jeremy7768

I am currently building a usaircore colt .40. THis is my first experience with coro, while cutting the hing for the tail I cut all the way thru the coro to the other side []!!! Can I use CA hinge material and contact cement to make the hing or is there a better way to make the hing?

Jeremy

Square Nozzle

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[quote]ORIGINAL: jeremy7768

I am currently building a usaircore colt .40. THis is my first experience with coro, while cutting the hing for the tail I cut all the way thru the coro to the other side []!!! Can I use CA hinge material and contact cement to make the hing or is there a better way to make the hing?

It might work if you are talking about putting the CA hinge on the outer surface of the Coroplast. I wouldn't try to install the hinge in the conventional fashion by slotting the coro and sticking the hinge in. I doubt that you would have enough contact area to securely hold the hinge.

FantzyPantz

I would not attempt to glue more coro to make a new hinge. I have cut through the hinge enough times, it's nothing serious.

Cut several 1-2 inch length of fiber strapping tape, using the over-under hinging method shown in the picture.


You could then cover the hinge with a length of sign vinyl to tidy things up, and make it look better. Be sure to check the hinge before each flight to make sure the tape is sticking, and no movement that will cause flutter during flight.

simhatus

Hi

Bit late now but for future reference the way to make sure you only cut through one side of the flute is to use the knfe blade only and run it through flat on its side in the flute, then the excess of the flute can easily be trimmed with a scalpel.

Hope the diagram explains it better.

Simon

FantzyPantz

There are a few methods I have seen that make cutting the coro hinge easier without cutting through the opposite side.

With your exacto hobby knife, push it into a small peice of 1/4"x1/4" piece of balsa stick making sure the blade does not come out the other end of the wood piece. (or smaller BBQ skewer - one that will slide through the coro flutes) Push the blade along the hinge line, the wood piece will be the guide as it moves along the inside of the flute to give a straight cut along the coro flute. When you have cut 1 side, turn the blade and make another pass to remove the entire flute wall, therefore creating a perfect coro hinge.

The Mugi build plans show how to make a flute cut. http://www.mugi.co.uk/tutorials_flutecut.php

(The Coroplast split-hinge is patented by Great Planes/Hobbico)

MrGreenSpeed

You could get a coro sign, usually 4 mil and cut a new tail fin.

You can also use hing points to make a good hing too.

I use a hook blade to cut hinges.


Jeff

Square Nozzle

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Have you ever made a long scissor cut in a piece of paper like when you are cutting wrapping paper off of a roll? I use that same method in cutting down the length of a flute to make a hinge. Just nip the edge of the coro to get a start and push the partially opened scissors the full length of the flute. You'll never cut through both sides again. This requires rather pointed and sharp scissors.

spadeng

depends on how much you cut through, if you cut through in a spot one or two inches, thats not too close to the edge, just cut the whole section out, on both sides and tell everyone you ment to do it and it is to loosen the hinge, if you cut the whole hinge off, I'd do like greenspeed said and get a new piece and make a new part, might as well get a whole sheet of coro for your next SPAD, and use two curved blades attatched to a yardstick as in spadtothebone

Clean

Can't count how many spads I've built, but nevertheless I built my club racer, had everything painted and ready to go and then hinged the ailerons. Left one went fine, did the right one and the whole thing fell off in my hand. Oops. Robart Hinge points or the Carl Goldberg hinge joints or regualr hinges will all work, the hinge points are just easier. Drill for the hinge, put some vaseline the point on the hinge and put some heat on it so that it flows into the joint but don't let it get on stud, then mist the hinge with water put a drop of Poly urethane blue on the hole and push the hinge in. Do em all and then flex the joint to line up all the hinge points. When you have it all working and the gap as small as possible, tape it to hold it in place. After 4 hours the glue will be done you can pick out the foam from the hinge line. Make sure everything is flexing right and go fly. If you want to seal the gap you can use tape. For a good, non pealing tape mist the coro where you want it to stick with 3m77 spray adhesive, let it dry for at least 15 minutes and then lay your tape down.

GPS

The coro I use is a bit stiff, so I usually make an interrupted hinge to take a bit of the load off the servos (see tips on making hinges at SPADtotheBone). I usually leave at least 4 inches of coro on the ailerons near the root before the first gap for strength (this is near where the control horn attaches). My planes get a LOT of abuse (stupidity, wind, stupidity, etc) and I've had the hinge rip at the root of the aileron twice on 2 different wings (Really bad "arrivals" - got to Love SPADs - dust em off and up they go again). To fix it I cut a piece of coro 2" x 4", and cut away one side and the flutes so I'm just left with a flat piece of plastic. I split the wing open for a bit at the site, insert the piece so it spans the broken hinge and reglue with medium CA. Have to Really clean it well, and I usually rub it down with solvent and fine sandpaper or steel wool. The first repair lasted 20 - 30 more flights until I gave the plane away, and the second wing probably has 40 - 50 flight on it since the repair and is still going strong.

OzMo

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Been there done that too. You can also go "old school" and make a hinge using string (heavy braided dacron fishing line is a bench tool must) . Sew a FIGURE 8 pattern with the middle of the 8 at the hinge line. This is perhaps one of the oldest hinging methods out there...everyone's mom had needle and thread. Also a good way to "TIE UP " those end tears spads get after some use.