If you epoxy two layers of glass together you get a laminate that is not very stiff. If you laminate something in between the two layers of glass the result is much stiffer. I don't pretent to understand the science of it all but I think it has something to do with what that intermediate something is and also how far apart the glass laminates are spaced apart. I think ignoring the second proviso can hurt you.

: So.... I find myself trying to beat the inclement (less than 60 degree)
: weather; I've sanded my deck, only to find a few joints have 'come loose'.
: Not a major, I simply slipped some glue into my less than pristine joints,
: and all seems well. But I wonder - is this a hint that perhaps I've sanded
: 'too thin'? My inclination is to think so, and stop, heat the shop, and
: epoxy. BTW, any thoughts on exactly how warm is a minimum? I'm using RAKA
: - I believe their website indicates to 'keep it above 60 degrees, 70 is
: better'. Perhaps a plastic tent and electric heater?