owned tanker previously had carried latex emulsion that had dried on the inside of the tanker a half-inch thick, and then carried apple juice. Robert DeLashmit heard truckers tell how they hauled engine oil, resin and formaldehyde in tankers that next carried refined cooking oils for his firm, Premier Edible Oils of which he is executive vice president. The truckers testified that Premium Transport supplied the Portland refinery with false information that they were hauling only juice. Yet, his company continues to use the company to haul refined kosher oils used by the baking, salad oil, margarine and the confectionery industries.

An official with a nationally known carrier that operates a fleet of more than 2,000 tankers, said the bottom line is cheap freight rates. He told a Yakima Valley, Washington, juice processor that tankers were hauling their juice South but backhauling asphalt emulsion North. "They just didn't want to hear that," he said. Don Roberts, a trucker from Kansas City, says he alternated food loads such as juice with chemicals more dangerous than those reported by the Northwest tank truck drivers. Roberts has hauled insecticides to the Yakima Valley, then loaded apple juice. He took a load of highly toxic phenolic resin to Oregon, after which he took on a load of kosher cooking oil. Other times, Roberts said, he dropped off a load of the wood preservative, Pentachlorophenol, containing the potent carcinogen dioxin, in North Dakota and then drove to Yakima to pick up apple juice. "Other tank companies were doing the same thing," Roberts says. "We hauled anything that was liquid. It was legal. There was no reason not to." The drivers who came forward to expose some of the hauling practices said they lied or falsified paperwork to hide the fact they had just hauled a chemical. Food companies, they said, never tried to verify the information. "If people are telling you this is not widespread, it's a blatant, outright lie," says a cleaning specialist at a large tank wash facility on the West Coast. This man cleans hundreds of tankers for carriers around the country, and he says many of them are hauling chemicals before going on to load a food-grade commodity.

These are not the "food-grade chemicals" that industry insists are being hauled, he says. Cleaning procedures for tankers can run into the hundreds of dollars. Even though the insides of these tankers are cleaned with various types of caustic washes, only a few trucking companies pay the additional expense that goes with cleaning internal valves and replacing various gaskets--most of the companies who do cleaning just use hot water. Determining the toxicological impacts of many of the chemicals that have been hauled is not an easy task, because many of the chemicals hauled are trade names or proprietary formulations--substances not found in handbooks or research literature. They don't even know what's in some of the stuff being hauled in tank trucks that also haul food.

....................End of Excerpt................

Regards,

[81Malibu]

well thanks for all of your replys and im glad someone's professional opinion like Engloid's was voiced I was really just unaware of the issues with welding that has to be food grade. But also good to know my machine can do stainless with different wire and gas I think my boss just wanted to save some money but im not going to do it if it conflicts with a quality food product. If he has some old pipeline laying around somewhere i may practise on it just to see how hard it actually may be. Anyway, thanks for your time everyone!


Cheers!