Designing heat sinks

Have any of you designed your own heatsinks and if so what method do you use?

I am currently planning a large COB grow with 50W "driverless" COBs. I am most likely going to do 3 per fixture, with 4 fixtures total. Each one will have 2 "full spectrum"(aka Blurple) grow cobs, and 1 "cold white"(6000-6500K).

My current plan is to create some copper plates that I will attach the COBs to, but beyond that I do not have an absolute plan. I am thinking I will probably solder those plates to a larger aluminum structure of some kind, but I am not sure what type of solder will give me the best heat transfer. I'm also not really sure how much cooling I need per 150W fixture, but I want to err on the side of excess. I have been scrapping metal for at least a decade on a serious level so I have PLENTY of metal to work with. I just need to figure out how to best utilize it. I will probably be running surplus 80mm PC fans for the active cooling since I have literally hundreds of them. Not sure how overboard to go on that though.

Suggestions would be appreciated. Pictures of your own solutions would also be really great!

hi Klompen, i think a cpu heatsink for cob is sufficient, complete cpu heatsink is all you need.

one like this for 50w cob is perfect and no need more metal working

I have gazillions of CPU heatsinks. I've encountered too many people who have had these particular COBs burn out using such. I want to go pretty overboard.

Klompen said:

I have gazillions of CPU heatsinks. I've encountered too many people who have had these particular COBs burn out using such. I want to go pretty overboard.

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i know, i read you post.
I read that you have a lot of heatsink cpu, that's why I said. it is better to use a large passive heatsink and make it active by adding fans. if a cpucooler is not enough I do not see alternatives

I'm going to build an oversized heat sink. I think basically what I am planning to do right now is put 3 cobs on each fixture(2 purple and 1 daylight). My current plan is to mount them on copper plates that are silver soldered to a large aluminum heatsink structure with fans mounted on it. I might eventually consider water cooling since these COBs are capable of being waterproofed and used in wet environments. The COBs themselves are sealed in silicone and I can seal the leads too.