Hello, and welcome to the forum!

From what I have seen of weather balloons, they are very thin and I suspect they would be difficult to work with.  A better choice might be a large beach ball, one of the really large ones.  You can find them described as being 48" in diameter, but you would need to verify if that is 48" diameter when inflated, or 48" diameter when flat, which would inflate to about 30".  If that would be large enough for your purposes, here is one from Oriental Trading:
http://www.orientaltrading.com/ui/brows … Beach+Ball

If something like that would serve your purpose, I would use the strip method for covering the ball.  I have used tracing paper (from a roll) to make a translucent ball, but it would be more expensive than a cheaper type of paper.  Another material to consider is old white bed sheets, torn in strips, rather than paper.

Mixing regular white craft glue half and half with water should be a good adhesive for this project, but you would need quite a bit.  But if you could find methyl cellulose adhesive (Elmer's Art Paste is probably the easiest to find and the cheapest), a 2-oz box would make a gallon of paste.  This stuff isn't meant to be thick and gooey, so don't panic when it appears to have a rather thin consistency.  it works just fine when mixed as directed.

The number of layers would depend upon the type of paper you use.  I'm thinking five or more layers.  Let it dry thoroughly and then deflate the ball a bit and press on the papier mache. If it doesn't seem strong enough, another two or three layers might help.

When it's strong enough and fully dry, paint it with acrylic paints.  A final coating of Varathane would probably help to strengthen it, and moisture-proof it as well.

Anchoring it against strong winds may be your biggest hurdle. If you can design a sort of cradle for it to sit in, and then use hot glue (or epoxy) extensively to attach it, you will be better off than just a small point of contact on a flat surface.  A cardboard collar + hot glue may do well, too.

If 55 mph winds are anticipated, a net is the only thing that may hold it down.  Do you happen to know any commercial fishermen?  Cover it and anchor the edges inside the car doors.  Nobody is going to be outside doing much in high winds in the desert.  Been there, hated it, blowing sand feels like needle darts.

If you make the wings from papier mache, I would try to find a way to make them removable, maybe with cotter pins, wire or long thin screws?  High winds will beat them up badly if you can't remove them.

Good luck with your project!  If you can, put some photos in the gallery here, and let us know they're there, okay?

Sue

The exercise ball would be fine.  I thought of that after I posted.  They're a bit smaller, I think, maybe 27" diameter, but certainly do-able.

I wouldn't add anything to the Art Paste, mix as directed.  Yes, I know that people add all kinds of things to PM, including dog kibble, but for what you're doing, stick with the basics.

Plaster will make the PM much less translucent, and it sets up really quick.  This project is going to take more time than it would allow you.  Concrete is even worse.  Neither bounce, just crack or split.

Linseed oil is okay for some projects, but it takes a looooong time to dry.  It might also interfere with the finish results you're aiming for.  I would avoid it.

That Art Paste is clear, kind of like eggwhites, so it shouldn't interfere with the translucency of the paper, if you end up going that way.  Mix it up the day before you intend to start using it, for best results.  Using a plastic ball, you probably won't need to use any kind of release agent, either.  Just stick it right to the ball.  When you deflate the ball, the plastic will pull away from the PM.  Easy. 

Tip:  for spheres, try triangular pieces of paper instead of strips, as they lay down quite smoothly. Experiment with sizes, and when you find one that covers as much area as possible but wrinkles the least, make all of them that size, although perfection isn't required.  The smoother you can get it as you go, the smoother and more professional the finish will be.

For UV-reactive acrylic paints, you could start here:  http://www.glomania.com/clear_uv_paint.html    I have also heard that Michael's Crafts carries it, but ALL of them may not carry it, or all the time.  It's mostly popular at Halloween.

Yes, that Varathane is what I meant.  It isn't suitable for PM projects that are going to outdoors for long periods of time in wet weather (like a garden gnome out in the rain all winter), but it should last through Burning Man and then some.  I would do a small test piece of PM (just a 6x6" flat piece) using all the materials you plan to use, just to make sure you don't hit any unexpected surprises, esp with the finishes -- that would set you back.

I don't know exactly what you're doing with the PPE, but you might borrow a book from the library system that would give you ideas (you might have to get an Interlibrary Loan).  The book is called Make Something Ugly -- For a Change by Dan Reeder.  He's got a couple of other books out, too.  They're all "creature type" projects, as far as I've seen.  He has some step-by-step instructions for open mouths and teeth that are good.

Another book that I'm SURE you would need to get on an Interlibrary Loan would be 3-D Wizardry:  Design in Paper Mache, Plaster and Foam by George Wolfe.

Just in case of accidents, take a roll of clear packaging tape with you for repairs.  Duct Tape is NOT suitable for this!  ;-)

Have fun!

Sue

oh and if I use tracing paper..should I still put on a layer of emulsion paint per the tutorial before painting with acrylics?

When I search on google for emulsion paint, I get results called "asphalt emulsion"..is that the same thing?  If not, can you post a link to the right thing?

You can tell I'm not particular familiar with a lot of this stuff..

I have the tracing paper and white PVA glue..going to start project tonight using 85cm exercise ball as armature.  I'll use the triangle method you recommended and I will take pics of my progress.

Ok, so we started up the project using tissue paper and 50/50 diluted Elmer's Glue-All... I really wanted to use the art paste, but I couldn't for the life of me find it locally.  I'm going to buy a box online though.

So last night, did the first two layers and found it probably 90% dry by this morning..  Looks pretty good so far except I have a concern that it seems the paper mache is going to have a hard time breaking away from the exercise ball when we go to deflate it later.  Maybe it's just because I've only got a couple layers on so far, but it seems so well glued to the ball (I painted both sides of the strips with the adhesive) I can't see how it is going to gracefully pull away without destroying itself.  Will more layers help that?  Maybe we should have used a release agent?  If I need to start over, I'd rather do it now before we get too far along.  Time is in our favor.. I have a month or so to finish this project

Since you've got the time, why not just get one of those 8" vinyl play balls that are carried everywhere (including grocery stores), glue  just a four-inch patch of two or three layers of paper using the same stuff you're using on the big ball and let it dry.  Deflate when dry and see what happens.  Don't try to peel off the PM, deflate the ball.

If it doesn't stick to the play ball, it's not going to stick to the exercise ball.  Vinyl is vinyl.  White glue usually won't even stick plastic toys together -- you usually have to use super glue or epoxy.

But since you are going to have quite a bit of time and effort in the big ball, I would try the patch test on a small ball and go from there.

Sue

My wife once made a very large 'goose egg' for a pantomime.  It involved many layers of paper as laminate.  It not only survived the show but lasted at the bottom of our garden for years - in a UK climate.
I agree with Alasdair about the release, though Sue (Catperson) is always a wealth of good sense.  Certainly to try the process on a smaller ball first is most wise.
If you do decide to wrap the ball in foil, you will need to secure it.  Masking tape is best for this; you'll probably need about three or four rolls.
For the layering, use strong paper - kraft or bond.  Newspaper just won't have the toughness.  I don't think you will be able to get strength at that size with translucency.
We wait with great interest to find out how you get on.
DavidO

I just wanted to give an update.. I tried using tracing paper + art paste and given the diameter of the ball, it was just too flimsy to maintain structure while trying to remove the ball from. 

I'm retrying the project this week, but I made a large amount of mache using the "hard mache" tutorial.  I am just going to try that with the art paste (minus the chalk & sawdust) this time using a release agent and see how it goes.  I'll be sacrificing the translucent nature for hardness and we'll just paint it in UV reactive paints and go with some blacklighting for effect.

Question: how much paper mache should I mix in with the art paste?  ..assuming I make a full batch with the 2oz of powder..which I think is 1 gallon.  I have several ziplock freezer bags full of this stuff to mix in.  I'm trying to figure out what consistency I should go for.