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AZSORT
08-23-2005, 08:49 PM
My 11 year old was just assigned a school project to construct a model of an egyptian pyramid. Best part is they are supposed to get help from parents. Finally, hands-on homework! Anybody got a suggestion on how to build a 2 foot high pyramid that doesn't weigh a ton? Does mixing a bunch of styrofoam pellets into mortar and casting it work? Maybe I'll set him to work with a cold chisel on a good sized stone to appreciate how hard it was to build stuff back then.

Hmmmmmm
Greg C.

aboard_epsilon
08-23-2005, 08:55 PM
there's something called vermiculite.
this is the very light weight concrete sort of stuff used as insulation around fireplaces etc.

http://www.vermiculite.net/

all the best.mark

Peter Sanders
08-23-2005, 09:08 PM
If I was doing this, I'd consider a simple wooden or steel tube frame covered with a thin "veneer" of ply or simmilar (steel sheet if you *have* to http://bbs.homeshopmachinist.net//biggrin.gif ).

Then source a good image of the pyramid and print out the block and limestone pattern (to a suitable scaled size) from the image and paste this to the model's veneer. That should look pretty good http://bbs.homeshopmachinist.net//biggrin.gif

Kind regards

Peter

aboard_epsilon
08-23-2005, 09:12 PM
if you do it peters way.......put tape onto it in the patern of bricks.......then cover with sand textured paint.....and peel away the tape just before it's dry to make an interesting relief to the bricks.
all the best.....mark

Rustybolt
08-23-2005, 09:18 PM
First you get some unemployed Egyptians...............................

darryl
08-23-2005, 09:21 PM
I think the sides are supposed to rise at a 51 degree angle from horizontal. Knowing the height you want it, do some math and find the dimensions of the base.

If you want the stone look without making it too heavy, you could start by building it out of corrugated cardboard. Wax the cardboard, then get some mesh, chicken wire maybe, and layer it with that, then cement or mortar over that. As with any mesh, try to get it into the center of the layer of concrete so the sides will have some resistance to breaking.

If you build it this way, using the cardboard, you won't need any structural supports since the four cardboard panels will form and maintain the shape. This is another use for duct tape.

Another way to go about building it is with corrugated plastic sheet. I forget the name of that right now, but it's everywhere. You can assemble that uniquely by threading string through the corrugations and then pulling the string tight. A round of string at the top and at the bottom, plus one around the middle should be enough to make it quite rigid. You'd have to cut the triangle sides such that each one's base has the corrugations parallel to it.

Another suggestion would be to roughen up the surface of the plastic, or if cardboard leave it as is, and then spray it with a spray glue, sprinkling sand all over it before it dries. You might end up with a stone look without having to go the cement and wire route. Or maybe just get some of that paint that is supposed to look like stone, and just paint it. Use some filler beforehand on the corners, so it looks ok.

One more thing you might consider is making a bottom with two of the sides on it as one piece. The sides would fold towards the peak of the pyramid, and the other two sides attached after. It would be stronger that way, and you'd have a floor to mount the tunnels leading to the sarcophagus-

Tinkerer
08-23-2005, 09:30 PM
I'd get some foam sheet. Miter the edges and glue together. Then scribe lines for blocks and paint with textured sand paint. That would have the look as they are now. Or you could make one side look like white marble to show how they originally could of looked. Or if you really want to impress.... lay it up in layers of foam sheeting and cut in the ramps and burial chamber and make it open up to reveal. But remember to let the little one help. http://bbs.homeshopmachinist.net//wink.gif

BillH
08-23-2005, 09:32 PM
Excellent, when I was in Elementry school, my dad helped me build a Pyramid. Mine was made out of plexiglass, and welded with the plastic welder. I then modeled the insides out of cardboard.

Evan
08-23-2005, 11:41 PM
"My 11 year old was just assigned a school project to construct a model of an egyptian pyramid"

Present day or back when they were faced with smooth white marble?

Mike Burdick
08-24-2005, 12:26 AM
Greg,

Have you asked your son as to his thoughts on how to build it? I'd go with his design and maybe nudge him with some ideas if he needs it.

Anyway, here's a suggestion:

Go to Home Depot and buy several of their 2x4 studs and cut them up so that you make perfect cubes( ie 1-3/8" X 1-3/8" X 1-3/8"). If you make rows that are 4 blocks less on each tier it will form a pyramid. Make it hollow inside and use Elmers glue to hold it together.

This way both of you can work on it – you whack up the cubes on the table saw and your son can glue it together, which will be the hard part. When the school project is over, he can bring it back home and he and you can set it on fire and have a marshmallow roast. That way you won’t have to store it for umpteen years. http://bbs.homeshopmachinist.net//wink.gif

-Mike


Oh...If your son wants it to look like stone just put a little Elmers glue on the cubes face(s) and press into sand.

_________________________


[This message has been edited by Mike Burdick (edited 08-24-2005).]

WJHartson
08-24-2005, 03:07 AM
In your large CNC milling center place a block of plastic and program it to cut away all of the material that doesn't look like a pyramid. Once the shape is obtained use the mill to put a proper marble texture on the blocks and finally paint it in your paint booth with the HVLP system. If it weighs too much burn out some steel parts to make a frame on your CNC plasma cutting table and make a form to hold the pyramid upside down so that the mill can cut the inside out to reduce the weight.

You say you don't have all of the necessary equipment then buy it you don't want your child to have a less than perfect homework project do you. A little money spent on this project to further his education will help him a lot in the future. You might even find a use for the equipment yourself in the future.

Hope this helps.

Joe

bobbybeef
08-24-2005, 06:01 AM
Rustybolt,
Dont forget the big nubian supervisors and the full size stockwhips.

Hey Kid,
Tell Dad to get his mits off your project and just ante up the dough for the gear you want. OR you could visit the local tip and get all the materials you need. Dad has probably got a pop rivetter and rivets to suit your job and that new sabre saw he bought and has never been given a proper work out is there also. Paint, sure thing he has tons of the stuff. Dad can be asked to clean the brushes afterwards. He will love that.
go for it.
Bobby.

Peter S
08-24-2005, 06:43 AM
Don't forget to include a place for the razorblades that need sharpening... http://bbs.homeshopmachinist.net//rolleyes.gif

sauer38h
08-24-2005, 08:07 AM
I've seen pyramids made out of sugar cubes. Not two feet high, though.

Sugar for mortar, too, and all those ants swarming all over it look like busy Egyptians. Or tourists.

Paul Alciatore
08-24-2005, 09:40 AM
I think this would be a great application for Lego. They do still make them, don't they. Get the kid a big set or two and both of you can have fun.

I had several of the old plastic brick sets in my youth and used to build pyramid like structures with them. They had sloping shaped blocks that made a perfect side. Only trouble was at the corners where you had to compromise. But I think the Lego sets would be better as they hold together when stacked. If they don't have the sloping blocks, you could improvise. Slice some at an angle and glue flat plastic stock on them.

You could do a cut away to show some chambers inside. Just an additional thought. If you are within range, I would just love to help. Sounds like fun. I did a wood turning for a co worker's son a while back. It was a model car for a school project. They wanted it very aerodynamic, like a rocket. Only wood I ever turned on my SB. I used regular wood chisels and it came out great: the lad was happy. I had fun doing it.

Paul A.

Evan
08-24-2005, 10:29 AM
You could just download a free copy of the raytracer program Pov-Ray and build it in the computer. Here's one I did...

http://vts.bc.ca/pics/erg6.jpg

madman
08-24-2005, 10:32 AM
Built the young lad a can crusher many years ago. Bushed pivot points cnc machinied. Absolutely ridiculous that a kid could build it. Teacher gave him a nice mark said it was interesting. HUH teachers dont have much of a clue at times.Anyhow mastercam a pyramid laser it from 304 stainless jig and tig. Polish to a brilliant sheen and go for the good mark.

Wirecutter
08-24-2005, 11:13 AM
Well, nobody had suggested it yet, so I'm going to have to...

Make it out of BILLET. He'll get the "A", and you can tell the hot-rodders that it will add 600 HP to their ricers. http://bbs.homeshopmachinist.net//biggrin.gif

Swarf&Sparks
08-24-2005, 11:15 AM
Ahermm. On a more serious (?) note. Build a base from cardboard. Over that, lay paper towel or similar, dipped in a runny plaster mix. When set, carve/scratch any detail you like. You can apply multiple layers of plastered paper to get desired thickness. Old scenic modelling technique, from an old scenic modeller http://bbs.homeshopmachinist.net//biggrin.gif
Rgds, Lin

chipeater
08-24-2005, 01:02 PM
Legos

decoy91288
08-24-2005, 02:26 PM
As a retired teacher I vote for the suggestion to ask the kid how he wants to go about it, then provide support and guidance and maybe a third hand if needed. A word of warning -- my daughter brought home an assignment for an art project. She decided to sculpt a figure for it. I told her how to make paper mache - helped her make a batch - then left her alone. She got an "F" - that sorry assed teacher said it was "obvious her parent made it for her; no child could do such finished work."

Daughter got an "A" from me, and I learned (another!) lesson in how not to relate to my students and their parents.

Kdahm
08-24-2005, 03:04 PM
AAAAAAAAAAARRRRRRRRRRRRGGGGGGGHHHHHHHHHHH!

Go to the local big box store. Buy one (1) sheet of 2" thick pink foam. Cut square sections so they will stack to form the pyramid.

Next, set up the mill. Put in something like a 4 or 6 flute 1" mill, turning at high speed. Put in a fence on the table. Run the edges through using the fence to cut the steps. After each pass on all edges of every block, raise the end mill and set the fence over by whatever step size you are using. I would suggest no more than about .03"-.05". Repeat until done.

Next, assemble and paint the pyramid. I would suggest a whitish tan color, with dark tan and light brown highlights. If lines are desired, use a very fine tip pen to add the line and indention.

Karl

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At a certain point in the course of any project, it comes time to shoot the engineers and build the damn thing.

[This message has been edited by Kdahm (edited 08-24-2005).]

halac
08-24-2005, 06:53 PM
Over the past couple of years I've built several small pyramids that I use for robotic combat.

Just for your information, the angle of the sides of the Great Pyramid is roughly 53 degrees, give or take a degree or two, depending on who you research. The mitre angle of the corners is half the angle of the sides. So if you have 53 degree sides you would make the mitre angle of 26.5 degrees.

As someone else pointed out, the pyramids were made out of a common stone such as sandstone, the sheathed in white limestone except for the peak which was covered in gold.

I've made my pyramids out of polycarbonate that I've gotten from Home Depot or a local plastics supplier. I use the solvent glue which welds the poly together. I make small blocks that match the angles of the interior for extra support. These I "glue" in and use screws for extra strength. After finishing assembly I paint the interior with a faux stone finish that I also got from Home Depot. If you go to my website you'll see a picture of it there.

Good Luck


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No matter where you go, there you are!

Hal C. , www.teampyramid.com (http://www.teampyramid.com)