From my experience the secret to making smooth pulp is what else you put in it in addition to the paper and glue.  Adding joint compound (joint filler in the UK) to a pulp mix, helps smooth it out.  I've also added extra calcium carbonate (whiting, or sno cal), and volcanic ash/pumice. 

Bear in mind that the extra fillers do also add weight.  And if you can start with a relatively smooth pulp that helps as well.  I use the advanced recipe technique listed on this site and grind dried paper pellets in a coffee grinder to make paper fluff when I want to make the smoothest layer possible. 

UltimatePaperMache.com also has a good paper clay recipe that can be smoothed out.  When I need something super smooth I apply the clay the surface with a knife or small spatula, smooth it as best I can.  Then I lightly brush a little water on the surface with a paint brush and lay a small piece of plastic wrap over that and then smooth it out using my fingers or hands. 

If you have enough filler in your pulp, you can get a very smooth surface this way. 

David is also right about sanding, tho.  You can get a very smooth surface that way as well.  If you think it's not sturdy enough to take a rough sanding, you can always add layers for strength and then sand it down.

Thanks for all the advice! This papier mache business is so addictive...

P/m works a lot like the wood that is its ancestor, if you have the thickness just sanding and paint should give you a finish suitable for a bed sculpture, start with something evil like 60 grit in a sanding block and work through 150 and  250 , sandpaper meant for wood will usually be called things like course, medium ,fine and extra fine,the hardware store will probably have a combo pack with a few sheets of each  . paying a little extra might get you longer lasting paper

if you want a yacht finish after medium you can fill in the hollows with fairing compound, for this I would think something like  3/4 flour ,1/4pva, thin w/ water for workability, and spread with a  putty knife,  then go back to medium to see how you did , if you can swing a self leveling paint that will hide really  small stuff

have fun with this, hand sanding is meditative work ,removing that witch is imperfect leaving that witch is pure and pleasing

if your in a hurry auto parts houses sell grinding disks  for body work ,BE CAREFUL THESE ARE VERY AGGRESSIVE  hardware stores sell sanding disks for drills too that are a good compromise,but hand sanding gives the best finish and it is pleasing work,  your call

another thing if you choose power sanding ware a dust mask . my teacher died of lung problems because of breathing stone dust ,not pretty, cheep paper has acids and clay fillers you can smell them when you burn paper ,most likely not good to breath... and your gona need your lungs to push that bed,,,good luck

Last edited by captain.ratsie (2010-06-02 15:37:32)