July 2009

I bought 4 more sheets of foam board and 6 more yards of canvas today. It’s making me nervous that there is only 4 weeks left and I’m building something so complicated that has never been built before. Plus the scooter needs work and so does the wagon!!!

Here is the first production zipper with canvas sewn onto each half of the zipper. This is a #10 coiled zipper. We could not get a long #10 toothed zipper fast enough. This coiled zipper is cheaper to make but looks to be strong enough for our uses. At first I ran just one row of stitches to see how strong the seams would be. They had some flex to them in tension. I added an extra row of stitches to each side of the zipper and it really didn’t make the joint any stronger. In fact it makes it a bit harder to unzip the joint due to the canvas being right up against the zipper pull. Zippers sewn into a K-Hing will only have one row of stitches on each side. I folded a 1/2 inch of the canvas under the bottom to make sure the canvas does not come unraveled with use. This also made for a nice looking seam.

Here is the zipper after it was installed and then unzipped to clean up any excess glue that might get into the zipper teeth. The glue set up fast today since it was warm in the garage. I’ll do it at night the next time. The foam weather stripping was added to see if it would compress ok and fill in the joint completely so it would be as heat and dust proof as possible. This weather stripping will probably go between each of the 6 roof sections for best insulation from heat, light and dust. The ends of each canvas joint will need to have the excess material trimmed away after the glue sets.

This is the completed roof and wall assembly with the zipper glued on. Normally the zipper won’t be glued on, but since this assembly was a prototype this is how I decided to make it a useful part of the Yurt so there is no wasted materials. It also showed me how to do a zipper repair in the future if needed. I could simply cut off the old zipper at the threads, and glue this zipper and canvas assembly over the joint. Maybe not as strong as a zipper sewn into a K-Hinge, but should hold up. We’ll find out, that’s for sure!

Here is a mock up using wood of a K-Hinge with a zipper sewn in. This is the closed position. This allows the hinged joint to be folded over on itself when unzipped or to stiffen the hinged joint when zipped together. Leaning on this prototype with many pounds of force showed that it held together well. Surely the foam board would have broken with so much stress applied to it. Since the glue and canvas are in shear during the stress test, then only the thread and zipper’s cloth are the only weak spots. You can see the one corner of canvas where I peeled it up to see how well the glue held up. The glue bond is much stronger than the bond that the aluminum foil has to the paper on the foam board.

This is the open or folded position. Leaving a couple of inches of zipper hanging off of the end, makes it easy to start the zipper when assembling the Yurt.

There is the end view of the K-Hinge and the zipper. I’ll try and sew the gap between boards a little tighter when I build the foam board versions.

We stood the assembled wall and roof panel up against the garage wall. The tip of the roof panel was set to 8 feet high. This duplicates the roof angle of a fully assembled Yurt. So now, we are looking at how to adjoin the next wall/roof assembly to the one we just made. I worked out an idea yesterday. Today I have to find the materials and make up a test section. The idea is to sew on half of a heavy duty zipper to one roof panel and the other half of the zipper to the other roof panel. The zipper will have to be sewn to the canvas before it’s glued to the foam board. A few inches of zipper will have to be free hanging in order to be able to start the zipper each time. Each seam where a zipper will go it about 54 inches long. So a 60 inch long zipper should work fine. The sewn zipper should have enough tensile strength as the tape it is replacing.

There are two zipper joints that have to be tested. One is with a K-Hinge installed as occurs between the upper and lower roof panels. The second zipper joint will occur between two unattached roof panels. This second joint will have half of a zipper attached to each of the canvas end caps that are glued along the edges of the roof panels.

I’ll find a couple pieces of wood and attach them together with a K-Hinge with a zipper sewn in as well. This way I can stress the joint to see how the zipper will fail.

Tonight Bill and I did the assembly of the toughest K-Hinge yet. The wall panel and an entire roof panel. It was way more stressful than it was real work. It came out fine. I came up with a simple jig that held both panels upright while we layed the canvas up against the drying glue. That jig was a great deal of help. I’ll let the glue dry all night and see how it all folds together tomorrow. If we like this prototype, then we get to build 5 more!!

Here is the jig. Just a pir of 2×2’s sitting against the garage door opening. That’s literally it!!

Here’s the front view of the jig with just a wall panel and a cured K-Hinge done days ago.

The roof panel is layed out on a table ready for glue to be applied. The height of the table saves wear and tear on the back.

Just like magic it’s done. Too many hands were needed to take any pics.

When the hinge hits up against the 2×2’s it just takes a little tug on the canvas to pull it straight. It takes 2 people pushing on each side of the canvas to push it tightly against the glue.

All done!!

Here is how the pieces for each of the roof panels get cut from one 4×8 sheet of foam board.

Here is this mornings idea for anchoring the Yurt walls to the ground, internally, without any ropes to trip people in the dark palya night. Staking them to the ground makes sense. However, I worry that trying to pound a stake into the ground will end up damaging the foam wall with a misplaced hammer blow. So I am going to try and use long, large diameter lag type screws, driven with a cordless drill into the playa.

This morning I woke up with a great idea for internally anchoring the Yurt walls to the ground using a K-Hinge, plywood blocks and metal stakes. I’ll post a pic a soon as I make a sketch.

Here is the 8 foot long K-Hinge attached to a wall panel as of last night. The edges of the canvas are ragged because I tear the canvas instead of cutting it with scissors. Not as clean, but way faster.

Here is the bumper sticker on my wagon that was taken to Burning Man sometime before 1993-1995 when I purchased it. I’m hoping someone can identify the year of the bumper sticker.

I bought the wagon back in 1995. Two owners before that it had been to Burning Man. I’ll get a pic of the old Burning Man decal on the rear bumper in hope that someone will know about what year the wagon was at Burning Man.

I’ve also got to finish leak testing the A/C in the wagon.

At about 9:30 pm pdt tonight we got started adding a K-Hinge to the top of a 4×8 foot wall panel. The cooler air helped give us more time before the glue started to set. The other thing we did better was to put down 3 narrow beads of glue instead of one large one. With just one pass of the spreader it almost covered the 3 inch wide x 8 foot long glue area in one pass. That bought us more time. Then we had to carefully flip the panel over without smearing glue all over everything, and do the other side and the edge. We will sorely need the extra time when we combine the wall panel with the roof panel using a K-Hinge. Alignment of the K-Hing takes quite a while when you have such a long hinge to glue down and align. Video or pics would help clarify this.

Everything we have learned so far will come into play the next time we joint the roof and wall. We were thinking of making a simple 2×4 holding fixture so the roof and wall would stack vertically on top of each other without us having to hold them. These 8 foot long x 8 foot tall assemblies are not going to be easy to handle. Better now than at the playa, and in the wind!

Today Bill and I took a brave step in the hot weather and glued the top roof half with the bottom roof half using a six inch wide 4 foot long K-Hinge. We learned that the blue printing on the foam boards comes off with the glue. So we will use a solvent like acetone to remove any blue printing where the glue is to be applied.

Here is the upper roof half with each of it’s halves permanently glued together several days ago. This permanent canvas joint is 6 inches wide, just like the tape that it replaces.

Here is the lower roof half with a K-Hinge glued onto it yesterday.

Here is the K-Hinge glued on from yesterday. This step was easy since one panel is much less bulky to handle than two of them.

Here is a shot of the full upper roof K-Hinge installed. This was tougher to do. The hot weather made the glue set quickly. So when it’s time to do an 8 foot hinge it will have to done in the evening’s cool air.

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