What does expanding foam do to polystyrene?

[maxi]

Need to enhance the insulation around the fridge, cannot get to and remove existing polystyrene sheets. So, after drilling suitable air vent holes, what would be the effect of introducing aerosol expanding foam?.

 

[VicS]

Theres no solvent in it AFAIK that will affect expanded polystyrene.

Worth trying it on a piece of scrap.

Can't use the polystyrene beads I suppose

 

[jwilson]

Need to enhance the insulation around the fridge, cannot get to and remove existing polystyrene sheets. So, after drilling suitable air vent holes, what would be the effect of introducing aerosol expanding foam?.

I used expanding closed-cell foam once to stiffen a very lightly built sailing dinghy, and put in more buoyancy than the small blocks of polystyrene that were fitted by the builder.

A test prior to filling the dinghy showed that the expanding foam sort of melted the edge of polystyrene blocks slightly, but that it all then set hard again quickly. So I left in the polystyrene, and actually added some more large chunks of polystyrene to save on the quantity of expanding foam needed. This was with a two-part liquid closed-cell foam, not Polycell aerosol stuff.

 

[prv]

I insulated the metal roof of my workshop using polystyrene sheets, and then used the aerosol stuff to fill in the gaps. Several years on, there's no sign of it eating the polystyrene.

Pete

 

[maxi]

Thanks Gents, just what I hoped to hear.

 

[alan17]

expanding foam

Cannot answer the question but just a word of caution. I once filled a punctured football to make a dan bouy. The stuff expanded mosr, much more, than I had anticipated. I had to cut off masses of surplus! Also releasing the trigger did not stop the flow!! You could end up with a frightfull mess!