making canopies from scrap plastic.

Discussion in 'Aircraft & Aviation' started by reklein, Jun 20, 2008.

  1. reklein

    reklein Member

    Someone was asking about how to make canopie so heres how I do it. The materials are free. The plastic used here is from apple packaging. I discovered when you heat such bubble packs it reverts to a relativley flat shape. So heres the material.
    Heres the carved form.The finished one is in the back.I use the paper framing from the kit.When I carve the form I use the paper framing to get the size right.
    Heat the plastic at about 250oF in the oven until it sags flat,using gloves,it HOT!!,jam it down on the form. Note that the form is elevated so you can pull the plastic down. Pull it down and hold it for a few seconds till it cools and voila! a canopy ,well ,you have to trim it out.
    Next trim the canopy out of the crumpled mess.
    It will look like this when trimmed out.
    . BILL
  2. JT Fox

    JT Fox Member

    That look so simple yet very effective. I guess the hard bit is the making of the former.

    Cheers JTF
  3. Lex

    Lex Dollmaker

    Thanks! I frequently burn the plastic when I try doing that, the idea of using an oven for a controlled temperature seems ingenious!

    PS For those who are more comfortable with SI units, 250 degree Fahrenheit is ~120 degree Celsius --or 393K :D
  4. SCEtoAux

    SCEtoAux Member

    That is another good idea for making clear conopies.

    A way to make the former for the canopy would be to glue the paper canopy together with the glue tabs on the outside, leaving a relatively smooth interior. Fill the interior with some plaster of paris mix or some other modeling compound and let it dry. Maybe coat the inside of the canopy with a release agent. After the plaster has dried remove the paper canopy and you have a plaster cast of the canopy with perhaps some sanding to get rid of any ridges . You could mount that plaster cast on a block to give you the elevation needed to form the plastic like in the example posted.
  5. exzealot

    exzealot Member

    I use the same technique - except that I use birthday candles to heat the plastic. No soot either. My wife won't let me heat anything in her oven.

  6. D-WHALE

    D-WHALE Utopia Planitia Engineer

  7. I saw that site a long time ago and never gave it much thought til now. I checked out the rubberband powered aircraft and downloaded all of the plans. I don't see why you couldn't build them out of paper. I am going to give it a go and see how it turns out. Anyone know where to get a rubber band engine and prop? I suppose they are available at the hobbyshop but I don't drive so I rarely go to them.
  8. cdavenport

    cdavenport Member

    Rubberband power

    Start here:

    Peck Polymers Laser Cut Peanut Kits and Rubber Powered Airplane Accessories

    There are many sites to service your needs. Go to Hobby Lobby to purchase an inexpensive motorized rubber band winder. I used to fly these and still have some unbuilt kits. Lots of fun.

    You can't build a rubber-band powered model from paper without a balsa frame to take the torque generated by the rubber band. The strength-to-weight ratio for paper is just too low. However, you can buy white Japan tissue, put it through a laser printer and cover the model that way.
  9. Lex

    Lex Dollmaker

    Also for people who don't have anything like resin or anything for the mould (like me...), a paper mould can be used just fine by reinforcing the inside with cardboard at the right places.
  10. reklein

    reklein Member

    You can power a paper airplane with rubber by just using a motor stick inserted in the nose along with the nose cone as a plug and a little pin to hold it in place. The motor stick takes the tension of the rubber band,just like a stick fuse. rubber powered plane. However I wouldn't expect much performance from a card model plane because of the weight of the card. I'm talking scale models here such as cubs etc.
    The point of the canopy thing was to show how simple it is to make em. Don't have an oven? Look around at yard sales and get one for cheap. It'll be yours and you can cook whatever you like in it.
    Carving a form is not hard,and wood for it can be found anywhere. I have a blind freind who whittles chains from sticks on a regular basis.
  11. atamjeet

    atamjeet Member

  12. jaffro

    jaffro Long term member

    wow, this is like vacuforming without the vac, very cool indeed... thanks for the tips.

    what do you make your carved form out of?
  13. reklein

    reklein Member

    I make the plug out of any easily carvable wood,in this case I used basswood, I don't know what species you'd use down under ,it doesn't have to be fancy.
    Carving the plug is not hard. Measure your model for the length and width of the canopy,then draw the outlines on the block and carve to the lines. Don't forget to redraw your lines as you go along. You can use a photo or good pic of the canopy as a pattern to look at as you carve. Its a good idea to compare the size of your plug to the actual opening it willl cover as you near the end of the carving process. Be careful to rremain a little oversize and leave a little material to be sanded to the final contours.These plugs maybe take a half hour to make,and just a few minutes more to pull the plastic down over. Make two or three so you'll be sure to have at least one that'll work.Remember to leave the form high as you need to pull the plastic down quite far so as to get the whole shape of the canopy into the plastic. Almost any plastic bubble packaging will do. The test is weather it reverts to its flat shape when it hits the sagging temp. somewhere under 250o F.
    I haven't done it yet but I think this would be a good way to make small boat hulls and then embellish them with paper details.

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