Aluminum Angle

No fins. It's really a "heat conductor", or perhaps just a thick bracket that conveys heat. I don't know what you might call it -- but it's not a device to better match the thermal impedance of a solid with the thermal impedance of the air.

Agreed but 1.5 x 1 adds quite a bit more waste into the equation...

--for some reason, I had 1x1 stuck in my head...

Before deciding on the size, it would be worthwhile to consider the alloy. I may not remember correctly, but I think 1100 would be cheaper and also conduct heat much better. So it might be cheaper and better to use angle with a rounded edge.

Dan

But machining 1100 is more expensive than 6061 or 6063 because it's so soft. Eric

Pretty sure 1100 isn't supplied in extruded shapes excepting for square, round and rectangular.

You mentioned 6063. That's the standard extrustion alloy for heat sinks. Conductivity is around 200 W/m-K in low tempers. For comparison, 1199-O or 1100 is in the neighborhood of 240.

Extrusion dies are so cheap to make these days that extrusion jobbers often accumulate large numbers of them, and offer standard extruded shapes, including simple angles and elaborate finned heat sinks, as off-the-shelf stock items. If you need a lot, you can get quite short runs on a jobbing basis.

Then you just bandsaw them to length. That's standard practice.

The reason dies are so cheap to make is that they're easy wirecut EDM work. They cut the die shape and the taper in one pass.

Last time I bought custom extrusion pretty sure the minimum run was =

2000lbs, but that was at least 10 years ago.

but that was at least 10 years ago.

Most of the custom extruders have no minimum, but of course the setup charge can make really small runs too expensive.

The better deal is to buy one of their stock shapes. I just took a look and saw that several of them offer sharp-cornered angles with

0.250" thick legs. Leg length seems to be 1.5" or more in that thickness.

...

Another possibility at onlinemetals is channel, eg 3" x 1" x 1/8" as at

so one cut gives two pieces of about 1.5" x 1" x 1/8" angle. Cost per pound looks similar (for angle and channel) but reduced waste using channel might lower the cost.

If kerf is 0.1", cutting the 2"x2"x1/4" architectural channel as at

or near middle of would give 2"x0.95x1/4" pieces.

Hey Tim,

I was looking for something else in the shop, and I stumbled across a piece of 3/4 X 3/4 X 1/8 wall about 18" long as you describe, no discernible radii anywhere. You are welcome to it if it is of use.

Available as "WORK-SAVER" line of products, available at a hardware store, but if not....

H. Paulin Co.

12400 Plaza Drive, Unit 1 Parma, OH 44130-1057 Tel: 1-216-433-7633 Fax: 1-216-433-7622

You might look here:

Duncan makes these aluminum extrusions and should be readily available through most lumber yards and box stores.

DanG fired this volley in news:jkn8ui$tm3$1 @speranza.aioe.org:

That was already suggested to him a week ago... no bite. Odd, that, because MD makes a whole line of very standardized extrusions you've been able to buy since the early 1960's with no changes in the line.

Lloyd

You should go to Hadco Metals to see what is/is not standard.

Architectural is sharp-cornered, structural is round-cornered. The heaviest in architectural is 3x3x1/4. If you need 4x4x1/2, AND you need a sharp corner, I don't think a machine shop would charge too much to square the inside/outside corners of structural.

And for what MSC/HD charge, you could get whole lengths from Hadco or other alum suppliers. PSC in PA will cut and ship UPS, nice people.

Btw, 4x4x1/2 is really hefty stuff. I've got 2.5x2.5x1/4 structural, and DATS hefty!!

"Existential Angst" fired this volley in news:4f702a7c$0$6257$ snipped-for-privacy@cv.net:

I have a machine shop, and I needed only 4' of the heavy angle, and the next morning.

Since I live in the boonies, not near any major cities, MSC was the supplier of choice. In truth, they were only about 20% more expensive than most on-line suppliers, once you figure shipping (which was a flat $8.95).

But the OP who asked the question didn't need anything that stout; I was ribbin' him about whether or not 4x4x1/2 would be big enough to heatsink one TO-220 transistor or regulator.

For standard architechtural shapes in small sizes, MD is the way to go.

LLoyd