Earth and Moon

If you can get some Tig welding wire, it is much thinner,pure, and stronger. You can harden it by tying one end to a fixed point, and gently but firmly pulling the other end, attached firmly to a wooden dowel. This is how we used to make the little flag stems for instrument gauges. The flags would drop if the air craft instrument failed. This process hardens the wire, so you can bend it once, and it will hold that shape for good. The wire for TIG welders is cheap and comes in .025", 035" and .o5o" of an inch. There are actually more sizes, I wouldn't go to thin. You could use it the way it comes. It's also very springy, and easy to form. I used it for a diorama of the LEM on the Moon, and a piece of wire holding the Apollo capsule in orbit on a very long piece. My son and I worked on it. He still has it. When you open the plastic case, the Apollo rocket module springs up into position, against a distance earth background, and sitting on the bottom is the LEM. All the other kids bought in collages, which the teacher said she did not want. He won the "unofficial" contest, and she had it displayed for the school year, to show kids what thinking out of the box means. :)
 
I'll look into it. I'm using galvanized utility wire for the stands because I have it handy. The axels are long pins (5") from a beading store that went out of business. They aren't long enough to do Venus which has a 177 degree axial tilt. I'm going to have to come up with longer pins or else use some wire.
 
20171216_224502.jpg 20171217_193142.jpg The work for today. I'm calling the first one done. I may go for clouds on another. I'm pleased with it. The white one is in process. This time I did the skin with 27 lb paper, not card stock. Then I filled with gesso and acrylic modeling paste then sanded. I'll decoupage another skin on top. We'll see how this goes.
 
Tig wire is around 3 feet long. Probably .50 cents a piece.

If you could find the right size plastic sphere, which splits in two, you could water form the pieces. As you are painting them anyways, you would get the compound curves you need. A wet sponge, Hemispherical surface, (I'd go from the inside out), and you would have nice contoured pieces to place on the surface. :)
 
I've got some spheres as you describe, plastic Christmas balls from Micheals. They are just a bit bigger. I might try it :-)

To me the surface is secondary to the inner structure. My initial plan was to design a system for freehand drawing on a sphere so that the panels can be removed and scanned to produce flat maps of science fiction and fantasy worlds. These models are spherical grids, so I want the lines between the panels. When I paint them I show what can be done with the structure.

I plan on making and selling kits so that other people can use them. I'd also like to put together kits which demonstrate the relationship between the geometric shapes used.
 
lizzienewell said:
I've got some spheres as you describe, plastic Christmas balls from Micheals. They are just a bit bigger. I might try it :)

To me the surface is secondary to the inner structure. My initial plan was to design a system for freehand drawing on a sphere so that the panels can be removed and scanned to produce flat maps of science fiction and fantasy worlds. These models are spherical grids, so I want the lines between the panels. When I paint them I show what can be done with the structure.

I plan on making and selling kits so that other people can use them. I'd also like to put together kits which demonstrate the relationship between the geometric shapes used.
Click to expand...


http://www.paperpino.net/cassinis-terrestrial-globe-globo-terrestre-di-cassini/
 
lizzienewell said:
I've got some spheres as you describe, plastic Christmas balls from Micheals. They are just a bit bigger. I might try it :)

To me the surface is secondary to the inner structure. My initial plan was to design a system for freehand drawing on a sphere so that the panels can be removed and scanned to produce flat maps of science fiction and fantasy worlds. These models are spherical grids, so I want the lines between the panels. When I paint them I show what can be done with the structure.

I got to playing around with this .. and you are into the age old search of how to map the surface of the earth ( or any globe/ planet ) and display as a flat map, which still has not been discovered, they have come close, but as yet , no joy. With the structures you are using/ and dealing only with the surface for now, it will have to be a "cassini-esque) surface.. I took a basic 8" globe and broke it down to one of your segments of a triangle mapped to a sphere ie. a Spherical Icosahedron, with the NASA earth mapped to it's surface, then "Flattened" one of the spherical triangles...this is the shape ( which is REALLY close to the shape you are using ) but notice the distorsion..

Globe-Mesh.jpg it is more like a shield. and of course because it is a globe..it will always be the same no matter what size the globe is.. But anyway..this is what you will have to do to get to where you want..3d!!! and all that world entails!
Click to expand...
 
That distortion is livable with I think. If your Printer uses Pigment Ink, you could water form it without the Ink Distorting. If you paint the continents, it becomes a non issue. :)
 
Here the latest iteration finished. And on the right it's spinning. I put in piece of thread so that it can be spun and the star shaped button for the north star just because. I may redo the thread so that it's counter twisted instead of just looped. And maybe I should close off the hooks so that the button and thread don't get lost. The landmasses are painted with titanium white acrylic an it has two coats of acrylic gloss medium. Oh I just had another idea. I can put a piece of twisted thread connecting north and south poles through the axle and maybe the diurnal spin will work. Right now it turns but I can't keep it spinning.
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I would consider mounting it from the bottom. A hole through the South Pole, with the tip of the metal sharpened to a point, set against the glue, just before it dries, would give a bearing surface. The Inside of the North Pole coated with crazy glue (Gel), so that a bearing surface can be formed. That would allow it to spin, and the Globe would be the center of attraction, not the mount. See Pic below (a Magnet attached to the inside of the globe with the appropriate counter weight could make it act as a compass). :)


Earth Stand.jpg
 
I like the idea of some versions spinning from below. I'll try it. Thanks.
It's somewhat similar what I have now. The axel is a 5 inch pin with two pieces of 1" square paper wrapped around the axel along with washers on the bottom. There is more friction on the diurnal axis(the pin) than on the annal axis(the thread). I like how the thread twists and untwists. So I'm going to try replacing the diurnal pin with thread. I'll put the axel through one bearing on the top and then have a tread connect the axel to an eye on the bottom. This would reduce the friction further and the thread would act as a spring as it twists and untwists. I could put in a rubber band but, I like the speed of a thread twisting and untwisting with the inertia of the globe. I'll see if it works. Ideally the two rotations should be in opposite directions, so that the diurnal spin is counterclockwise and the seasonal spin is clockwise.
Hm actually it could spin this way. The axel is like a crank. When turned the thread above and below twists in opposite directions. Hm suppose the top thread is really long. It might untwist slower than the thread below.
 
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Find a cheap small clock mechanism, and you could mount it to a base, and choose which shaft to mount the rotational shaft off of. The second hand shaft would be on top, might be a nice speed. :)
 
I bought a 24 hour clock mechanism. I want the earth to go counterclockwise which means placing the mechanism at the top. I set that project aside. I don't like the look of the housing for the mechanism. It's a cool idea since the model would show both time in all time zones.
The other option is to put the mechanism at the bottom and place the Earth south side up.
Or get ahold of a digital printer and make two gears to reverse the direction. Maybe I could even make gears with the silhouette cutter. Or maybe a speedometer cable so the mechanism is on the bottom but turns the globe from the top.
But I've got other things I want to try first.
 
Mounting two equal gears would be the best route, changing he ratios would allow you to set the timing, if you wanted to. A good R/C shop will have gears for you to choose from.
On the sphere set up I described (above), you would use crazy glue (Gel Type) an push the pointed shaft into as it's drying. When hardened, it will act as a bearing surface, much like a watch and Ruby set up. You would also apply crazy glue at the whole at the a the bottom to allow that it to turn freely and not wear out. I have done this with car models that I have put steel shafts through and the crazy glue makes a great bearing surface. Also, if you get thin Piano wire, and do the stretching process I described, it will harden the shafts and they will make excellent mounting shaft, and will not bend, as they will be hardened.**

**Method was wrapping one end around a wooden dowel, secured, and fixing the other end, you then pull gently but firmly until the wire seems to "stretch" to a fixed length, that's how you draw harden wire. You can't find this stuff on Google, it was a proprietary method we used wen making aircraft instrument gauges. We used a fine, not too thin, piano wire. Probably .030" of an inch. :)
 
I may have some piano or guitar wire. Good pointer on bearing surfaces. I was think about using polyethylene if I could find it in thin sheets. I also thought about spray silicon. I wonder how hot melt glue is for bear surfaces. It might be polyethylene. There's also ski wax.
 
Hot Glue gets brittle and falls apart after some time. Crazy Glue has held a piece of Cast Iron on the Alternator pulley of my '73 M.G. Midget for 27 years. ;)
 
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Wow.
My experience with superglue is that it's brittle. I assume that Crazy Glue and Superglue are the same thing. I was thinking polyethylene because it's what forms the bottoms of skis, snowboards, and sled runners. Repairs on these surfaces are done with a tool which is a lot like a hot melt glue gun. Further treatment of these surfaces with wax holding silicon, graphite, or perflorocarbon(Teflon) increases slipperiness further, but that's for slipperiness on snow and ice.
 
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