Hammond die cast al case, heat sink?

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solar3000
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Hammond die cast al case, heat sink?

Post by solar3000 » Sat Jan 13, 2018 4:54 pm

I have various Hammond cases.

It says die cast aluminum. But it feels like low grade aluminum. Looks like compressed wood. Well see for yourself and some of you already have ones.

Would it be a good heat sink?

https://www.hammfg.com/electronics/smal ... t/1590.pdf

dyarker
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Re: Hammond die cast al case, heat sink?

Post by dyarker » Sat Jan 13, 2018 6:44 pm

How much heat that can be "sunk" depends on outside surface area of the case. (not counting the area where it sits on the shelf or table)

Without fins the number Watts disappated will seem small for the size of the box.
Dale Y

solar3000
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Re: Hammond die cast al case, heat sink?

Post by solar3000 » Sat Jan 13, 2018 8:12 pm

So, it sounds like you're saying the quality of aluminum is ok compared to the type of aluminum in a typical heat sink.

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jwax
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Re: Hammond die cast al case, heat sink?

Post by jwax » Sun Jan 14, 2018 5:50 am

Better than no heat sink!

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Re: Hammond die cast al case, heat sink?

Post by dyarker » Sun Jan 14, 2018 8:43 am

solar3000 wrote:So, it sounds like you're saying the quality of aluminum is ok compared to the type of aluminum in a typical heat sink.
I have no way to test the thermal conductivity of the aluminum, so ditto jwax. But I doubt Hammond purposely concocted thermo-insulating aluminum to make their boxes. I do believe the limiting factor is the amount of air exposed surface area.

((Out of curiousity - how many Watts, box size, and max ambient temperature to operate in?))
Dale Y

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Re: Hammond die cast al case, heat sink?

Post by solar3000 » Sun Jan 14, 2018 4:20 pm

dyarker wrote:
solar3000 wrote:So, it sounds like you're saying the quality of aluminum is ok compared to the type of aluminum in a typical heat sink.
I have no way to test the thermal conductivity of the aluminum, so ditto jwax. But I doubt Hammond purposely concocted thermo-insulating aluminum to make their boxes. I do believe the limiting factor is the amount of air exposed surface area.

((Out of curiousity - how many Watts, box size, and max ambient temperature to operate in?))

the pdf in the original post is what I have.

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Re: Hammond die cast al case, heat sink?

Post by dyarker » Mon Jan 15, 2018 4:52 am

The pdf linked to in the original post is the spec sheet for all the cases in the model series. (as in many sizes)

There is no way to tell if a box (unknown) will be a good enough heatsink for a particular project without more info.
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haklesup
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Re: Hammond die cast al case, heat sink?

Post by haklesup » Mon Jan 15, 2018 11:53 am

The difference in surface appearance is probably from the casting process which takes up imperfections and texture of the mold surface. if you are comparing to extruded aluminum or machined aluminum then that surface will be smoother and brighter and have less dark oxides from cooling. Sand with 220, 400, 800, 1600 and you'll be able to brighten it up. Scratch it and you'd find bright Al underneath. Its thermal conductivity should match that of any Al with minor variation for alloys. Thermal resistance depends on a lot of other construction factors but I'm sure you can dump at least 5W into a box like that and maintain low device case temp.

Casting is the best way to make a 5 sided box. with extruding you can have 4 sides max requiring removable 2 to 4 sides made of flat panels. Both methods usually require small machining touch up to remove flash or thread holes or cut extrusions

solar3000
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Re: Hammond die cast al case, heat sink?

Post by solar3000 » Thu Jan 18, 2018 7:43 pm

thanks. I dremeled it shiny. Definitely not as silvery as Al in heatsinks. But plenty of surface area for a single transistor.

looks like compressed particle aluminum. Like compressed wood.

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haklesup
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Re: Hammond die cast al case, heat sink?

Post by haklesup » Fri Jan 19, 2018 8:20 pm

if the polished surface still looks like round beads with voids between, I will believe it but the "Die cast" process formally uses molten metal and the molds are often very rough, maybe even sand molds or bead blasted surface. its not very different from plastic molding for a low melt temperature metal like aluminum

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Lenp
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Re: Hammond die cast al case, heat sink?

Post by Lenp » Sun Jan 21, 2018 11:42 am

Without definate specs and a headache full of calculations, it boils down to....
Clean the paint off the mounting surface, mount whatever makes the heat with thermal transfer paste, and try it. :razz:
Or if your insist...go to http://celsiainc.com/heat-sink-size-calculator/
Len

“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)

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Re: Hammond die cast al case, heat sink?

Post by dyarker » Sun Jan 21, 2018 12:37 pm

Can you calculate with Ohm's law? The thermal calculations are about the same. Temperature (degrees C) instead of voltage. Thermal resistance (degrees C per W) instead of Ohms. Power (Watts) instead of current (Amps).

But as you say, it is IMPOSSIBLE without the specs.

Cheers,
Dale Y

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