304 vs 316 Stainless for Closed loop systems

[Lono]

Ironfist is trying to say that 304 isn't suitable for our application.

Gray Wolf has suggested 304 in the past, and I know he wouldn't recommend anything that wasn't safe, so pretty much just looking for some credible information to fire back with

It seems like 316 is better, but is it necessary?

 

[flatslabs]

Ironfist is trying to say that 304 isn't suitable for our application.

Gray Wolf has suggested 304 in the past, and I know he wouldn't recommend anything that wasn't safe, so pretty much just looking for some credible information to fire back with

It seems like 316 is better, but is it necessary?

I am not an expert in metallurgy, but you can easily google the differences. 316 is a little more resistant to corrosion, but is that really necessary in our application? As far as I understand butane is not corrosive.

These parts are all made for sanitary food grade applications, your beer and milk and tons of other stuff you consume every day goes through this same 304 steel.

I have priced out the stuff, and you are going to be paying a couple hundred bucks more wholesale if you want all 316 vs 304 parts. Personally, I don't think it is worth it for anything more than bragging rights.

 

[pharmco]

He also recommends the Caresaver, a pump that is known to be unsuitable to our application.

 

[icdog]

GW has also said that butane is non corrosive and he is generally on the ball with everything

 

[Permacultuure]

Butane is non corrosive with metals, in the brewery industries I imagine the components see a lot more corrosive things other than one or two hydrocarbon, like in a CLS.

Ironfist may be a good welder, or team of welders but he has no idea about extracting or engineering. He built f'ing gates and rails before he saw the money in extractors. His first design six months ago was using single pin clamps on his 10" spools. He has slowly evolved his design to be a knock off ETS, caresaver and all. To post pictures of information you've gotten through google and make statements is an interesting tactic.

Still waiting to see an extract made with one if these.......

 

[gekolite]

316 ss best less carbon content, 304 corrodes a lot easier

 

[HUGE]

He also recommends the Caresaver, a pump that is known to be unsuitable to our application.

Pretty sure he recommends the Haskel pneumatic recovery pump.

 

[flatslabs]

316 ss best less carbon content, 304 corrodes a lot easier

I think we have established that it is "better", and doesn't corrode as easily, but does that matter to us?

I don't do my extractions in the middle of the ocean, and I am not using brine as my solvent. So again I ask, is that $300 difference in parts worth it for this application?

The only thing I have seen corrode is a handle and nut on a ball valve on my friends passive machine because he soaks it in salt/ice solution during extractions.

 

[prune]

I don't know how you can worry about 316 vs 304 corrosion resistance when no one even bothers with a proper passivation protocol on the various components in CL systems.
I thought it was mandated for food grade production?

 

[flatslabs]

We etch markings on our brew kettles and make sure to re-passivate anything that we engrave, because it will corrode quickly if you dont. We have never had the problem with factory sanitary parts corroding so I have to wonder if it is already done.

 

[Gray Wolf]

Ironfist is trying to say that 304 isn't suitable for our application.

Gray Wolf has suggested 304 in the past, and I know he wouldn't recommend anything that wasn't safe, so pretty much just looking for some credible information to fire back with

It seems like 316 is better, but is it necessary?

300 Series austenitic stainless steel is corrosion resistant by virtue of the chromium content. If you heat 300 Series stainless between 650 and 850C, the chromium and carbon present will form chromium carbides, taking the chromium out of solution, so that it loses its corrosion resistance.

There are three ways to deal with that. One way is to solution anneal the weldment afterwards, which heats the metal until everything is back in solution, and then rapidly quenches it through the 650/850C range by plunging in water, so the carbides don't form.

The second way is to use a low carbon grade like 304L. If the carbon content is kept below .05%, it is less prone to form chromium carbides.

Lastly, you can add more chromium, so that even with the carbides, there is still more than 12% chromium in solution, which is what they have done with 316, 321, 347, etc, stainless alloys.

Welding can also leave enriched iron deposits on the surface, so it is common to passivate or electropolish to remove it, as it can rust and make local spots of corrosion.

As far as alloy selection, if 304SS were not suitable for the application, the sanitary industry most certainly would not have standardized on it for most applications. 316SS has more corrosion resistance, but it typically isn't required and they are more expensive. 304SS and 18-8 stainless are typically used for cookware and sanitary applications, at around 18% chromium.

 

[pharmco]

Pretty sure he recommends the Haskel pneumatic recovery pump.

Nope. He is apparently is bringing a new oilless pump to market (which we have yet to see)

But for the time being, he's been recommending the Caresaver because it's rated for R600. His response to the fact that it's an oil-bath compressor? "We haven't seen any problems".

http://instagram.com/p/sWDMpCPZTl/?modal=true

Well sure, none of us saw mystery oil for a good few years either.

Ironfist is just a new CLS maker, spreading a fresh load of FUD (Fear, uncertainty, and dismay) onto the market.

 

[HUGE]

That isn't GW's in the pic. I am looking at the manual for GW's machine right now and he clearly calls out a Haskel recovery pump.

Nope. He is apparently is bringing a new oilless pump to market (which we have yet to see)

But for the time being, he's been recommending the Caresaver because it's rated for R600. His response to the fact that it's an oil-bath compressor? "We haven't seen any problems".

http://instagram.com/p/sWDMpCPZTl/?modal=true

Well sure, none of us saw mystery oil for a good few years either.

Ironfist is just a new CLS maker, spreading a fresh load of FUD (Fear, uncertainty, and dismay) onto the market.

 

[pharmco]

Misunderstanding, I'm referring to Ironfist

 

[Dick Turpin]

Listen to GreyWolf,

He is the knower of knowers !

 

[HighStateToke]

Butane is non corrosive with metals, in the brewery industries I imagine the components see a lot more corrosive things other than one or two hydrocarbon, like in a CLS.

Ironfist may be a good welder, or team of welders but he has no idea about extracting or engineering. He built f'ing gates and rails before he saw the money in extractors. His first design six months ago was using single pin clamps on his 10" spools. He has slowly evolved his design to be a knock off ETS, caresaver and all. To post pictures of information you've gotten through google and make statements is an interesting tactic.

Still waiting to see an extract made with one if these.......

You should get your facts straight before you run your mouth.

 

[HighStateToke]

Ironfist is trying to say that 304 isn't suitable for our application.

Gray Wolf has suggested 304 in the past, and I know he wouldn't recommend anything that wasn't safe, so pretty much just looking for some credible information to fire back with

It seems like 316 is better, but is it necessary?

His main point is that 304 won't hold up to constant daily use as well as 316, especially with dramatic heating and cooling cycles. And that the parts most people are buying, are not intended for our application. Sure they will work, but its a fact that they were intended for dairy/brewery applications. His original comments on IG got way blown out of proportion.

 

[HighStateToke]

He also recommends the Caresaver, a pump that is known to be unsuitable to our application.[/QUOTE

Iron Fist has I-502 certified machines, therefore an R-600 pump is required. No one seems to whine about ETS. And unlike some other CLS companies, Iron Fist doesn't just recommend a pump like the appion G5, whose manufacturer explicitly says not pump butane with it. He is actively working to find a permanent bulletproof recovery pump. The dude is making progress, much respect to him.

 

[Gray Wolf]

His main point is that 304 won't hold up to constant daily use as well as 316, especially with dramatic heating and cooling cycles. And that the parts most people are buying, are not intended for our application. Sure they will work, but its a fact that they were intended for dairy/brewery applications. His original comments on IG got way blown out of proportion.

Keeping things in perspective and proportion is a good thang.

To put things in perspective, my original Mk III was loaned to the Skunk Pharm Research cancer program, and run heavily for about three years, before being returned. It was made out of 304 and exhibits no evidence of rust.

Except for the welding, as far as I know, the weldments haven't seen service between 650 and 850C, so haven't precipitated out the chromium in the form of chromium carbides, and still maintain levels above 12%.

Our process can routinely see subzero temperatures, but rarely anything above about 100C, because that is where the water in the pots boil.

In testing new equipment, we spray them down with soapy water while under 100 psi press, and have noticed that some soaps will cause any iron left on the surface from the welding operation to oxidize and leave a red spot.

Electropolishing or passivating is normally used to remove those iron deposits after welding and/or heat treating, and the parts clearly are electropolished, so I infer just not long enough.

When welding, there are small microbursts that sends metal flying out in small droplets, which deposit on adjacent surfaces. Some of those specs are iron, which corrode easily. A large enough droplet, will also create a small void under it, which can actually increase corrosion rates at that point.

Alloy 18-8 Stainless was specifically developed for the food industry, which routinely sees far more aggressive solutions than we process, and at far higher temperatures. 18-8 and 304SS are both 18% Chromium grades.

Even 316SS precipitates chromium carbides in the reactive range, but it can lose more chromium to carbon before losing its corrosion resistance, and is more suitable for mildly corrosive fluids.

For the highly corrosive fluids, more nickle is required and you move into the the Hasteloys.

Back to perspective, a properly solution annealed and passivated or electropolished 304SS weldment, is a slam dunk for our application with a wide margin of safety.

A 304SS weldment that was not solution annealed or passivated after welding may exhibit signs of corrosion when exposed to corrosive medium, like the salt spray commonly used to test them.

I would venture that none of the weldments are solution annealed after welding, so it becomes a matter of how long they were in the reactive heat range.

As we are attaching thin wall tubes and pipes, little heat is required, so typically that shouldn't be an issue, but we still have the little dingle berries of iron scattered about on the surface adjacent to the weld, which need to be removed to remain totally corrosion free.

Of note, is that I used to build rinse tanks following HF/HNO3 chemical milling solution tanks, out of 304L SS, without suffering corrosion at the welds or adjacent heat affected zones. We didn't heat treat the weldments, but did grind the surfaces adjacent to the weld to remove the dingle berries from a GMAW welds process, and stainless wire brush the welds. Any remaining iron smeared on the surface was soon gone and the tanks endured decades of service.

 

[Permacultuure]

You should get your facts straight before you run your mouth.

What facts are not straight? I'll continue to run my mouth though...

The guy just pushes big shiny things to people. These labs get approved my uninformed fire marshals, so I502 apporoved means squat to me here in Oregon.

Taking pics of googled information and posting it and claiming all of us not using domestic 316ss are too uneducated to know any better is a marketing strategy, and a poor one at that.

Back this dude up all you want HST, I'm with the wolf pack.......

If I was bulding extractors I'd be showing off extracts out of my designs, just like every other company and not bragging about my steel nuts.......