Kapton Heater / Polymide Heating Element

[68Stratocaster]

Hey there everyone...

First of all for those who don't know what a kapton heater is,
its a polyimide (KaptonTM) insulated etched foil heater. Basically looks like a etched resistor sandwiched between kapton film.

Kapton Heater

That being said its not easily available, let alone in Australia and its really expensive if buying from overseas with shipping and all.

But i did find something similar and its perfect

http://www.herpshop.com.au/pictures/hs_MultiHeat_0.jpg

HW320 320mm wide 70 watts per metre

LW320 320mm wide 35 watts per metre

HW090 90mm wide 20 watts per metre

As you see in that picture i want to use 4 inches (length) of the heating element, power it with batteries to reach 35°C for a few seconds, is that possible?

If not i was thinking of making my own using nichrome wire sandwiched between kapton tape, how would i go on about doing this?

This post may seem stupid and very newbie like, but I have an idea in my head that's been bugging me for weeks and i know no ones ever done it before so i might aswell give it a go even though im not very good with electronics.

Any help will be appreciated.

Thanks

 

[Resqueline]

HW320; 320mm wide, 70 W/m = 7 W/dm = 219 W/m2
LW320; 320mm wide, 35 W/m = 3.5 W/dm = 109 W/m2
HW090; 90mm wide, 20 W/m = 2 W/dm = 222 W/m2

Those power levels (2-7W) & the time (seconds) mentioned is no problem for any battery technology.
The questions however are;
1: do you need any kind of temperature accuracy?
2: is the foil to be mounted on something or in air/ insulated?
3: is it the foil or rather an object that needs to reach this temperature?
4: is it important to reach this temperature quickly (and then stay there)?
5: what voltage are those panels made for?

 

[68Stratocaster]

1: do you need any kind of temperature accuracy?

No not really as long as it stays between 30C to 40C

2: is the foil to be mounted on something or in air/ insulated?

It will be covered by paper/ insulated and mounted behind paper.

3: is it the foil or rather an object that needs to reach this temperature?

Yep the paper does but only for a few seconds as i will be using a switch to turn it on and off.

4: is it important to reach this temperature quickly (and then stay there)?

Yes it needs to heat up with in 10 seconds but no it doesn't need to stay there. Im hoping itll heat up the object to the desired temperature and when it does ill just turn it off.

5: what voltage are those panels made for?

Well that's what i was wondering about, if it was possible or not. For that heating panels actual use it would plug into a power outlet (220V-240V) and controlled by a thermostat.

Heating element link
It says that "The heating element can be cut to any length (through the clear bars) but not the width"
I would only use about 6-8 inches in total.

 

[Resqueline]

Ok. I don't see how you'll determine the paper temperature but the manual control & the rest sounds ok. The only challenge is the voltage. You'll need an inverter circuit.
Do you have any design limitations/spec's on the battery and the inverter circuit?

 

[68Stratocaster]

I have a infrared thermometer gun for the paper. The only specification is that it all has to be thin, i was thinking along the lines of multiple button cell batteries. Cant i simply just connect the heating element to a switch and batteries and when the paper reaches the desired tempreture ill turn it off?

Like i said, im not that good with electronics lol

 

[Resqueline]

The IR control is ok, but you'll have to rethink the battery choice. You have increased the power 50-100% and delivering 4-14W will require a certain mass of batteries.
Without using an inverter you'll need 230V/1.5V = 153 alkaline cells, or 230V/3V = 77 lithium cells. With an inverter you might get away with a 6-pack of alkaline AA cells.

 

[68Stratocaster]

If I made my own heating element using insulated nichrome wire, could i get away with button cell batteries? considering it only has to heat up for a few seconds.

(edit)

would doing something like suggested here work?
Nichrome Heating Element at 37 C

 

[Resqueline]

No, there's a fixed power loss from an area at certain temperature differences, and such small cells are unable to deliver high powers no matter how short the time.