'food Grade' Stainless

[uniiqueuser]

Hi, I am looking to perhaps weld up a new fermentor. I have done a fair bit of non-food grade TIG welding and I generally pickle the weld with an acid solution. Does anyone know what post-weld treatment is necessary for 'food grade' stainless equipment? Using pickling paste sounds kind of unhealthy to both your beer, and more importantly those who drink it, unless it was properly neutralised of course.

Material will most likely be 316 stainless.

If this venture is successful I might look at making some kegs. This would cost about the same as buying a post mix keg, but you could make it a bit bigger than 19 litres. I have not counted labour in this cost, however.

Thanks for any answers.

 

[barls]

just one thing if you dont have the qualifications and experience to weld presure vessels ie kegs dont do it!!!!! there is a good chance someone will end up getting hurt if it lets go under pressure.

 

[schooey]

You're going to make and sell a brand new, food grade kegs, bigger than 19L with posts, hatch, spear and pressure relief cheaper than someone can buy a good as new corny?

Good luck with that...

 

[porky]

Where did he say he was going to sell them??

 

[uniiqueuser]

Thanks for your insightful reply, but I was not going to sell kegs but rather make them for myself. I wanted something bigger than 19 litres. I know there are larger kegs available but finding them is like a lottery.

The point of the exercise is to perhaps make a 50 litre keg where the cost of material is about that, or perhaps slightly less than buying a used 19 litre keg.

I have made a few pressure vessels an none have exploded or killed anyone yet, which operate under higher pressures than the +/- 45 psi for carbonation.

Don't forget that commercial kegs are paper thin and should not be welded- my design is made from tube with a 2mm wall thickness. Of course I can always test them by hooking them up to my compressor and wrapping them in a ballistic blanket (like those used on gearboxes in drag racing).

Of course if I come across a large wad of cash I will buy a swag of 19 litre kegs.... but you have to weigh up the price of making vs price of buying. There is a point where it wastes less time buying something which is more expensive than you can make yourself, even if it not exactly what you want.

 

[chappo1970]

Firstly welcome to forum HellBoy i am sure you will get a lot from here as I am sure you can offer a fair bit to us.

Any food grade stainless will be fine 302, 305 or 316. Comes down to price and application like all things, yeah? Fabricating a set of kegs is commendable however but I guess it's like anything you fabricate or modify, the more customised it is the harder it becomes to replace/repair parts from off the shelf.

19lt cornies are ideal for us home brewers as generally a single batch is 21lt or so and doubles are 41/42lts so I would firstly consider that fact for starters. Cornies are also relatively cheap and can be picked up from as little $60 (from the the sponsors above). Also I would suggest that you would have to buy some anyway to canibilise bits and pieces anway, like lids, dip tubes, connection posts etc. Also it might be prudent to buy a couple first to get into kegging and learn the ins and outs and discover what you really need for your situation. If then your left wanting by all means fabricate kegs till yours hearts content. I guess what the other boys are trying to say is why reinvent the wheel?

As for pickling it is a must and won't effect the final result obviously keep you and the work piece well ventillated. TIG is by far the best option IMO and the only option for our applications in home brewing.


Cheers


Chappo

 

[schooey]

My apologies... I was a little hasty in assuming you were going to sell them, and sorry, welcome to this wealth of information, albiet not always correct...

and still, good luck with making them even for yourself...

 

[technocat]

Don't forget that commercial kegs are paper thin and should not be welded- my design is made from tube with a 2mm wall thickness. Of course I can always test them by hooking them up to my compressor and wrapping them in a ballistic blanket (like those used on gearboxes in drag racing).

Can't agree with that, welding nipples or sockets into a keg is a breeze as the keg walls are quite thick resulting in a strong weld. One thing of interest is that with sockets they appear to be tapered from each end into the centre and you have buckly's trying to get a temperature gauge with probe screwed through them. Answer is to run a 1/2" BSP tap through the socket which will really test the strength of your welding as I found I had to use a 15" shifter to turn the tap to cut the thread out in the socket.

Cheers.

 

[Leigh]

Compressed gas is v.dangerous to do pressure tests with. The lab in Mulgrave that pressure tests gas cylinders to the Australian Standard uses pressurised water as when they let go there is not as much energy to spread the schrapnel. They also do this in a specially designed containment room.

Safety first.

 

[Supra-Jim]

Hydro testing is the way to go. As mentioned above, it is safer.

Just my 2 cents, but once you source your materials and all of the necessary fittings, i can't see it being cheaper than buying pre-made kegs.

If you want bigger than cornie's, try here: www.kegking.com.au

You can get a reconditioned 50l keg (ex-brewery and legal!!!) for between $130-$150. I reckon this will be cheaper once all is said and done and you've checked your maths on DIYing it.

Cheers SJ

 

[Offline]

Don't forget that commercial kegs are paper thin and should not be welded- my design is made from tube with a 2mm wall thickness. Of course I can always test them by hooking them up to my compressor and wrapping them in a ballistic blanket (like those used on gearboxes in drag racing).

Can't agree with that, welding nipples or sockets into a keg is a breeze as the keg walls are quite thick resulting in a strong weld. One thing of interest is that with sockets they appear to be tapered from each end into the centre and you have buckly's trying to get a temperature gauge with probe screwed through them. Answer is to run a 1/2" BSP tap through the socket which will really test the strength of your welding as I found I had to use a 15" shifter to turn the tap to cut the thread out in the socket.

Cheers.

He is probably referring to corny kegs, not 50L commercial kegs

 

[bigfridge]

If this venture is successful I might look at making some kegs. This would cost about the same as buying a post mix keg, but you could make it a bit bigger than 19 litres. I have not counted labour in this cost, however.

Thanks for any answers.

Another day .... another poster intending to do something illegal on AHB.

All beer kegs used in Australia must comply with AS 2971-2007 Serially produced pressure vessels. This standard describes the design, manufacturing and testing procedure required to ensure safe operation.

If someone gets hurt using a keg that does not comply then the manufacturer becomes liable. Even though you may not intend to sell your kegs if you get hurt it means that you may lose all insurance entitlements etc.

New and second hand kegs are readily available for about $150 each so it is not really worth taking the risk.

Dave (Fully affiliated with the new and used keg market)

 

[Supra-Jim]

^^^ As posted above, I believe the design of the said pressure vessel also requires registration.

Cheers SJ

 

[bigfridge]

^^^ As posted above, I believe the design of the said pressure vessel also requires registration.

Cheers SJ

Hi SJ,

The design used to require registration but it looks like the OH&S regualtions in each state has recently changed to no longer require it. We have just gone through this process for the supply of kegs to the major breweries and they have accepted that a certifocate from the factory's own QA section stating compliance with the standard is sufficient.

But I guess this doesn't help a smaller manufacturer as they probably don't have ISO9001 certification.

Dave

 

[Zizzle]

Ever heard of metal fatigue?

It's not just a matter of making sure it will hold a great pressure once.

Welds especially can cause metal grain size changes as well as residual stress and stress concentration points.

Go look up the Comet passenger jet for the ultimate example of catastrophic fatigue induced failure of a pressure vessel.

That being said, I would also look at the risk factors, and if you overengineer like it sounds you would, and treat it like a bomb, then there are more dangerous things.

 

[Supra-Jim]

Hey BigFridge,

Point taken, I think to the regs for registration are based on a calculation comparing internal volumes, design pressure and the hazard levels of the liquid /gas being stored (feel free to poke fun at the hazard levels of leaking/exploding megaswill!!).

I guess the overriding theme here is that despite the enthusiasm and access to materials and tools, the economics and probably more importantly the safety issues involved with attempting to produce one's own kegs does not stack up.

Cheers SJ

 

[chappo1970]

Another day .... another poster intending to do something illegal on AHB.

All beer kegs used in Australia must comply with AS 2971-2007 Serially produced pressure vessels. This standard describes the design, manufacturing and testing procedure required to ensure safe operation.

If someone gets hurt using a keg that does not comply then the manufacturer becomes liable. Even though you may not intend to sell your kegs if you get hurt it means that you may lose all insurance entitlements etc.

New and second hand kegs are readily available for about $150 each so it is not really worth taking the risk.

Dave (Fully affiliated with the new and used keg market)

What a load of BS. The Australian Standards are a set of guidelines or STANDARDS and do not form any legal binding law or legislation but rather a set of "agreed" industry best practice guidelines. A product complying with a set of AS XXXX standards merely says it is in compliance with a set of guidelines, parameters and test regimes.

ABC or Australian Building Code which is an Australian Standard is often countered and debunked by Local Authority rules and regulations. Does this mean every house in Australia is not insured?

If I am believe this rubbish then anyone tinkering with a widget and blows oneself up then you will not be covered by insurance. Absolute crap! I would like to see this said legislation which proclaims the Australian Standard as the law. Would it not open the whole Australian Standard platform to litigation?

Chappo

 

[schooey]

Geez I dunno, Chappo... I'm pretty sure if you got a 'mate' in to do some wiring and he didn't do it to the relevant standard or industry code, or wasn't qualified, and your house burnt down then you'd want to hope said sparky had a nice bank account.... I doubt your insurance company would fork out for it

 

[chappo1970]

Geez I dunno, Chappo... I'm pretty sure if you got a 'mate' in to do some wiring and he didn't do it to the relevant standard or industry code, or wasn't qualified, and your house burnt down then you'd want to hope said sparky had a nice bank account.... I doubt your insurance company would fork out for it

Yes agreed but I was refering to the notion that if a product does not fully conform to an Aust Standard it is therefore illegal. This is simply not the case. The Australian Standards do not express anthing as being illegal or against the law. The Standard itself is not law or legislation, the law or legistlation will refer to the standard as being "Best Practice" but the standard itself is not the law otherwise it would be near impossible to change and move with the times or as technology improves. The Aust Standards job is not as a law maker but a guideline to best practice within an industry.

A classic example was the use of steel/iron to copper and then poly pipe in house plumbing. Copper was thought to be inferior many years ago until it became apparent that heavy metals and alike where being leached into you drinking water. Copper has since been replaced by poly pipe because of economic convience as well as it's stability in it's application. If the Standards formed the law these products, processes and practices could not be changed unless passed by the relivant Authority (Local/State/Federal).


Chappo

 

[schooey]

Yeah... but I think the pressure vessel standard is pretty well the same as the gas bottle one.. It has to be manufactured to meet or exceed that standard and pass test criteria to be passed and 'stamped' for filling... Try getting a gas bottle without a test stamp filled... Of course you could fill it yourself, but if you whacked yourself with it, when it all came out at the workcover enquiry, I doubt your Life insurance company would pay your missus and kids a razooo...

anyway this is just getting into semantics and it's a bloody moot argument...

You wouldn't be able to buy all the material to build a keg for the price you can buy a second hand one. Being a pressure vessel, you'd ad least have to buy pressed dished ends for it, then posts, PRV, a hatchway... Getting my point?

Then you have to hope like bejesus you were good enough with a TIG to achieve perfectly purged food grade welds all round the indside of the vessel, no mean feat... Or else you just spent all that money for two pots to put some hops in when you cut it in half because everything you put in it ends up infected