Stirling heat sinks

[kiwi2]

Hi all,

I've started building a stirling engine. Most of the pictures I've come across show the heat sinks as being shiny and polished.
Is this the correct finish?
I would have thought that it would need to have a matt black finish to maximise the radiation of heat away.
Or do the fins lose heat primarily due to air convection at their surfaces?
If a matt black finish is desirable, are there any suggestions as to the best coating to use? At present I'm thinking of a black marker pen.

Regards,
Alan C.

 

[vederstein]

Some time ago I built a heinrici stirling and after I got it running, I painted it with hi temperature flat black paint.

Not that I was taking any measurements, but there was no noticeable difference in performance between painted and unpainted.

...Ved.

 

[kiwi2]

Thanks Ved.

I'll polish it an see how I get on.

Alan C.

 

[Hopper]

A matte surface will have more surface area so can disperse more heat. But the advantage is so small you would be lucky to notice it.
If you like polished, polish away.
If you want improved cooling, make the gaps between fins slightly wider than the fins themselves to allow better convection flow.