Home‎ > ‎

Preparing a workshop

In  summer 2009 and 2010 I led five Gray-B-Gon-building workshops in the SF area, each with ten participants or fewer.  While they built 44 evapotrons,  I continued to shorten and simplify the workshop process.  Organizing a workshop to build multiple evapotrons is now something many burners can successfully undertake.

Plan to build a first Gray-B-Gon ("GBG") well before your first workshop.  You'll get essential familiarity, it will be a valuable guide at your workshop, and it'll attract interest at local activities.  On request, I'll get you started with the only difficult bits, the pulley flanges and the metal angle brackets (and the nameplates: see "Shopper" below.)

The Workshop Flow page tells organizers how the day will go.  It is based on my 2009-2010 workshop experiences, with improvements.   The Construction Steps Outline page is for participants; it relies on the CG but is streamlined for the workshop environment.

For organizers, the Workshop day will last about nine hours: two for setup, six to build evapotrons (and some won't be finished), one hour to clean up.  If you want to make the day shorter, varnishing is the most time-consuming step, about two hours for four people plus drying.  Consider holding a varnishing party before Workshop day.

People and Activities

First, mobilize your helpers.  You will need a few core people with specific capabilities, and many who will help simply by gathering materials.  In fact, activating your obtainium-gatherers should start right away: their job will take time.  They’re looking for:
  • Five-gallon plastic buckets.  Smaller buckets are okay too.  Buckets must have a protruding lip, so panty-hose can be slipped over the top and tied in place.
  • Three or four short wide-mouth plastic jars, with lids.   These are used to hold varnish poured from a gallon can on Workshop day.  The best jars I've found are snack food containers, at Costco.
  • Plastic bottles.  Construction Guide Step 17 shows the usable bottles.  I've had scant luck in recycle bins.  Probably much easier: ask community members to buy Crystal Geyser or Kirkland (Costco) water in 1-liter bottles.   A case of 20 bottles, enough for 10 GBG propellers, costs under $5. 
  • Sheer stockings, panty-hose, and towels.  For one GBG, you need one panty-hose for the filter, 3 legs of stockings or panty-hose for the drive belt, and one towel scrap 14" square to cushion the filter bucket.
  • Borrowed folding work tables, or other tables; 6-foot length desirable.  For a workshop with 8-15 participants, you will need five to seven tables: two for tools, materials, sheet cutting and propeller-building; one for tray-building; and about one more for every four GBGs being built.  More is better.
  • Old bike wheels.   Construction Guide Steps 3 & 4 describe the usable wheels.  Wheels require storage space, and a person with bike-mechanic skills to work on them.  More below. 

Woodwork and PVC

You will need someone with access to a table saw with an accurate miter gauge.  Buying and cutting wood and PVC can wait until your workshop plans are firm.  Here are Lumber and PVC cutting plans.

Metal drilling

As shown in Construction Guide Step 12, the Simpson A34 brackets must be drilled to receive axles. The GA2 brackets must be drilled to receive skewers or axles, and the side holes on the other face must be drilled out to 3/16”.   Anyone with a vise and a step drill bit can do this easily.

Bike wheel collectors and mechanics

Rounding up old bike wheels can be challenging.  Wheels that aren't repairable don't stay long in a bike shop; mostly, they get tossed into the dumpster the same day they come in.  You will need to talk in advance with a mechanic, or maybe a manager.  Show them some pictures.   They know about Burning Man; they may be Burners.  They are often sympathetic to helping worthy causes, and may agree to hold sad wheels for a few days so you can swing by once a week, say.  Mostly, the more upscale the store, the less willing to cooperate.

Here's what finally worked really well:
  1. Connect with a nonprofit, community-oriented bike shop.  They also discard, or more likely recycle, old wheels.   At the Missing Link in Berkeley I met with the mechanic who organizes their recycling.  I proposed giving them $4 for each wheel that gets used in building a GBG.  It's a good deal for them -- recycled for the metal, a wheel is worth about a dime.  I described what we need: alloy-rim wheels 24" and up, with usable bearings, gear clusters removed, and spare axle nuts if available; bent rims and broken spokes not a show-stopper.
  2. I or a helper pick up a truckload of his wheels, take them home, and select the usable ones.  I adjust them and put them in groups of three.  The unusable ones I recycle, after I remove and save the axle nuts and cone nuts.
  3. On Workshop day, I hand them out and ask for $4 per wheel, all proceeds to go to the bike shop.  Builders are happy to help out.
  4. The money goes to the bike shop on my next trip to pick up wheels.
One heads-up -- I want to pay for wheels only when they get used, so it's particularly important to track each wheel, where it came from and when it gets used.  So far, I'm making do with a strip of masking tape around a spoke, with the bike shop's name written on it.

You will need someone who's able to remove tires and to adjust bike wheel bearings.  The page For bike mechanics spells out what needs to be done.

Record keeper

Someone will need to record
  • costs of purchased materials.
  • money owed or paid to bike shops.
  • workshop rosters: who's signed up, who has confirmed, who has paid the materials cost.


Someone to go shopping!  And also to keep track of the parts inventory.  The Shopping List page is ordered by store type, and tells what quantities will build how many GBGs. 

There's one item that you need to ask me to send you: nameplates.  A nameplate displays a cheerful 1950s-advertising housewife presenting a GBG propeller, along with a URL.  It's for builders to mount on the GBG arm, beside the propeller.  Nameplates are laminated, and withstand weathering pretty well.  I hope you will restrain any impulse to hand them out freely.  Nameplates are for real GBG builders, not just anyone who's attracted or amused by the image. 

Parts Kits: a workshop without the time pressure

Some GBG builders prefer to work on their own.  What you can offer them is a parts kit -- all the stuff you have for workshop participants, at the same cost -- and the option to watch and learn from your workshop.  Offering parts kits may reduce the size of your workshop, and the stress of conducting it. 

Workshop Checklist

The Workshop Checklist includes pre-workshop todos,  items from the Shopping List (this time organized by their purpose), and all tools and other materials you'll need.  Nearly all tools are already in the toolboxes of the builders on your team.

Gauges, Jigs, and Templates

These informal, single-purpose tools that you can make from cardboard and wood scraps will ease GBG construction.  You need only one of each:
  • Using the gusset-tray gauge is faster than a measuring tape, and prevents two common errors.  Large cereal boxes made of fine-grain corrugated cardboard are an ideal material. Align the corrugation with the two dashed lines; cut it out, label with marking pen, and fold.

  • The tray warp gauge is made of scrap plywood, possibly leftovers from  1/4" plywood trimmings from tray bottoms.  Hang the crooked piece from the diagonal corners of a tray's 2x4 frame (before it gets a floor).  Stand the straight piece on edge over the other diagonal corners.  There should be about 1/8" air where they cross.  Swap corners and there should be a similar amount of air.  If it's off by more than 1/4", refer to Construction Guide Step 9 on removing warps.
  • The PVC vise,  a saw, and some blue tape make it possible to hand-cut precise pipe ends by following the procedure in Construction Guide Step 15.  Put a clamp on the left end of the vise, and saw alongside the blue tape.
  • The Flashing Cutting Jig holds the end of a roll of 12" flashing for cutting, and guides the knife.  Score the flashing by running a box knife tip alongside the bar.  The score line must be continuous from one edge to the other.  Remove the flashing from the jig, and bend it gently along the score line.  Flex back and forth if necessary.  The rectangle (a blank for two blades) will snap off. 
  • The trapezoid drilling templates are just a gusset and an arm, with holes drilled and with labels written on them; 1/2" plywood, or sheet metal if you expect a lot of use. These images are taken from CG Steps 11 and 13.

  • Use the flange marking  jig and a marking pen, then scissors to trim pulley flanges to 1/2 in. width.

Worth at least 250 words each: