???DIY Cage Question???

[micha08txburm]

Hello all--I'm in the planning stages of building my first cage for my burm. I'm building it out of birch plywood. I want the stained look so I picked up some MINWAX POLYSHADES, its the stain and polyurethane in one step, for the outside of the cage. Would this be safe, and if so--will I need to seal it with anything else or will a few coats of this be enough?

Another question--On the inside of the cage I plan on using bathroom/tile board. What is a good adhesive for the bathroom board? I was thinking liquid nail, and then some bathroom/tub caulk sealer on the seams, but I'm not sure.

Any suggestions would be great!

Thanks! :)