Glue Two Heatsink Together

Thread Starter

slevesque

Joined Jan 31, 2023
43
Hello everyone,

I am designing an electric box for an aircraft and I need to use a diode which require to add a heatsink.

Overall dimension of the diode is (L x W) 92mmx22.6mm.

I was looking to use that heatsink https://www.fischerelektronik.de/web_fischer/en_GB/VA/SK63100SA/datasheet.xhtml?branch=heatsinks
Which would have fit perfectly, not too big long enough and have the perfect space in the center for the diode. Problem here is I can't find it nowhere in stock and reaching the company they want me to buy 32 of them and I only need one.

I am wondering if sticking two heatsink together would be ok. I am thinking using this one

https://canada.newark.com/fischer-e...-Shopping-PMAX-CATCH-ALL-NEW&gross_price=true

but it is only 50mm long. If I stick two of them together would that work fine? Heat will dissipate the same as if it was only one piece?

Thanks in advance
 

ElectricSpidey

Joined Dec 2, 2017
2,758
If you are passing half the heat into one and half the heat into the other you should be fine.

Maybe post an image of how you are mounting the diode to the sinks. (a drawing will do)
 

Thread Starter

slevesque

Joined Jan 31, 2023
43
Yes there is two copper thermal pad under the diode. One will be on one heatsink and the other thermal pad on the other heatsink. Thanks for the reply
 

Thread Starter

slevesque

Joined Jan 31, 2023
43
This is how it will be attached. The diode will be mounted to the boxe through the heatsink. Only thing is I can only put one screw on each heatsink like this.
1679498336845.png
 

KeithWalker

Joined Jul 10, 2017
3,063
The two different types you mention have almost identical thermal dissipation properties so there should be no problem. Do you really need to glue them together? Will mounting them firmly end to end in the box not be sufficient?
 

ElectricSpidey

Joined Dec 2, 2017
2,758
Looks ok, I would use some thermal adhesive between the sinks and look for some way to get a mechanical connection between them rather than rely on the adhesive.

Also don't forget the thermal compound between the sinks and the diodes. (not adhesive in this case)

Perhaps an aluminum plate behind the sinks that can also be glued using thermal adhesive.

I really feel kind of queasy giving advice on an aircraft product, be sure to acquire proper expert advice or inspection.

BTW...nice rendering.
 

Thread Starter

slevesque

Joined Jan 31, 2023
43
Thanks a lot with the reply, I will apply thermal compound between the sinks and the diodes. I think same as you the two screws should hold them good on the box.

Best regards everyone
 

KeithWalker

Joined Jul 10, 2017
3,063
Thanks a lot with the reply, I will apply thermal compound between the sinks and the diodes. I think same as you the two screws should hold them good on the box.

Best regards everyone
Use some thermal compound between the sinks and the box, too. That will help to radiate the generated heat.
 

LowQCab

Joined Nov 6, 2012
4,023
Is this a custom "one-off" design ?
It may be possible to eliminate the Heat-Sinks by replacing the Diodes with some other device.
But we have no Schematic of the Circuit, or any description of it's operation.
.
.
.
 

Thread Starter

slevesque

Joined Jan 31, 2023
43
Is this a custom "one-off" design ?
It may be possible to eliminate the Heat-Sinks by replacing the Diodes with some other device.
But we have no Schematic of the Circuit, or any description of it's operation.
.
.
.
This design will be repeated in many aircraft. This is to run an added system in the aircraft for petrolum leak detection. The diode is use so the current from the system don't go come back to power the aircraft. There is a new battery in our system.

We are talking about D1 here.
1679575396033.png
 

LowQCab

Joined Nov 6, 2012
4,023
Your AC to DC Power-Supply/Charger should have a Bridge-Rectifier on it's Output,
so it doesn't need or want an additional Diode-Drop.
The other Circuit doesn't seem to make much sense,
there appears to be no Power-Source to supply the Battery.
.
.
.
 
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