I'm sure this question has been asked before but I'm asking it again. What glue should I use to secure those flexible hinges that come with ARF planes?
Before everyone says 'CA'. I'd like to rule that out. Mainly because of a couple of failures. And I find that when glueing in aileron hinges, there is not enough time to do the epoxy on the torque rod and the CA on the hinges before it all starts to set even before the aileron is pushed into place. Its all too much to do in too little time (for me anyway).
I was wondering if anyone had tried using aliphatic or PVA to secure their hinges.

I'm in the same boat. I just got an ARF with CA hinges. I don't like them. I want to upgrade to a hinge with a pin in it - it just seems proper. I'll follow this thread with you.

Hey guys wassup?

Bill

I'd still like to use the plastic ones that come in the box. Mainly because of a lack of $$$ and I'm too cheap to buy the pinned ones - though the same question still arises - what glue to use?
Many people advocate putting cut-off pins through the hinges to keep them in place. Is this because they have no confidence in the glue they are using?
I'd like to hear of a hinge glue (other than hit-and-miss CA) that they are 100% happy with.

longdan,

I've never heard of any other glue that is used but if your not happy with CA hinges then get some round Robart style hinges, a drill guide, and epoxy. There is really nothing wrong with CA hinges if installed properly.

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.

Don't get me wrong - Most of the CA hinges that I have done have worked out fine. Just a couple that didn't, with disastrous results. One time, my whole 1 piece elevator came off in a high G pull out after a dive. It was thrashing around on the end of the pushrod until that let go and it went in. That was 6 CA hinges that all let go at once.
Had an aileron let go in a similar fashion, except this time it was rebuildable.
Maybe it's my technique of gluing them in. I usually think I do a good job using CA but I was just wondering if there were any alternatives that may take a little more time to set up, but I don't mind waiting if it's gonna give me a bulletproof hinge.

Has anyone tried Gorilla Grip polyurethane glue? I've heard this can be used, but you have to keep wiping away the foam that comes out at the hinge line. I'd be happy doing this if someone told me that they have done it and it works - preferably better than CA.

if it is a CA hinge....use CA....

I use DuBro or Great Planes flat nylon hinges and Gorilla Glue

http://www3.towerhobbies.com/cgi-bin...970+&search=Go

Hi guys.

longdan, you never really specified what kind of hinges you are inquiring about. I know you said "flexible" hinges, so I am going to assume you are talking about CA hinges (but I don't really know for certain).

I have lots of experience with CA hinges. Before I started using them I didn't think they were a good idea either. But now that I've used them on so many models, I haven't had any problems with them - except for one time. It was on a larger model that was using a gas engine. After a while the vibration caused a couple of the hinges on one of the ailerons to fail, but it wasn't something that happened quickly, so a post of pre flight inspection caught it before it was too late. CA hinges on models powered by gas engines may not be a good idea.

And I have also heard of CA hinges delaminating (where the fiberous outer layer becomes detached from the plastic inner layer), but this has never happened to me and I have never seen this personally.

I'm not trying to talk you into using CA hinges and I know many prefer to just stay away from them, but I believe there are many more modelers who do use CA hinges with great succes.

That said, I would never glue in CA hinges with anything other than thin CA. I don't think your technique is correct for installing the hinges. What you do is glue in the hinges with thin CA AFTER the surface (aileron, rudder, elevator) is joined to the main part. In the case of your ailerons with torque rods, you fit the hinges into either the aileron or wing (without any glue), apply epoxy to the torque rod and in the torque rod hole in the aileron, then join the aileron to the wing and torque rod. THEN you wick in your thin CA. If the hinge slots are cut correctly, the CA will wick into the slots and hinges, thus providing a permanant, secure bond.

Glues other than CA won't be able to "wick" all the way down into the hinge slot to the back of the CA hinge and into the hinge fibers.

There are a couple of techniques that make the job easier too. Here's a link to the instruction manual for the Great Planes Venus II ARF. Go to page 9 and read steps 1 through 3. Use CA tips (like the one on the CA bottle shown in the photo) to pinpoint and control the amont of CA that goes in.

Here's the link;

http://manuals.hobbico.com/gpm/gpma1027-manual.pdf

I know there are some people who just don't like CA hinges and I would not use them on larger, gas-powered planes my self. But for your every-day, glow-powered sport model there isn't anything easier or faster than CA hinges and they really do work well.

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

About 40 years in this hobby. Here is what I do. For CA hinges where you have a torque rod involved (from the point everythings is fitted and ready to install):

-drill a 1/16 hole in the center of each hinge slot (this facilitates the wicking process)
-install the CA hinges dry (with a pin in the center of each one to hold it centered) and the torque rod into Tightbond and wipe off the excess
-now bend the joint as far as you want it to move and drop 4 drops (this will vary with the size of the hinge, but the CA should not puddle up in the joint) of CA on each hinge and no more
-flip it over and do the same from the other side
-now take some matching covering (or clear) and go around the torque rod and seal it to the elevator on both halves
-when dry, and this is important with CA hinges, seal both side of the gap with clear or colored covering, touching in the center.

Now you have a tight joint that is essentially one long hinge. When the Tightbond is dry, it is a perfect pocket that won't allow the torque rod to move in the wood. You have worked at a nice pace with no reason or need to rush anything, and this hinge set WILL NOT FAIL. I have had many crashes that didn't blow the hinges installed in this way!

This Extra had CA hinges installed just this way. As you can see, they are about all that is still in tact. I'm of the opinion that most problems with CA hinges stem from poor installation, and too much CA is just bas bad as not enough.

Now I do still use hinge point and flat pinned hinges as well, but CA hinges are not the devil.

OUCH! Such a pretty ship. Sorry.

Bill

I can't add much to the wonderful advice these fellows have laid out but would roughing-up the hinge glue areas with 400 grit wet/dry paper help adhesion a-bit?

Bill

With CA hinges? They're a fibrous material, you'd rip them up with paper.

All of that advise for CA hinges is very good (I've never had a CA hinge fail). Except when it comes to applying the CA, I'm not a fan of appying only X amount of drops of glue. I usually soak the hinge pretty good. I've seen some models where only 5 or 6 drops of thin CA was used (per side) and after the model crashed (for different reasons, not hinge failure), if the hinge came out, looking at the wicking pattern, you could see that the thin CA hadn't wicked throughout the hinge. I've seen this even with a hole drilled in the hinge slot.

FB

As noted, the amount of glue is largely dependent on the size of your hinge and the type of material it is being glued into, but the key is to have enough, but not too much. Too much can cause the hinge itself to crack and tear. As the glue is applied, I watch for when the wicking stops, usually 3 to 5 drops. In foam, it will take less than in, say, balsa.

As for lightly sanding the surface of the hinge, the only possible time this may help is in the case of using old floppy discs as hinges. But very fine sandpaper should be used (maybe 400 grit). Deep scratches could actually cause tears over time.

I use Zap Hinge Glue it does not set up immediately, So this gives you time to insure everything is aligned and tight . I think it sets in a couple of hours and is fully cured in 24..

Yes, I use Zap CA too and I think it's just groovy. I prefer super thin CA for this purpose.
One thing:- Not all CA hinges are equal! I think the ones supplied by Seagull are particularly good because they have a central slot that wicks the CA into the depths of the hinge slot. I threw my Great Planes ones away because they were so difficult to saturate.
I use Great Planes CA applicator nozzles that allow you to direct the CA right into the slot and I pump until I can see that the hinge is saturated. CA reacts with cellulose, so you can't be hesitant here. If you apply drops, then they go off immediately and prevent more CA from wicking in; so a steady and "prologed" application is the order of the day. I've taken to covering the Pro-Film with magic tape to stop the CA forming blooms.
I can't see any reason why you couldn't pin the hinges if you really wanted.

I don't use CA hinges as hinges.

What I do is:

For flat style pin hinges I use the CA hinge to apply epoxy into the previously cut hinge slot, wipe it clean with a paper towel and alchohol then slide the hinge in.

For robart style pin hinges I first put vasoline on the pivot part of the hinge, put 1 1/2 dabs of gorrila glue in the previously drilled hinge hole and push the hing in making sure that hing is correctly rotated to allow proper functionality. For these the hinge hole is usually tight enough to prevent the gorilla glue from expanding outside the hole, instead it expands on the inside creating a gorilla grip on the hinge.

MR G