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        Discussion how to install CA hinges

#1 FlyValue Apr 14, 2012 11:11 PM

how to install CA hinges
 
Hi folks,

I have been flying for years but fairly new to building. This is the first stick build I have done where I need CA hinges. Could you direct me to a how to on getting a good cut into the balsa to instal the hinges? What is the best tool to insure a straight cut. The instructions seem to think doing it is a given...

Thanks for your help,

#2 dmcquinn Apr 14, 2012 11:50 PM

Just use an exacto blade. force it into the surface and wiggle it back and forth to make the cut. Do not remove any material. Just slit the wood. Make the slit wider than the width of the hinge.

Force the dry hinges into both surfaces. Completely assemble the part (e.g. rudder) to the airframe (e.g. Fin). Apply 4 or 5 drops of super-thin CA glue to the joint from both sides. The glue will wick up into the hinges and they will never come back out.

#3 cynjon Apr 15, 2012 12:16 AM

The only thing I'd add to that is that I put a pin through the center of the hinge, that way I can be sure that it is centered between the flight surface and the control surface. Otherwise, the CA hinge will slide in further on the side with the least resistance. Once I get all hinges installed and ready to glue, I remove the pins before gluing.

#4 lindart Apr 15, 2012 12:26 AM

It helps to trim a little off each corner of each hinge...easier to install in the slots.
Check your local hobby shop for a Great Planes Precision Hinge Marking Tool # GPMGPMR 4005
or equivalent tool. $4 and worth every penny.
This assures a centered slot.

#5 JohnSH Apr 15, 2012 12:23 PM

2 Attachment(s)
Quote:

Originally Posted by FlyValue (Post 21333754)
Hi folks,

I have been flying for years but fairly new to building. This is the first stick build I have done where I need CA hinges. Could you direct me to a how to on getting a good cut into the balsa to instal the hinges? What is the best tool to insure a straight cut. The instructions seem to think doing it is a given...

Thanks for your help,

Here are the instructions that Great Planes provides in their kit assembly manuals.

#6 DGrant Apr 19, 2012 09:01 PM

IF.. I do say "if".. the surface is thick enough, so you can "center-cut" it.. you can use any straight-edge rule.. mark it.. slit it... otherwise the jig mentioned works very well too..

When you're positioning them.. the way I do it is to hold/tape/secure the surface itself to the component attaching it too.. then I simply lightly pencil my positions.. after that is when I start cutting slots to centers..

There is a tool made just for that too.. Its about $15..maybe $20.. maybe less if you can get one used.. I got one years ago.. when theres a bunch of slots(I'm talking 25-35 hinges or so..) multiply that by 2(one slot each side).. that's 50-70+ slots... the GreatPlane slotter just bores through them.. it takes a tad of practice.. as its a thin blade.. and can skew if its hurried.. but still takes about 4hrs or more work and gets it done in 15-20 minutes.. on the other hand if you like to tinker.. and enjoy the time spent doing it by hand.. that's cool too.. can't knock a craftsman.. so.. one other thing..

Be sure to use "thin" CA glue... it doesn't matter whether its odorless or not.. just make sure its thin.. I put about 5-6 drops on one side while flexing the surface.. then same on the other.. just working the surface for about 5 minutes. it doesn't take alot of glue.. but just be careful to not get too much too quick.. and watch for runs.... less is probably best.. and I do a second app of a few drops after about 15minutes..

There's some good instructs in this thread.. so use whatever works for you.. I'm just sharing what/how I do hinges/slots.. Good luck. :)

#7 macro Apr 20, 2012 02:40 PM

2 Attachment(s)
I've had very good results with the setup shown in the attached photos. You obviously need a drill press, but I expect that many of the builders have one. I use the thinnest little circular saw blade I have, about .015 thick, on a mandrel. It's set above the table the right distance to center the slot, or offset it if that's what you want. Just move the control surface toward the saw until it's the right depth. For parkflyers, I just cut the CA hinge into a circular shape. If it's a bigger model, I use either an Xacto or my Great Planes hinge slotter to deepen the slot. Once the cut is started with the saw, it's easy to assure that it continues through the center of the workpiece.

I've used this technique successfully on material as thin as 1/16, and for other types of hinges that neeed a slot. As long as you keep the same side of the surfaces down, a few thousandths error will not affect the alignment of the hinges, They should always come out perfectly aligned. If the material is tapered, you can either make the slot parallel to one of the sides, or shim the piece to cut on the centerline.

One of the photos also shows the little guard I use with the saw, the other has the guard removed so you can see the setup better.

#8 StayQuiet Apr 20, 2012 02:54 PM

[QUOTE=DGrant;21381789
There is a tool made just for that too.. Its about $15..maybe $20.. maybe less if you can get one used.. I got one years ago.. when theres a bunch of slots(I'm talking 25-35 hinges or so..) multiply that by 2(one slot each side).. that's 50-70+ slots... the GreatPlane slotter just bores through them.. it takes a tad of practice.. as its a thin blade.. and can skew if its hurried.. but still takes about 4hrs or more work and gets it done in 15-20 minutes.. [/QUOTE]

The Great Planes Slot Machine is worth every penny (about 2100 of them). Add in the available cutting guide for 4 bucks, and it makes it hard for even a klutz like me to mess the job up!

#9 JohnSH Apr 20, 2012 06:22 PM

Quote:

Originally Posted by StayQuiet (Post 21388326)
The Great Planes Slot Machine is worth every penny (about 2100 of them). Add in the available cutting guide for 4 bucks, and it makes it hard for even a klutz like me to mess the job up!

It is a great tool and there are blades for thicker hinges available. Also a cutting guide.


http://www3.towerhobbies.com/cgi-bin...Fb%3E+machines

#10 DeadstickDuck Jul 31, 2015 12:42 PM

For simple hinge slots just make the 1st cut with a fresh blade, then flip the blade around in the handle so the blade bottom is now sticking out. Now wipe that back and forth inside the cut to make a square "slot" for your CA hinge to fit.

#11 pathfinder Aug 02, 2015 08:30 AM

Get the Great Planes slot machine.I guarantee you'll like it.

#12 T_om Aug 02, 2015 09:59 AM

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Keeping the slot perfectly centered sometimes puzzles beginners... and some times you need the slots off center anyway.

The easiest way for either situation is with a woodworkers tool called a marking gauge. I made my own in a couple of different styles. Here is one. They can, of course, be purchased. If you buy one be SURE to get one with a cutting blade, not just a scoring pin.

It has two adjustable bars that slide in the body of the gauge so it can be set for two distances if necessary without having to stop and reset the thing. Not really necessary, but since I built it, I figured what the hell.

A setscrew on top tightens or loosens the bars for adjustments.

The blade is ground from an old hacksaw blade and is razor sharp.

Be sure to use the same side of the control surface as the guide so if you are off a tiny amount, it does not matter.

Tom

PS: It is also a great balsa stripper.

#13 ZAGNUT Aug 02, 2015 03:38 PM

i clamp the blade down on my bench with shims under it to get the right height. then hold the part to be slotted firmly down on the bench and slide it into the blade. sorta the same idea as the higley hinge slotter....i usually use some funny looking double edged blades i found at a crafts store.

all those doodads that remove material are for thicker hinges, not CA hinges. and the best CA hinges by far are the ones from radio south.


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