I want to collect and record the final design of the monolith here before scraps of paper start to get lost. I'll start with the framing. It is MetalMate brand 32 x 32 x 1.5 mm black slotted steel angle
available from many hardware stores including Bunnings.
It's nice that it really is metric, when so many items sold in Australian hardware stores are not, 38 years after metric conversion. But just because it's metric doesn't mean it's accurate.
The distance between slot centres is usually constant on any given piece, but it can vary between pieces, from 49.8 mm to 50.2 mm. This makes a repeatable design challenging, as there are of course only certain distances between bolts that are possible (using the slots) and the variation in slot spacing means the ranges that can be guaranteed to work get smaller as the distances get bigger.
Add to that my aesthetic (or obsessive) requirement that the outer dimensions be in the ratio 1:4:9, and that the shelves fit LiFePO4 cells of a useful capacity without needing any actual shelving, and that its width allow it to fit in the back of a Prius when fully assembled. Then the possibilities are fairly well constrained.
I allowed for 10 mm thick cladding on the top and three sides, and 5 mm thick cladding on the back (fibro against the wall). I also allowed 2.5 mm for bolt cup-heads, 1 mm margin for error between cladding and bolt-heads and 1 mm of height for the plastic feet.
I settled on overall dimensions of 225 x 900 x 2025 mm between outer faces of the cladding.
This resulted in cut lengths for the slotted angle of
2013 mm for the 4 long verticals,
863 mm for the 10 long horizontals,
194 mm for the 11 short horizontals, and
568 mm for the 2 short verticals either side of the PIP-4048MS.
There were also a few short pieces that completed the mounting of the PIP and the smaller of the 3 switchboards, whose precise lengths I did not record, but they were approximately 180, 100 and 100 mm. The two shortest required one side to be cut away so they are not angles but flats.
Because of the aforementioned variation in slot spacing, and the need for pieces to be symmetrical, all but the four long verticals should be measured by starting from their centre and measuring half their length in each direction. Their centre must be placed midway between two slots in all cases (not in the middle of a slot).
The long verticals should not have an open slot near the floor as this would be too weak and put too much pressure on the plastic feet, so these are just measured from their factory cut end, which results in an open slot at the top end.
You need two Starter Packs to get the 16 corner braces that are required, and one Add-on Pack to have sufficient additional nuts and bolts. http://www.rcr.com.au/metalmate/metal-m ... eel-system
Here's a view of the whole frame (with Coulomb working hard on software).
Here's a closeup of the bottom of the PIP mounting, with a cutaway to clear cables and a flat horizontal for the lower PIP mounting bolt. Ignore the fly screen with casement-window portal in the background.
The gap between steel angle and cladding was filled with black self-adhesive (one side only) 15 x 2.5 mm foam tape, to take up the thickness of bolt-heads and margin for error. I can't find this foam tape on the Bunnings website although that's where I bought it, along with the polycarbonate sheets. The label says "SUNTUF BACKING FOAM 20m For Single Use with Suntuf SUNLITE". The 20 m roll was just enough.
The cladding was cut from 2 sheets of 2400 x 980 x 10 mm Suntuf Sunlite solar grey twinwall polycarbonate
. Don't bother trying to cut it with a knife (wanders like crazy) or a panel saw (jams like crazy). Use a jigsaw or sabre saw with a fine toothed blade.
Cut sizes of cladding were:
Front 2020 x 890 mm
Back (fibro) 2020 x 890 mm
Top 890 x 195 mm
Two Sides 2010 x 195 mm
[Edit: I think in future the two smaller dimension should be bumped up by 5 mm, to 200 mm and 895 mm given that more accurate cutting implements will be used.]
Vents were described and shown in photos in a previous post.
Corners were dressed with mitred 40 x 40 x 1.6 mm aluminium angle screwed to the steel angle, screwed only on the sides and top, by 6 gauge x 25 mm 316-stainless countersunk self-tappers. Photos in previous posts.
[Edit: The screws need 4 mm clearance holes in the aluminium and 3.17 mm (1/8") pilot holes in the steel for self-tapping. The holes in the aluminium were 10 mm from the edge, but should be 15 mm in future. They are spaced 450 mm or 500 mm apart.]
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).