New Project Maybe?

So I found this little gem at work getting ready to be thrown away and being the reef nerd I instantly saw a nice cube tank.  It was a box used for suggestions or drawings or something like that.  So far it has passed two days of holding water but I am still not convinced.  I was thinking of running some weld-on down the seems on the inside.  I also thought about using the acrylic lid and making a euro brace for some extra durability.  Any suggestions?  Will it work or should I just give up on it.
Specs are 15.5 x 15.5 x 15.5 and acrylic is 1/4"
And for the pics