I am assuming that you are in N. America, so I will use 'AmeriSpeak' and terms. Please correct me if I'm wrong!

Yes, papier mache would stick to the hardboard just fine, unless it's treated with something slippery or repellent; if it is, it's probably not on both sides, so use the rough side for the outside that will have papier mache applied to it. 

Use white PVC glue like Elmer's, diluted half and half with water.  If you've already got Elmer's Wood Glue, that will do just as well.

If you've got the framing done, I would consider using sheets of luan paneling, that thin, flexible, manufactured stuff that used to be used for walls in mobile homes.  They still sell it at Home Depot, etc.  That will help to keep the weight down, and it's relatively inexpensive.

You could use chicken wire over the framing, but if you're going to use any wire (and can afford the difference in price), I would go with hardware cloth mesh. It's stiffer and lies flat, but fits most curves very nicely.

Since you're working on a large project, I would suggest that you cover the hardware cloth with fairly thin cardboard that won't make ripples and waves when it gets damp. Something a little heavier than cereal-box cardboard.

Corrugated cardboard flexes in one direction, so if you have to use that, use the thinnest you can find, and then roll it to get it to curve smoothly before you try to apply it.  Just roll it like you were going to make a post out of it, and try to avoid putting ridges in it.  There is also a corrugated cardboard that only has one facing on it, and it comes in rolls, but you would want the smooth side out, and I don't know how well the rippled side would stick to wire (unless you tied it with thin wire). It looks like this: https://www.staples.com/Singleface-Corr … uct_948855

If you end up applying sheets of papier mache, use heavier paper, like the rolls of brown packaging paper.  This won't wrinkle as badly as thin paper, and you shouldn't have to apply as many layers. Apply your diluted glue with a brush on one side of the paper, and don't saturate it. Enough to do the job is all you need.

For papier mache 'icing' (like the trim around the edges here: http://cradlerockingmama.com/wp-content … ngMama.jpg), use thin paper, maybe even tissue paper. Apply glue, and then crumple it lightly and press it onto the cake where you have already applied a strip of full-strength glue.

Good luck!

Sue

Hi Jimbob, As a fellow Brit, I would recommend getting a big tub of pva glue from a builders merchant. It will be stronger (and cheaper) than craft glue. Good luck with your project.

Sorry about that! I heard you typing with an American accent! ;-)

If you're using chicken wire, using two layers with the holes offset will make it less flexible and easier to apply the paper. Tying them together occasionally with thin wire should keep them from shifting.

Sue