Just out of curiosity, how do you plan on checking for leaks at your pump?
As there will be no access.
In regards to your last post, i read your link and in it you said you weree going to make one out of aluminium. Have you actually tried?
As panyan said aluminium is expensive, wood is cheaper. However you could make it using a side panel from an old case.
2 pieces of angle iron and a hammer and a couple of clamps.
Cut out your size-443mm x 366.
Measure out your cuts and bends, using a thin marker pen.
With a dremel or jigsaw make 2 cuts, to allow you to fold the end(36mm hole) down.
On the other 2 sides add 10mm to allow for an overlap, total length=365mm.
Place the end where the cuts were made between 2 pieces of angle iron. making sure both are inline with the marked line and clamp tightly. Press the the strip down using your hand or block of wood. Then using the hammer tap a long the bend, until you have an even edge. Do same for the 2 10mm overlaps.
Then do the same for the other 2 sides.
You can either use metal glue, solder, spotweld or pop rivets to fix end panel to the overlaps. Bit of carbody filler down the edge or any ripples and then spray.