Aluminum Heat Sinks

General Discussion
1

I’m thinking of printing aluminum heat sinks to use for TIG. They would be for the BB and head tube.

Would they risk bonding or other issues if I go too hot on a weld?

2

Pithy bikes YouTube used aluminum heat sinks on his builds. I am not sure about contamination of the weld but he did it successfully

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3

I use aluminum. Solid plugs turned from 6061 roundbar to a somewhat close fit, around 5 thousandths clearance. They’re tight coming out due to the bit of scale that forms on the backside of the weld. Not enough to gall the aluminum. Burn through would likely put up some resistance.

You’ll want lots of aluminum if it’s going to be effective as a heat sink. Lower density means lower heat capacity. Aluminum as raw material is relatively cheap and common so machining a massively overkill aluminum heat sink is still a good deal if you have the tooling. I don’t know how that works out for printed aluminum though.

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4

So your heat sink is fixed diameter, no expansion?

5

Exactly so! I don’t have a bandsaw on hand and detest the hacksaw, so I figured I’d try it out before making them expandable and it worked. If I was making bikes for income I’d make them into expanding collets to fit tubing variances and minimize galling risk. But I’m making a frame for me, so my time is worthless and it’s free to spend it at the lathe turning a precision fit.

Which shouldn’t be less than a few thousandths / 0.1-ish mm clearance to accomodate the coefficient of expansion differential between aluminum and steel. A snug push fit may enlarge the tube ID just a hair during welding. Also makes the tube rounder after welding than before, which is a neat party trick depending on who you party with.

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6

That’s a good idea for a cheap and simple heat sink. So far I’ve just been using exhaust pipe expanders, which are much more janky , but fine for me so far mostly for keeping the tube shape, and they absorb some heat.

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7

Ive made a few non-expanding aluminum heat sinks in a pinch. The main issue is getting them out. Of course Im not patient enough to let it cool all the way down and wind up having to smack them out with a hammer.