"Treetops" wrote in message

EPS is horrible to cut and shape at home; lots of bits of foam,
impossible
to collect, and not a smooth cut. Core needs a taper shape of 4" to 2".
Cutting this taper at home would destroy any fused surface.
Extruded foam is easily cut by a home-made hot wire and is used by all
kinds
of hobbyists to make models, airplane wings,sail boards. It is readily
available in thickness up to 2" and easily glued and painted if desired.

You can cut EPS foam with the same equipment. I got into the EPS business
in 1970 with a company that started by making molded EPS airplane wings in
1955.

If you need any equipment for working wit either of the foam,s thee is a
company in Wester PA that carries simple hot wire cutters. Wind Loc is the
name, but hte city does not come to mind. They have many products for the
construction industry and ICF's. (insulating concrete forms)



My question remains; Styrofoam does not seem to waterlog, seems as strong
and as good an insulation as EPS and can be cut fairly easily with the
required taper, would I be making a mistake in using it on my hot tub?

No

I
would still put it in a sealed poly bag for good measure and inside the
vinyl cover.
What are the downsides in using it for this application?

None that I know of. Chemically, it is the same material. Extruded is more
rigid and will probably hold up better for your use.
Ed

http://pages.cthome.net/edhome