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25th Oct 2020, 1:58 pm | #1 |
Octode
Join Date: Nov 2013
Location: Penrith, Cumbria, UK
Posts: 1,993
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Adhesive for aluminium heatsink
Any recommendations for a heat conductive adhesive or adhesive film to attach a pair of 200mm x 75mm extruded aluminium heatsinks to a sheet aluminium chassis? The other side of the chassis will have the aluminium heatsink brackets of the power amplifier module and I intend to do something similar here as the conventional approach of drilling a set of holes and bolting it through will be awkward and cosmetically poor. Its a finned heatsink from RS and fits the end panel of the chassis perfectly.
The amp boards could be bolted through the chassis but its thin aluminium and not sufficiently thick to be able to countersink a mounting screw. I considered drilling the back of the heatsinks and tapping a thread in but again they aren't really suited as inevitably I'd have to go through one of the fins which wouldn't look nice. I've seen heatsinks stuck on computer and digital amp chips but not sure how that translates into the larger scale. All ideas appreciated. Andy. Last edited by bikerhifinut; 25th Oct 2020 at 2:00 pm. Reason: typing errors |
25th Oct 2020, 2:02 pm | #2 |
Nonode
Join Date: Mar 2010
Location: Sunderland, Tyne and Wear, UK.
Posts: 2,475
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Re: Adhesive for aluminium heatsink
Have you considered pop rivets ?
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25th Oct 2020, 2:31 pm | #3 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
Posts: 1,558
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Re: Adhesive for aluminium heatsink
I think the Arctic Silver people do a thermally conductive 2 part adhesive - it won`t be cheap though.
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25th Oct 2020, 3:02 pm | #4 |
Guest
Posts: n/a
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Re: Adhesive for aluminium heatsink
If the surfaces are flat enough for there to be a small/non existent gap good old slow set Araldite will do nicely. Unlike a transistor or module you have a large surface area to play with, the small additional thermal resistance of Araldite won't matter. Done hot (60C, preheat in oven) Araldite will flow like milk.
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25th Oct 2020, 3:11 pm | #5 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
Posts: 1,558
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Re: Adhesive for aluminium heatsink
If you drill and tap the heatsink between the fins you can fix them with black finish screws - this looks perfectly acceptable.
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25th Oct 2020, 3:39 pm | #6 | |
Octode
Join Date: Nov 2013
Location: Penrith, Cumbria, UK
Posts: 1,993
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Re: Adhesive for aluminium heatsink
Quote:
So how about using half a dozen "spots" of epoxy and filling the gaps in with heat conductive paste? The idea of drilling a small set of holes through and tapping could work I guess and use black finish set screws? they'd have to be M3 or smaller though. I like that idea as being reversible if needed in the future. The power amp boards on the other side can be butted hard against the chassis side with some heatsink paste as they have mounting holes on the PCB so could bolt them down on standoffs and rely on the mechanical joint. I've yet to drill the chassis/boxes to take the socketry and switch and then its Spray can time, etch primer followed by a satin black paint finish. These things are likely to hide behind a speaker but all the same I'd like them to look presentable in case they end up on the bottom of a rack. Thanks for the ideas guys, I am sure there's an elegant and practical solution. It could be argued that the aluminium case itself might have enough thermal mass to cool the boards but I would rather not take the chance. Always a sensible answer on here. Andy |
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25th Oct 2020, 4:18 pm | #7 | |
Guest
Posts: n/a
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Re: Adhesive for aluminium heatsink
Quote:
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31st Oct 2020, 3:43 pm | #8 |
Dekatron
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,715
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Re: Adhesive for aluminium heatsink
When I needed to attach some anodised aluminium floor edging to the back of a big LED array to replace the useless LED light in a cooker hood I found a product called "heatsink plaster" Cost me 99p delivered from China last year.
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31st Oct 2020, 4:32 pm | #9 |
Octode
Join Date: Dec 2019
Location: Owston Ferry, North Lincolnshire, UK.
Posts: 1,701
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Re: Adhesive for aluminium heatsink
Depending on how thick the actual flat area of the heatsink is, you could try drilling through the aluminium sheet and then drill blind holes into the heatsink. You could then use tapping screws, rivets or even bolts into tapped holes in the heatsink, non of which would be visible from the heatsink external finned side. I would then use normal heatsink paste between the fixed flat areas.
Dave |
31st Oct 2020, 4:41 pm | #10 |
Octode
Join Date: Mar 2011
Location: Sheffield, South Yorkshire, UK.
Posts: 1,453
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Re: Adhesive for aluminium heatsink
I've seen an an article in the March 1984 issue of Radio & Electronics World that tells you to use epoxy to fit a home-made heatsink to an LM380 so it's certainly a recognised technique.
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1st Nov 2020, 4:22 pm | #11 | |
Octode
Join Date: Nov 2013
Location: Penrith, Cumbria, UK
Posts: 1,993
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Re: Adhesive for aluminium heatsink
Quote:
However I figure using a nice long drill bit between the fins and drilling through and into the chassis to ensure it all lines up will work a treat and I have a set of taps and dies so I can cut a nice thread in the heatsink holes and use a suitable length of screw to bolt it on. The other sides the biggest challenge in respect of keeping the amp boards bracket in full contact as it must be easily removable for future servicing, but I have an idea there too. Thanks folks, there are some very good solutions you have suggested. Andy |
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1st Nov 2020, 5:17 pm | #12 |
Octode
Join Date: Dec 2019
Location: Owston Ferry, North Lincolnshire, UK.
Posts: 1,701
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Re: Adhesive for aluminium heatsink
You probably already know about this but do remember to use a smaller correct diameter drill bit for the holes that need tapping, then enlarge the holes where the screw needs to pass through unhindered. It's an easy error to drill the wrong size and I dare say that we've all done it at some stage or other.
Dave |