Elapor is a type of foam manufactured by Multiplex that is similar to EPP. It is very durable and is easily assembled with regular CA glue. It is used in all Multiplex airplanes and the new Funcopter heli. Elapor has a smooth surface and is very flexible, making it ideal for trainers and aircraft that take a lot of abuse, though it is subject to hangar rash and should be carefully stored to avoid inadvertent damage.
Repairs can be made to Elapor parts that have become deformed by applying very hot water to the damaged area. This causes the foam beads to expand slightly and take on their original shape. This repair method is often called "Elapor Soup" because it often involves boiling a pot of water and dipping the damaged foam part into the pot. The hot water can also be poured over the foam directly or onto a piece of cloth that covers the deformed area. The surface of the foam will often become bumpy or pebbled following a repair. The bumps can be smoothed by rubbing the surface of the foam with the back of a spoon.
Elapor has some unique characteristics when it comes to paint. The propellants in regular spray paint can cause the foam to expand badly, causing a very bumpy surface. Spray paint can be used without a primer with caution. Care must be taken to hold the can several inches from the surface of the foam so the propellant has time to evaporate before it hits the foam. Using this method to cover the model with several light coats usually produces a good finish. It is also advisable to wipe all surfaces to be painted with a rag dipped in alcohol to remove the waxy mold release from the surface of the foam. This helps the paint adhere to the foam better. A primer of water based polyurethane can also be used to help the paint stick and to create a smooth finish and mitigate the problems with spray paint. Air brushed paint also removes these issues. Krylon H2O is often suggested for Elapor, though it is heavier and bleeds into the foam so care must be taken to keep the coats very light. Krylon H2O Black causes the foam to bubble when placed in the sun, even after the paint has dried, and should be avoided. Regardless of paint application method, the paint with usually chip and flake from the foam over time.