by KCStudly » Fri Oct 06, 2017 12:49 pm
XPS is the way to go. It handles, forms and cuts much better than crumbly polyiso.
Glues and techniques that work with XPS/EPS are well documented here; polyiso, not so much.
Panther pink ("Foamular" brand) or Dow blue ("Styrofoam" brand). I think Menard's used to carry an equivalent XPS that was colored green.
As noted above, just to recap;
EPS = Expanded polystyrene... the little balls pressed and molded together, like foam coffee cups and those cheap coolers that you buy at the convenience stores, usually white.
XPS = Extruded polystyrene... wall board insulation, "folded fan board" insulation, underlay insulation for concrete slabs and foundation walls, usually pink or blue, thinner sizes (below 1 inch thk) may have a clear film reinforcing that should be peeled off before attempting to glue.
polyiso (for short) or polyisocyanurate = more fragile, brittle and crumbly, usually has a reinforcing film, yellow-ish... not good for "traditional" foamie construction techniques.
The thermal performance and cost differences of polyiso do not win out against the workability and handling properties of XPS.
KC
My Build:
The Poet Creek Express Hybrid Foamie
Poet Creek Or Bust
Engineering the TLAR way - "That Looks About Right"
TnTTT ORIGINAL 200A LANTERN CLUB = "The 200A Gang"Green Lantern Corpsmen