Urethane Heat Sinks

Good morning, here was my test setup.
1.5" thick samples placed on a hotplate and the temp differential between the surface closest to the heat source compared to the surface furthest away from the heat source after 30 seconds and one minute then averaged. As an example, if the heat source side was 200 and the side furthest away was 100, I call that 100/200 = .50 expressed as a percentage is 50%


Aluminum block: 69%

Untreated Urethane: 29%

5% load Urethane: 39%

10% load Urethane: 57%

10% load / Aluminum is 57/69 = .83 expressed as a %, the 10% loaded material is 83% as efficient in transferring contact heat as Aluminum at 1/2 the mass.


Probably the best application for this material that i can think of is using it to encase ESCs and mount them to the deck directly outside an enclosure, but having something that can protect a motor can while not sealing in heat (and indeed allowing it to be shrugged off) would be awesome.

no-feature direct drive cans like Carvons and meta surfs and others like them could benefit from this as well. Sealed brushless outrunners may benefit from this because keeping magnets cool is important, but most of the heat from motors is generated in the stator, however i don’t know how much heat the seal bearings transmit to the cans so maybe the benefits there may be better than expected.

maytech style outrunners with “mag wheel” style end caps probably wouldn’t benefit at all where stator cooling is concerned, but again, keeping magnets cool and also protecting the cans from smashing would be a great benefit.

cell cases would lower cell density, but if you’re using lower cell counts on larger cells for competitions this could be a great benefit for boxless race rigs.




@hummieee , John you may find this of intrest

Keeping batteries and esc cool would be a great benefit. No need to implement air cooling, just like tesla batteries.

urethane is an insulator. you could fill it with metal powder or something to increase thermal conductivity and reduce its mechanical properties to a point before it fell apart and still wouldn’t conduct well. a urethane heatsink is an oxymoron until someone shows otherwise.


Well for a start it would be wise to stop gluing batteries tightly together and just add some space for each cell. Can help maintain a better temp level for your pack.

I’m curious to see how this would turn out @RipTideSports, if it is still a bit stretchable I have an use for this kind of compound.

I don’t have a problem, but if you want to have a smaller pack and push it that cooling will come in realy handy.

Agreed :beer:

Just imagine, you can just make a mold for batteries and you got a cooling body that you can connect to the outside of the enclosure and insulation at the same time. Same thing for ESC or other electronics. I am hyped. Any update?


I will repeat the data again from above and add that the compound conducts heat but does not conduct electricity as tested by @Psychotiller


So any update when you are gonna release that stuff?


That’s good data! Is it easy to cast? Any ways to print it in filament? How is the elasticity / duro?

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I just need an application where it would make sense

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I am gonna second @Vanarian . Are you gonna sell it in bottles for casting?
Also, how stiff is it? Like can it be made to be almost like rly hard concrete mold PUR.

63mm motor cans?


nothing is easy to cast but it is no more difficult to cast than other products we make. Duro range is low A through the D scale. @Vanarian - filament for 3d printing? Sorry but no, we use thermoset Polyurethanes

Main Difference – Thermoplastic vs Thermosetting Plastic
Thermosetting and thermoplastics are two different classes of polymers, which are differentiated based on their behavior in the presence of heat. The main difference between thermoplastic and thermosetting plastic is, thermoplastic materials have low melting points; therefore, they can be remoulded or recycled by exposing it to heat. Unlike thermoplastic, thermosetting plastic can withstand high temperatures without losing its rigidity. Therefore, thermosetting materials cannot be reformed, remoulded or recycled by applying heat.


Not sure if motor can covers is a good idea since the urethane sleeve will be less efficient at heat sink than the uncovered can. It will add protection 4sure but contain more heat unless we increase the surface area to overcome the 17% deficiency…perhaps finned


So are you gonna sell it raw in bottles for diy casting or only in finished products?

Why would he do that?