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Using silicone and ash to increase insulation?

PostPosted: 11 Nov 2015, 14:21
by alanb1976
Hi all

Nice forum. First time posting as I can't seem to find anything about this so was hoping someone here would be able to assist.

My BBQ loses a lot of heat as it's fairly big. I actually struggle to keep the temperature above160 C without using a ton of coal.
So, I wanted to look at insulating it a little. I can't afford to spend a lot of money on it so have come up with an idea I wanted to throw past you. One thing to note, I still want the BBQ to look normal so would prefer not to bolt welding mats on (or anything like that) and use jackets/blankets unless needed.

So, what I was thinking about was to use the good insulating properties of the ash I end up with in a productive way. To do that I was thinking of buying some high temp silicone ( 320 C), smearing that over the inside of the BBQ and sticking ash onto it. So, that would give a thin layer of ash and silicone which, while not delivering a lot of insulation, would at least be a hell of a lot better than the great conducting steel.
Do you think that would make a difference?
I was also thinking that mixing the ash and silione may make a paste that would work better and be stuck on thicker. I don't know any other adhesive that will allow flexibility with the expansion of the steel with the heat.
I read that the coals burn at about 250 to 300C, so that silicone should hold as long as I don't subject it to open flames. Or would it?

That also brings me on to the worry that while I will be using silicone that says nontoxic, would there still be a risk as I'm heating it up with my food?

Any ideas?

Thanks
Alan

Re: Using silicone and ash to increase insulation?

PostPosted: 12 Nov 2015, 12:37
by PDC7
Personally I would definitely NOT be insulating the inside of a BBQ with anything, and I would not eat from a BBQ that had been lined with silicone.

Im guessing you would risk food contamination, just because the silicone can resist heat upto 320c doesn't mean that flames wont destroy or that over time it may break down and seep into the food.

Additionally, I wouldn't put anything that is not food safe near food.

Id look at may sealing any gaps, what type / style of BBQ do you have? maybe some cheap heat rope would seal gaps? If you have a BBQ that is purely designed for hot & fast grilling it may be unsuitable for other uses?

Re: Using silicone and ash to increase insulation?

PostPosted: 12 Nov 2015, 14:23
by Kiska95
Hi

You can get food safe high temp silicone but you would never be able to make a paste out of it to spread anywhere as the ash would form a film over the silicone and it wouldn't stick. But I'm with PDC7, I wouldn't eat anything off it regardless. Its high temp not flame proof so goodness knows what nasty's would come off it when subjected to flame.

You could put some sand in the bottom if its a regular barrel type direct grilling BBQ or some vermiculite and cement to form a light layer but both options are for the bottom. I bought a purpose made jacket for my GMG Daniel Boone but they didn't look hard to make so for the top it has to be an insulated cover me thinks.

Re: Using silicone and ash to increase insulation?

PostPosted: 12 Nov 2015, 21:18
by alanb1976
Thanks for the replies. I'll take your advice and not poison myself.

In terms of sealing the BBQ lid, would I run into similar issues if I use one of those silicone cement sealants that can withstand up to 1200C (also since it won't be in contact with the flames). I read they seal ovens with that so I would assume it would be safe for food. Your thoughts? I was thinking that and not the rope as I could get a better seal.

But again, would prefer not to take any risks if you guys think that I shouldn't use it

Re: Using silicone and ash to increase insulation?

PostPosted: 13 Nov 2015, 10:49
by essexsmoker
Envirograf 1200C food safe sealant might be an option.

Re: Using silicone and ash to increase insulation?

PostPosted: 13 Nov 2015, 12:34
by PDC7
Ive had flames come up quite high on my BBQ, so unless it was food safe, high temp and flame proof i'd avoid it.

Given the cost of the insulting items, it might be worth trying to pick up a cheap weber kettle, winters coming, there should be some good offers about

Re: Using silicone and ash to increase insulation?

PostPosted: 14 Nov 2015, 10:41
by gavinbbq
If you're trying to get more heat you could try this https://www.chefsteps.com/activities/ti ... lled-meats


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Re: Using silicone and ash to increase insulation?

PostPosted: 21 Nov 2015, 10:39
by Smokin Monkey
Bit late to this one, but, have you thought of using Vermiculit, mixed 5-1 with cement then enough water to bind it. Then line the BBQ with it to what thickness you can get. Sets as hard as concrete, but much lighter and has great insulation value. Can be purchased on EBay, buy the finer grade, easier to smooth out.

Kiska has seen a Tandoori Keg I have lined with it, holds up to the heat great.

Re: Using silicone and ash to increase insulation?

PostPosted: 22 Nov 2015, 12:19
by alanb1976
Thanks for the replies.

Firstly, I know my BBQ isn’t a great one but it has sentimental value (gift from my mother which I don’t get to see much anymore). So while I know I could do a lot better with another, I will be sticking with this one until it falls apart. It is one at the link http://www.landmann.co.uk/charcoal-bbqs ... oiler.html

Thanks for the Vermiculit idea Smokin Monkey. Two questions, does it not break or come loose when the steel expands due to the heat? And will that stick to steel or will I need to do some adaption to get it too (my BBQ has flat vertical sides which may be difficult to grip too)?
That does sound a lot better than my latest idea (below).

I've been obsessing over some way of adding a little insulation easily (and cheaply) that would leave it looking as it was meant too, from the outside at least. The blanket/jacket is still a good idea as I could take it off but that may be such a hassle (I'm lazy at heart). The thought I had lately, and yes, I laughed at this too but it still seems like it would work, was to use a food substance to stick on the inside and then sticking tinfoil over (thanks for the link GavinBBQ). I figured, a food substance can't be toxic so all I need is something sticky that will burn on when heated. This idea also came from when I've had to chisel off tinfoin from a baking tray before after it got some of the wine/stock mixture the meat was slow cooking in the oven with. So, I was thinking of spreading some honey/syrup over the inside of the BBQ and then sticking tinfoil to it. Then give it a run through and the honey/syrup should burn and harden up, sticking the tinfoil to the side and providing that extra layer that will help with insulation. Worse case, it can't do any harm if it doesn't work and comes off.
So I know that sounds so ridiculous but I can't see anything that is actually wrong with it. Sure it won't be a fantastic insulator, but it will be a lot better than the steel, and compounded with the tinfoil should just give me that extra I'm looking for. You can stop laughing now ;)

I’ve also bought some sealing rope to get a better seal on the lid.

Re: Using silicone and ash to increase insulation?

PostPosted: 23 Nov 2015, 12:48
by PDC7
I think you've got an inventive idea, but at some point the food substance will go rancid.

What is it you're trying to achieve from insulating the BBQ? if your just looking for grilling methods / foods then it should be fine, but if you're looking for low and slow it may be worth keeping the Landmann for grilling (sentimental value also) and another item for the low and slow? The new item could be sizzling away with a pork shoulder and you could be banging out burgers on the landmann as an appetiser?