CA hinges
 

Hi all;
Quick question:
I'm putting a H9 Cub ARF together and I have to install the CA hinges. My last project was a CG Tiger 60 ARF and I was not happy with my hinge install. It's strong enough, just a might sloppy. I had the thin AC run onto the Ultrakote and it doesn't look great. Is there a way to prevent this?
Thanks!
CB36

RE: CA hinges
 

Just being carefull when you apply the CA is the best way to prevent that from happening. Make sure you apply the CA one drop at a time and apply directly to the hinge, and not on either side of it. RCU member Minnflyer has and excellant how-to on installing CA hinges, check it out at:
[link]http://www.rcuniverse.com/magazine/article_display.cfm?article_id=55[/link]

Hope this helps

Ken

RE: CA hinges
 

I've also found that CA Debonder is worth it's weight in gold!! The link Ken put up for you of Minnflyer's how to for CA hinging is how I learned the right way to do them. My hinges come out much better after reading what Mike had to say about using them. I now have the Debonder on the ready whenever I do anything with CA, just because no matter how carefull I try to be it seems like I allways get a little more on than I intend to so the Debonder works great for any little runs that might happen, as long as you get to it quick before it has a chance to set up it will clean it right off for you.

RE: CA hinges
 

Another thing that can help a lot (if you aren't already using them) are CA applicator tips. They let you dispense a lot smaller drop of CA at a time, as well as being able to place the tip exactly where you want the CA to go. You can find them at Tower here: [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXL490&P=7]CA Applicator Tips[/link] . You might also want to check at your LHS for them. Most places that sell CA should have them.

Hope this helps

Ken

RE: CA hinges
 

Thanks so much, as always!!!! This will help a lot. I'll get the tips and debonder before I start.
This site is an invaluable resource, made so by it's members!
CB36

RE: CA hinges
 

And if you don't have Debonder, Acetone works great too (So does Nail Polish remover since it's mostly Acetone)

RE: CA hinges
 

Its always good to pin your hinges as well. I haven't had any come loose since I started doing that. ;)

RE: CA hinges
 

Use the CA Sparingly. Have a paper towel there to absorb any that doesn't soak in.

CA Hinge Installation

There are several rules to follow for an easy, correct CA hinge installation. These rules are good for hinges from different manufacturers, including Great Planes and Radio South. I’ve used them on many planes from pylon racers to Unlimited class Fun Fly planes to even a giant scale Stinger (the 1/4 scale size hinges). I have never seen an in-flight failure using this procedure.

I have seen only two in-flight hinge failures. One failure was from catastrophic flutter, which also destroyed the wing panel. The other was due to doubled hinges and the use of thick CA.

Here we go:

Use a #11 blade to cut the slots.
Cut only once per side/per hinge.
Use only thin CA.
Do not double the hinges.
Do not use “kicker”.
Install after covering.

1. Slot the wood pieces, install the hinges, and mount the control surface. Gently push the pieces together.
2. Flex the control surface both ways for the maximum amount of travel you expect to use. This will automatically create the proper hinge line gap.
3. Slowly drop 2-3 drops of CA on each hinge at the hinge line on one side only. If any CA puddles in the hinge line, blot it with a paper towel.
4. When that is dry, apply 2-3 drops of CA to the other side of each hinge.
5. When both sides are dry, flex the control surface both ways.

That’s it! The wood will pull out before the hinge will let go. The surface will tend to stay centered and will not flop around. Both will help prevent flutter.

RE: CA hinges
 

In reading the instructions in an ARF I had it said.
After opening the covering around the hinge slots it said to drill a small hole (don't remember what size hole) in the center of the hinge slot to act as a channel to allow the CA to fully contact the entire hinge. Made since to me as just applying CA to the hinge gap and allowing to wick in would only allow CA to go a small distance into the hinge. Is there any merit to this method?
And by the way, debonder will clean up CA even after it has cured so there is still hope with that wing you dripped on ;)

RE: CA hinges
 

I've never drilled any extra holes, Missleman. I HAVE pulled control surfaces off crashed planes and found the CA to wick in between 1/4 and 3/8". Many trailing edges are only that wide, so it's plenty. I've never had an in-flight failure. Some CA hinges seem to have a shiny finish on them that I believe would inhibit the CA soaking into the hinge. Avoid those and you're OK.

Dr.1

RE: CA hinges
 

I took this guy's trainer up, maiden flight, and it was handling squirrely so I brought it right down. The alierons were loose. CA on the hinges had wicked in less than 1/16". Turns out the guy used medium CA. So two lessons: use thin CA on hinges, and tug on the control surfaces before you take a guy's new plane out.

RE: CA hinges
 

i get acetone by the gallon jug,keep the acetone and a rag handy when using the ca on hinges specially.it cleans off mono coat or ultra coat pretty easily if you get it when it first spills.

RE: CA hinges
 

Acetone is a MUST HAVE for modelers who're using CA. And for modelers who're using epoxy. That's just about everybody, right.

It works great to wipe the CA off monokote. Works like magic, doesn't it.

And it's actually the exact thinner to use for epoxy. Matter of fact, it usually says this right on the can. And when you use it with epoxy instead of rubbing alcohol you're not weakening the epoxy.

Great stuff. [sm=thumbup.gif] [sm=thumbup.gif] [sm=thumbup.gif]