drilling robarts
 

Anybody ever made this mistake? One of my rudder hinges had some space around it at the opening due to my removing a little too much wood to give the knuckle room to move so, without much thought, I dabbed a little gap filling CA in there. BIG MISTAKE!!! CA and ROBARTS DON'T MIX!!!! It basically melted the hinge. Now I have the whole rudder off and have to drill out the old hinges and pray the new ones go in OK.

Any tips or advice would be GREATLY appreciated.

RE: drilling robarts
 

sharpen a brass tube use it to remove the robart. glue in a balsa plug.

or take the easy route and just move over a 1/2 inch.

RE: drilling robarts
 

Robart sells a drill jig if you want to buy one. Another method is to make your own using a short piece of 1-1/4 to 1-1/2"" diameter wood dowel. Cut a 45 degree "vee" at one end and drill the appripriate sized hole lengthwise through the center. You now have a drill jig that's pretty difficult to set crooked since it fits the hinge line bevel.

RE: drilling robarts
 

A good way to get the old ones out is by using a pencil soldering iron. You can simply melt the old ones out then you are clear to put the new ones in. when you put the new ones in make sure you use a Qtip to coat the knuckle with vaseline. Hope that helps.

RE: drilling robarts
 

Thanks for the advice fellas. The sight of my rudder with busted up hinges was discouraging. Off to my LHS to see if they have any in stock!

RE: drilling robarts
 

If not let me know I am happy to send some .

TF

RE: drilling robarts
 

Thanks Tom. They had some. I went with the soldering iron technique and melted the old hinges out. I then cleaned up the holes with a 3/16 drill bit and have the new hinges going in now. It looks like all is well. Thanks again to all who chimed in and helped me reverse my mistake. - :D

RE: drilling robarts
 

As you know, CA isn't a correct glue for Robart hinges but if CA melted the hinge, it wasn't a Robart hinge. It was probably one of the knock off, Robart look alikes made with a different type of plastic. I've had durability problems with cheap, look alike Robart hinges and if in doubt, change them out when assembling the plane. The look alikes can usually be detected by dipping them in acetone or lacquer thinner ... real Robarts are not affected by these solvents, the chinese knockoffs will usually soften and even go to pieces if left in the solvent for any length of time. Airplanes and engines are too expensive to loose them to a few $$ worth of counterfeit hinges.

RE: drilling robarts
 

I didn't know CA would melt a Robart hinge until I found out directly from the Robart website. The hinges that come with the WH hardware kit are not the real deal and don't seem to be as nice as Robarts, but the name of the game is to keep the overall cost down without sacrificing necessary quality. I've read where folks have broken hinges (Robart or copies I don't know), and they replace them as needed. As short as these flights are, and as many hinges as there are in each control surface, if I do a good pre and post flight, then I'm betting on only having one fail at a time (if they ever do).
I leared my lesson on a .60 glow Edge 540 this year when I rebuilt it after an engine-failure (stale nitro) and crashed it the very next flight on a high-speed run, without sealed gaps, on a single plastic-geared elevator servo. You can guess what happened when one half of the elevator had a CA hinge pull out and flutter the surface.

RE: drilling robarts
 

The Robart website says that CA will make their hinges brittle, nothing about melting them. But ... maybe I missed that part. Doesn't really matter though when CA isn't the correct glue anyway.

None of the copies seem as good as the real Robart hinges but the ones currently being supplied by Wild Hare seem very good.

RE: drilling robarts
 

I've broken one hinge point over hundreds I've used. That one was mounted at the mottom of a rudder hinge line and after smacking the end of the rudder on asphalt during a couple of pull ups into a hover it finally gave up. I don't know of anyone else that's broken one where the surface didn't flutter like crazy first. Even then, most hinge [points get pulled free of the mounting holes during flutter after the holes have been enlarged from the vibration.

Flat hinges are another story. I've broken many ca and flat plastic hinges over the years during maneuvers in flight.