On Fri, 16 Oct 2009 22:36:18 -0700 (PDT), Matty F wrote:

... solder the bottom on with silver solder. They need to be oil-tight!

2mm sounds a bit thick for some thing quite small. Think I would use
thinner plate and fold the sides up so that you have a mechanicaly
stable box with minimal gaps at the corners then just solder the
seams.

A loose base and sides I can envisage being a nightmare to solder
unless you can hold all the bits in place and do it almost in one
hit. Even with folded loop sides and loose base might be fun.

I've not soldered brass before. Any suggestions?

Just like soldering copper. Not a problem.

--
Cheers
Dave.