Hello,

 

I am wondering if anyone has heard of anything that can be used as a heating element , yet is transparent. Like transparent metal for example ? Glass as we all know is a poor conductor of heat ! But there has to be something else

 

Thanks

Hello,

 

I am wondering if anyone has heard of anything that can be used as a heating element , yet is transparent. Like transparent metal for example ? Glass as we all know is a poor conductor of heat ! But there has to be something else

 

Thanks

 

Bulk metals won't work, since good electrical conductors won't be transparent. I'd suspect that some kind of conductive glass, ceramic or possibly even plastic or polymer would be a possibility. Doping/deposition of some conductive material or really tiny wires.

 

Time to Google:

 

http://www.minco.com/products/heaters.aspx?id=76

 

ooh, a transparent toaster that doesn't get hot enough (yet) to toast bread: http://www.yankodesign.com/product_info.php?products_id=1015

 

"heating glass" that has a super-thin metal-oxide layer to heat the glass http://www.iqglas.com/en/text_product.html

Hello,

 

OK so do you know were you can buy this micro thin sheets of metal to instert inbetween the glass

You'll have to Google that for yourself.

what is it for exactly?

I`m thinking perhaps something like double glassing with hot oil flowing through the gap, or maybe even a gas.

I'd suggest very very thin wires embeded in a ceramic, like some cars have in their front windscreens for demisting. Easier to manufacture than metalic thin films which are thin enough to be transparrent.

YT's idea is, as always, a good one. and probably the most realistic. a simple heat exchanger is a pretty good way to go, just try and get a working fluid that has a similar refractive index to the glass, perspex, diamond, whatever. Heat the fluid with your standard metal heating element and pump it through the tube. hey presto. you have a transparent heating element.

 

diamond is another way to go as it has an extremely high melting(sublimation) point and very high heat conduction properties but as of yet, is still pretty expensive to manufacture in tube form.

Front car windscreens have ultra thin wires in them ? I know back windows do have small cables running throught them.

fronts don`t afaik!?

they tend to rely upon the air vents inside the car directed at them to de-frost/fog.

never seen wires in a front window. always vents and the use of a cloth to keep it clear for me.

no i did not think they did either . I have been looking into these ultra thin cables on google , can they really be thin enough that they are not visible to the nacked eye ! I will carry on looking see if i can find anything

 

Thanks

plus once they heat up to a certian point they will give of enough energy that they will glow

which is why a simple heat exchanger would be better for your purposes.

 

actally, what the hell are your purposes?

well it was for another purpose altogether but then i saw the link for the toaster and fancied one of them myself you cant buy them yet and i probably would rather make my own one anyway !

ok, the toaster idea. lets go with that.

 

You could wait for the heat to transfer up the glass which would be a bit slow and the gradient would cause the bottom to be black and the top to be white.

 

OR you could have the mini wires which is bound to be hard to make or you can have a clear oil running through the glass (means the glass has to be kind of thick but not too thick) which will give an even heating and can still get high temps. its also REALLY easy to make. and won't burn out as easily as i suspect the tiny wire version would.

yeh , im asuming the thin wires would burn out once enough power is put through it to toas bread . Therefore you would need a lot of wiring and therefore once it glows it wouldnt really be transparent. So yeh some sort of liquid that can be heated enough , the glass wouldnt need to be thick would be toughend glass and heat resistant on the users side. This would need to be really hot fluid!

For the toaster you could just blow heated air at/past the bread. That would keep the elements hidden and you could use glass baffles for the air.

yeh but that hot air would blow out of the toater wouldnt it ? It would need to be a sealed unit otherwise you would have hot air blowing out

 

CHeers

Front car windscreens have ultra thin wires in them ? I know back windows do have small cables running throught them.

 

Modern fords (for about 5 years) higher spec ones have had ultra thin ones that are bearly visable.

 

Let me find a link....

 

ok so fords site is being slow but look for "heated windscreen" on ford models in the UK...

 

 

||edit:

http://www.ford.co.uk/ns7/mondeo/mdo_0504_body/mdo_0504_body_st220/-/-/-/-

 

Have a look at "quickclear"

where do you get these wires from ? but surely when they are heating they release light energy :S ?

Front windscreen heating elements do exist. My dad had the Ford Mondeo for many years and you could see them if you looked closely. They're significantly thinner than the standard heating elements on rear windscreen and you could probably miss, especially if you weren't expecting it.

 

Just do a google search for ultra thing wires or go to an electrical supplier and see the finest wire they sell.

 

It doesn't release energy as visible light. It will emit IR, and if you passed a very high current through it could glow red. However the currents are nowhere near that high, consequently only IR light will be given off. Just like most warm bodies.

yeh but a lot of heat is required to cook toast but i spose if you coiled the wire a lot maybe that would work ?

how about Halogen? or even gas-plasma like a photo-flash tube?

 

if you break it down, heat has 3 modes, Convection, Conduction and Radiation.

I`m assuming that you`re after the radition type since the the thing has to be transparent.

yeh also the heat has to be equally dispersd , a halgoen bulb would be placed in the main part of the unit at the bottom and would burn the toast at the botton and not cook the top ?

You don't even need it coiled, the real life examples usually the wire is almost straight but with a very slight squiggle (a sinusoidal curve with a very low amplitude - how do you say that simply?!).

 

The main thing you would be relying on is the conduction, surely. Most of the IR radiation will not pass through much of the glass. The wires heat up because of their resistance and the warm wire, via conduction, heats the surrounding glass.

 

Now we all know that glass in not a very good thermal conductor, which is why the wires are very close. About 5mm between them. That is quite close, but remember these wires are so fine that you have to look very closely just to see them, so it does not effect the transparency in any significant (to the human eye) way.