# Insulating my kettle what material?



## Damn (2/7/13)

As I do, I've trawled the web but I would still like to start another debate on this topic.
I've recently bought an aluminium chef inox 50l pot to do a stove top BIAB. That method failed. I then purchased 2200w element from KegKing had that fitted to my new pot. I decided to measure my evaporation rate and water heating times prior to my next brew day/night. I setup my pot outside on 2 x 4x2's balanced on 2 "A" table supports. It was a chilly 10o. I used QldKev's water heating calc which was spot on at arriving at 70o. But by no no fault of Kev's calcualator it took an additional 12min to arrive at close to boil. Which I suspect was my un-insulated aluminium pot impeding the progress. In that cold night I could only achieve a very slow boil. I measured the water at 97o. So my debate is.....

Do I

insulate with a couple of *camping mattress's* that I have.
insulate with *13mm Airflex Nitrile Rubber*. Anyone know where I can purchase this? Clark rubber don't have it.
Insulate with *10mm Formshield*. Clark Rubber do have this but would be interested in another supplier in the Eastern burbs of Melbourne. ($27/m or $40/m with adhesive back)
or What else do you suggest for an easy non mechanical solution.
I did look into *Air-Cell* but many seem to advise against this for good reason. I welcome your views.

On another note, as I boiled outside I noted a massive concern was boiling under a flouro light. The bugs.

Thanks for any opinions.

Damn


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## Black Devil Dog (2/7/13)

I use a big piece of black geotextile material that I may or may not have allegedly "taxed" from a job that I was working on.  It's like a big black blanket. I've folded it a couple of times and wrapped it around my urn, then I wrap one of those thin foam mats around that and secure it with an elastic cord. On the top of my urn I have 2 big thick cheap towels and I tuck the sides into my foam mat. Works for me, others use sleeping bags, rugs, etc.

A couple of cheap blankets or sleeping bags from an op shop would do the job as good or better and at a fraction of the cost of some of those things you mentioned.


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## woodwormm (2/7/13)

I have no experience yet, but i'll be in the same boat soon I expect, outside under 'buggy' lights, i guess they hopefully don't make it through the hopscreen?

i'm also keen to see the insulation answers, i'm gas fired so i expect i need to be careful insulating for boil too close to the bottom of the pot in case flames lick up the sides!


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## technobabble66 (2/7/13)

I beat you to it by a month or 2. Again w much reading & hunting

I went with the 10mm Formshield from clarke rubber around my Birko - too hard to resist the shiny silver-backed foam!

I agonised for a while on whether it should face shiny side in or out. I went with it facing out. No idea if i was right or wrong, TBH. It seems to work well, though i've noticed after a while the side feels warm - so maybe some leaking heat. I have a second piece (i bought 1.2m x 1m width, that i then had to cut in half to fit it) so i'll probably wrap the second piece around it to make sure. I also used a sleeping bag on top during the mash, though i probably could've cut out a piece of Formshield to fit the lid.

I then found the heat loss through the top to be a major problem. I could get it to a boil quickly, but once the lid came off, it gradually reduced to a slight simmer at best. 2 little tins floating in the wort seems to solve that problem nicely, though.

Blankets/towels &/or sleeping bags certainly work for the mash. Not sure about the boil. Definitely could be the cheapest option compared to what i did. But less style: more ghetto, not as shiny...


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## wbosher (2/7/13)

printed forms section said:


> I have no experience yet, but i'll be in the same boat soon I expect, outside under 'buggy' lights, i guess they hopefully don't make it through the hopscreen?
> 
> i'm also keen to see the insulation answers, i'm gas fired so i expect i need to be careful insulating for boil too close to the bottom of the pot in case flames lick up the sides!


Shouldn't have any issues with gas, depending on how may rings and pot size obviously. I use a 3 ring gas burner and have no trouble boiling 35L on a chilly 5 degree night with no insulation.

For the mash blankets do the trick.


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## 431neb (2/7/13)

Did you say insulate your kettle?


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## djar007 (2/7/13)

That's awesome neb. It would make a handy bed when the brewing day was done.


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## 431neb (2/7/13)

For those times when it's safer to sleep in the shed.


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## KingKong (2/7/13)

431neb said:


> IMG_2421.jpg
> 
> 
> 
> ...


Is there any insulation against the concrete its sitting on?


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## 431neb (2/7/13)




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## TSMill (2/7/13)

I use polytuf Eva closed cell foam from bunnings. It has a diamond plate surface and I've glued 2 layers with the textured surface outwards. This gives a small air gap against the vessel which may aid insulation.


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## Adr_0 (2/7/13)

TSMill said:


> I use polytuf Eva closed cell foam from bunnings. It has a diamond plate surface and I've glued 2 layers with the textured surface outwards. This gives a small air gap against the vessel which may aid insulation.


Should do the trick, I'm going to do exactly that on the top 1/2-2/3 of my MLT and kettle. Just watch the air gaps on your MLT.

I'm getting all giddy at this thread! (chemical engineer)


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## emnpaul (2/7/13)

431neb, do you work in the rail industry by any chance? 

I have the same insulation around my keggle, held in place semi-permanently with a tripple layer of duct tape. It does the job really well. My boil temp went from 96.8 to 101.2 with that addition alone and ramp times cut by heaps. It's good stuff.

Edit: Not sure where you'd go to actually buy some. It was given to me by a mate that builds train cabs. I think he said it was R6 Dacron.


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## 431neb (3/7/13)

I don't use it for the boil as you can probably see emnpaul. I use an over the side electric element to get my uninsulated keggle up to the boil and a 3 ring burner after that... but to the point, the insulation is simply polyester wall batts. It's a common alternative to glass wool batts like pink batts and the yellow (bradford?) glass wool batts.

From memory, I lost 10 degrees that day but my mash time was 6 hours or so. Next time I will use some foil house wrap / sarking as well to see if that radiant heat barrier makes much difference.


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## aaronpetersen (3/7/13)

technobabble66 said:


> I agonised for a while on whether it should face shiny side in or out. I went with it facing out. No idea if i was right or wrong,


I've also been wondering whether insulation should be shiny side in or out. I went for shiny side in as I reasoned that it would reflect the radiant heat back towards the pot.
Does anyone actually know which is right?


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## technobabble66 (3/7/13)

Supposedly the shiny surface reflects radiant heat, & needs an air gap (facing the heat source) to do that. If it's in contact with a solid or liquid, then the reflection stuff doesn't really occur and the heat is just conducted through. That's the basic theory.
How that applies here, i wasn't sure. The shiny surface is textured, so maybe there's a moderate number of little air pockets to allow the reflection to occur from that side. Otherwise, the same kinda applies to the foam side - tiny pockets of air trapped in the foam against the shiny inner surface.
I went with the idea that both might be similarly valid, such that the shiny effect is somewhat compromised anyway and only works a bit, and decided that the shiny side on display would be a better finish to keep clean, etc (& look shiny!).
No-one at Clarke Rubber had a clue (including the manager/owner).

I've already cut mine to fit, so i now can't be bothered to try to do a temp comparison on shiny side out compared to shiny side in...

Maybe best to do 2 layers - inner facing in, outer facing out.


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## Damn (3/7/13)

Thanks for all the input.

I'll try the "ghetto" method first brew with my camp mattress's. Then may upgrade as you suggested with a double layer of *10mm formshield.*

I can't find any more info on *Airflex Nitrile Rubber. *That's what the guy(s) use at beer belly and it looks slick too.


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## slash22000 (3/7/13)

All this talk of insulation has got me thinking about insulating my BIAB urn again.

Anybody have any tips for insulation that I can cut to fit sight tubes, handles, etc?


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## keifer33 (3/7/13)

I went with the silver insulation from Clark Rubber for my last two brew rigs. Its pretty easy to cut out the necessary parts and hold it on with a few straps.


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## Adr_0 (3/7/13)

AaronP said:


> I've also been wondering whether insulation should be shiny side in or out. I went for shiny side in as I reasoned that it would reflect the radiant heat back towards the pot.
> Does anyone actually know which is right?


It should be shiny side out, particularly if the rest of it is foam or something with good conductive resistance (low thermal conductivity). By the time your temperature drops going through the insulation the surface temperature on the outside of the insulation won't be very high and you won't get a hell of a lot of heat loss from radiation, but anything you DO have will be reduced to very little when you have the shiny side out and every little bit helps.

If you have the other side out, it probably radiates heat a lot better than something shiny, so increases heat loss. And the only benefit of the insulation on the middle is the conductive resistance the shiny stuff offers, which probably isn't that flash (probably actually has high thermal conductivity).

But the best reason of all - never mind heat transfer fundamentals - is that it looks heaps *blingier* with the shiny side out.

Just some rough numbers, comparing my stainless mash tun (0.4m diameter, 0.6m high and ~1m2 of surface area) the heat loss from radiation from the bare metal at 50°C was about 140-150W. With 75L of water that means I would be losing at least 1.5°C per hour. At 65°C it was 250W, or about 3°C per hour.

With a product with an emissivity of 0.03 (i.e. shiny insulation stuff) that goes down to about 7W, or insignificant. The air/foam on the middle reduces the surface tempearture a bit (because heat doesn't get out as easily) and then the shiny surface poorly radiates it so it reduces heat loss in two ways and is theoretically 0.3°C per hour. Actual measurements are about 0.5°C per hour.

EDIT: *Note that white is just as good as shiny, believe it or not*


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## aaronpetersen (3/7/13)

Adr_0 said:


> It should be shiny side out, particularly if the rest of it is foam or something with good conductive resistance (low thermal conductivity). By the time your temperature drops going through the insulation the surface temperature on the outside of the insulation won't be very high and you won't get a hell of a lot of heat loss from radiation, but anything you DO have will be reduced to very little when you have the shiny side out and every little bit helps.
> 
> If you have the other side out, it probably radiates heat a lot better than something shiny, so increases heat loss. And the only benefit of the insulation on the middle is the conductive resistance the shiny stuff offers, which probably isn't that flash (probably actually has high thermal conductivity).
> 
> ...


Thanks for the very comprehensive answer Adr_0.


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## Doogiechap (3/7/13)

Damn said:


> Thanks for all the input.
> 
> I'll try the "ghetto" method first brew with my camp mattress's. Then may upgrade as you suggested with a double layer of *10mm formshield.*
> 
> I can't find any more info on *Airflex Nitrile Rubber. *That's what the guy(s) use at beer belly and it looks slick too.


If you Google Aeroflex Nitrile you might get some better returns. This is one Aussie supplier (sorry not in your state)
Cheers


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## CosmicBertie (3/7/13)

Just run around your mash tun point a large mirror at it. Works for me.


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## Damn (4/7/13)

Doogiechap said:


> If you Google Aeroflex Nitrile you might get some better returns. This is one Aussie supplier (sorry not in your state)
> Cheers


Thanks Doogie,

Found a local who sells sheets of aeroflex sheet insulation. Reasonable price for 13mm @$35 for 1.2 x .9.


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## Adr_0 (4/7/13)

Cosmic Bertie said:


> Just run around your mash tun point a large mirror at it. Works for me.


The thing with that is that you need another mirror on the other side of the hydrometer to see the reading... so because there are now two mirrors you have two people and need to make sure you don't bump into each other and drop the mirrors...


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## Damn (8/7/13)

Well, I ended up insulating my pot with *13mm Aeroflex Nitrile Rubber*.





Easy enough to prepare the template. But boy, once you put the glue on it doesn't move easily. Make sure you've got putting the rubber on straight before putting on the glue.

It works as a treat as an insulator but still didn't solve the problem on my slow boil with my KegKing element.


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## snoozer (11/7/13)

Hi guys,
I'm still trying to find suitable insulation for my gas fired kettle, MT & HLT. I have tried the foil backed foam from Clarke rubber and it shrivelled and softened and started to smell. Even when I moved it up about 5 inches from the bottom of my keg the heat still softened it. The flame was not overly large but the heat shimmer could easily be seen travelling up the sides of the keg. I could turn the flame down further but then my brew day would be lengthened more than I'd like.
The only thing I can think of that may be suitable for insulation are batts or blankets of either fibreglass or ceramic (kaowool). I know ceramic blankets are flameproof but what about fibreglass (Bradford batts etc), does anyone know how they stand up against flame? I'd prefer to use them as they are considerably cheaper, easier to get and less of a health hazard to install (I think). I am thinking some high-temp aluminium foil tape may work to wrap around the keg and seal the fibres, but I guess I'd have to try it. I really like using gas and dont plant to switch to electricity, so...
Has anyone got any other ideas or used this stuff successfully? What are people with direct-fired vessels using for insulation? any help appreciated!
Cheers.


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## Coalminer (12/7/13)

Hi Snoozer
I checked out that foil backed foam at Clark Rubber for my Braumeister and the guys there said it is only rated to 80C so on with the search
Cheers


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## 431neb (12/7/13)

Snoozer if you are gonna go that way, would you consider rockwool? It's like fibreglass insulation except its made from super-heated minerals and the batts are stiffer and more resilient. They were often used as wall batts where sound insulation was as important as thermal. I haven't seen it for a while but I'm sure it's still available. Maybe that with a layer of foil sarking over the top and then wrap the whole thing in your high temperature tape? 

I have considered many of these things to insulate my 50 L keg mash tun but I think I'll end up keeping the insulation simple and add an electric element. Then I can put and STC 1000 on the element (maybe with a relay) and maintain my mash temp that way. I'm actually mulling over a RIMS system that might use my immersion chiller but I have to do a lot of research first.

PS Does anyone actually KNOW if aluminium foil or several layers of it, is as effective as a radiant heat barrier as normal building house wrap / paper/ sarking? It just occurred to me that ally foil might be an easier option and less expensive for Snoozer if the above method is tried.


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## snoozer (12/7/13)

Thanks for the response guys. Neb I have heard of that rockwool but I need something flexible that can be wrapped around the keg. 
Fire blankets could be an option, they are fairly cheapish so I could probably wrap several around. Or maybe a welding blanket? Are they made of wool?


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## 431neb (12/7/13)

snoozer said:


> Thanks for the response guys. Neb I have heard of that rockwool but I need something flexible that can be wrapped around the keg.
> Fire blankets could be an option, they are fairly cheapish so I could probably wrap several around. Or maybe a welding blanket? Are they made of wool?



Try this


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## Cocko (12/7/13)

I used 'Wetsuit' material on my 70L MT and it is a great insulator... also, cleans easy...

I know you are talking kettle; thus I mention; I did a BIAB in my MTat a mates place a couple of weeks ago, double batch and boiled with OTS 2400w element...

It boiled at a perfect intensity and came no where near 'melting' the wetsuit wrapping.

2c.


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## snoozer (12/7/13)

That stuff looks the goods! Appears to be safe, unlike ceramic blankets which are carcenogenic according to the MSDS, plus installation and handling of that stuff is a nightmare.
I will have a look at the MSDS for this stuff but I think (hope) it will do the job! One wrap of the 25mm stuff should do it.
Thanks Neb!


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## snoozer (12/7/13)

Im referring to the rockwool not the neoprene, I reckon flame may melt that.


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## hop_it (7/8/13)

Hey guys,

Has anyone in WA found a supplier for Airflex nitrile rubber? I know these guys sell it, but at $230/m for 9mm stuff it seems a bit expensive, esp when Damn got it for $35...

Thanks in advance!


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## snoozer (23/8/13)

Well I ended up getting some mineral wool blanket similar to the Bradford rock wool but made by another mob. It cost $125 for a roll 900mm wide by 3 metres long and 25mm thick with foil backing, not cheap for sure but was actually preparing to be slugged more than that considering its a specialty item.
The aluminium foil tape on the other hand is RIDICULOUSLY expensive! The highest performing stuff I could find is made by 3M, withstanding up to 316 degrees celcius! and its flame proof too, but a 12 metre roll 50mm wide costs over $300! so obviously I am still looking, especially considering to completely wrap my beer keg would probably require 2 rolls. $600+ just in tape? I don't think so!
I am still wondering how to fasten the batts on.


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## seamad (23/8/13)

Check out whitworths for Al tape used for engine insulation in boats. A little cheaper, not sure what temp it's rated too though.


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## snoozer (23/8/13)

Thanks, I shall check it out.


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## DJ_L3ThAL (18/11/13)

Wish I saw this thread earlier (or thought to search for it). Went to clarke rubber on saturday before brewing and got some of the "fire-resistant" blue foam as advised by the sales guy when I described my intended use (they were out of the silver backed rubber). Bloody stuff ain't very flame proof, still melted and charred the edges around bottom of keggle even though I made sure it was at or above where the vertical internal wall of the keggle starts! Might just take it back to clarke rubber and tell them where they can put it...


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## Feldon (18/11/13)

Don't fight the force.

You've spent hard-earned cash burning LPG gas to create the heat that you are now trying to keep away from your kettle with insulation.

Why? Use that otherwise wasted heat energy to help boil your wort.

To save explaining here, have a look at this product.

www.homebrewtools.com/heat-guide

Click the tabs at top of page and learn the principle behind it (its the same idea behind Rocket Stoves).

Anybody with basic sheet metal skills should be able to knock up something similar using old metal drums as cheap/free raw material.


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## Tilt (18/11/13)

You've spent hard-earned cash burning LPG gas to create the heat that you are now trying to keep away from your kettle with insulation.

Anybody with basic sheet metal skills should be able to knock up something similar using old metal drums as cheap/free raw material.[/quote]


The stainless "outer skin" from old kitchen bins work a treat for this. 10 mins work with the tin snips and a couple of bulldog clips halved my rise to boil time and meant I could get a rolling boil from a 3 ring burner on a normal low pressure reg


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## mr_wibble (18/11/13)

DJ_L3ThAL said:


> Wish I saw this thread earlier (or thought to search for it). Went to clarke rubber on saturday before brewing and got some of the "fire-resistant" blue foam as advised by the sales guy when I described my intended use (they were out of the silver backed rubber). Bloody stuff ain't very flame proof, still melted and charred the edges around bottom of keggle even though I made sure it was at or above where the vertical internal wall of the keggle starts! Might just take it back to clarke rubber and tell them where they can put it...


Under the trade practices act, if the sales-drone suggests something that is not fit for the described purpose you are entitled to a refund.
See: http://www.consumerlaw.gov.au/content/the_acl/downloads/consumer_guarantees_guide.pdf Section 04, page 14.


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## Camo6 (18/11/13)

DJ_L3ThAL said:


> Wish I saw this thread earlier (or thought to search for it). Went to clarke rubber on saturday before brewing and got some of the "fire-resistant" blue foam as advised by the sales guy when I described my intended use (they were out of the silver backed rubber). Bloody stuff ain't very flame proof, still melted and charred the edges around bottom of keggle even though I made sure it was at or above where the vertical internal wall of the keggle starts! Might just take it back to clarke rubber and tell them where they can put it...


I found with BIAB it was easier just to wrap the insulation around the keggle once mashed in. This way it stayed cleaner and didn't affect my immersion chillers efficiency. I just had to remember to remove it before firing up the burner. :unsure:
I had a peek under the insulation on my HLT the other day and found a couple of rusty stains where water had been trapped on some scored steel. Starting to think I should of made it easily removable to prevent this.


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## DJ_L3ThAL (18/11/13)

I didn't think of the ill-effect of having the insulation on while heating the vessel with gas! Will head back to Clarke Rubber and get a refund on the "fire-resistant" insulation.

I like your idea Camo, just wrap it temporarily for the mash, will make something up. Now to work out how to scrub the charred/melted foam off the sides of the keggle :unsure:


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## andrewl (18/11/13)

I wrapped/siliconed a camping mat from kmart around my MT and then throw a sleeping bag over the top. A ghetto way of doing it but it holds temps perfect for the hr


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## Ninegrain (30/11/13)

Anyone considered exhaust wrapping?

Reasonably cheap if a single wrap of the kettle is enough. Heat resistant to 900'c too... 

http://www.ebay.com.au/itm/EXHAUST-HEAT-WRAP-BLACK-20M-2-x-10M-X-50MM-ROLLS-12-STAINLESS-TIES-/251195386123?pt=AU_Car_Parts_Accessories&hash=item3a7c69690b&_uhb=1


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