Suggetions please to replicate this set up

[Welder]

Why we thinking 2" better? That's what I was thinking but wasn't sure why. I guess the bigger it gets the more force it requires to spin it. But it could be cut into smaller sections to counteract this.

The larger dia the better as the animal will not be able to hook its 'arms' around the pipe...

I did something very similar for my custom bird feeder to discourage the pigeons. I used 12mm studding and cut 20mm long pieces of 15mm plastic plastic pipe and slid them over the studding. When the pigeons land on the studding they can't transfer their weight forward as the pipe they are sat on then rotates. Was hilarious at first to see then toppling over. The buggers soon adapt tho.

 

[Ben-gee]

Why do you want the fins watertight?

I would have thought plain pipe would work as well if not better.

However; try googling “aluminium extrusion star shaped” I got this

I think it’s some sort of heat exchanger - ideally you want to find a scrapped “thingumejig “ that has lots of these in it - good luck with that!

 

[Last Plumber]

The larger dia the better as the animal will not be able to hook its 'arms' around the pipe...

I did something very similar for my custom bird feeder to discourage the pigeons. I used 12mm studding and cut 20mm long pieces of 15mm plastic plastic pipe and slid them over the studding. When the pigeons land on the studding they can't transfer their weight forward as the pipe they are sat on then rotates. Was hilarious at first to see then toppling over. The buggers soon adapt tho.

The 'arms' comment tickled me!

 

[Last Plumber]

Last Plumber have you got a bigger version of the second pic you posted or any other pics of it/more info? Looks pretty good but can't quite see what's there other than the pipe

I found it on google images. I think it is just tube threaded through 2" waste and secured with saddle clips.

 

[Welder]

This is the concept. It works well and costs virtually nothing.