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Morning Lab 8:00 – 11:00am

First I did a little research into different types of bamboo joints, check out the link below:
http://www.used-hq.com/used-website/assets/pdf-downloads/Bamboo%20Trailer%20Instructions%20Email2.pdf
and
http://bamboo.wikispaces.asu.edu/7.+Types+of+Joints

I decided a good place to start would be to build a join of each of the following types then we can compare them on how challenging they are to make, how strong they, how applicable they are to a particular application, etc.

Type 1: Double Butt Bent Joint
Type 2: Friction-tight Rope Connection
Type 3: Plug-in/Bolt Connection
Type 4: Positive Fitting Connection
Type 5: Interlocking Connection

Type 4: Positive Fitting Connection (Type A)

I started with this type as it was the simplest.

1. I cut two short sections of bamboo of different diameter using a hacksaw.

2. I used the drill press and a v-block to roughly put a hole the shape of the smaller bamboo tube in the larger tube.

The vice is easy to overtighten and I heard a crack when I was too aggressive tightening, so be careful and only tighten it enough to hold the stock in place.

3. I used a round file to get the hole to the right size and shape for the smaller bamboo pole to fit through.In line with text | Fixed position

4. I used the plastic rope that came with our bamboo to bind the structure together.

Type 4: Positive Fitting Connection (Type B)

1. I cut a short section of the smaller diameter bamboo pole and used the drill press and file to put an appropriately sized hole in the larger diameter bamboo pole, however this time I only drilled through one side of the bamboo. I also added a smaller hole offset 90 degrees from the large hole to accept a pin/wedge.

2. I used the same small diameter drill bit to put a hole in the smaller bamboo piece. I located the hole by inserting the smaller rod into the larger rod and holding it at ninety degrees and used a pencil inserted in the small hole on the large rod to mark the smaller rod.

3. I used a the bandsaw to cut a small long block from scrap wood and then used the disc sander to make it into a round dowel approximately the same size as the small holes on the big and small bamboo rods.

4. Lastly, I pressed the round rod into the bamboo connecting the two pieces.

I was messing around with pushing the rod in tighter and may have cracked it at the end of lab, it was a really soft piece of wood, but when it fit in tightly it did a surprisingly good job of holding the pieces together without a lot of play between them.

Concluding thoughts:
Binding the bamboo with rope (possibly also dipping the rope in the prickly pear juice) certainly would be interesting. Drilling holes in the bamboo is time consuming and weakens the bamboo so binding methods that don’t involve cutting holes certainly are appealing. I think we should get some hemp rope or investigate ropes of common materials (i.e. what ropes are currently available in developing worlds). I also was thinking about the plastic bag rope idea and thought it may be interesting to pursue that further, it may be possible to head shrink the plastic once has lashed the poles together creating a stronger/tighter type of connection.

Don’t feel any compunction about doing anything different than what I did or pursuing any of the multitude of approaches we could take, I’m excited to hear and see what you guys do.

Afternoon Lab 12:00 – 3:00pm

Hey Ethan, we tried out the Type 2: Friction-tight Rope Connection today, and tried out different machines with the bamboo.

Machines:

-Vertical band saw works a lot better than a hand saw (what we tried first).
-Also another type of saw with clamps–Audrey/Kimber/Mariah what was this called?
-Drill
-finer teeth to prevent splinters
-Note: when we used a clamp to secure the piece of bamboo we were drilling a hole in, the bamboo flexed with the pressure. Maybe we should consider using a cloth between clamp and bamboo when we use this again. Or maybe something we can use to test the strength of the bamboo.

45 degree angle for the angled piece of the Friction tight-rope connection

To accommodate the roundness of the bamboo piece below the angled piece, Pete suggested using a piece of sandpaper and sanding the mouth of the angled piece to become more curved. This took me about 10 minutes to get the angle piece flesh with the bottom piece. Next time we can try the rotary/round sanding machine.

Simple, x-shaped joint of two bamboo pieces with twine Audrey made. I think this is our best bet so far.

Twine:

-We need more. Definitely. Next lab we were thinking of trying out different thicknesses of twine, or even different materials.

Prickly Pear:

We also tried out a bit of prickly pear on the bamboo. After applying and letting dry, the bamboo really had no difference to it. Maybe slightly shiny-er (for lack of a better description). However, I think we should consider staying in contact with the prickly pear group to see if they might make some sort of bonding agent with the pears, which we may be able to then use. Or the juice might make a seal, to protect the bamboo from weathering. Thoughts on the prickly pears?

We also began working on a plug-in/bolt connection but our time was cut short. Although a structure/joint prototype wasn’t created, we built our confidence in dealing with the machines.