ultra low shop skill custom heat sink idea - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: December 23, 2018, 05:23:16 pm
content: I had an idea for a ultra low shop skill heat sink design.You can take copper sheet, cut it into strips, then make a metal flower (with metal bases) that overlap. If you heat the whole thing up with a torch and seal it with solder (preferably silver bearing) it should make a structure with alot of fins and a solid base. You would only need a torch, snips, copper sheet and solder to do this.When its done you can take a piece of sand paper, lay it on glass, and sand the base down to very high flatness if you use alot of different sand papers. Glass will be flat to 20 micrometers IIRC.https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ_Lk4TwUEUW8lxpbbcjxXHDOrhjKJ0c0jlLpuHv3dokTVxGKCYIf you drill some holes in it and stuff it might actually perform decent and be a very good option for prototyping. You might need an oxy acetylene torch if you want to use high silver solder (56%).

author: Nominal Animal
author_rank: Super Contributor
timestamp: December 23, 2018, 08:00:12 pm
content: Wouldn't mixing narrow and wide strips, to get a laminate with the traditional fin structure, work also?Wait. I think the copper sheet is actually more expensive than a chunk of copper, or even a ready-made heatsink.(Right now, I'm looking into getting someone to mill existing CPU heatsinks, like Arctic Alpine M1s, to fit my Odroid C1+ and other SBCs for better passive/convection cooling.)

author: soldar
author_rank: Super Contributor
timestamp: December 23, 2018, 08:29:05 pm
content: Not the most efficient heat sink nor the cheapest but I guess it is artistic if you want to place it where it can be seen.

author: coppercone2
author_rank: Super Contributor
timestamp: December 24, 2018, 02:01:58 am
content: but you can make a custom base size for anything you want. The flower is an exaduration, I more imagined it like a upwards bent matrix of concentric cube walls . yea i imagined the strips being mixed in size too. you can easily mount a suction fan on top. i said flower because its a new way of thinking about it in terms of bending leaves and bonding them together.the idea is that you can buy some copper sheeting and be good for heat sinks if you normally get slowed down on finding one that fits your circuit nicely and is the correct size. for fast medium power prototyping. Lots of old power components to play with taken from stuff but if you decide to make weird power circuits that are also layout sensitive like cascodes, amplifiers, h-bridges, etc from old power electronics salvage you can get into problems with heat sinks.you can also make them differently for active cooling by just making fins out of individual sheets that are silver soldered together.with a guillotine or some big sheers you can probably crank these out real quick out of a roll. Otherwise you need to mod existing heat sinks with a band saw or use copper blocks etc.just careful drilling copper because it might stick to the drill and cut you up.

author: Nominal Animal
author_rank: Super Contributor
timestamp: December 24, 2018, 02:27:25 am
content: If you happen to have access to copper sheet cutoffs or such, it sounds like an interesting approach.How would you clean the flux residue after silver soldering it? Would you? I don't think it matters much for thermal properties, but it might be pretty ugly without cleaning.

author: coppercone2
author_rank: Super Contributor
timestamp: December 24, 2018, 03:17:07 am
content: boil it in a pot for a whilea paper guillotine will do it if its a decent one, or tin snips (long ones make it fast).you can flatten it with a heavy roller or even possibly a wooden dough roller, more so if you throw it into a fire and into a pot of cold water afterwards. you can clean it with stainless steel wool (like those for pots and pans)

author: james_s
author_rank: Super Contributor
timestamp: December 24, 2018, 05:47:05 am
content: Copper is expensive, aluminum is much cheaper and premade heatsinks are readily available. You can even buy extruded stock and cut to size with a bandsaw or even a hacksaw if you're patient.

author: coppercone2
author_rank: Super Contributor
timestamp: December 24, 2018, 05:56:47 am
content: where is your 90's fashion sense?What is a good commercial design that is well suited for trimming in both directions? I think a over-sized aluminum 'pole' style one would be good, the one that looks like the reactor from the movie Total Recall. The one that looks like a grid of machine pins sticking out of a plate.I am not sure I like the idea of trimming the ones with fins.one like this maybe since it would cut nicely in both directions and you can debur it pretty easily.https://i.pinimg.com/originals/fe/a7/ac/fea7accd8dddcb8ea3cb0bed89e7744a.jpgbut in a square. If you can buy a big one thats like 6x6 inches then it could be good for prototyping and cutting.if you do make one out of little strips I wonder if a agave plant shape would be a good design. or aloeyou could make it out of aluminum strips too, if you can figure out how to solder them good. IMO it will be a complete mess to try to solder that, I am not going to even try. Maybe if you dip it in hydrochloric acid, vacuum evaporate it and vacuum braze it, I don't think you will be doing that process with low shop skills though.