Modded my deluxe cap!
View attachment 114942 Used some ss lashing wire, should help a bit keeping birds out! Ive never used it but from reading here i figure id try something.
Hey, excuse the necro-post from a n00b, but I DID do a search. We have this exact same cap, and still getting birds in the stack. We had the dude who installed it (wife does NOT want me on the roof, but I digress....) put a spark arrestor on, but he put it on the OUTSIDE, between that bottom ring and the outer cylinder:
So the top of the outer cylinder is wide open, and given its shape, it's an inviting location for birds. They can drop in from above, go around the flat cap that's directly above the pipe, and whoosh, down the pipe. Got lucky (well, the bird did...) one day when we happened to be there, had to open the pipe inside the cabin, then take a window screen out to let him fly out. Three others weren't so lucky.
So I'm thinking, he shoulda put the spark arrestor on the INSIDE, between the pipe and the flat top, where you put that SS wire. So whether a bird goes in from the outside or the top, she'll be stopped at the pipe.
Another option I thought of was to find some bulk material that the spark arrestor is made of (presumably some SS, 304 or the like), and cut a round piece of it, big enough to cover the open top of the outer cylinder. Bend the outer edge down so it's like an upside-down pie crust, then SS fender washers and screws/nuts to fasten it to the top of the outer cylinder. This would keep them from getting inside the thing anywhere, so they wouldn't leave any nests up there either (haven't had that happen --- yet --- ).
Anybody have any thoughts on whether that would work?