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[quixotic]

I tried various methods of making cooling vents for my 2013 Zero S (I adapted a Airtech fairing, so the original venting had to go).  I first tried utilizing some 1" x 4"'s and some 1/8" 3-ply plywood.  That didn't work.  then I went for the same, but substituting in some vinyl.  That worked...sort of.  Then I tried fiberglass.  That didn't work...mainly because it was the first (and last) time I'd ever played around with the stuff.  Then I searched on line for paper mache techniques.  I found a method which uses white glue, drywall paste, and the blue shop rags that are sold in hardware stores and look like rolls of paper towel.  Unlike fiberglass, I could use this stuff indoors and with bare hands.  Just like playing around with porridge.  The photo below shows half of a 20 pound dumb-bell resting on a paper mache vent that is about 3/16" thick, and with an average of 3 plies of the blue shop rag.  I'm sure it could have supported twice or three times the weight, but I didn't want to tempt fate.

The foam off to the right is the form I used (carved from styrofoam that I got from Michael's craft store...with a saran wrap covering not shown).  The vent obviously looks like crap, but it's not the material's fault.  I pulled it off the form too early, and like cake in the oven, it sank.  I also didn't take a lot of care laying down the strips of fabric.  My next attempt will look a lot better. 

Here is the link for the method (about 1/3 of the way down the page under "joint compound").  I found that a mix using about the same amount of water and joint compound works well for consistency.  http://www.ultimatepapermache.com/paper-mache-recipes

Of course, the material isn't waterproof, so I had to paint it and then add a coat or two of varathane.

[Doug S]

You made a composite material, very much like fiberglass. It's a bunch of fibers in the form of a fabric, which provides the strength, and a solid matrix which causes the fibers to maintain their shape, so their strength is realized. I once reinforced the door of my perpetually broke girlfriend with a couple layers of brown paper, saturating it with waterproof glue...yeah, papier mache. It was amazingly sturdy and out-lasted our relationship.

I'd recommend trying again with the fiberglass, however. It's WAY stronger, only a bit more expensive if you don't waste materials, and just impervious to anything. If you REALLY want a strong part, don't discard the foam -- brush on a thin coat of epoxy (or polyester resin, or whatever you're using -- you can thicken it a bit with "microballoons" to make it thicker, which works better) to adhere the cloth to the foam, wet the fabric out, let it cure, dig out all but a 1/4" thickness or so of the foam, then glass the inside of the foam the same way. You won't believe how strong and lightweight a "foam-core sandwich" like this is, even with just a couple of very thin skins of composite.

[MrDude_1]

If you stick with the fiberglass and learn how to do it properly, its both cheap and easy.... although I always spring a little extra for the epoxy based resin, mostly for the smell, but also for the strength increase. I like West Systems epoxy. I have pumps on the cans, and disposable plastic cups.. makes it all super easy for small projects like your scoop.