I had to reinstall the elevator on my 1.20US and decided to try some Hinge Points I had. I had always liked the look of them but never could figure out a way to mount them easily. Still can't. All that garbage about vasoline the hinge, etc seems really a hazzle. I very carefully used epoxy pushed up in the holes and wiped on the Points, seem to be holding just fine, but there must be an easier way. I would also appreciate comment on the fact that these things are really difficult to fit in any wood except very soft balsa because of the taper.

I just went through this ordeal with my Extra and trying to install hinge points. This is the conclusion I came to.

The hinge points work best when there is enough wood to cover the barbs on the hinge point itself. Many elevators and H-stabs do not have a "deep" enough piece of wood, except maybe on the corner by the fuse. Therefore, the hinge point goes all the way through the wood with the barbs sticking out into dead space with nothing to grab onto. All that is holding it in is the epoxy and the smooth tapered section. Not enough in my latest experience. Plus, Epoxy does not stick to plastic.

The flat hinges seemed to be a better choice in this application. Also, CA is a better choice to glue them in. Rough them up a bit with sandpaper and clean them with alcohol either way you do it.

As far as getting them to fit nice and flush, here's what I was doing. Drill your hole for the hinge point. Then go a couple sizes up in drill bits and drill just the first 1/8" or so. This will enlarge the hole enough to let it sit farther in. Keep going deeper if you need to.

Good luck.

Mike

I have pretty much decided I will never use these things "instead" of CA hinges. I used them this time because it would have been a pain to cut new slots with the old hinges already in. The thing that really screws things up with the HP's is the taper. If you have to dremel out the taper, it is not an easy and quick thing to do.

I usually have used 30 minute epoxy (devcon) with good but messy results. I recently tried CA to put my hinge points in. I have a H9 1/4 scale Cap, and believe it or not, there is enough meat to hold the hinge point, without adding wood blocks. Anyway, I drilled the holes for the hinge points, removed the covering from the bottom of wing. After having the hingepoints posistioned, I then used thin CA from the inside of the wing panel, and applied directly to the "barbed" area that was sticking out inside the wing panel. The thin CA, penetrated the entire hinge barb, but did not get on the flexing or pivet part. After letting the thin CA dry, I then added some epoxy over the CA area, and I truly believe, these hinges will never come out! I experimented on a piece of balsa with a hinge point and CA. I could not come close to pulling it back out! I had to use a pair of plyers and twist it, only breaking the hinge! I must admit, this is my first experiment, and I would not suggest using CA from the outside! In other words, do not install the hinge point, and add CA right at the pivot point. IT WILL STICK IT UP! If you can remove the bottom covering, and have access to the hinge from inside the surfaces, you will be good to go! (using CA will allow you to keep your points in alignment immediately, without the fear of bumping them while waiting on the epoxy to dry! Just make sure each one is aligned as you go!)

I also have an H9 1/3 scale that Im hinging with the points. Im using the devcon 30 minute epoxy, with balsa filler mixed within. The reason being, it makes it less runny! When you have your flying surface ready to fill with epoxy, gravity takes effect, and some or most epoxy drops inside the surface to be hinged. What I usually do is drop epoxy with filler into the holes, get a good fill, and then wipe clean. While keeping the holes with the epoxy mix facing the workbench, I allow the hingepoints to dry this way. This is the only good way I have found to keep the epoxy where I want it! ON the barbs! So in otherwords, with the hinges in place, turn the surface hinge side down to the bench and allow gravity to keep the epoxy on the hinge barbs! I also use a straight edge to check alignment of my pins! It is a bit tedious, but well worth the effort! Good luck!

Oh one other thing, I install the hingepoints flush but not sunken into the trailing edge of the surface. The pivot is almost completely protruding from the trailing end of the surface. Next, I ream out the top of the holes in the leading edge of the surfaces to be mounted to ie. ele, ail rud ect. with a dremel tool. This allows the pivot to counter sink into the leading edge, and while glueing I separate the two halves (wing/ail ect.) with 1/32" balsa. This allows a small gap between the two surfaces, but not excessive! This also allows for a more free movement up and down! On larger models, of course this small gap will be sealed anyway! (I ALWAYS GLUE THE HINGE POINTS TO THE TRAILING EDGES OF THE WING, STAB, FIN ect. FIRST! ONCE DRY, I THEN GLUE TO THE SURFACES ie. AILERON, ELEVATOR, RUDDER. THIS ALLOWS GREATER CONTROL IN GLUING!)

I have had great success with poly probond by elmers glue for installng the robarts all the way up to 35% planes never a problem . It is very easy to install them you just wet the hinge with a spray mist of water and use a little probond on the barbs it expands in to foam or wood as it dries and yo dont have to worry about gumming up the hinge point as it comes off very easily with a exacto knife around the hinge point after glue is dry it takes about 10 hours to set up completly so you have plenty of time to get everything correct .

I have found, if you will use the tapered (handle) end of a file, and push it into the hole, and move it up and down, it will taper the hole so the hinge will set flush w/ pivot pin.

I like the Pro Bond idea. A glue that can be easily scrapped off and doesn't penetrate into the hinge seems like a good idea. The idea about cutting the covering off and replacing it again reinforces my point that the HP's are not user friendly. I got to admit the file idea is a good one. My problem is that I had to mount a HP in the hard stock joining the two elevators halves. It was a job to say the least. In my own particular case my goal is to do things the best I can and still be quick and easy. I have never had CA hinged surface fail and my one trip with HP's seems bullet proof also. If I had to grade the two I would give "coolness" and cutting the slots advantage (soft wood only) to HP's; but the mounting advantage definitely goes to the CA hinges by far.

If the probond can be scraped off of the hinge, how secure is the bond? I like the expanding foam idea, but it needs to adhere to the plastic to be effective.

Mike

I do the same thing as TLH101. I drill the hole and use the tapered end of a file to ream or taper the hole a bit.

I ground the barbs off of a few hinge points. (edit: this is an old trick - I did not invent this). I use these to test fit the hole - to make sure I tapered the hole enough and the hinge will go in square.

I also sink the hinge into the leading edge of the control surface. I drill the hole, use a small round file to create half moon shaped recess, taper the hole, test the fit with a "barbless" hinge point.

I use white glue to set the hinge. The white glue causes the balsa to swell in around the barbs. There is no way to pull the hinge out once the glue dries. I did a test hinge with two hinge points and some 1/4" balsa - nobody could pull it apart - you will smash the balsa first.

MHawker is definitely correct. There has to be enough wood to grab the barbs. Also the glue does not stick to the hinge point. I used hinge points on a kit I built - I purposely added wood at the hinge locations so I could use the hinge points. For an ARF - one would have to modify the hinge areas so the hinge points would grip. For this reason - I have never used them on an ARF - too much work.

By the way - I think we all will agree - hinge points are a pain in the neck to install. I think they are super strong. Once they are installed - you will not regret it. But they are a pain in the neck to install.

Also - I tend to have a bit of a gap when using hinge points. For this reason, I seal the hinge gaps. This too is a pain in the neck because the hinge points get in the way. Again, I think its worth the pain. I will probably use these on every kit I build. I will probably use a flat hinge of some type on every ARF I build.

Moses

edit: added some text - accidentally posted the message before I was done.

Not really. That's why the barbs are there. Don't forget, epoxy doesn't stick to plastic either, but that's what most people use. The epoxy will bond with the wood, and it will make a collar around the barbs in the hinge so that it can't pull out.