LEDs work for interior lighting but not heat.
Some people have used outdoor light ropes and outdoor christmas lights LOL to actually GREAT effect. Always use outdoor rated lights when you can in a humid environment. Many puck lights are outdoor rated because of the humidity in the kitchen.
I'm using flexwatt heat tape in one bator but it's much smaller than DARTHbator.
Tinker with simple things - later tinker with whatever floats your boat. Some people use curling iron insides. The choices are actually endless.
Now the strict purists say buy the heating element MADE for bators and the thermostats made for bators, and for simplicity's sake - you can absolutely recreate the wheel as it has already been done and voila it works.
<shrug> What fun is there in that? The cost can be prohibitive if you don't have several $20's to throw at the construction. And you actually CAN make a perfectly working bator for a lot less than the cost of those things.
Yeah, you might have to (gasp) tinker, and learn, and fiddle, and moan a bit. But you actually figure out what works and WHY, and how to fix it. Experience that is, to my mind, invaluable.
I'm hoping to work on my fourth and fifth bators over the summer, and to rework Darth some just because I can... I gave the first one to a friend. I won't give away the wine cooler bator because it is an AWESOME size for a small hospital incubator, for when broodies go wrong or a hatchling needs help.
Darth is good for incubating beside the computer. And the new antique redwood one is ........ appealing as heck and coming indoors once I finish refinishing it. (huge grin)
It holds 600 eggs I'm told, a fact that nearly got me killed. LOL. But I only plan on using three trays at a time.
Chuckle.
I'd rather fiddle with learning things than do it as it has been done before. And if you can keep within a tight budget and make a working bator I think that's the ultimate in good common sense.