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CA hinges

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I've never used CA hinges before and just need some clarification...

If I understand correctly, you insert the dry hing into slots in both the control surface and the wing/tail and *then* (once you've set the gap and are sure everything's lined up) you wick in some thin CA. The thin CA is then drawn into the slots/wood by capillary action and then sets.

If this is correct -- won't the hinge be very stiff with all that hard CA impregnated along the line where it is supposed to bend?

And won't it be rather hard to keep the hinge-gap very small so as to reduce the tendency to flutter with this method?

How do you make sure you don't end up just gluing the two parts together?

Before I stuff this up I'd like some input from those who know.

If the instructions hadn't said otherwise this is how I would have done it:

Push the hinges into the slots and position the control surface, setting the gap to the minum that would allow adequate control deflection.

Drill a small hole through the control surface and the surface it's hinged to - so that the hole goes roughly through the middle of each end of the hinge material as well.

Drip some thin CA into the hole so that it is then soaked up by the hinge material -- using just enough CA to ensure that it doesn't reach the actual hinge-line itself.

What say you?
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Yeah you've got it about right. I use a pin to keep the hinge centred when I push the two surfaces together, then remove the pin before i throw in the Ca. Make sure the CA you have is really thin and well if I can put it that way fresh. An older bottle of CA will have become a little thicker and won't wick in too well. You can drill hole on the centre of the hinges as I've done this alot with good results. However if the CA is right you're wasting your time. The Ca will wick in very well don't worry. I also never push the surface completely onto the other but one can really never get this right. There is always something like a 0.3mm gap so that the surface will get full deflection. Just push the two surfaces together and hold it there while bending the gap open. Other words hold the surface at say 45degrees deflection and then drop say 3 to 7 small drops of CA on the hinge. You'll have to work quick otherwise you will have the CA drying to quickly and the following drops just sitting on top of everything and making a mess. As soon as you've dropped the CA in work the surface up and down or whatever so you don't get a stiff hinge. If you move it it'll break the CA on the hinge line and the surface will move free enough.

Also if you have too much Extra CA that sits on the covering you can always remove it with some clean Nitro. I've done this plenty and works well to clean the useless CA off. Just wet some TP with nitro and wipe the excess off.
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Another thing Ive found is you need to hold more surface deflection that you actually want. Somehow it seems like after your done glueing them in that you lose a few degrees of throw. I have some shims made up about the right thickness that I put in the hinge line, dont have to worry about deflectiong the the surface at all, just put the shims in glue and voila a nicely hinged surface. Im using an old plastic card thats dbl thickness, like an old credit card or drivers liscense.

On another note CA hinges do not like to be to tight, meaning you dont want your surfaces to pull against them when there deflected because they will break with use. Id rather have a little to much of a gap and just tape my hinge line, which is a good idea anyway.
Another thing some use...mark the hingeline on the CA hinge with a crayon. The wax in the crayon will keep any CA from sticking to the hinge directly in the center, makes for a nice free hinge.
Chuck: Do you buy the 24 pack or 48 pack of crayons? :lol:
I just have the little 8 pack. It's a real bummer, hard to color coordinate with so few choices.
ChuckAuger said:
Another thing some use...mark the hingeline on the CA hinge with a crayon. The wax in the crayon will keep any CA from sticking to the hinge directly in the center, makes for a nice free hinge.
that's exactly how I do it. Works great and is rock solid.
Another thing you can do is drill a small 1/16" - 3/32" hole in the center of the slot. This helps the CA to wick down the center of the hinge and locks it in.
I've been using the Sonic-Tronics hinges for years and they are the best on the market that I have found.
They have a slot cut in them so you get very good penetration of your CA and are very durable. They also have some sorta fuzzy stuff that really grips to the wood and holds fast.

Check them out at


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Scat-r-d said:
They also have some sorta fuzzy stuff that really grips to the wood
Damn, sold me a pack right there! :D
very good penetration
thats what i need
while repairing my EF edge I decided to change out the hinges on the ailerons (damn ADD!). it seemed to me that CA hinges always resulted in increased resistance for increased throw, or at least MOST of the time. [granted, this is PROBABLY because I usually try to close the gap as much as possible while hinging... so i end up with rubbing, etc.) anyway, i decided to try with pinned hinges, so i cut the ailerons off and added pinned hinges x4 on each aileron. it takes a little more prep-work, because you have to cut the slots wider (around 1/16", rather than razor-blade thin)(super secret: run your exacto blade through the slot backwards to clear out the necessary dado) and there's more of a problem if the hinges arent aligned vertically, so be careful when prepping.
a little 30-in-1 oil keeps epoxy off the pins, and you're good to epoxy them in. now my aileron's swing like scrotums at a nudist colony. I LOVE IT!

-im so drunk.
I've used the hobby lobby bulk ca hinges exclusively for the last 4 years. I just slot, stick pin through to center and set gap, and c.a. NEVER had one break or tear out. and they are cheap. I usually throw away the ones supplied with the kit unless they are the sonic ones. I will use those.
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