Flat power resistor

[senso]

Good morning, looking for another component, this time I'm on the look for flat power resistors, the idea is to make a big heated plate to remove broken digitizers from tablets and laptops, my idea was to use the typical cylindrical power resistor that have a built in heat-sink(photo attached in the end).

But given that the aluminium slab will have around 30x40cm those would be too localized I think, so I tried to find some nice big planar power resistor, like the ones that are used in this type of hot plate:
http://www.aliexpress.com/item/free-shipping-high-quality-LCD-separator-Machine-Hot-Plate-for-Screen-Glass-Repair-iPhone-5-Galaxy/1278138825.html

I have one and the resistors are two rectangular pieces, each half the size of the heat-plate, but I can't find anything as big as those at Mouser/Digikey/Farnell.

Any ideas where to find big power resistors, the total heating power needs to be around 1-1.5kW for fast heating, the max temperature needed is just 80ºC.

[PA0PBZ]

 

[Cliff Matthews]

Remove handles, clamp on a thick sheet of aluminum, and you're in business with a 10amp Variac (adjustable auto-transformer).
Use a thermal probe to find Variac's sweet spot for it. It's a nice piece of kit for any bench..

[matseng]

Planar resistors then?   

http://www.newark.com/webapp/wcs/stores/servlet/Search?st=planar+resistors&catalogId=15003&categoryId=800000059511&langId=-1&storeId=10194

[Cliff Matthews]

Those planar resistors are expensive! (almost as much as the unit specified). I suppose if one does a lot of this type of repair, that unit is worth it then.. Along-side all the micro tools, molybdenum cutting wire and special pastes, it's not too pricey.

[tszaboo]

A reel of 1206 is like 6 eur, and a two sided PCB this size must be cheap at the local manufacturers. Bonus if you integrate the temperature controller in the middle. Get an intern to solder it.

[zapta]

What's your target temperature?      Is it to desolder or just to loose glue?

[mikerj]

Maybe a contact grill element would be useable?

[N2IXK]

Remove handles, clamp on a thick sheet of aluminum, and you're in business with a 10amp Variac (adjustable auto-transformer).
Use a thermal probe to find Variac's sweet spot for it. It's a nice piece of kit for any bench..

Since it is a pure resistive load, a simple (and cheap!) incandescent lamp dimmer is all you need to control that thing.  No need for a big expensive variac to do it.

[Cliff Matthews]

No need for a big expensive variac to do it.

True, but I'll take the Variac since it can be used on a thousand other issues 

[electr_peter]

If low temp is enough, search for "car/bus/truck mirror heater".

[firehopper]

what about heated beds for 3d printers?

[Cliff Matthews]

..given that the aluminium slab will have around 30x40cm those would be too localized I think

Thick aluminum spreads heat evenly. Spread out 6 pasted 50-ohm 50-watt resistors wired in series with thermal sensing at the center and it should be quick enough at both 120 and 240v. I still think a flat pan is best on $$... You've just got to control the temp, have fun!