silicon

[pargyle]

Basically as per Erichalfbee.

As usual, some posting on the forum seem not to know the difference between the words 'withstand' and 'insulate'. They do not mean the same, by any stroke of the imagination.

Yes ... but we are talking about insulating an aluminium block only being heated for a matter of two and a half minutes after which the current will be switched off and the heat will dissipate fairly quickly. All Redwood is looking for is something that will protect the plastic covered mesh of his hive floor from the direct heat of the aluminium for the duration of OA sublimation treatment.

I make my own yoghurt and use a heated tray under the bowl to maintain the temperature ... I cannot put my hand on the metal tray when it's hot but I stand my yoghurt making vessel on one of these silicon pie dishes and it takes the heat transferred down to much less than hand hot.

We are not talking about long duration totally prevented heat insulation ... it's a thin, easy and potentially successful solution to Redwood's problem ... you're a bit over the top on this occasion RAB !!

 

[oliver90owner]

you're a bit over the top on this occasion RAB !!

So you don't think the thickness of this 'sheet' might make a difference? I do. I learned a long time ago that a cigarette would burn skin before a single pound note between the two, whereas if a whole folded newspaper were used, the paper would char before it got warm the other side. All a matter of principle, really. The two words 'withstand' and 'insulate' are not now any more related than before your reply.

Most physical principles are well known and do not change appreciably with time. Einstein made some changes but Newton's Laws of Motion still hold true for all situations bar for velocities exceeding about 0.6c!

 

[pargyle]

you're a bit over the top on this occasion RAB !!

So you don't think the thickness of this 'sheet' might make a difference? I do. I learned a long time ago that a cigarette would burn skin before a single pound note between the two, whereas if a whole folded newspaper were used, the paper would char before it got warm the other side. All a matter of principle, really. The two words 'withstand' and 'insulate' are not now any more related than before your reply.

Most physical principles are well known and do not change appreciably with time. Einstein made some changes but Newton's Laws of Motion still hold true for all situations bar for velocities exceeding about 0.6c!

Yes of course ... but from my PRACTICAL experience with a similar (if not identical) silicon dish with a substantial heat source against it I found that it does reduce the heat transmitted .. I wasn't talking about empirical situations merely offering a practical and simple (words you often use !) solution to Redwoods problem .. you, for once, appeared to be making things more complicated than they needed to be ...

 

[farbee]

This is the product I use for heat shields, I should have read what it said on the tin.
http://www.ebay.co.uk/itm/1-X-CLEAR-INSTANT-GASKET-100ml-TUBE-ENGINEERING-GRADE-300-/251582834237

Yes, but where is the fun in that.

 

[oliver90owner]

http://www.mgchemicals.com/products...-greases/silicone-heat-transfer-compound-860/

You might care to check out the above link. Withstands high temperatures but is a very good thermal conductor (ie not an insulator). I would not want a good insulator as a cooking utensil -my cakes may be frazzled at the surface and uncooked at the bottom.

An oxalic acid sublimator likely gets to around a surface temperature of 200 degrees or perhaps more, dependant on several factors, so could quite likely melt a contacting plastic with melting point of a little over 120 degtees, even with an intervening 'coat' of silicone. 'Suck and see' was not the advice wanted, I feel. Furthermore the thread starter was quite precise, even if a bit wooly.

For what it is worth, my advice would be a piece of 5 or 6mm ply, if space permitted. But I would not be relying on a thin coating of silicone - if good surface contact was achieved at both interfaces - that is for sure.

Perhaps I should now go and withstand my wasp hives with some sheet insulation over the super brood. Nomenclature is likely close enough for some.....

 

[pargyle]

I would not want a good insulator as a cooking utensil -my cakes may be frazzled at the surface and uncooked at the bottom.

I think that's the reason the damn thing ended up being used as a sheet of insulation for my yoghurt making ... the old blackened tin plate flan tin cooks so much better !! Particularly in a fan assisted over ...

Perhaps I should now go and withstand my wasp hives with some sheet insulation over the super brood.

That's more like the RAB we know and love !!

 

[Gilberdyke John]

It is a good heat insulator and I use to coat exhaust heat shields for racing cars so I was thinking if I coated the underside of my oxalic acid vaporiser it would stop it burning the mesh on the omf but I needed to know what temperature it would withstand without burning

Talk to a boiler service engineer about a bit of thin FIBERFRAX sheet. It's a derivative of space shuttle heat shield tiles, alternatively try a bit of plumbers soldering mat. Both will stand direct flame for long periods.

 

[Ely]

What ye want is one of those tiles used under Bunsen burners at school.

 

[Erichalfbee]

They were made of asbestos when I was at school

 

[wessexmario]

They were made of asbestos when I was at school

does that mean we're going to have 'old school' vs 'new school' debate?

 

[Ely]

Its OK unless you intend on cutting it up and breathing in the dust.

 

[REDWOOD]

I won't be doing that then

 

[pargyle]

does that mean we're going to have 'old school' vs 'new school' debate?

No - because in beekeeping circles the geriatric beekeepers outnumber the young and middle aged ones about 10:1 so if you are young and thinking of starting a debate ... think again ... Pensioners Rule .. OK ?

 

[REDWOOD]

I think the most important thing is to be prepared to change weather your young or old, the world doesn't stand still for nobody. Weather you agree or disagree with change is another thing but one thing for sure, don't get your feet too stuck in the mud

 

[pargyle]

I think the most important thing is to be prepared to change weather your young or old, the world doesn't stand still for nobody. Weather you agree or disagree with change is another thing but one thing for sure, don't get your feet too stuck in the mud

+1 ....

 

[wessexmario]

I've just seen this on ebay which could be used for vaporising oxalic.
http://www.ebay. co.uk/itm/301352140200

It's regulated to 175C which is just right for oxalic, it looks good value even if you have to buy and fit a lead and croc clips for the battery yourself.

 

[REDWOOD]

I conducted a little test yesterday, I cut a 100x100 aluminium plate and coated one side with silicon about 2mm thick, I subjected the uncoated side with 200c heat for 5 minutes, I checked the temperature on the un-coated side at it was 100c.

I have found an alternative material, It is an exhaust pipe wrap that is a fibreglass weave with a silicon outer coating

 

[itma]

Discovered the other day that Sugru claims to be safe (stable) at up to 180C.
Amazing stuff.