You broke a canopy on your scale aeroplane, and no replacement is available?

Here is how I made my large canopies-the simple way!

I use a styrofoam block, and carve a canopy shape.  At its edges, I made that shape (lets call it »positive mold«) larger  for about 2,5 cm (1inch) so we could later trim the finished canopy to proper size.
Shaping of the positive mold starts with transfering outer contour to sides of the styrofoam block and cutting it. You can use very sharp knife (beware, not to cut yourself!!) using motions as knife was a saw. You can use hot wiring bow, going carefully over the drawn lines, or over prepared templates, made from hard paper, masonite, or other apropriate material. Now we should refine the shape, to give it proper shape (oval cross sections). We can use some cross section templates, to check our progress. I usually cut away the edges at approx 45°.  Afterthat I cut again all edges. Now the canopy positive mold is comprised by about 9 surfaces.  We use sandpaper or sanding block, to smooth the positive mold surface.

When satisfied with the shape, we must cover the surface with some kind of filler, that can be later easily sanded.  If we intend to use this mold many times it is not a bad idea to strengten its outer surface. You can use glass laminate and filler if you are master in this technology.

My prefer method is more low-tech. I use white carpenter glue thinned with a water and small pieces of newspaper to cover the surface. I pour allmost milk-alike glue in a pan and troughly soak paper pieces in it. I apply about 3 layers of paper over the mold surface, and leave over night in very warm place so water from glue could evaporate. Well, somethimes take two days for evaporating the moisture from the paper skin.

Now I sand the surface a bit, and apply filler. I use a filler that is made for wood and can be sanded easily. After each layer I leave to harden and then sand. I repeat this process for about  3 times, or until get satisfied result. I use fine grade sandpaper.

We can use that positive mold already, but we can also paint it to get smoother surface, and find out possible areas, where more filler should be applied.

And now to the making of our canopy!

I use a 0,4mm thick thermoplastic foil. I clamp two sides between a pair of wooden sticks and use woodscrews to tight them together.

I insert a nail on each of four ends , cut their heads off, and bent it to a hook shape.

I heat the kitchen owen and insert the plastic in. I hook those bended nails into side rails of the owen, so plastic will be hanged nicely in the available space.

I  look into the owen trough a windoow in the owen door. The plastic will soon starts to be soft. You will notice, that it shakes a bit under the air circulation inside the owen. The plastic will became soft and it will starts to streech under its own weight, which is visible by its lower side slowly sinking down. Plastic can also starts to look foggy. Dont worry, it will became clear later on the process by itself.

Now a helper should cool the canopy surface with a wet piece of cloth. Now you can stop pulling down.

Carefully remove your plastic canopy from the mold.

If canopy looks well, cut it on the proper size and install it on the model.