For glueing the grocery bag to the wood, you spray it with contact cement, 3M 77 is the best, but other kinds work or I heard you can also use a glue stick. The contact cement is going to spray everywhere, so put the wing in front of cardboard (a pizza box works great), spray the top, then put it on wax paper and cover it (unless you are going to drop it on top of the covering like jander14indoor said).Where can i get a good stretcher frame. Thanks for the tips but in the wing there are other pieces of wood between do i just put mylar on top of it all or between each and every one of the? Also how can i stick the grocery bag onto the wood?
If you want to use a stretcher frame, I'm fairly certain it's just a square frame of wood. Make it. Attach the covering to it with some slack to accommodate the curve of the ribs. I personally don't like the stretcher frame, and I just get someone to hold two corners as I hold the other two, and we we pull it taught and set it on the wing, then I rub my finger over the wood to make sure it is attached everywhere.
When you talk about other peices of wood between the wing do you mean the curved ribs and some supports? Yes, you want one peice of covering for the whole wing, or two if you make it a certain way:
There are two common ways for making the wing. For simplicity I'll assume you have only 1 dihedral point (making a V shape). Black line is your wing, red line is the covering you should use. You can build your wing flat like this:
________________ EDIT: Imagine the covering is centered over the wing, with some slack on either side.
put two ribs close together in the middle, partially break the wing between them to get your dihedral, and glue the break.
Or, some people make two wing halves separately:
________ and ________
then glue them together.
Note: I didn't include the hight of the ribs in my drawings.
I hope I answered your questions!