Sunday 9 June 2013

Under Construction

Piece R in progress
I've started building proper cube pieces. It's taking a lot of measuring, double-checking, and Pythagoras' theorem to make sure the pieces don't end up too warped. I suppose the process would be less laborious if I had been able to cut the faces and frames to higher precision.

Roughly speaking, the steps to build each piece are:
  • Collect all the parts required.
  • For each length of frame:
    • Clamp it onto the side to which it will be glued.
    • Drill pilot holes for all the screws it will need.
    • Secure it temporarily with just two screws.
  • Fit the faces together, and add more pilot holes and again secure with two more screws on each edge. This is the step where the alignment of the holes can be fine tuned, to help keep the faces flat.
  • Number the faces on the inside, and also mark which other faces they are adjacent to, for easy reassembly on site.
  • Drill pilot holes for all the feet.
  • Remove the second set of temporary screws.
  • For each side:
    • Label the corners with letters on the inside, and label the ends of the frame with the same corner letters.
    • Remove the first set of temporary screws, to release all the lengths of frame.
    • Countersink all the pilot holes.
    • For each length of frame:
      • Glue it onto the side, and secure it permanently with all the screws it will need.
Preliminary construction of piece S
I weighed piece S after assembling it. It is 16.7kg, which is about what I was expecting. One person can lift it, but it would definitely be more fun for two people.

Gluing the frame onto one side
Meanwhile, I did a bit more work on the maths. I found that, by adding variables that model how much of each solution face appears on the outside of each solution, I can use the same integer constraint solver as before to discover a set of ten solution faces where solving for one face doesn't nearly reconstruct any of the other faces. This required 360,000 constraints and I wasn't sure the solver would be able to deal with that. But it turned up an answer in only 30 seconds ... in spite of being single-threaded.

Back in the physical world, I still need to work out how to varnish and paint the thing. The wood is very absorbent, so it could probably use a coat of varnish before painting with acrylic or similar.

If you've got any recommendations, let me know.

Ready for decoration







2 comments:

  1. Undercoat for wood... usually used for skirting boards/ doors made of similar wood. You usually only need one coat. It leaves it gleaming white and ready for any gloss or emulsion. Unless, you want the knotting to come through, then there are good selections of outdoor wood-paints in natural and/ or vibrant colours. I guess you need to decide if your cube will be mostly for inside or outside. Good luck.

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  2. The cube is definitely for outside ... in Spain.

    I think it'd be nice to leave some of the wood texture visible, because the designs I have in mind will be quite blocky and loud and some natural pattern would make a good contrast to that.

    I'm going to try out some lacquer that one of my friends has going spare.

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