ORIGINAL: longdan
I guess it's the 'installed properly' bit that I don't get. I use good quality CA, smear it evenly over the whole surface on both sides, and even clamp it afterwards when I can. Otherwise I use weights to squeeze it down.
Hey Dan - I think I just found out why you don't like CA hinges - they work great if you do them the RIGHT way, and you'll find you have plenty of time even with torque rods. The one thing you do NOT want to do when fitting CA hinges is to put glue on the hinges BEFORE you fit the control surface (aileron etc), the CA is applied AFTER the conrol surface is in place with all of its' hinges, torque rods etc installed. Using ailerons with torque rods as an example, the fitting order is as follows. (I'm assuming you're doing an ARF here - if it's a kit you'll need to shape the leading edge of the control surfaces first etc.)
Using a toothpick or similar push a little vaseline into the tube the torque rod fits into to stop glue getting into it, then fit your torque rods to the wing centre ensuring they move freely. Mark the aileron leading edges and wing trailing edges for your hinge locations, and remove a small piece of the covering about 2mm/1/16" high and a little wider than the hinge from both the aileron & wing at each hinge location. Mark a line along the middle of the trailing edge of the wing. On an ARF you won't need this on the aileron leading edges as they'll already be beveled. Then use your hobby knife (with a new sharp blade) to cut your hinge slots in both the wing and aileron. This is done by pushing the blade into one end of the slot location, and wiggling it along the centre you've marked till it gets to the other end. Don't try to widen the slots, they should only be as thick as the blade and the hinges should be a very tight fit in the slots. If you haven't already done it, drill the hole for the torque rod. This one should
not be a tight fit as you need a little room in there for glue. Roughen the end of the torque rod with sandpaper to make sure the glue will stick well. Test fit the aileron with all its hinges and torque rod to be sure it's right and has full movement without binding, then remove it and fix any problems. Push a pin through the middle of each hinge - this will stop the hinge being pushed too far into either the wing or aileron, and will give the correct gap. Push ALL the hinges (still without glue) into the aileron till the pin is firmly against the leading edge. Using a toothpick fill the hole for the torque rod with 30 minute epoxy, then fit the aileron to the wing, ensuring that the torque rod is fully seated in its slot in the aileron, and that all the CA hinges are in their slots all the way to the pins. You've got half an hour to get this right so there should be plenty of time. Allow the epoxy to cure, then remove the pins from the hinges.Ensure the aileron has full movement in both directions with the least gap possible. Move the aileron "down" as far as possible and apply six drops of
thin CA to each hinge gap. Immediately turn the wing over and apply another six drops to each hinge with the aileron moved "up" as far as possible. The CA will soak along the hinge in both directions and firmly glue itself to the balsa. While it's setting flex the aileron in both directions to keep the centre of the hinge flexible. Clean up any mess with paper towel and acetone (be careful - acetone will take the colour off some cheaper coverings).
You won't need weights or clamps (the CA will have cured before you get to use them anyway) and if done right you shouldn't need pins either. Some people like to drill a small hole in the middle of each slot to give the CA a "channel" to run along so it gets all the way in, and I've seen a lot of ARF's supplying hinges with a "slot" in the middle of them for the same purpose. Both these methods work but I don't really think either of these are needed and it introduces a weak spot to the hinge. The main points are to remove enough covering so that the CA is not hindered in soaking into the hinges, to have a TIGHT slot so you get good firm contact between the balsa and the hinge, and to apply enough CA to soak the entire hinge BEFORE it gets a chance to set (and it only takes about 5-10 seconds), since once it's cured you're not getting any more CA in there. You might like to look at getting one of the "hinge slotting tools" the hobby shops sell - tho they're really just a V shaped hobby knife blade with two edges.
Hope this has helped, and that I'm not "teaching my father to suck eggs". If I am, my apologies.
Matt