Kettle Fabrication

[raven19]

Fellow AHB'ers,

I have just negotiated the services of some stainless steel fabrication in exchange for the structural calculations I provided for a friend.

I am keen to get stuck into AG, and have sourced thus far:
55L Esky
Urn (30L & 20L)

Now just needing a decent sized kettle, as such my basic sketch is attached.



I was thinking keeping it simple as per attached, however I am keen to hear fellow AHB'ers thoughts and ideas.

I will be doing my AG with a friend, hence at least double batches are required.

Q1: Keen to hear thoughts on dimensions (diameter in particular), keeping in mind we shall be probably going with an italian/nasa burner in lieu of immersion heaters. So minimum 50L batches, maybe even triples. Is 500mm diamter too large? Any thoughts on the best diameter for burner efficiency/heat transfer?

Q2: Allowing for some head space, thoughts on 80 - 100L capacity? More or less?

Q3: Thickness of Stainless Steel required. Say 5mm base and 3mm walls? Other suggestions?

Q4: Not being a plumber myself, am I better off just having just the holes drilled, or shall I have stainless steel nuts (or similar) welded to the inside of the holes for ease of fitting valves/taps, etc.

Q5: Is a lid a worthwhile?

Q6: Dimension from tap to floor of the kettle? Minimal to reduce loss? 20mm or more? (Sketch indicatively shows 50mm)

Thats a lot of questions... sorry if overloading...

I am not looking for something bigger than ben hur (just yet :lol: ), however I understand that additional holes for Temperature Probes, chillers, depth guages could be added now.

I have been accumulating photos of relevance from this brilliant site and many great threads, however please feel free to add links/pics to aid in support of your suggestions.

Our setup will be tiered gravity.

Cheers to all, and bring on the weekend...!

 

[PJO]

Q1: Keen to hear thoughts on dimensions (diameter in particular), keeping in mind we shall be probably going with an italian/nasa burner in lieu of immersion heaters. So minimum 50L batches, maybe even triples. Is 500mm diamter too large? Any thoughts on the best diameter for burner efficiency/heat transfer?

Q2: Allowing for some head space, thoughts on 80 - 100L capacity? More or less?

Q3: Thickness of Stainless Steel required. Say 5mm base and 3mm walls? Other suggestions?

Q4: Not being a plumber myself, am I better off just having just the holes drilled, or shall I have stainless steel nuts (or similar) welded to the inside of the holes for ease of fitting valves/taps, etc.

Q5: Is a lid a worthwhile?

Q6: Dimension from tap to floor of the kettle? Minimal to reduce loss? 20mm or more? (Sketch indicatively shows 50mm)

Thats a lot of questions... sorry if overloading...

Q7: I am not looking for something bigger than ben hur (just yet :lol: ), however I understand that additional holes for Temperature Probes, chillers, depth guages could be added now.

Q1 & Q2: Not sure about heat transfer, but a 500mm diam will only require a height of 500mm to get just under100L. If you want to brew 50L (post boil volume in the kettle) I wouldn't go less than 80L capacity, 100L would be comfortable. (I have a 18gal ≡ 82L kettle and can comforatble do 50L batches even 60L aren't too much of a stretch)

Q3: 5mm base is way too much and the walls do not need to be so thick. It will cost you a packet and way a tonne. I reckon you could get the whole thing made from 1.2mm.

Q4: Depends on how much money you want to spend, but I would get stainless nipples welded in.

Q5: Definitely

Q6: If you whirlpool you could have the tap as low as practically possible.

Q7: Personally I wouldn't add any other holes unless you are going to start using them straight off, but thats just me.

Cheers
PJO

 

[jel]

Raven,

You may also have issues relating to using a gas burner on a stainless steel only base. There is a reason the better quality stock pots have sandwich panel bases. Stainless is not the best conducter of heat. You may be able to use a plate of aluminium under the pot to better spread the heat but it wouldnt be my first choice.

I agree with PJO. As this is a kettle, I would be keeping the amount of fitting to a bare minimum. Personally I would only have a single tap connected. I really cant see the point of monitoring the temperature (either its boiling or its not), and its easy enough to use a dipstick to check the volume rather than worry about trying to clean a sight glass etc.

Cheers
J

 

[porky]

Mate,

I use a Keggle and it is 1.6mm thick. I just went and measured it. It is strong enough for sure.
It will heat up well, but maybe a skirt around the base like a keg would be a good idea?
i use a nasa burner and can get 28 litres boiling in 8 1/2 minutes, which of course starts
at around 65 plus degrees out of the mash tun.

Cheers,
Bud

 

[wessmith]

There is no problem with direct gas heating a stainless base. It is done in commercial breweries and certainly in many HB setups and my 120ltr kettle is set up just like that. The fact s/s is not a great conductor of heat is also not an issue. Sure you will get some hotter spots depending on the flame type (this is why cooking pots have an aluminium base to spread the heat a little better) but the wort will handle that OK. I would however recommend at least 1.6mm material in AISI 304 grade regardless of kettle size. Make sure whoever is welding the kettle up knows it is to be direct heated. This usually requires a double butt weld to be able to handle the thermal stresses.

Re the fittings to be welded in - I would go with at least a 1.0" BSP socket. This will allow you to use the kettle as a mash tun if you ever decide to go the Euro way of brewing and enable the mash grist to be run off to the lauter tun. You can easily bush the 1.0" down to a more practical size for straight kettle usage. My kettle has a 1.0" ball valve which works fine.

Wes

Raven,

You may also have issues relating to using a gas burner on a stainless steel only base. There is a reason the better quality stock pots have sandwich panel bases. Stainless is not the best conducter of heat. You may be able to use a plate of aluminium under the pot to better spread the heat but it wouldnt be my first choice.

I agree with PJO. As this is a kettle, I would be keeping the amount of fitting to a bare minimum. Personally I would only have a single tap connected. I really cant see the point of monitoring the temperature (either its boiling or its not), and its easy enough to use a dipstick to check the volume rather than worry about trying to clean a sight glass etc.

Cheers
J

 

[matho]

I have been told that the ideal ratio is 2:3 that is 2 units wide by 3 units high

just my 2c

cheer's
matho

 

[Tim]

Dont worry about a kettle - go straight in and hot him up for a conical fermenter!

 

[raven19]

Just an update on progress on the custom kettle.

After numerous hours pondering and researching on kettle make, size, etc., I have gone with a 100L custom 2mm thick kettle. 750mm high, 420mm diameter.

Majority of research was towards either gas or electric. I have decided to go with Electric, as this shall work well with the electric urn and esky mash tun.

Stokes (no affiliation, etc...) have 2400W elements for $65 each, 2 of these for double batches, with my brother in law helping with the wiring and a microcontoller to adjust the temp on one of the elements.

So now its just a matter of confirming hole size in kettle for these 2 elements, plus 1 hole for the tap.

Thanks all for the input thus far on this project. Will be posting pics once we start putting it all together.

 

[raven19]

Dont worry about a kettle - go straight in and hot him up for a conical fermenter!

Tim - I am thinking this might be the next suggested exchange! I like your thinking!!!! :icon_cheers:

 

[mika]

A little more research on the height/diameter ratio may have been a good idea

 

[raven19]

cheers mika, I am planning on mainly double batches - meaning the volume of wort would be around 1:1 for my intended size (50L in 100L pot). SS has been ordered, sure they can adjust... more reading for me now!

 

[raven19]

Update on my stainless steel kettle with photos of course.

2 x 2400kW elements, yet to be wired up, These are ceramic elements with a low heat density, good for the wort I hope!

Just one outlet at the base for the ball valve outlet to gravity drain to the cube.




Ceramic element partially inside sheath


Inside of Kettle

Just a few finishing touches required for wiring, then I am good to go full AG.

:icon_offtopic: Have a double batch of Dr Smurto Golden Ale grain ready to go as my first AG.


Back OT:

More Photos can be found at:
http://www.aussiehomebrewer.com/forum/inde...m&album=400

Cheers and thanks to all for your input thus far...

 

[raven19]

Some more pics of the element & surrounds.


Ceramic element


Metal sheath


Side view of connection plate

 

[porky]

Update on my stainless steel kettle with photos of course.

2 x 2400kW elements, yet to be wired up, These are ceramic elements with a low heat density, good for the wort I hope!

Just one outlet at the base for the ball valve outlet to gravity drain to the cube.

View attachment 23570

View attachment 23571
Ceramic element partially inside sheath

View attachment 23572
Inside of Kettle

Just a few finishing touches required for wiring, then I am good to go full AG.

Now that's what I call brew porn
You just have to get a stainless brew stand like yardy has for it
http://brodiescastlebrewing.com/index.php?topic=956.0
A real beauty mate.
What size did you end up with....height and diameter?

Cheers,
Bud

 

[scott_penno]

Are you able to provide further details about the elements like where you got them from and how much they cost?

sap.

 

[Carbonator]

Has this vessel been leak tested before electricity is applied?

Nice clean design.

 

[Bribie G]

I'm no sparky but when I had the 2400 watt 40L urn on the other day and then switched on an electric jug to make a temperature adjustment the circuit breaker tripped so I can only run one at a time.

Like I say no sparky but since you are using two elements you might want to try out the power point (s) you intend to use.

Lucky man, I'm currently drinking the first pint of my first AG :icon_drool2: and foremost in my mind is "Shyte if only I had brewed a double batch of this" :lol:

 

[raven19]

Now that's what I call brew porn
What size did you end up with....height and diameter?

Cheers,
Bud

Bud,

Final dimensions were 415 mm diamter x 760 mm high (internal dimensions), 2mm thick SS metal was used. This was fabricated by a friend in exchange for engineering calculations. He was happy to barter, as am I!!! hehe.

The dimensions above = 102 L, however I lost around 2 L to the element sheaths. Hence capcity is about 100 L, but biggest I dare say we shall do is a triple maybe one day? (Who am I kidding, we shall try to max it out one day I am sure!!!!)

Plan is to do double batches (one for me, one for a mate) for most brews, around 50 L.

Costs to other parts to follow shortly...

I am thinking the stand will have to wait till we buy a house (with shed of course). In the meantime it shall be used on a makeshift stand in my mates shed.

Cheers.

 

[Carbonator]

Like I say no sparky but since you are using two elements you might want to try out the power point (s) you intend to use.

I'm no Sparky either and it may be against the law for me to advise you to use a Power Outlet, Plug and Wiring no smaller than this;


It may also be against the law for me to advise you to use a CB no smaller than this;


The red hat wearing rat has a good point!

 

[raven19]

Are you able to provide further details about the elements like where you got them from and how much they cost?

sap.

Sappas,

No affiliations of course but my costs and suppliers on the kettle to date:

2 x 2400W Elements $66 each from Stokes (Richmond Rd Adelaide)

Stainless steel 2inch tube - free leftover length - thanks Prochem! used for element sheath

Ball Valve $18.70 from Prochem

Hosetail $6 from Prochem

Threaded nipple (welded to kettle for tap) $4 from Prochem

Electrical housing boxes, 2mm thick Stainless steel plate and stainless steel welding and fabrication included in barter.

I still have to source 2 extension leads and grommets, etc to safely wire it up...

I shall be double checking for leaks, etc prior to switching it on for sure!