5
Tue 22nd Jan 2013
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Corrugated Card and Paper Tape Truncated Icosahedron

I'm pretty sure it is one of the laws of thermodynamics, perhaps the forth. If not it is certainly one of the fundamental attributes of the Universe.

"In a closed system the number of single, unpaired socks always increases."

And so with the inevitability that accompanies physical laws, here at robives.com towers we have a pile of unpaired socks known to us as the sock orphanage. We currently inelegantly store them in a plastic bag while we wait for the return of the sock siblings.

Obviously we "can-nae break the laws of physics" but here's a possible work-around.

Like many bibliophile families, we have a lot of used Amazon packages ready for reuse. Time to press them into service. I decided to make a nearly spherical store pod thing, the actual shape I used is a truncated icosahedron, the same shape as a carbon 60 molecule and the classical soccer ball. The shape is made from twelve pentagons and twenty hexagons.

I made pentagon and hexagon templates. (Members can download the file at the link.) If you make you own template make sure that the side lengths on both are the same. Time to switch to instructional writing style...

Collect together several sheets of corrugated card. Using the templates, draw out twelve pentagons and twenty hexagons.

Carefully cut out the pieces using a ruler and sharp knife.

Twenty hexagons, twelve pentagons and a roll of brown paper tape ready to go. For ease of assemble it is worth spending a little time cutting the paper tape to length. You'll need ninety strips each the length of one side.

Start with a single pentagon, tape five hexagons round it as shown.

Fold the hexagons up and tape then together.

Add five more pentagons between the hexagons. Be as accurate as possible in the alignment of the pieces. Small inaccuracies multiply!

Work your way round the shape adding hexagons and pentagons as appropriate. Each hexagon touches three pentagons on alternate edges. Each pentagon is entirely surrounded by hexagons. Use these rules to help you choose the appropriate shape for each position.

I finished off leaving one hexagon off as an access hole. The finished shape makes a fantastic sock orphanage, a stylish litter bin or a play house for a curious kitten.

The spare hexagon makes a rather natty coffee mat.

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3
Thu 10th May 2012
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As fans of real paper books we have a stack of old Amazon packaging waiting to be recycled.Happily it turns out that corrugated card can be used to make a very clear sounding whistle. The downside is that corrugated card doesn't fit into your average desktop printer so the pattern has to be transferred from standard paper to the card manually.

Members can download the parts sheet at the usual place. The sheet shows the dimensions of the parts that you'll need to make a working, single note, whistle. The parts are all lined up so that the corrugations run vertically up and down the page.

Marking out the pieces

This section shows how to mark out the pieces ready to cut. I'm making the Pipe Body piece as an example.

Start with a piece of card cut into a large rectangle. The card used was 1.5mm thick.

Mark out the three dots arrowed above at 20mm, 40mm and 60mm

Repeat the process further down the card, again marking out the dots.

Join up the three pairs of dots with ruler and pencil. Using pairs of dots rather than a single dot ensures that the line you draw is parallel to the edge of the card.

Cut along the third line with a sharp knife. The cut needs to be roughly 100mm long.

Mark out two dots both 70mm from the end of the card. The further apart these dots are the more accurate your cut will be.

Line up your ruler with the two dot and cut out the piece.

Score along the two pencil lines with your knife by cutting through the top layer of card only. Fold up the piece with the score lines on the inside of the fold.

Other parts are made in the same way. Be as accurate with your measuring and cutting as possible.

Assembling the Parts.

Cut out the base and cut out the two holes. Notice that the base has construction lines on both sides, be sure to mark them up correctly and accurately.

Apply a little PVA glue to the two long edges of the pipe body.

Glue the pipe body to the back of the base lining it up with the two long lines. Line up the end of the pipe body with the arrowed line.

Glue the two end caps into place. Make sure that all the joints are air tight.

Flip the base over.

Make up the two throat sides by gluing a throat angle to the bottom right of one (above) and the bottom left of the other so that it is a mirror image of the one above.

Glue the two throat sides into place so that they are within the two long lines and are lined up with the 7mm line.

Glue the airway top into place so that the gap, arrowed above, is approx 1mm high.

Glue the airway cap to the back of the throat sides to seal the airway. Only the slot at the front should now be open.

Glue the air inlet into place to complete the project. Once the glue is dry blow through the hole to make the Whistle work.

Bellows next.

Using Flash

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1
Mon 7th May 2012

It's possible that the source of the problem in my previous paper pipes project was the flexibility of the card that it was built from. The card flexes and everything moves out of line. With that in mind I thought I'd revisit corrugated card pipes. Unlike my previous efforts with corrugated card pipes (more of which later) this time I'm aiming at a high pitched pipe compact enough to be fitted with an integrated set of bellows.

I have a few different ideas to try out, starting with this. The air goes in through the arrowed slot with the dark hole on the top surface being the throat where the sound comes from.

Viewed from the underside, the air inlet slot is on the left. On the right is the tuned tube.

Mk 1 works but needs a couple of tweaks. I have a few other designs to try out as well. I'll be reporting progress as I go.

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