Abstract: Just thinking out loud. Also please comment if you know any low quantity PCB manufacture (like OSH park or dirty pcbs) that also makes aluminium base PCBs or have any experience with those manufactures.

Star bases are probably not the best way to mount LED to other materials, so I googled about making a PCB for high power LEDs. That led (pun intended) me to eBay where I found out, that there are cheaper and better options than star bases for mounting LEDs to aluminium.

$2.8 for 14 LEDs, for example would be sufficient for my experiments, easier to mount and cheaper than the star bases I bought.

And than there is this board. At $6.50 with shipping, it's more expensive than the star bases but at least it's smaller and easier to mount.

Anyway, I am not sure if I will put only 50 3W LEDs on the LED pcb. It would probably be a good idea to also have 30W of blue LEDs mounted on the PCB with a switch that would switch between the string of blue LEDs or another string of Full spectrum LEDs.

The thing is, that plants need more blue light during there grow stage, and that I think that the full spectrum ones provide too much red light for the growing stage (but enough for the flowering stage).

I searched around for a cheap manufacture of metal core pcbs and found a page on the EEVblog wiki. There are some and I decided to not worry about that too much, but I am not sure if I would even need a meta core PCB, because I looked at a cree application note where it said that it can also be done with just a FR-4 PCB if you transfer the heat to a heat sink. I would need to do some calculation but there is some data missing. Maybe the Chinese seller will help me but I doubt it.

I am planing to go to a university near my high school on Wednesday with a LED and a supply for it, and hopefully get the LED tested with a spectrometer in the light laboratory.