Help on building an enclosure

[EddyCurrent]

1. How big will my enclosure need to be? I am housing a standard off the shelf 48v PSU, along with the leadshine mx3660. How much free air space do I need to leave around them?
2. What material would be best? Ali or steel, or does it even matter? Can I paint it?
3. What other features should I incorporate? Such as a dedicated earth fixing point?

1. I used Sketchup to draw my components in the form of boxes, save them as 'groups' that way you can rearrange them at will until you find the best layout. There's never much detail supplied about free air space other than with the VFD that likes about 75mm top and bottom.

2. Steel is the best, it's cheaper than aluminium, has better shielding properties than plastic, it's strong. Painting is the best idea, personally I like the grey that standard panels come in.

3. First thing is you want a removable back plate where all your components are mounted, steel is normal but aluminium would also be fine. The last thing you want is drilling holes in the panel itself to mount things.
It needs a hinged door because likely you will be mounting buttons etc. on it.
Normally they have a removable gland plate top and bottom where your cables pass through.
You might want to take into account cooling fans, these should be mounted to blow into the panel at the bottom drawing air through replaceable filters, this is keep air pressure inside the panel greater than that outside which keeps crap out, you will need an outlet at the top that does not let dust in by gravity.
You want an airtight gasket around the door when it's closed.
You might to fit a 'door interlocked isolator' for safety.
The panel itself, the back plate and the door should all be electrically connected to earth for safety, normally there is a stud spot welded to the inside of the door and one inside the panel, a short length of earth wire connects the two but still allows the door to open, the back plate is normally secured by four corner studs that raise it high enough above the back of the panel to clear nuts, etc. you used to mount components on the back plate with. The earth stud inside the panel can then become your 'star' earthing point.
You need a method of mounting the panel on a wall, this can be four holes in each corner of the back or a lug welded externally at each corner. Whichever way you choose you need to have access to these mounting points with all the guts installed in the panel.