Sometimes I cover planes made from EPS (expanded polystyrene) foam with paper. This process adds tremendous strength for very little weight gain, and also provides a nice paintable surface. I use regular white copy paper, but others will work too.
1. Prepare the foam surface by lightly sanding with a fine sanding pad and repairing any major problems with lightweight spackling compound. Remove sanding dust with a brush or compressed air.
2. In a bowl, mix a solution of glue and water until you get a nice paint-like consistency (a little more water than glue). I use Elmerís wood glue.
3. Cut out the pieces of paper covering. Allow for some overlap, much like you would using a film covering. Itís easier to make relief cuts for compound curves when the paper is still dry.
4. Place the paper on a surface (waxed paper works well) and paint the glue solution onto the paper using a paint brush. Let the solution soak into the paper for a minute while doing the next step.
5. Paint solution onto the foam.
6. Carefully lift the soaked paper off the table and apply to the foam.
7. Using the brush, press the paper onto the foam and make sure the edges of the paper seal down well. Try to get most of the wrinkles out of the paper, but small ones will disappear as the glue solution dries. Donít apply too much pressure or the paper will tear. You can also use your fingers to press the paper onto the foam. Optionally you could squeegee excess glue from the paper, but be careful because the wet paper will tear easily.
8. Let the foam and paper dry thoroughly.
9. Once dry, small wrinkles can be sanded down. You could also hide the paper edges with spackling, but they can also make good panel lines.
With whatever foam part youíre covering, try to paper the entire part and then let it dry together. The paper expands when wet and shrinks when dry, so some foam parts can warp easily. When covering wings, do one side of the wing right after the other and allow the entire unit to dry. The same goes for tail surfaces. Fuselages are generally not an issue for warping.