1. Against flour & water: rodents and pets eat your work. And many people think thicker is better, which it isn't.  Salt is corrosive in the long term, and isn't necessary in the short term. For your current purposes, COOKED flour & water should be fine.

2. Lifespan: You can use it for things that don't have to last too long (as for posterity or a museum), but they should easily last a year if kept dry and away from various munchers. Once a piece is totally dry, put it in a plastic bag to keep any safe, dust-free, and from absorbing moisture. A friend puts hers into clear plastic garbage bags so she can see what is in them.

3. Sphere size: the larger it is, the thicker (more layers) the PM has to be. Two-story houses can be made from wood, but skyscrapers are made with steel. While newspaper is fine, it is soft; if you have any used copier paper, tear it into triangles and use that, as it's a harder paper. Triangles cover more area over curves than strips, because if you make the strips too wide, they wrinkle at the edges.

I needed a complete sphere once, and formed it over a large inflatable ball (larger than an exercise ball). I thought I had enough layers, but when I deflated the ball, it wasn't thick enough, and there was some flex. So I cut it at the 'equator', set each half in a large tub, and sprayed that canned foam insulation all over the inside of each half (this was long ago and the foam was a lot cheaper than now), and let it set overnight.  Then I taped the two pieces together (Tip: MARK a spot on the cut so you can fit it back together properly, or leave an attached 'hinge'. And still, it wasn't perfect. With all of the time and expense of doing it this way, it would have been better to just add additional layers in the beginning. Live and learn. (Tip: paper isn't the only thing you can use for PM; I have used old bedsheets ('cloth mache'?) dipped in the adhesive.

4. Drying round objects: Do half or less at a time. Set the form in a bucket or plastic tub and get to work. Let it dry, then flip it over and do the other half. Sometimes, it's easier to do smaller patches than the entire half, esp on large works. Without a bucket/pot/tub, the weight of what you're applying will cause an unsupported ball to roll so the heavy side is down, which you don't want. And it gets heavier than you would think. If you can, set a fan to blow on it to speed the drying.

5. Primer: I use the Kilz brand, the cheapest indoor one is fine. Nearly all primers except specialty types are acrylic. My personal experience indicates that the cheaper primers are really thin and take more coats. But I have heard that you can use the el cheapo primers and add powdered chalk (calcium carbonate - check plant nurseries), but I've never done it myself. Add it gradually so it doesn't make it too thick.

6. Acrylic paints should be fine. Flat finish is good, although they're often not as flat as you expect. Personally, I would try one can and see how much coverage you get. With having to go over and over to cover up thin areas, the brush-on kinds might actually be more cost-effective.  Sometimes paint/hardware stores have a basket of mis-mixes, with a daub of the color on the lid for cheaper. OTOH, a custom mix (usually free w/the paint) can get you exactly what you want, even in quarts.

7. Glue: Hot glue could be okay, as long as you use the hot-melt type, and not the lower-temp types (unreliable). Also consider clear acrylic caulking, but test it first. Glues/adhesives/caulkings are usually plastic-based, and not all plastics work well with all adhesives, but MOST cause problems in the longer term.

If adding things with wires (like flower stems, etc), consider drilling a hole where it goes, bend the end into an L, and hot-glue it in place. Just a bit more support.

8. The Mess: I've never heard of an easy way out of this! But keep in mind that you don't have to dip all (maybe any) of the pieces, you can paint the glue on with a paint brush. The sloppier and thicker you apply the glue, the longer it takes to dry, and the more there is to clean up.

If you can't keep your artwork, ask your kids' friends if they would like to have the pieces. They might get some play milage out of them, and you wouldn't have to destroy them yourself to get them into the garbage can.

Have fun!

Sue

Acrylic paint itself is quite water-repellent, but you could coat it with a sealer. See Jackie's article on various ways to do it on this site at http://www.papiermache.co.uk/articles/w … r-mache/2/

I would wrap the form with plastic before applying the papier mache, taping it in place, just to make sure.  Sometimes PM won't stick to some plastics, but you would have to test it first.  Sometimes it will stick in some places, and not in others, and you still have to rip it to get it loose, damaging your work.  But it is less likely to stick to plastics than anything else (wood, glass, metal, etc).

Is fire really going to be a hazard where you'll be using these objects?  While you can't make paper FLAME-PROOF, I've read where you can make it FLAME-RESISTANT if you want to treat it with borax.  But that seems to be just treating the paper itself.  If you coat it with paint, it is the paint you have to worry about.  If I understand correctly, water-based paints (acrylic, latex) are relatively fireproof, but their oil-based forms are not.

If you're going to be around things like flaming torches or drunk cigar-smokers, I would rethink my plans... or ban those things.

Chicken wire: I'm not a big fan of chicken wire, myself.  It's a nuisance to work with, and can be tricky to cover smoothly. And the mess would probably be considerable.  Depending on how large they would have to be (for crawling kids or walking adults?), chicken wire would probably be too flimsy; 2x4" welded wire fencing would be the minimum, and you might need two layers of that.  Expensive, difficult, time-consuming.

If you are determined, use cardboard, not papier mache at all.

How long they would last would be determined by your climate, pets, rodents, insects and the age and destructiveness of your kids, for starters.

Sue