saywhatthat wrote:Thank you rruff
Rmax Thermasheath-3 1 in. x 4 ft. x 8 ft. R-6 Polyisocyanurate Rigid Foam Insulation Board . This is for the side walls . The side walls, will have no doors. Door is in the rear
I'm not familiar with that, but you may want to look at Extruded Polystyrene (XPS). The blue or pink stuff at the big box stores. It is pretty structurally sound for foam. Most of the Foamies are made from it.
To get a strong bond with closed cell foam you need to texture the surface. I use a carpet seam roller, but there are other options. PL Premium is a good glue to use for XPS foam. Buy the big tubes, rip them open, and spread the glue with a notched trowel. Probably best to lay the glued foam on top of the steel rather than the other way, and try to get even pressure. Try some samples to see if you are happy with the results.
PLP draws moisture to cure, and it isn't going to get any through the steel or foam faces. I don't know if a little water mist would help before slapping them together or not. I've only glued foam to wood.