I'm trying my hand at hat making this spring.
I ordered 12 wool felt hoods from hat-supply.com, and bought a large sheet of styrofoam from Hobby Lobby for the hat block. I cut the foam into slabs and glued them together. I had a difficult time getting the slabs to stay glued, though; I bought the harder, more porous type of styrofoam, so finding a glue to bond well was hard. I ended up using lots of craft bond and several toothpicks. It took several hours to hack, chop and carve the square of foam down into a hat shape. So if your time is money(mine isn't), just buy a hat block! This hat block had better last longer than I do.
The Big Bad Wolf investigates the foam carving mess. Definitely an outdoor job.
When I got it down to what I thought was a decent shape and size, I sprayed the block with paint and craft shellac and covered it with a plastic shopping bag. That seemed to make it a lot stronger and less prone to break. But it almost wasn't worth it, because it was still too large and I had to trim it again.
The too-large first attempt.
The Hood of Evil
Most tutorials online said to steam the hood. I did steam the hood over a violently bubbling electric teapot, but even after several tries I just could not get the thing over the block, mostly because it was still way to big. I then tried soaking the hood in very hot water, and that worked markedly better. Still, it wasn't until the seventh or eighth try that I got the hood pretty much all the way down over the block without bubbles still on top. It was exhausting. Because the hoods are fairly short and my block came apart again(glue problem), I ended up with a four inch tall hat. Rather shorter than these two extant examples.
The second try went a little better; I cut the block down again so the hood went on much easier. I may have to give up on having any flare at the top, because it does make it much harder to take the hood off the block. Now my main issue seems to be puckers at the brim of the hat. The hoods are basically bowl shaped, so getting the wool to constrict down to a head-sized circle? I'm not sure how that's supposed to happen without bubbling.
Next: stiffen the hats and add hatbands and lining.