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Construction Steps Outline

Here's a list of steps for Gray-B-Gon workshop participants, condensed from the Construction Guide ("CG").  The numbers on these steps match the CG step numbers.   You need not perform the steps in strict sequence.  Some steps have already been performed for you.

The early steps here are done mostly by small teams doing a single task multiple times.  Then, when trays are available, you will use one to build  your own Gray-B-Gon by mounting parts and subassemblies.   Don't let your parts get mixed with those from other units:  label your wheels, tray, drum axle, masts and bucket with your or your camp's name. 

You will receive three bike wheels: one with an angle bracket mounted on the axle will become the propeller; the other two will become drum ends.  Any wheel with wire woven through the spokes around the hub is a drum end; the wire is to center and stabilize the PVC axle.  Wheels with freehubs (splined ratcheting cylinders) may be used either as propellers, or as drum ends.

Some 1-1/4" PVC pipes fit bicycle drive trains almost exactly, but other pipes may be a tight fit, needing wiggling or twisting. In building the pulley, the 1"-long pipe has to fit over a freehub.  Usually there's a good or loose fit; but if not, consult with me before applying excessive force.

1. Sand edges and varnish all wood.  The wood parts you get may already be sanded and varnished.  For those that aren't,
  • Use coarse sandpaper to grind off splintery edges and sharp corners. 
  • Before varnishing  plywood squares ("staples"), drill a 1/8" hole through the center, of one or of a stack.
  • Spread a plastic sheet dropcloth and put on surgical gloves.
  • Start varnishing 2x4's and 1/4" plywood floors; then 2x2's and plywood trapezoids and rectangles (feet); finally plywood staples.
  • Coat end grain and plywood edges, then coat surfaces, then end grain again.
  • Wipe out drips or heavy areas, so the coat will dry evenly.
  • Keep your brush in a "damp bag" when you're not using it. 
  • Dry trapezoids on a drying rack, between close-spaced screws.  Dry floors and  2x4s against a wall.  Dry feet and staples on a piece of shadecloth.
  • Don't leave wood pieces resting on the drop cloth while they're wet.  Dry them touching other wood pieces or shadecloth, and move them occasionally.
  • When you're all done, pour back unused varnish and rinse out your bucket.  Rinse brushes at least 4 times.
While the varnish dries you can do any of the next group of steps.  To hold your propeller wheel upright, clamp a wheel-clamping jig against a tray wall with your wheel sandwiched between. 

5. Cut two liners from a 10-ft-wide roll of plastic sheet.

    •    The table has blue tape marking 42" and 55".  Unroll a folded sheet to 42" and cut.  Turn it sideways.
    •    Fold 10' length in half, measure 55", and cut about 5" from the doubled center.  Fold liners so they'll fit in gallon ziplocs.

6. Cut 54"-wide tulle in half lengthwise.

19, 20, 21, 22. Mount a pulley on your propeller wheel. 
  • Clean the 1"-long PVC pipe surface with alcohol and a paper towel, and wrap anti-slip tape around it. (CG step 19.)
  • Hook three 3-1/2" wires (16 gauge copper) on spokes and assemble the pulley. (CG step 22.)
  • Label your propeller.

23. Cut blade shapes.
    •    Using the flashing-cutting jig and a box knife, score the aluminum flashing, then flex til it snaps to make rectangles: either 4 rectangles or 5  (for a 32- or 36-spoke wheel respectively).  Score along the outside edge of the guide for 9" blades (large wheel) or along the inside for 8" blades (medium wheel).
    •    Flashing is slippery -- have a helper hold it immovable in the jig.
    •    Using a template and marking pen, trace two blade shapes on each rectangle.
    •    Cut and smooth blades with a file or emery paper, so they don't draw blood.

24, 25. Mount blades on your propeller.
    •    Blades go on the opposite side from the pulley.
    •    Follow CG Steps 24 and 25.
    •    Use a C clamp to hold the blade stack, and drill pairs of 1/8" holes. Start and end zipties on the side opposite the pulley.

27. Make a drive belt from a stocking leg and cotton rope.
    •    ("Fisherman's knot.") Tie a loose overhand knot close to one end of the stocking leg.
    •    Lead the 8ft rope through the overhand knot, and  tie an overhand knot in the rope that surrounds the stocking leg.
    •    Tighten knots by pulling on long ends.
    •    Later, in operation, you will be able to increase tension by sliding apart the two overhand knots.

When the varnished wood is dry enough,  assembly can begin.

8, 9, 10. Make the tray.
  • Use a 1/4" plywood floor as a work surface.
  • Clamp the end 2x4's between the side 2x4's and align carefully with hammer taps.
  • Each corner gets two screws.  Drill  (1/8" pilot, 11/64" body), countersink, and install a 3" screw.  Repeat with  second screw.
  • Use the warp gauge in both orientations to check for flat, and shim as needed ( CG Step 9.)
  • Assemble the tray upside down.  Make a "deep end" with 4 builders' shims. Staple each shim twice.
  • At one end, drill 7 pilot holes, hitting each foot twice. The holes in the plywood feet must be countersunk.  Use 1-1/2" screws and drive flush.
  • At the other end, align the 2x4 frame and the plywood floor, clamp, and repeat the drilling and screwing.   Drill and screw the sides, hitting each shim twice.
11a. Drill gussets & propeller arm from templates or from pictures in CG Steps 11 & 13.
          •    To protect worktable, drill into scrap wood.
          •    Position one gusset hole to prevent symmetric hole pattern.

13. Mount the arm on the power mast.
  • Bolt the GA2 bracket to the arm, with one 3/16" bolt.  The nut goes on the metal side.  Drill 2nd hole and mount 2nd bolt.
  • Drill pilot holes (5/64") into the nameplate corners and the arm, and mount the nameplate with #4 screws.
  • Fasten the arm to the power mast near the top with one 1-1/2"  screw. Tilt the arm to point the GA2 face very slightly downward, and drive a second screw.
11b. Mount the masts on the tray.
  • Label gussets and tray. 
  • Mount one gusset over the "deep end" shims, using the mast-gusset gauge.  Align the bottom faces of the gusset and the 2x4, and clamp them.
  • With the gusset as a template, drill one hole and run the bit in and out several times.
  •  Insert a bolt from inside the tray and screw on a wing nut.
  • Fasten the other three bolts similarly, then mount the other gusset on the opposite face.
  • Align a mast with its gusset, clamp, then drill and bolt masts to gussets with two bolts, one bolt at a time, using hex nuts.
14, 15. Mount wheels for the drum.
  • Label your wheels and the 3 pvc drum axle parts.
  • You will be working on the sides of the masts that face the long end of the tray.  Place a 1/4"  plywood scrap in the tray under the power mast.
  • Rest one wheel vertically against the power mast, with any woven wire cages, threaded hubs, and freehubs facing the opposite wheel.  Slip an A34 angle bracket over one wheel axle, and place it against the side of the power mast.  Clamp it in place, or fasten it by driving a single screw.
  • Repeat with the opposite wheel.
  • Do a trial fitting: Assemble the 3-piece drum axle between the wheels, making sure the pvc axle ends fully bottom  on the wheel hubs.   Have a friend slip the A34 angle brackets over the wheel axles, and align them with the masts.  Fasten one bracket with a single screw, then the other.
  •  The brackets must press inward against the wheels with moderate force. You may need to adjust their positions  left or right by up to 3/4".  Fasten the A34 bracket with a single screw.  Tug gussets outward to check that the wheel axles stay caged.
  • Remove the 1/4" scrap.  The assembly will sag, until Step 16 is completed.
16. Rig diagonal twine bracing.

About twine: To open a ball of twine, poke a hole in the end of the wrapper and fish out the twine end.  Don't tear off the wrapper.  To keep twine from fraying, tie an overhand knot in every twine end.   When you cut twine, tie an overhand knot close to each new end.

  • On both wheels, use blue tape to mark spokes at 12:00 , 3:00,  6:00, and 9:00.  On a 36-spoke wheel this will be only approximate.
  • Cut a 25-ft length of twine, knot one end, and at the other end tie an overhand knot in doubled twine to make a loop.
  • Thread twine through the spoke space from Left 12:00 to Right 4:00, taking the path shown in the figure.  Lead the twine in through whichever spoke space is nearer to where you came from, and out to the nearer spoke space at 8:00.   Continue by 4-hour steps, alternating wheels, with a friend rotating the wheels in sync, until you reach Left 12:00 again.  If you've done it correctly, the twine never crosses itself near the taped spokes.  If the bracing suddenly looks unsymmetric, one wheel may need to be turned by four hours.
  • Put the twine end through the loop, tension softly, and fasten with a slipknot.
  • Check that at each taped spoke, the twine loop rests against the rim and spoke nipple, and isn't hung up on the end of the nipple.
  • Have your friend gently oscillate the wheels in opposite directions, 4 inches or so.  This lets the twine slide, while you align the wheels as needed.  Spin the assembly to evaluate wheel straightness.  Apart from aesthetics, if nothing scrapes it's good enough.
  • To unite the elements at each taped spoke, slide a ziptie over one strand of the "u-turn" and under the other strand.  Surround the spoke and the two twine braces with the ziptie, and pull it into a small  loop without tightening it.
  • If bracing has increased the wheel axle play, unscrew and move A34 brackets inward as needed.  If either axle end is less than 1/2" long, tug the masts apart gently and remove that play too.  Screw A34 brackets into place with one more 1" screw in each mast.
17. Lace a zigzag twine surface.
  • Tie an overhand knot in doubled twine to make a loop at one end.
  • Zigzag loosely between the wheels.  The first zig goes through a spoke space that's not straight across, but offset by two spoke spaces on the far wheel. The zag returns over both rims, offset by four spoke spaces from the preceding zig. Continue zig-zagging, advancing four spoke spaces each time.  If the other wheel has 36 spokes and this one has 32, advance by only three spoke spaces at every quarter-revolution, and you'll come out even.
  • On return to the starting spoke, put the twine end through the loop and tie it with a slipknot.
  • Raise tension gently and uniformly.  Note that when you try to re-erect a collapsed drum, high twine tension may make it nearly impossible.
18. Attach tulle.
  • Wrap a tulle panel once around the drum; anchor two corners (including the rims) with zipties poked through material  and around  nearby spokes. Repeat at the opposite end, with only slight tension. Cut off the excess.  You should now have an inconspicuous opening in the tulle surface, through which you can reach inside the drum if necessary. 
  • Build tulle trim from two tulle strips of contrasting color.  Form a bulge by wrapping one strip in a spiral around 6" of rim, forward then back, then ziptie both ends to a nearby spoke. The object is for the bulge to brush the tray floor gently as the drum rotates.
  • Ziptie the tulle's other corners, then ziptie again at one half, and at one and three quarters.
26. Balance propeller.   If it's windy, go indoors or skip this step till later.
  •  Cut a length of 12-gauge copper wire to rim-to-axle distance, and make a small flat coil.
  •  Tape the coil to the center of the top (lightest) blade.  Move the coil inward or outward where the wheel's balanced, or at least close.
  • Measure the coil-to-axle distance, and cut the coil to that length.  Wrap it over the rim, hooking one end or surrounding a spoke so it can't slide.  Bend the wire ends inward to prevent snagging.

26. Label and drill your bucket:  two 3/8" holes in the bottom, and two opposing 3/8" holes halfway up the walls.

Be sure you take home:
  • Tray
  • Power and idler masts with gussets, and arm with Gray-B-Gon nameplate.
  • A transparent big bag ("drum liner") holding
    • a propeller with attached GA2 bracket and
    • a tulle-clad collapsed drum.
  • One-gallon ziploc bag holding
    • a black plastic liner
    • a spare big bag, 
    • forty zipties,
    • eight plywood staples with 1" screws,
    • two small (10-24 gauge) wing nuts and carriage bolts,
    • and, unless they're in use clamping the gussets, eight 1/4" carriage bolts and wing nuts.
  • Bucket holding three-part PVC axle, drive belt, small towel, and  twine ball.
  • If construction is unfinished, you may need to add items not yet mounted such as blades, tulle,  zipties (twenty for blades, six for bracing, ten for tulle, plus spares), two A34 angle brackets and four 1" screws, one GA2 angle bracket, propeller arm and two 1-1/2" screws.
At home, print Construction Guide steps 28-34, read it before travel, fold it and seal it for the playa in a large ziploc.  Note that you still need  to gather some materials, like Clorox and solar path lights.

Questions, comments, communication: please visit www.evapotrons.info or email ember at burningman.com.  During the event, I live in the Alternative Energy Zone.  I bring spare parts and a friendly interest in how your device is doing.