Best PCB Etching design for a heat plate?

[EasyGoing1]

I want to use some PCB etch board to make a plate that gets a little warm ... maybe 35C at the most.

But, I'm unclear as to the best way to go about this in terms of the layout of the copper.

Would it be better to leave the etch board un etched and just connect the leads on each side like this?



Or would it be better to etch it so that there is a longer path of copper for the charge to follow, like this?

[diif]

Re: Best PCB Etching design for a heat plate?

This has been done several times before and they all use the wavy track design.

[EasyGoing1]

Re: Best PCB Etching design for a heat plate?

This has been done several times before and they all use the wavy track design.

Is that because etching the board in that configuration causes its resistance to increase from end to end?

Edit: Actually, I found this article which I should have Googled in the first place.

Thanks

[diif]

Re: Best PCB Etching design for a heat plate?

This one has a trace calculator. https://hackaday.io/project/181170-reflow-pcb-hotplate

[eccerr0r]

Re: Best PCB Etching design for a heat plate?

Nothing special about PCB heater boards. The trick is where the required placement of the inlet power is - when they are on opposite sides, it's easier; on the same side, it requires some more careful track placement.

Do note while an unetched board will "work" but the resistance would be so low that you'll heat the PSU more than the board not to mention it's tougher to calculate the wattage, as compared to a serpentine etched board.