Wow! Have you tried it out and seen any difference in temperature compared to the stock heatsink?

No, not yet. Next on my list after recovery from current sinus ailment.
(From inhaling copper dust?)

This dummy didn’t wear a mask or respirator. Of course will do so with the next one.

Maybe call it an "iSink"… after indibil’s original approach?

It isn’t pretty (yet) but the first “replicant” here is finally complete.


                     Could use a bit of cleaning (copper dust particles, etc.) and some emery cloth smoothing of the rough fin edges.



Used a metal hack saw blade to cut the 50 x 50mm standard size down to 40 x 50mm and then a palm sander to smooth the rough cut edges. indibil used a 4” grinder with abrasive blade to remove 10mm - but I didn’t trust myself to go that route. Even tested a very small mini table saw and a mini chop saw… but they were too under powered for the task (so much so that the hack saw blade seemed better for a more controlled cut between the fins.. For the next one - may try a metal jig saw (or sawzall) blade clamped and held with vice grips to cut that 10mm excess off (again, by hand). Smaller and more teeth than shown here.



You may note the black dots on the face of the middle one in the second image above. Those are the projected locations for holes. I even created a paper template by scanning an actual G4 mini heatsink @1:1 for this approach but finally settled on a variant of indibil’s mating of the old heatsink, plus the new one (clamped in a vise) and then drilled.



Also in the second picture above… red dots denote one fin that was later removed, which brought this total fin count to 19. Unknown whether fewer fins will effect overall cooling but that’s a test to be done soon. (indibil’s copper heatsink has 20 fins.)

Also, the green outlined area (also 2nd image, left side) denotes the thicker base of the copper heatsink compared to the lesser thickness of the original stock heatsink. Thought might need to countersink the holes on the copper to facilitate use of the original “spring-pins” length but indibil said unnecessary and that the original “spring pins” worked well even with the slightly greater thickness of the new heatsink’s copper base.

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Trimming the fins. Where the real fun is!

Not really. Struggled and fretted over this more than anything and still have not arrived at a comfortable, set approach. I’ve enough finned copper stock here to make three more iSinks - so maybe by the last one I’ll have a better approach? For this first one, you might see where I drilled down through the copper to help locate the area where the spring-pins would enter the base in relation to the fins. This helped to guide how far back the fins would need to be trimmed. Then using very small metal snips, the fins were cut back as far as possible AND then used a Dremel tool with an abrasive bit to grind the fins back further. Also tried the Dremel with a circular abrasive disk to cut the fins, but definitely need more practice with that. Perhaps a combination of all the above would make it all easier / better?

CNC machine.
Yeah, I know.

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From here, the next step for me will be to test what effect the copper heatsink might have on air exhaust temperatures compared to an original heatsink in a stock 1.5 GHz G4 Mac mini (if any at all). I think the temps may be hotter but those I have asked seem to think that: (1). The temps will be the same, or (2). Fan speeds will decrease.

AND all of this in prep for possibly overclocking a G4 mini to 2 GHz. My thanks to indibil and to sailorMH for their efforts in relation to the entire subject of overclocking the G4 minis. Might have to eventually send one of these finished heatsinks over to the Czechia (sailorMH).

For more in-depth, G4 mini overclocking info (warm up your Google website translator):

indibil…
https://rosysumenteinquieta.blogspot.com/
https://rosysumenteinquieta.blogspot.com/2023/12/mac-mini-g4-192ghz-con-disipador-de.html

sailorMH…
https://www.amigaportal.cz/node/156189

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"fastest" flash, and using a pencil to overclock - MacRumors

More info on overclocking the G4 Mac mini? There’s a thread over on MacRumors where ervus (in 2020) first mentions overclocking a mini to 2 GHz w/o a 7448 - but it still overheated. Read all (currently) 8 pages of that thread. Perhaps this is what Jubadub previously referenced?

Begin with ervus:
https://forums.macrumors.com/threads/fastest-flash-and-using-a-pencil-to-overclock.1973903/page-2?post=29415588#post-29415588

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Random errata:

Drill bit size = 3.0mm

Harbor Freight (in the U.S.) sells a small set of metric bits for less than $5.00!
HSS Micro Drill Bit Set 3 / SKU 61526 / $2.99. (30 assorted small bits)


                                                                                                                                                               Hole template with fin trim-back info

You can either trim back 1/4” (6.35mm) of the fins in the front and back locations
(like indibil has done) OR… take a full 5/8” (15.875mm) from the back location.
See first image here at the very top.

Sourced the heatsink blanks, 50 x 50 x 20mm and the 100 x 50 x 20mm from:
YOLOWIN / AliExpress. 100 x 50 x 20mm can yield two for a few dollars more.

https://www.aliexpress.us/item/3256804076300199.html  50x50x20

https://www.aliexpress.us/item/3256804078907505.html  100x50x20

AND - used slow speed on the drill press as copper is very soft metal.

AND - AND… thanks to Philgood for first mentioning indibil!

[...] perhaps some installed 7447s have more stability at 2GHz than others, perhaps mine do not, others perhaps do.

Correct. The probable reason yours and @GaryN's didn't work, and the probable reason @Knezzen's worked, is a matter of what we call Silicon Lottery. There is something else called Processor Binning. I found one of the MacRumors PPC threads I go on and on about those, and the custom 7448 dual 2.0GHz upgrades. To understand processor binning, and why it matters, refer to this comment, and about silicon lottery (plus a lot else), check this comment instead.

In short, @Knezzen won the lottery! But all of you may acquire and try more 7447 processors with the highest binning, until you win that same lottery. From experience, I will say your chances are very good with very few tries. Also keep in mind there are 3 main different MDD coolers (go for copper if you can, else the pure aluminium one. The other one reportedly freezes MDDs during stress, according to House of Moth, whose links describing this I no longer have), and they matter and differ a lot, but if you can LCS it with a silver base, that would be best, but not at all needed. I would also recommend, again, going for 7448 processors (if you find them) with the highest binning, and getting those instead, because the Sonnet MDX daughtercard can be used without requiring an interposer board, unlike with the stock MDD daughtercards. The 7448s also run cooler.

Anyway, be happy that you guys even have access to an MDD, let alone MDX daughtercards! I couldn't find the latter even when in Germany for 2 whole years of stalking eBay and the like. If you can find an MDX card, you can find A TON of 7448s! I know I did. Keep looking!

I actually have one now running nicely,

the only parts i would like now are

the 1.42ghz processor or some other upgrade from 1.25ghz just because i can
and a vst to rtas wrapper for using those sweet vsts in pro tools

thanks for all your help tho dudes

Just as a note; mine is still running stable at 2ghz in my MDD. It’s what I have used ever since I did the overclock. No issues at all.