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Hello,
My son and I want to make a giant iguana (8 - 10 feet not including the tail) that can bob it's head. It must also be strong - but not brittle, water resistant, and lightweight. It will be bolted on top of a four person, human powered, amphibious all terrain vehicle.
I've done papier mache pinatas, and bowls, and things, but nothing on such a grand scale.
Any thoughts on armature construction, recipes, finishing techniques, or whether papier mache is even a viable option for our project, would be greatly appreciated.
Thanks
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Jackie's experiments in surface sealants for PM indicate that marine varnish is the best to seal this media. However, even that is no guarantee; if you miss one tiny hole or crack, water will enter and destroy your work. PM just isn't the material of choice for projects exposed to water. You could try it, and it might last for a while, but I really don't think it would do well for the long-term exposure you have in mind.
The material you should probably use is fiberglass and resin, as used for boatmaking and repair, but this stuff isn't cheap.
But you could make your iguana from PM and then use it as the mold for the fiberglass, or forget the PM and apply the fiberglass directly over formed chicken wire.
Sorry that I can't be more optimistic.
Note: Head-bobbers are made in two pieces, the body and the head. The base of the head narrows to fit inside the neck and is attached to the upper part of the neck/body with two eye-bolts that are joined together.
Sue
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Hi Sue,
I should probably clarify the goals of our project.
The whole sculpture is for a one-day event. The iguana part of the vehicle will be purely decorative. We had thought to make it modular (head, body, and tail) and have the whole thing bolt on to the top frame-rails of the vehicle providing both a roof and frivolity.
We'd be riding a total of 13 miles that would include a sand pit, a mud pit, and a u-turn in the harbor. The basic idea is that the iguana ride on top of the vehicle without encountering any of the substrates over which it is being joyfully transported. There is, however, the possibility of rain.
We are definitely still in the brainstorming phase of this project, but we want to use as many recycled materials as possible. Fiberglass is out of our price range.
My biggest concern is that the vibrations and jostling about might cause PM to crack, break apart, and litter the ground with body parts.
Would PM that is super varnished with marine varnish be durable enough to stand up to a day on the road without totally falling apart by the end of the day?
If we did use PM, would pulp, strips, or a combination of the two be more durable?
I am guessing that chicken wire would probably make the best frame, but I think there may need to be some other sort of structural support to prevent collapse of the loooong, wide body.
I am trying to visualize the eyebolt mechanism to make the head bob. I have the concept, just not the physical arrangement. I think you mean that there is an eyebolt in the head that is connected to an eyebolt in the neck with both eyebolts securely attached to the frame of their respective sculptural pieces.
I'm not sure we want the head to bob continuously, though. I think we want it to bob when we tell it to.
Thank so much for the your input. Sorry this post is so long. I've never built anything like this before, so this is definitly a huge learning experience, and I have a lot of questions.
Jamie
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It sounds like a great idea and for one day of use it might work, I would see if you can contact Chris Shilling (he of the pm narrowboat) to see how long it took to waterproof his boat. shilbo@shilbo.com
I don't know if he still maintains the site and address as there hasn't been much new on it for a while. But he would be your best bet for info.
I assume you live near a marina? It might be worth doing some grovelling and seeing if the drydock people would be willing to help you varnish the finished piece, particularly if they have spray equipment for varnish.
Alternatively, ditch the pm and build yourself a wire armature pad it with old fabric , then make a skin of ripstop nylon and cover it, that would probably last for a day!
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I would still go for paper layering. Don't think of using pulp at all. You could use cardboard boxes - ones you obtain or ones you make - to support the main sections; any bits and pieces, quite honestly, bound with strong packaging tape. If you want to sculpt a bit more over that you could use chicken wire.
Then laminate with thick paper, about ten layers. Use a good quantity of PVA in your paste mix, which will help flexibility and water resistance. A varnish then should be enough for your needs, or a water resistant paint.
As Sue said, you can use the 'bobbing' mechanism - a large almost closed hook screwed upwards into the top of the inner neck, a large eyelet into the top of the neck which is part of the head group. Take a string from the end of the head/neck down through the body and hold it taut. When it is released, the head will bob. If you really want to be clever you could work out some means of bobbing the eyes as well!!??
Good luck
DavidO
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So, if we choose the PM option...
For the skin, we should use strips and wallpaper paste mixed with PVA and water to yield a more flexible skin, then the whole thing should be marine varnished to a fare-thee-well. What would the ratio of wallpaper paste to PVA to water be? Are there any other additives that would lend strength and flexibility without brittleness?
The controlled bobbing head mechanism is now clear, and if we have the time and energy to add another design feature to this already monumental task (we are also designing and building the vehicle-proper from recycled bycicle parts collected from the local dump), the bobbing eyeballs would be hysterical.
Fabric is another possibility we have been researching. Once we have the basic procedures for all of the different options down on paper, we are going to compare them side by side, and make an informed decision about which way to go.
Thanks to all of you for your help. If anyone has any more ideas or suggestions, we'd be happy to hear them.
Jamie
Last edited by JamieB (2008-08-31 16:53:38)
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Okay, if you are willing to use fabric, that would have more flexibility with movement than paper.
Forget the wallpaper paste and go with PVA+water (about half and half). PVA is water-resistant, wallpaper paste is water-soluble. PVA also flexes more when dry, probably more than any other adhesive (it's a plastic). No organic adhesive will do what you need.
David's idea of using cardboard as a base is a good one. And if you have access to sheet-type foam insulation, you could add carved foam pieces to the cardboard. Use PVA straight, not mixed or diluted, for this. Sheet foam insulation is carved fairly easily with a longish serrated knife.
The marine varnish should do fine for such a short-term existence.
It sounds like a fun project. Funny, too.
Sue
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p.s.
Slotted cardboard is another way to make an animal. See the deer head drawing at http://www.cardboardsafari.com/shop/product_cbs1001.php
for an example.
Sue
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The slotted cardboard as an internal form looks fantastic for whatever surface medium we choose!
Thanks for the heads up.
This project is fun. It is also my son's 7th grade homeschooling curriculum for the year. It will encompass all of his required subjects: English, math, natural science, physics, art, social studies, and so much more...
It will culminate in the kinetic sculpture race that is held in Baltimore in May that is sponsored by the American Visionary Art Museum. www.kineticbaltimore.com
We went as spectators last year. I haven't had so much fun in a long time.
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Homeschooling --- EXCELLENT!
Sue
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