I decided to build a big box.
the outer box is wood box, inner lenght 60 cm.

the inner box is a plexiglass box, lenght 50 cm, covered with copper


detail, plexiglass 2mm, copper 0,5 mm

placing the inner box inside de outer box
between the lead plates and copper his a sheet of 1 mm pure tin

after de sample is put inside a lid of plexiglas (2mm) , copper plate (0,5mm) is put on top

after that a pure tin plate (1 mm)

after that lead sheets
The objetive of this setup is that is eaily upgradable, if I want to add more copper it's easy, if I want to add more tin, it's easy, if I want to add more lead it's easy, lead can even be added outside the wood box, but for that I have to place the whole setup somewhere that it will not be moved, becuase it's a heavy setup.
looking foword for your comments, and sugestions.