Author Topic: cheap heat sinks (Read 6330 times)

Ding123 · « **on:** February 01, 2006, 01:12:17 AM »

I was looking to purchase a heat sink . I called around, found one 4" x 4" , they wanted $40.00 for it. SHE heard me on the phone, and gave me that funny look...that look that means " NO !!!" So...from now until summer.....I am using the head off the lawn mower. I figured , if it kept the lawn mower cool , it will keep a couple of rectifiers cool..So, just remember...before you throw the ol' gas mower away or power saw....keep the head!

Ding123

FrankG · « **Reply #1 on:** January 31, 2006, 06:24:23 PM »

that's clever...

DanB · « **Reply #2 on:** January 31, 2006, 06:48:27 PM »

yes - not a bad way to go. I've got two dead onans here (4 heat sinks) - we've used one so far.

windstuffnow · « **Reply #3 on:** January 31, 2006, 08:51:34 PM »

I've used a old aluminum air compressor head as well, not as beefy as a gas engine head, they work very well. You can usually find some good scrap aluminum plates at the bone yard fairly cheap... aluminum pipe or just about anything you can find with some surface area. Lots of things that get discarded make nice heat sinks !

Old gas engines are a dime a dozen and can be found just about everywhere ! Great thinking Ding123 !

.

ghurd · « **Reply #4 on:** January 31, 2006, 09:39:23 PM »

DON'T DO IT !!!

Never ever call around when 'She' is home. 'She' can't give the look if she's not home.

It's OK. Its expected. Might even be a law. They do it to "us"... just to stay within the confines of the law I'm sure.

My 'She' will kill me if she reads this.

G-

hiker · « **Reply #5 on:** January 31, 2006, 10:01:06 PM »

now thats using your head...........

terry5732 · « **Reply #6 on:** January 31, 2006, 10:46:13 PM »

The cast aluminum isn't that great of a heat conductor though. I have some made of 1-1/2" angle aluminum and others are 1/8" sheet cut well oversize for large suface area. Large copper plumbing would probably be even better. Or old copper kettles, or .....

Chagrin · « **Reply #7 on:** January 31, 2006, 10:51:31 PM »

Cast aluminum is not too bad. Maybe only 2/3rds as good as copper, but still acceptable.

wildbill hickup · « **Reply #8 on:** February 01, 2006, 02:50:00 AM »

What about old extruded storm window frames(talk about a dime a dozen) ? Cut to length you want, if you need to bolt 2 or 3 short pieces side-by-side. Not sure if extruded alum is better than cast or why.

amiklic1 · « **Reply #9 on:** February 01, 2006, 06:38:45 AM »

I am using computer processor heatsink. It has huge area of heating, and is just enough for two rectifiers if cut to two equal pieces. So, one processor heatsing for four rectifiers. Processors are geting really hot in work, and if thermal conductive paste is used, it works great. Just put it inside the box, so that cooling "plates" are on the outside (need some cutting, of course), and the rectifiers stay inside, and tht's it. And it's cheap, also.

Shadow · « **Reply #10 on:** February 01, 2006, 07:11:25 AM »

I've cut up running boards off a vehicle for heat sincs.Seems to work.

RayW · « **Reply #11 on:** February 01, 2006, 07:50:23 AM »

Check with a tv repair shop, many of the large screen tv's have large heatsinks in them and they are often thrown out with bad circuit boards.

RayW

Ding123 · « **Reply #12 on:** February 01, 2006, 08:16:05 AM »

Glad to hear you can use all these different materials for heat sinks.SHE read these comments as well! She told me to stay away from the aluminum door and the running boards on the truck! But, it is good to hear that you can use other things for heat sinks...Thanks

ding123

BigBreaker · « **Reply #13 on:** February 01, 2006, 08:27:36 AM »

Casting your own heatsink is practical and cheaper if you need something really big. Check out backyardcasting.com for help on doing it.

electronbaby · « **Reply #14 on:** February 01, 2006, 09:11:23 AM »

ive used 4" wide aluminum channel ive had laying around. I bolted it back to back. this seems to work good for large heat sinks.

This is a large 3 phase rectifier im using for a 16' diameter machine. it has 6 200A diodes. Barely gets warm @ 200A output @ 24vdc.

RoyR

KB2UHF

Jerry · « **Reply #15 on:** February 01, 2006, 10:10:30 AM »

Stop by the local car stereo shop and ask for an old dead car amp.

These are made for the job. I use an old amp heat sink in my e-car to keep my Curtice speed control cool.

JK TAS Jerry

terry5732 · « **Reply #16 on:** February 01, 2006, 01:54:07 PM »

And don't forget the housings of those burnt out cheapy inverters.

BT Humble · « **Reply #17 on:** February 01, 2006, 02:45:41 PM »

I showed this thread to my wife, and she said:

"Their fear is so cute!" ;-)

BTH

tecker · « **Reply #18 on:** February 01, 2006, 03:15:04 PM »

You can get a p1 heatsink for almost nothing.

jackforeman · « **Reply #19 on:** February 01, 2006, 03:29:27 PM »

Good idea, could you also canibalize broken air conditioners (assuming the freon is already removed)? I always see alot of them thrown out in the fall when people are done using them

vawtman · « **Reply #20 on:** February 01, 2006, 03:38:18 PM »

How about a baseboard heater.

Drives · « **Reply #21 on:** February 01, 2006, 05:38:16 PM »

I agree Copper is one of the best heatsink materials, but Aluminum is the most common.

If you examine a quality "power" heatsink, you will find a number of important aspects. Mass and total surface area being of great importance. Therefore, the bigger the heatsink the better.

One of the overlooked characteristics is the mating surface of the power module (diodes, or bridge in this case) to the heatsink. An expensive heatsink will have a mounting surface that is precisely machined, and in extreme cases even polished to a mirror finish.

So if you want to ensure you get the best thermal transfer, make sure your heatsink surface is perfectly flat & clean (deburr any mounting holes), and use a good quality heatsink compound. Noalox will work in a pinch, but it is runny.

Speaking of applying heatsink compound, too much is as bad as too little. First, apply a paper thin layer of compound on BOTH the heatsink and the power module. Second, push the module onto the heatsink, and give it a little twist back and forth. Third, remove the module, it should be very hard to pry off the heatsink. Fourth, examine the thermal compound pattern, if it appears to be lacking adhesion in places, apply a little more to those areas. Finally, mount the module with your hardware. If 4 screws are being used, then tighten in a star pattern.

Hope this is of interest.

nothing to lose · « **Reply #22 on:** February 03, 2006, 03:46:17 AM »

Both aluminum and copper work well, a combination of both is best. But are we really talking about extreme heat in a small area like a Computer CPU??? Probably not but we still need good cooling anyway of course.

Some heat sinks for Computers have either a copper bottom or a round solid copper rod up the center. The theory is suposedly copper will suck the heat off the tiny CPU chip faster than aluminum and then the copper spreads that heat out over a larger area fast. Aluminum is then used to suck the heat out of that larger area of copper and release it to the air with a large surface area. Copper collects heat faster than aluminum but aluminum releases heat faster than copper.

The two react to each other and can corrode, funny how so many things use them both in contact like that though. Base board water heating (copper tube aluminum fins), some cookware, Cpu heatsinks, etc...

wpowokal · « **Reply #23 on:** February 03, 2006, 12:27:33 PM »

Gee don't know if Im more jellous of the diodes or potential 200 amps.

allan down under

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Author Topic: cheap heat sinks (Read 6330 times)