diy heatsink

is there any way to make a cheap heatsink out of houshold itemes, like maybe nickels glued together or something like that :-?

You could grab a whole bunch of washers, drill every one of them to the size you want, and then glue them together with thermal epoxy. Although I don't know if that would make a good heatsink, it's something that just popped in my head. ;D

thats a good idea, tho i dont have any thermal epoxy, is that special to heat sinking (im guessing it is bc of the name) but would hot glue or super glue work? are there like metal particals suspend in thermal epoxy?

clwatkins10 said:

thats a good idea, tho i dont have any thermal epoxy, is that special to heat sinking (im guessing it is bc of the name) but would hot glue or super glue work? are there like metal particals suspend in thermal epoxy?

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Thermal epoxy is supposed to favor heat transfer.
You can also take a CPU heatsink and drill a hole through it.Or a heatsink from some other devices/appliances.Or an aluminum block.

Would you coat the inside with the thermal epoxy too, or just the use it on the surface of the washers to bind them together?

iewed said:

Would you coat the inside with the thermal epoxy too, or just the use it on the surface of the washers to bind them together?

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If you had them nicely drilled there's no need for epoxy inside the new "heatsink", but if they don't fit perfectly aroung your module , it's probably gonna help.

Yeah, it's better to have whatever you're putting in the heatsink fit tight and not have to use the thermal epoxy. You only need to use the thermal epoxy when you glue the washers together, and like switch said, only use it in case the module doesn't have a tight fit.

hmm, where could u get thermal epoxy, a hardware store?

oh, and what size do you think the washers would have to be, like diameter wise

If thermal epoxy is what I think it is, thermal paste, then you should be able to obtain it at most computer stores. And I would assume that the diameter of the washers should be the same or 1-2mm larger than the diameter of the Aixiz housing.

As with most things, the answer to your questions is: it depends.

First, thermal paste is always a good idea - there will be small spaces between even flat washers (or coins). The paste fills even the tiniest of gaps and improves heat conduction significantly.

The sizes of washers or coins you need depend on the housing you have. When I made my
Liberty Torch all I did was fill the space inside the flashlight reflector - a parabolic space. So I used several sizes of washer, until I got to the big end... and for the "face" I drilled out a $1 coin (not an easy task, they're hard).

I didn't need to size most of the washers' holes for the Aixiz module though - because I didn't use the back part of the module. I only used about 1/8" of the threaded part, as a nut, to hold the front of the module to the big coin. So only the washer closest to the coin needed to have the right-sized hole.

Every layer is slathered liberally with thermal paste as the next washer is added, including the holes. The washers and coin are tight in there so there are no unnecessary gaps; but there's a lot of space filled with the thermal gunk too.

There is an advantage to this kind of heat sink: it sinks more heat! That is, it has a higher thermal mass and so absorbs more heat than a block of aluminum. But - the pieces don't conduct heat as well... so the thermal paste is useful, because it increases thermal conductivity on the surfaces (by way of increasing the surface area used). A large aluminum block holds a lot of heat too, just not as much - and depends for its effectiveness on radiating heat more than sinking it.

A heavier metal heatsink will take a lot longer to heat up than an aluminum one - but it will also take a lot longer to cool! The Liberty Torch runs at about 275mA for several minutes without heating appreciably; but if it did get hot I'd have to give it a significant rest to cool down.

BTW, thermal epoxy is different from thermal paste. The former is a glue, sets hard; the latter isn't.


DanQ

If I don't own a drill, could I go to a Lowes and have them drill a hole in the washers, then slather the epoxy over all the washers, slide the Aixiz housing in while the epoxy is still wet, wipe of the excess, and then let it harden?
Also, what would be a good diameter for the washers, 10cm?

You could always gather a bunch of pre-1982 pennies, melt them down into an ingot, take it to a scrap metal dealer, and take the money earned to buy a nice heatsink ;D

iewed said:

If I don't own a drill, could I go to a Lowes and have them drill a hole in the washers, then slather the epoxy over all the washers, slide the Aixiz housing in while the epoxy is still wet, wipe of the excess, and then let it harden?
Also, what would be a good diameter for the washers, 10cm?

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You could do whatever you want to get the right size - it's easier to go find washers that fit without drilling though. The right size is: whatever fits the hardware you have. I guess I really don't understand why this is a question...

I've never bought washers before for anything, I've seen them used at school before, but I wasn't sure how many variations they came in.

iewed said:

I've never bought washers before for anything, I've seen them used at school before, but I wasn't sure how many variations they came in.

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Ahh, now I understand... What I would do - this is what I often do for things like this - is: take the housing down to the hardware store, and just compare it to different washers until I find what fits (you could also measure the module, and then look up the washer sizes, or measure each size of washer). Sometimes smaller hardware stores have things like washers loose in bins or drawers, so you can pick them up and do a real fit... often the larger chain stores just have them in plastic packaging and you can't handle them individually. In many stores, especially the independents, the workers will help you find what you need if you explain it to them.

So if I didn't have a lot of different sizes here at home, I'd go down to the local store with the Aixiz module and the DX flashlight head that I'm using; and then just start fitting washers. I'd probably start with a big one for the outermost; then a small one for the innermost; then different sizes for the in-between space. Because it's a parabolic space there will be some places where there isn't a perfect fitting washer; in those places I'd need to use the closest fit, probably a duplicate of the previous smaller one.

I hope this was more helpful than my last answer!

DanQ