CrazyEyes Posted August 21, 2015 Share Posted August 21, 2015 Im currently trying to figure out how to mount the fans to my heatsinks, Im trying to keep this light as thin as possible, I thought about milling the fins so the fans would sit inside the fins, I also thought about taking another piece of aluminum, something like 1/4" thick and mounting the heatsinks on it, then running a single fan in the middle but I'm just concerned about heat transfer issues still. The heatsinks are 90x90x15mm, each one will have a single Nanobox v3 puck. Any thoughts on this or should I just mill the fins on the heatsinks? Link to comment
gus6464 Posted August 21, 2015 Share Posted August 21, 2015 Im currently trying to figure out how to mount the fans to my heatsinks, Im trying to keep this light as thin as possible, I thought about milling the fins so the fans would sit inside the fins, I also thought about taking another piece of aluminum, something like 1/4" thick and mounting the heatsinks on it, then running a single fan in the middle but I'm just concerned about heat transfer issues still. The heatsinks are 90x90x15mm, each one will have a single Nanobox v3 puck. Any thoughts on this or should I just mill the fins on the heatsinks? What's the size of the fan you are planning on using and the CFM? Link to comment
CrazyEyes Posted August 21, 2015 Author Share Posted August 21, 2015 70x70x10/15mm 22-25cfm I know the fan will be enough, I'm just not sure if there will be an issue with heat transfer from the aluminum plate and the heatsinks with them being mounted together opposed to 1 solid piece. Link to comment
gus6464 Posted August 21, 2015 Share Posted August 21, 2015 70x70x10/15mm 22-25cfm I know the fan will be enough, I'm just not sure if there will be an issue with heat transfer from the aluminum plate and the heatsinks with them being mounted together opposed to 1 solid piece. As long as there is a good contact between the plate and the heatsink you will be fine. Just use good thermal adhesive. Link to comment
CrazyEyes Posted August 21, 2015 Author Share Posted August 21, 2015 thermal adhesive between the aluminum plate and the heatsinks correct? My other question is, I know 1/4" is pretty thick. Do you think 1/8" would be thick enough for the aluminum plate? Link to comment
gus6464 Posted August 21, 2015 Share Posted August 21, 2015 thermal adhesive between the aluminum plate and the heatsinks correct? My other question is, I know 1/4" is pretty thick. Do you think 1/8" would be thick enough for the aluminum plate? The thickness of the plate doesn't matter as much as long as it has good contact with the heatsinks. You want to maximize contact with the sinks for maximum heat transfer. Link to comment
CrazyEyes Posted August 21, 2015 Author Share Posted August 21, 2015 One last question, how would you suggest actually fixing them together? I'm sure I could have them welded together but what do you think about bolting them together? I feel like bolting them together would be a better option just due to the fact that welding them is only going to connect the outer parts whereas bolting them I could make good contact on the inner parts. Link to comment
gus6464 Posted August 21, 2015 Share Posted August 21, 2015 One last question, how would you suggest actually fixing them together? I'm sure I could have them welded together but what do you think about bolting them together? You need proper thermal transfer for it to work so proper thermal adhesive is the only thing you can use. Get this: http://www.amazon.com/Arctic-Silver-Alumina-Adhesive-AATA-5G/dp/B0087X725S/ref=sr_1_sc_1?ie=UTF8&qid=1440177566&sr=8-1-spell&keywords=arctic+ilumina Just having 2 pcs of aluminum touching doesn't do anything. Link to comment
CrazyEyes Posted August 21, 2015 Author Share Posted August 21, 2015 Right but is that going to have the strength to actually hold together? I know people use that stuff with LEDs but LEDs are almost weight less compared to what I'm doing. I was thinking I could just use regular thermal paste and screw them together, the same idea when people mount LEDs so a heatsink with screws instead of thermal adhesive. Link to comment
gus6464 Posted August 21, 2015 Share Posted August 21, 2015 Right but is that going to have the strength to actually hold together? I know people use that stuff with LEDs but LEDs are almost weight less compared to what I'm doing. I was thinking I could just use regular thermal paste and screw them together, the same idea when people mount LEDs so a heatsink with screws instead of thermal adhesive. The stuff is very strong. It's not coming off. People mount LEDs with screws so that they can be removed later, not for strength. Link to comment
CrazyEyes Posted August 21, 2015 Author Share Posted August 21, 2015 I know but I'm almost certain I read somewhere that people also mount LEDs with hardware because it gives you a higher clamping force therefore a more effective heat transfer. Link to comment
evilc66 Posted August 21, 2015 Share Posted August 21, 2015 For something that large, you don't want to use thermal adhesive. Your best option is to use a good thermal paste and bolt the plate to the heatsink. While a thermal interface material is useful, nothing beats good old physical contact, and the more you can get the better. Much of that is derived from clamping pressure, which you will only get with bolting the two parts together. You could get away with using the epoxy and placing the plate and the heatsink under high clamping pressure to assure good contact, but generally, bolt everything together is a better option. Welding is a no go. Welding only bonds at the edge of the heatsink, so you have a potential air gap under the center of the heatsink, drastically reducing the effectiveness of the heatsink. The only thermal transfer path will be at the weld site. Now, as for the fan... If you are going to mount the fan centrally between the two heatsinks, having the fan just sitting there in the open isn't going to do you much good. You will lose a good portion of the airflow to the open gaps between the two heatsinks. You will need to create a duct/plenum that forces the air towards the heatsinks. Ideally, you should extend the duct to completely cover the top of the heatsink (leaving the end open to vent) so that all the airflow runs along the heatsink maximizing contact time. If the heatsink top was open, then you lose some airflow as it spills out the top of the heatsink before reaching the end. Is the fan you picked framed or frameless? If it's frameless, then you will be ok, as the air will leave the tips of the blades rather than flowing axially (following the axis of rotation) through the fan. If it's a framed fan, then that axial flow is going to be a problem. You have a 15mm tall heatsink, and a 15mm tall fan. You would have to raise the fan up at least 10mm to not impede the airflow which will possibly change the look of the fixture you were going for (if as low profile as possible was your goal). Link to comment
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