How do I make a giant mushroom that can support an 80lb kid for an Alice in Wonderland play?

I want this mushroom to be cool and look really good for the play. I was thinking a wood structure and a chicken wire for the shaping but what do I fill it with to support the weight of a kid? Or any better ideas for the whole thing? Thanks!

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orksecurity6 years ago
Start by building a stage platform of the right height/size, using all the structural and safety precautions you would for any other piece of staging. (Wood or dexion, appropriately cross-braced...) THEN build the mushroom facade over the front and sides of it. And remind the kid to stay on the platform since the mushroom won't take weight.

Chicken wire is certainly one approach. Another is spray foam of the type sold for insulating/sealing houses. You need to handle that stuff carefully -- I wouldn't let kids under 18 near it until it dries -- but spraying to build up and whittling to trim down can construct some pretty impressive things. I may be misremembering, but I believe the dragon head for Irving (http://www.northernlights.pothole.com/gallery.html) is fabric over foam over a support structure.
irvinecb (author)  orksecurity6 years ago
I like the idea of the foam. Do you know what kind of volume one can produces? Is the dry foam hard enough tot support weight? I have never used it before.
No, the foam won't bear much weight. (Actually, it isn't bad under compression, but it will shear easily.) As I said: Build platform first, then use foam (or paper mache, or whatever) to construct a facade over that.

Volume depends on how much you use and how much space it has to expand into.

READ AND HEED THE INSTRUCTIONS. UNTIL IT CURES, THIS STUFF BONDS IMMEDIATELY TO SKIN. SAFETY GOGGLES ARE NOT OPTIONAL, GLOVES AND LONG SLEEVES AND DISPOSABLE CLOTHING ARE HIGHLY RECOMMENDED. ("With power comes responsibility...")
thegeeke6 years ago
This isn't cyt dupages play by any chance is it?
irvinecb (author)  thegeeke6 years ago
No, it's for a grade school.
Ahh... CYT DuPage is opening in a week... that's why I asked.
lemonie6 years ago

Bar-table/stool, and embellishments.

L

mole1 lemonie6 years ago
+1
I'm a bar stool embellishment.
aeray caarntedd6 years ago
Ha!
aeray6 years ago
I built one using a wooden cable spool. I wrapped it in 1" open cell foam and then covered it with stretchy fabric stapled to the wood. It was then painted a bit for embellishment.
caarntedd aeray6 years ago
Excellent answer. The "bottom" of the mushroom stem, (side of the spool) would make it very stable.
CameronSS6 years ago
I helped Dad build one for the school play when my older sister was Alice (that was 8th grade, she's now an English teacher, go figure). The base was either a concrete form tube (cardboard) or a built-up stand of lumber. The cap was a plywood circle to hold the weight, with canvas stapled over the top (upholstery style) and stuffed with polyfill/cotton batting/something like that. The canvas was then painted red with white spots.
willywoozle6 years ago
Build a small wooden crucifix with big limbs and another pair of limbs adjacent to those then at the bottom fasten a wooden plus diameter smaller than the diameter of the upper limbs. Then put a mesh all around it in a mushroom shape except at the plus at the bottom then fill it with a resin or something similar to help it sustain its shape. after filling it cover the bottom like the rest in a mesh. Paper Mache the mesh and paint it like a mushroom.
voila one mushroom capable of supporting a child.
jeff-o6 years ago
Build the structure out of wood. Cover it in fabric of some sort, it doesn't really matter what sort. Then, spray the entire inside with expanding foam. The foam will fill the gaps between the wood support structure, and when dry should be able to support a fair amount of weight.

Then, finish the outside of the mushroom with a few layers of paint. If you like, you could even integrate lights into the mushroom before blowing in the foam.
rickharris6 years ago
Either a kitchen stool with a bigger top covered in foam

Or a small table with a single central leg.

Either way if they are going to climb onto it you may need to anchor the bottom to something wide and sturdy.
Burf6 years ago
I would start with a steel barrel cut down to about 2 1/2 feet tall for the stem. Then for the cap, cut a piece of plywood in the appropriate shape and cover it with foam and fabric upholstery and secure that to the top of the barrel.
It should be plenty stable for an 80 pound child.