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Hello,
I am in the process of making a 3metre space shuttle for the Knaresborough Bed Race (!). The model is mainly made of wood an polystyrene, and I am sculpting the shape of the nose cone and wings using PM. I have applied several layers of newspaper strips and I am happy with the shape, but the finish is a bit rough. There is so much advice on this site that I am not sure what will be the best technique to try. I have tonnes of egg boxes - would an egg-box pulp applied over what I have already done give me a smoother finish? I am not after a perfect finish, but smoother than I have achieved so far!
Thanks.
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Don't be afraid to get rough with it. It is probably best to smooth the surface first by using a rasp or Surform. This will work providing your laminate is thick enough. Then rough sand and apply some paste to bond the surface before applying more laminate. Don't apply pieces that are too big because they will inevitably wrinkle.
I would normally suggest applying a coating of extra smooth pulp but that needs quite a lot of experience (and time) to do properly and you don't need that level of finish and strength anyway.
DavidO
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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.
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Is most of your unevenness in the surface lumps or dips ?
Sanding should take care of lumps; just fill in the dips with joint compound (joint filler), remembering that the smoother the application, the smoother the final effect will be. And you can sand it, too. You could use a fine pulp for filling deeper holes, but it would be incredibly time-consuming to cover the whole thing with it, and there would still be no guarantees.
Sue
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Thanks for all the advice! This papier mache business is so addictive...
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Hello imperfectimp0,
Drying time depends on several variables:
Thickness of PM clay and/or number of layers of paper and paste and the shape of your piece.
Kind of paste used and its viscosity when applied.
Humidity and temperature of area where it is drying.
Drying time can be reduced several ways:
Using a fan, this works surprising well.
Placing piece in a convection oven ( 200ยบ F works for me)
A microwave oven but be careful not to have any metal (wire or otherwise) inside your work. Most modern microwave ovens can handle some metal without damage but fire is an issue too. Metal can get so hot it can ignite the paper.
When I was starting out not so long ago I made test pieces of the same material to test how it looked, acted and dried as I experimented, a nice learning experience for me.
And finally if a mistake is made it can almost always be fixed or "adjusted" easily. Just another advantage of PM.
Have fun.
Bob C.
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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)
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