I guess this particular thread might be better suited in another section like Tips & Tricks or something, anyway it's posted now obviously and I just hope it's alright.
The cone is made from rolled cardboard and fiberglass and I have used spray adhesive to attach the fabric to the cardboard before it is saturated, this is a very helpful method in many situations. The spray adhesive is only applied very lightly like a quick brief mist spray from a little distance at both surfaces, and it is slowly dissolved by the epoxy. I have just set the cone in place in the cylinder at once I was done saturating the fiberglass so it is stuck in there when it's hardened.
With the air inlet I have not used the spray adhesive trick simply because I don't need it, here I have however used a slurry of epoxy and some filler (milled cotton fiber) in all inwards corners. This makes it easier to get the "twill" fabric to conform nicely without attracting air bubbles under it in those sharp corners, and as you can see it also makes nice filled and rounded shapes.
There will be a spiral inside the top cylinder as well to enhance the downwards motion of the vortex inside and I thought perhaps I'd make that from fiberglass too, I will show you how I solved that when it is done.
need coffee... need ... coffee