Insulating my kettle what material?

[aaronpetersen]

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

Thanks for the very comprehensive answer Adr_0.

 

[Doogiechap]

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

 

[CosmicBertie]

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

 

[user 25501]

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.

 

[Adr_0]

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...

 

[user 25501]

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.

 

[snoozer]

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.

 

[Coalminer]

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

 

[431neb]

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.

 

[snoozer]

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?

 

[431neb]

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

 

[Cocko]

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.

 

[snoozer]

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!

 

[snoozer]

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

 

[hop_it]

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!

 

[snoozer]

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.

 

[seamad]

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

 

[snoozer]

Thanks, I shall check it out.

 

[DJ_L3ThAL]

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...

 

[Feldon]

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.