I'm new here, and never built a suit or anything. But whatever kind of tail you're doing, just purely physics, I'd think use a rather heavy foam for the first few inches, to foot (depending on length, width etc) of the base, and go to a light springy foam after that. You want it to be a bit heavier at the base, so you have a bit more control over swing and bounce; also would help avoid unwanted droop. And as @Mambi said, a tube core will give it nature bounce, reduce weight, and give you a solid base to build on.
I guess I should update this, I ended up building another practice tail and filled it with polyfill stuffing. The weight was significantly less and the stuffing didn't end up shifting much though what I found is it was a bit too light overall. I think you are right and I should have added some weights, though I think I might want some in the tip as well as the base to keep the weight balance.
Lol that's great. Yea, gotta start somewhere. Yea, a cat tail is a bit more tricky than say a dragon tail, because it's thin, generally uniform. But something a bit more Ridgid, and a little wieght at the end, I'd think that would make for a good stable tail, with a bit of swing. Keep us posted.
Thanks for the tips, I ended up unpicking and re-sewing certain parts of it. It did help the twist somewhat but I think I will probably have to restart to fix it completely. I will post the next questions I have in the main forum.
Well, that is relatively cheap fiberfill if you're not near a Joanne's Fabrics but that has nothing to do with the twist problem. Twist occurs when you either don't mirror your cuts for left/right or top/bottom or you don't fully binder clip the material before stiching to keep uneven stitching from causing twisting.
