somegeek
Posts: 2113
Joined: 8/1/2005
From: Vancouver,
WA, USA
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Building a coroplast fuselage for my Sickle and figured I'd take some pics to share if someone out there is pondering building a coroplast fuselage . Originally read about this cross-flute groove cutting over on spadworld.net where a guy used his table saw to cut the grooves. I don't have a table saw so my Dremel was put to use.
I used 6 mil coroplast and a Dremel with a Dremel Multi-purpose Cutting Kit for the grooves. Practice on a scrap first to assure your're cutting deep enough but not too deep and to get a feel for the speed you need to move to cut a smooth groove. I noticed the tip jumps a little when you hit the flute walls so going slower minimized this jumpiness. I have a nearly flat groove with slight ridges from the removed flutes.
Square up your lines across the flutes. I squared up my first line running perpendicular to the flutes and then just measured for each groove as I cut them.
I used a level which had some rubber grips on it which gripped the coro to help keep my guide straight. When cutting with this attachment, keep the Dremel facing the same way for the entire cut. The bit won't be perfectly centered in the base and if you rotate the Dremel while cutting your groove you could get a wobbly line. Also turn the bit when lining up your guide so it's widest point touches the line so you can assure you're putting the guide in the right spot. Perform this measurement at the other end of your material cut line.
1st groove cut. After cutting your groove, running back and forth over it again with the Dremel will remove some of the hanging material which was removed from the groove. I had some left over scrap but it was in the flutes - no biggie.
As I was cutting, I used a shopvac to clean up after each groove cut to pull out what material I could. Works pretty well.
Depending on the thickness of the coro you're using, you'll want to cut your sides taller than your top and bottom to get a final square result since the sides will over lap the top and bottom. I cut my grooves so my top and bottom are 2 5/16" wide and the sides are 2 1/2" wide. This will give you a square with 6mil.
I missed the opportunity to take a pic of this coro laying flat before starting to glue up.
I sanded, flashed(ran over with a torch lighter) and cleaned each joint with acetone to get rid of the manufacturing oils and also give the surface a rough texture for the CA to bond better with.
I used two pieces of 4x4 and about 150 lbs of dumbells to keep things in place. The fuselage folds tightly and you have to stretch the coro a little to bend into a 90º but this assures a very tight joint. Pre-creasing these corners will allow it to set square between the 4x4s. if you need to you can add some weight to keep the bottom flat.
For the front flute of the fuselage , you'll want to reinforce with some bamboo skewers for the firewall mounting. I used bamboo skewers cut to length and coated in poly-u glue to expand and fill the flute. Can see the pieces remaining n the right a few pics down.
Make a reminder or what not to remind yourself to install these as you glue up your fuselage ! If you forget you can poke holes and install them later but it doesn't look as good.
After getting your fuselage in the jig with the one skewer in place, run CA down each seam. After 10 minutes it is solid enough to pull out of your jig.
Repeat the creasing and bend the top down and add weight as needed to keep it straight and in place and add a bead of CA. After this dries, you can remove it from the jig and run beads of CA down each inside seam yet to be CA'd.
Next is to glue down the flaps and the fuselage core is complete. The flap is created by simply cleaning out about a extra 1/2" groove on one edge of your coro fuse before gluing up. This works great to keep that fuse together.
This one is a little different since I tapered the tail end a little.
Some folks install formers in their coro fuselage s. I found on my dogfighter fuselage built using the above method, that the firewall holds the front shape. The back end is not deformed at all. This method of gluing up a coroplast fuselage is very solid!
somegeek
< Message edited by somegeek -- 7/11/2007 8:27:46 AM >
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Fly safe, have fun. Measure three times, cut once. The man who makes no mistakes does not usually make anything.
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All Forums >> RC Airplanes >> S.P.A.D. Aircraft - Coroplast design >> Building a coroplast fuselage...(w/ some sickle build pics) 
Building a coroplast fuselage...(w/ some sickle build p... - 
Home Depot has some large 22" stir sticks which when spliced with 
