Solder Heatsink

[Dvorhagen]

My upcoming build is going to be a high power LPC, in what I'm hoping to be a from-scratch, heatsinked metal host. I'm trying to do everything myself, and I don't have access to a drill press. I'm wondering about the feasibility of molding a heatsink around an AIXIZ module using solder or possibly straight lead. Lead's specific heat isn't much higher than aluminum, so I'd think its heat transference properties would be almost as good...Any thoughts?

 

[Morgan]

Sounds perfectly feasible. The aim is just to remove heat and lead or solder will do that. I just don't think it will be very pretty. There is a page on Wiki that looks at thermal conductivity and lead doesn't appear to be anywhere near as conductive as Aluminium, but it is Wiki I suppose! Thermal conductivity - Wikipedia, the free encyclopedia

The most important thing to do is get as good a contact between the two surfaces as you can. Thermal compound, (there are plenty of them out there), is something to bare in mind as this effectively fills the gap between two materials and creates a much better path for the heat. You don't need a lot of the compound but it will help tremendously! ("tremendously", what a word!)

Good luck... and photos please when it's done.

M

 

[Benm]

The thermal conductivity of lead is not nearly that of copper or aluminium. I suppose you could cast heatsinks out of solder, lead or tin, giving you the desired shape, but at poor conductivity. Also, mechanical strength isnt very good, which can be a downside once its fitted, but makes it easier to work on the material - you can easily drill holes in lead, or sand off large portions to get the final shape.

 

[photonaholic]

Get a dremel tool and never look back.

You can grind cut & drill aluminum with ease using one.

The best hobby money you will ever spend.

 

[Benm]

Well, grinding down some aluminium stock bars to th desired shape using a dremel sounds like a daunting task to me

On the other hand, it would perhaps be possible to cast aluminium for heatsinks, giving the finish with a dremel or similar handheld tool. I suppose its not really worth the effort though, considering the prices of prefab units.

 

[Tim71]

I was planning on taking a trip to the local Home Depot and browse the copper fittings section for something I could fashion into a heatsink for an Aixiz module. Has anyone else done the same with good results?

Thanks,

Tim

 

[3zuli]

it's possible, someone here (Flaminpyro afaik) already made a host using solder heatsink
try to serach 'solder heatsink'

/edit: ok, so it wasn't FP :na:

 

[Flaminpyro]

I rember someone soldering copper pipe pieces together with a Aixiz module and filling in the gaps with the solder, I suppos this would work ok but I wouldn't want to trust a 12x diode to it as lead is way down on the thermal conductivity poll. lead is better than air however

it's possible, someone here (Flaminpyro afaik) already made a host using solder heatsink
try to serach 'solder heatsink'

 

[phoenix77]

Perhaps you could use SILVER SOLDER instead of the standard solder alloy. rob

 

[Benm]

Silver solder usually only has 3% silver or so, at least the kind that you can use with a normal soldering iron. The main use is for soldering silver(plated) parts, because it prevents silver from dissolving in the solder mixture. For the same reason, a few percent of copper is sometimes added to lead/tin solders.

There is something like silver solder for jewelry work, but that is hard solder, requiring very high temperatures to work with.

 

[phoenix77]

Thanks for the info. Ben. It was just an idea though. rob

 

[Benm]

And not a bad one at that - if you want to cast heatsinks its fine, but not easier than casting them out of aluminium. Some people actually make alu castings as a hobby, but they often use sand molds, so the results are very rough.

Things like aluminium enclosures are often cast as well - but i suppose its not feasible for heatsink production on a small scale.

 

[Tim71]

Sorry to get off topic a bit here, but...

@Flaminpyro

Just saw some of your handiwork...those are some really nice copper heatsinks! How much for a basic one to fit an Aixiz 12mm?

Thanks,

Tim

 

[Dvorhagen]

Somebody tonight was just telling me about a DIY "coffee-can foundry" which will let you melt and cast aluminum. I might look into that..

 

[Benm]

I've seen videos of it, doesnt look that hard, but the problem is still getting the mold to cast a heatsink. Aluminium isn't that hard to melt - just under 700C will do it. You can easily achieve such temperatures with ordinary wood/coal fires... just look at the pictures of cars left in forest fires, where the alloy wheels often end up as puddles of metal.