Homebrew PCBs

Hi,

Probably a somewhat silly question, but...

I need to attach a small populated circuit board on top of a
(much) larger, also populated, circuit board. Next it should
be easy to separate them, without destroying anything, later
on if that should be needed. That is I want to achieve the
same as one usually do with using spacers, but with using
glue.

Is there any type of glue that can be used this? Can one use
"hot-gun" glue for this?

Thanks in advance!

br,
kmm