Help! I'm looking for an electrical insulator that radiates heat.

[pjl83]

I want to bend some resistor wire into a coil shape and then insulate it electrically. However, the coil will be used to stir and heat liquid so the material must not insulate the heat from the resistor wire. I would also like to experiment with this at home so can it be achievable in a DIY sense?

 

The coil will be no bigger than a hand-held whisk (just for an example of size!)

 

Any ideas welcome

 

Thanks

Paul

[Mokele]

Is there a particular reason a standard aquarium heater won't work? They're fairly cheap, and you don't have to fuss around building it yourself.

[pjl83]

it needs to be a solid object as the liquid may at times be thick and the coil will need to be pushed through it. it has to stand alone as a customised piece. It's one piece of design that I am working on.

 

I am calling it a coil but that may give the wrong idea. It's more like a fork/whisk type of of shape.

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Consecutive posts merged

Another member suggested ceramic but I think it may insulate too much heat.

[insane_alien]

say your element puts out 100W of heat, it will do this whether insulated or not. all it means is that at equilibrium the core temperature will be higher. you could have 3 miles of insulation bout it will still put out the same 100W.

 

also, ceramics can be good conductors of heat approaching that of metals. not only that but if the only purpose is electrical insulation then it doesn't need to be all that thick either. the thermal resistance will be low whatever you use, you just need to make sure it can withstand the temperature.

[pjl83]

maybe i could give it a try then. Thanks for your replies guys. I guess I'll have to have a play and see what I can come up with.

 

Maybe something like this could work -

http://cgi.ebay.co.uk/1kg-ceramic-polymer-coating-brushable_W0QQitemZ320411365943QQcmdZViewItemQQptZUK_CarsParts_Vehicles_BoatEquipment_Accessories_SM?hash=item4a9a017237&_trksid=p3286.c0.m14

 

Thanks again guys. I reply apreciate the replies

Great Forum

 

Paul

[insane_alien]

as long as it never has to exceed 177*C

[pjl83]

i recon that my output would need to be around 70 degrees c, so hopefully i'll be ok. i'll post some results in the projects page once i start to play around with some examples.

 

thanks again.

Paul

[insane_alien]

then yes, it will be fine. you'll want to have some sort of temperature control on the heating element though because the heat transfer will be greater when you are whisking than if it is just lying on a work surface. a thermistor would do.

[pjl83]

yeah I need to look into tmeperature control. I'm no too sure how thermistors work. I was going to use a pot' for the voltage until I'd got it right and then move on from there.

[Externet]

Hi.

Seen variations of your post in several places.

Your whisker,

http://virtue.win.mofcom.gov.cn/www/23%5Cvirtue%5Cimg%5C2008829174856.jpg

with a metallic tubular handle could host a few automotive light bulbs inside. (there is some cylindrical ones that could well fit) http://www.autoguide.net/apf/images/products/engineparts/5y89947950lhi.jpg

 

Solder the connections, bring the wires out at the end of the handle, and being powered by 12V, pose little risk of electrical shocks, will transmit their heat easily trough their glass to the handle; and the supply is not a hard thing to find (a spare laptop supply works)

Then, the whisker can be held with an oven mitt.

 

Miguel

[pjl83]

thanks externet.

 

would the wires not short out where they cross at the bottom? I was assuming that the voltage would need to run through each wire without touching another on the way through. ???

[Externet]

Hello Paul.

The wires can be made/insulated/routed to not short circuit.

 

Or, if you prefer, insert a car cigarette lighter element at the end inside the handle. That will really put you cooking... Same safe low voltage (12V or less for less amount of heat)

 

http://www.coolest-gadgets.com/20080716/heat-me-usb-heated-stirrer/

 

http://www.surplusandoutdoors.com/ishop/877/shopscr3059.html

 

Miguel

Edited August 23, 2009 by Externet