How To Make A Purple Plywood Boomerang
Or how to make a boomerang (the long and unnecessarily complicated way, with almost no power tools).
Hi guys! First things first: Please excuse my terrible use of English woodworking vocabulary (sorry about that, not at all my first language). ;)
So, I've decided to use some old "scraps" (very valuable scraps) of amaranth wood veneer... And make a boomerang with it. The plan: cut and prepare 8 layers of veneer; glue them together to obtain a 4 mm purple solid plywood shaped as a boomerang; carve the leading and trailing edges to a good profile; smooth it, and apply some finish (detailed informations with the pictures in the "build" part).
I was a little crazy with the depth of field, sorry about that, not my camera. ;)
I started with a boomerang I worked out two or three years ago. The shape is a complex omega false two-wing boomerang (the profile of the elbow is active and adds a pseudo third wing). On this design there is also a "trigger" (left wing) to facilitate the throw and torsion of the blades (the boomerang isn't perfectly flat, the two wings tip are up). Because of that last point, and its general form, I call it a corsair.
That's a "hard to throw / easy to catch" boomerang, which will fly 30/35 meters (or more if weighed down with lead) on a low to high trajectory and a nice slow down-glide on the finish. On the bottom left: The first prototype (lightweight cheap plywood) which has already broken into pieces several times, but after quite a few repair sessions is still flying today. On the top right we have the plywood cut plan. And finally, on the bottom right, the new eight veneer layers cut plan.
On this magnificent pizza box I've indicated the cut lines and wood orientation for each of the veneer layers.
The junctions between the parts of each layer were "calculated" to maximise the amount of veneer saved and ensure the strength of the resulting boomerang. There is always a 90° counter-orientation between two consecutive layers, except for the layers 1 & 8, the most visible ones... These two have their own specific orientation, the nicest veneer parts and are made of only two pieces.
Last but not least, because I wanted my wings tips to bend up a little, I chose very carefully some veneer pieces to generate tension in the plywood, eliminating the need to use a curved clamping mold...
... It was a risky move, and certainly not the "good" way to do it, but it saved me some work. I attempted this only because I know my wood, I know my glue, and I knew how much pressure I needed during the gluing. If this trick was unsuccessful: I might have had to correct the shape post gluing (steam, hot water, or microwave).
With that, I cut my veneer pieces. My amaranth veneer was very dry, hard, and breakable, so it's a slow, complicated, and painful process, but you can do it in 3 to 4 hours with a good razor knife (Tajima LC-302 small one or Olfa big yellow one, everything else is crap), or even less time if you have a good veneer jigsaw (lucky fellow).
I also used masking tape to protect the veneer before a cut, and avoid (minimize) breakage.
Same technique for the inlays... Some masking tape, some patience, and a good cutter knife. The elbow inlay (logo) is a pear tree veneer. The other one (which will indicate the rotation speed of the boomerang on the catch) is sycamore veneer.
Here you can see my eight layers, in order, a lot of masking tape and the different wood orientations. The seventh layer is sycamore (I wanted a clear and bright edging line for nice contrast).
I grouped them two by two (paying close attention to the order)... And I glued them in pairs.
The resulting four dual layer pieces... My two delightful assistants, who just came back from swimming were impressed.:)
They helped me with the next step by cutting some more pizza boxes (the old ones had been damaged by the glue)... Next we had to glue the four layers together.
To detail the gluing process: I stacked, in order: A clamp mold (melamine coated chipboard, flat), cardboard, waxed baking parchment sheet, the first layer of veneer and glue with successive veneer and glue layers until it was time to mirror the clamping stack. Applied pressure with cheap clamps and I was done for the day.
Clamps, clamps, clamps everywhere.
The resulting plywood, with a transfer of the final shape, from the plan. As you can see I made a rookie mistake: I should have been more careful and glued my inlay layer after the others, to be sure that the inlays were nicely aligned with the outline of the boomerang. Silly me! But let's carry on...
I used a belt sander (you can do it with hand tools, but this wood was damn hard) to define the final shape (you can see the misaligned sycamore inlay). And I copied the profile line (leading and trailing edges) from my plan.
This is the small "up curve" at the tip of my wing. The tension in my plywood contributed well to lifting the tip, same height for both wings (approximately 2 mm). The other sections of the boomerang are dead flat, no correction needed (for now), it was a total success (phew!).
I worked slowly and methodically on the profile. It was critical that it be absolutely perfect. I needed a constant thickness for all of the trailing edges, a good angle on the leading edges and smooth and progressive transition zones between leading and trailing edges.
To do that I started with several rasps, uses a sander (cautiously), and smoothed it (by hand sanding, grit 80 to 320 with a cleanup between each)... The different layers of wood act as a visual aid and the hand (by touching) does the rest. Final touch, a very slight chamfer on the underside of the boomerang (using the sycamore layer as a guide) to help the flight. The motto is: Take your time.
When it's « tout doux » (all soft), your lovely assistant can marvel at the quality of your work... While you are drinking a well-deserved beer (the sanding is really exhausting).
Something else that I didn't show here (it's a messy process and because of that I could not take pictures): I used acrylic fine arts paint to obstruct the wood pores.
I used this paint because it's compatible with the finish that I used, it's durable, it remains relatively flexible (there are strong mechanical constraints on a boomerang), it's easy to find, and this way I can obtain exactly the right color... About that, the wood tint will change with time (more purple/red), so I've used an old amaranth boomerang to match the future color...
... I pushed the paint into the wood pores with a cutter blade, removed the excess paint by scraping, waited for the paint to dry and gave it good hand sanding (320 grit to 600, following the grain). When that was done I started again (paint -> push -> scratch -> sand).
I chose a simple finish, because some amount of adjustment is inevitable (a perfect flight at the first launch is rare with a boomerang) and, sometimes, I need to do repairs. For this one it's linseed oil (2 passes) and an encaustic (turpentine + wax)(2 passes).
And with some of its older siblings...
To anyone who asks: "And what about the nice boomerang curve in the sky?" and/or "Is this purple thing can actually fly?" Well... I don't know yet. The weather has been rainy windy and cold for the last
four five days, so I wasn't able to test it yet. :/
Thank you for reading. ;)
nb: If you want to try to make your own boomerang there are a lot of plans here. And start with a Mini Fuzzy in cheap plywood... This little magic thing won't fail you (easy to build, throw, catch, and not at all dangerous if you use a cheap lightweight plywood).
nb2: Reddit users /u/azoq, /u/ButtsexEurope, /u/ByrneAfterReading and /u/taishakukaiten helped me with spelling, syntax, vocabulary and translation. A big thank you to them.