Instructables
Picture of PCB Heater (Diy Joule heating)
Resistance Heater.png
I found a website whilst searching online which documented some experiments done with printed circuit boards with a serpentine pattern etched onto them, To use them as a heater.

Uses for a heater like this could be:
• To submerge in a liquid & heat it.
• Coffee Cup warmer
• Possible heat bed for a 3D Printer ?


It is resistance heating in its simplest form, Its essentially the same as putting a high current through a resistor, The resistor would heat up. This is doing the same but on a larger scale, on a Printed Circuit Board.

*I do apoligise for the bad pictures*
 
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Step 1: Design of the Board

Picture of Design of the Board
Firstly I looked on the internet to see if there were any available Vector format images of a serpentine pattern, But I was unable to find one. I quickly designed one in Eagle
(A design program to design printed circuit boards & schematics)
It’s a simple pattern with a trace in a serpentine pattern, which would provide resistance. Once a current is applied to this, it will heat up.
I have included the Eagle files below, for those of you who don’t have eagle on your computer I have supplied a picture in .PNG format.
yaly1 month ago
I need to make a 50 cm x 50 cm version of this, any suggestions how to do it ?

Hi guys , can some one tell me if I can use this to make a 40 x 40 heatbed ?

if so what should be the thickness of the copper? if I buy copper sheets and place them on a mica sheet or some other material that is suitable will that work?

that way I can directly make my glass a heatbed

looking forward to ur reply :)

Jim Jose (jimjose99@gmail.com)

nodoubtman9 months ago

After the iron,under the copper it's all black, is it possible that my
iron is too hot, the iron settings is before steam. What do you suggest?
thank you!|

redwolf00766610 months ago
concerning the power supply. can this be done by a simple AA battery or batteries?thanks
waldosan2 years ago
you need to put a potentiometer in series with this, it'll allow you to limit the amount of current going through it, i think you'll find also that dc power supplies will work better than ac, just on principle and what not.

hooking it up to a car battery though will set fire to something, prototype boards aren't supposed to be able to catch on fire but then hydrogen peroxide and chlorine isn't supposed to glow.

it seems though like a solid concept, i'm sure you've heard of peltier devices (hot on one side, cold on the other) but this seems more like it'd function better as a space heater!
stephenniall (author)  waldosan2 years ago
I intend on building a LM317 Adjustable current regulator to regulate the current that flows through, I've been using DC Power supplies, All the devices i've used are DC, They transfer the power from the Mains sockets (240V AC) to the voltages in DC, Via transformers.

Thanks for your comment !

Also, you might not want to control current through the thing with a linear regulator; it also will express a lot of heat and fail quickly if it's not rated. Pulse Width Modulation or duty cycle modulation (sometimes used to describe a slower frequency of PWM) will be an effective method of controlling the heat output of the thing. Basically, it should be ON or OFF at any point in time; the ratio of ON to OFF is what controls the heat output. If you do choose to use the LM317, select one that can take 1.5 amps and shed 5W of power; my calculations say max. current with a mimimum of 1.25V output would be about 1.34A, and max. power would be about 4.75W. I think PWM control would be sexier; just a PWM-controlled fixed-frequency oscillator switching a power MOSFET and that part of the system would run cool.

unless your getting your mains from a dryer plug your voltage should be 120ish though i could be wrong about that if your living in Europe or something like that, the lm317 is a variable voltage regulator rated for one amp so if you try to use it as an amperage regulator you'll just fry it, actually you won't even do that, it has built in safety features so it just wouldn't work. dc power supplies, like car batteries and wall warts, are rated for certain amp levels usually this is below the amount of amps you'd be pulling if you'd shorted out the leads, in batteries this means they get very hot and might burst if your not careful, in wall warts this means that they make a funny buzzing noise and depending on how much your trying to pull they can catch on fire!

it's a great idea you got here, i'm thinking more and more about using it as a heating pad for a 3-d printer or something like that.
stephenniall (author)  waldosan2 years ago
We're using an ACCOUNT to DC wall adaptor, which changes our UK 240Vac plugs and converts it to the voltage the lm317 takes, the lm317 will be on its on circuit board with a big heat sink for best heat distri ution.

stephenniall (author)  stephenniall2 years ago
AC* sorry, autocorrect. Seems to change everything I type.
stephenniall (author)  waldosan2 years ago
We're using an ACCOUNT to DC wall adaptor, which changes our UK 240Vac plugs and converts it to the voltage the lm317 takes, the lm317 will be on its on circuit board with a big heat sink for best heat distri ution.

Bad idea, as the potentiometer potentially will overheat quickly, heat unevenly, and fail quickly. It would be best to use PWM to control its power. Keep in mind, there do exist pots that are rated for high-power use, but they are expensive and bulky, and still produce waste heat.

PocketBrain11 months ago

Your etching looks really clean, good work. I am thinking about using this kind of element to heat my 3D printer's build plate. Of course, it will require a good PWM controller. ;-) I have also thought of using this type of heater to warm the etchant solution when doing my own board etches; warm, agitated etchant works quickly and more efficiently. Thanks for the Instructable!

Roshy101 year ago
you could use it to heat a pcb etching tank/tray, but you would need plenty of lacquer to stop it etching its self
DIY-Guy1 year ago
Stephenniall: Nice work.
This could be a nice little small batch yogurt incubator, or a seedling germinator with moisture protection. Perhaps one of the high temp plastic films could be bonded to the surface, mabe Kapton?
eefmf2 years ago
Very Interesting.
What is the resistance of the board?
What voltage and current did you use?
stephenniall (author)  eefmf2 years ago
It says above, the boards resistance is 8ohms. But increases with heat, I've been using 12vdc at 16amps
Do you know the width, thickness and length of the track?
There is a website that gives current capacity= htp://pcbinfo.blogspot.co.uk/2005/04/current-carrying-capacity-of-tracks.html

12vDC at 16 amps gives 0.75ohms and 192watts.
Dont run that out of liquid or it will melt the copper.
If it is 8ohms 16volts would give 2amps and 32watts.

Another problem is that copper corrodes in liquid.
stephenniall (author)  eefmf2 years ago
No, Will measure them with a set of calipers tomorrow. It has been fine so far.

I was thinking of trying a simple electroplating & Electroplating it with tin to see what happens. Its all still in the 'thinking' stage yet.
Nice Instructable. There is a company that makes a similar device on flexible circuit boards for use in video & film cameras. They are used to keep the batteries warm & the lenses from fogging up. It would be interesting to see if double sided boards would work better or if the heat would be too much for the substrate...just a thought.
stephenniall (author)  Lectric Wizard2 years ago
Haven't thought about using it with double sided boards, It might be something i'll look into.
if that is standard fiberglass board, it should handle the heat just fine. Probably work better for heating two different things, rather than trying to soak the heat from the secondary through the board to the primary surface.
Well, I should amend that a bit. as long as your heat levels are below 220F(104C) you should be OK. over that temperature, you run the risk of melting the epoxy that binds the fiberglass together.
nadav2 years ago
I would change the design to be a large spiral (like on an electric stove top). Because, right now, the heat will cause stress on the 90 degree bends on the PCB.

Also, the corners (90 degree turns) would heat more then the straight sections, so having a spiral layout, would give you a much more evenly heated surface.

Still though, its an interesting project, it definitely gets me thinking what it could be used for.

Cheers,
Nadav
stephenniall (author)  nadav2 years ago
That will be in my second version, I will use bended corners in my straight sections aswell in future revisions.
Why would DC cause the bends to heat more than the straight runs ?? I can see high freq doing that but DC ?
rimar20002 years ago
Very interesting.