Nylon hinges

GREETINGS: Does anyone have a foolproof method for installing Du-Bro Nylon hinges without getting them glued shut? (these are the ones with the pin that doesn't come apart.) I used to use Titebond because the dried glue can be picked out of the hinge joint. But Titebond doesn't hold very well.

I've been asking some pretty basic questions lately. But I'm using techniques I haven't used in my 61 years of modeling (Oh yes, I turned 70 last month...pretty soon I will be a Senior Citizen).

Thanks,

Floyd

Good question!!!!! Don't have the answer, everything I've tried has worked only to some degree. Thinking that just inserting two pegs made from round toothpicks might be the way to go. Of course this means they have to be installed prior to painting/finishing.

LAST EDITED ON Nov-07-03 AT 05:57 PM (CST)
 
Joe Bellcrank (John Miller) has the best system that I have heard about. I think it is included in the Legacy epic on the Product Reviews Forum. Maybe somebody will give him a nudge. (for D.Dirt) Steve

Edit: I didn't find any reference to the final hinge install in the Legacy article.

>Joe Bellcrank (John Miller) has the best system that I have
>heard about. I think it is included in the Legacy epic on
>the Product Reviews Forum. Maybe somebody will give him a
>nudge. (for D.Dirt) Steve
>
>Edit: I didn't find any reference to the final hinge install
>in the Legacy article.

I think that I outlined the method taught to me by Gordy in the now lost for all time Pathfinder review.

But, for those who may be interested, here it is again.

For really free hinges, it's most important to get the alignment correct. Whatever method you use to create the hinge slots, please take the time to center them. Make sure they are all in line and true.

Kieth Varley has outlined how to prepare the hinges with Valsoline so the glue cannot wick into the hinge barrels. Take the time to re-read his post.

While most people use epoxies, or some other standard type of glue, the method I'm outlining uses thin Ca. I like the speed and ease I get by using Ca, but before learning tis method, I never trusted Ca for hinges.

You may doubt the stregnth, but prove it to yourself. I've never had one fail since I learned this method.

The key is to use an interface, something to help the Ca wick deeply into the slot, and help grab and hold the hinge. The interface of choice is common ordinary Silkspan. Other tissues may work, but since there's always some scrap pieces laying around the shop.......

Cut a strip of silkspan abpout the same width as the hinge. Cut the strip into legnths that are about 1/4 to 1/2 inches longer than the hinge tab times 2.

Fold these small strips in half.

We'll install the hinges in the movable surface first. There's a reason for this, I'll explain in a minute why.

Take one of these folded pieces of silkspan, and slip the hinge tab between the two surfaces of silkspan.

Push the silkspan and hinge tab into the slot. Do the same for all the hinges, but don't glue just yet.

Once all the hinges are basically in place, take a minute to align the barrels.

I promised to explain why we start with the movable surface first. It's so we can align the barrels to help prevent binding later.

You did prepare the hinge barrel relief pockets didn't you. I hope so.

Hold the leading edge of the movable surface agianst a straight solid surface. A door frame works good for this purpose. Put pressure agianst the leading edge. All the barrels should be aligned to the same depth. Those that are too deep should be re-positioned until they all are in line.

Use one of those small ca applicators. The one with the small tube. This allows you to accuratly place the Ca exactly where you want it to go. Place the tip agianst the silkspan that is sticking out of the hinge pocket. You want to be right next to the pocket and the Silkspan. Squeese in some Ca, not too much, but enough to wick deeply into the pocket. Wait a second, and turn the surface over, and do the other side in the same way.

Wait a few minutes, and you're ready to install the surface onto the fixed surface.

It helps to partially start the silkspan with a spare hinge. Just push them in a fraction of an inch.

Carefully insert the hinge tabs that are mounted in the movable surface. Once all are correctly positioned, and started, put some pressure on the trailing edge of the movable surface and seat all the hinges. Take some care to see that all the hinges are seated to the desired depth, and that the gap is what you want.

Push down slightly on the surface. By down, I mean in the direction of travel, and use your Ca applicator to wick some Ca into the top of the hinge tab. wait a minute, turn the plane over, and push down on the surface again, You'll be bending it opposite from before, and again wick some Ca into the hinge slot.

Wait a few minutes. Work the surface a bit to make sure it's free.

Take your exacto knife and cut off the excess Silkspan protruding from the hinges.

You're done. Takes longer to type this than it takes to do it.

Good clean, aligned, and, if you did it right, free moving hinges.

Another great thing about this method is, You can easily install them after you've finished the plane.

Try it on that old plane first if you have any doubts, Or at least make up a test piece first to try the method before you commit it to your new world beater.

I'm wondering why everything is spinning around?

Floyd (the good one),

I don't know if it's the best way, but first I clean the hinges with something like acetone. I have no idea if there is any sort of release agent on them, but even oil from handling them with hands that just finished working on some old sparker may cause problems.

My hinge pockets are just thicker than the hinges themselves. And only slightly deeper than the hinges extend into the surfaces to be hinged.

I only use slow-dry epoxy. SIG's "30-minute" stuff doesn't set up in near that amount of time, so it works fine. With PA models I have been known to use the same epoxy used to laminate ply to the front end, and so it is definitely an over-night cure time.

No glue is applied to the hinge itself. Instead, all glue is inserted into the hinge pocket. A 6-inch stainless steel ruler, one of those things that is about 1/2" wide, works well. If one is not availlable, I have made glue-pushers, -packers from strips of 1/32" ply.

Regardless of the instrument used, the idea is to glob on just enough glue that hinge pocket is covered, yet it won't run all over. Push the glue into the hinge pocket with your stick or ruler. Repeat. While I know there are a couple variables here, over the years I have learned how much glue to apply to open pocket and how many times to do it. Takes twice with my method. Your results will no doubt vary.

With hinge pockets loaded with glue, wipe all excess (and accessible) glue away from pockets. Q-tips help a lot. I go so far as to clean the area with a methanol-soaked rag, noting that typically I am hinging MonoKote-covered surfaces.

As I do only one side at a time, I will load (for example) the elevators with hinges inserted into dry hinge pockets. This surface is brought up to the elevator, the leaves of the hinges pushed into the glue-loaded pockets. As one goes along it is relatively easy to see if there is too much glue in any of the pockets: It'll start oozing out. Wipe off excess with a Q-tip. Try again.

When the surfaces are brought into proper alignment, flip the movable surface around to see if there is indeed free movement.

Let dry. Do other side.

And please note that, this one time only, just as a favor to you, I was able to stay on topic.

Obviosly Dan has done this many times successfully as have millions of guys , but he left out one step that most of us do first. Put small amount of vasoline in metal jar lid and lay it on your monocoat iron till it liquifies then with the hinge folded in half dip the hinge side in the very thin layer of melted vasoline and flip it inside out and do the same thing with the other side then let it sit for a minute till the applied vasoline solidifies and start with the slow cure epoxy trick . If yoiu glue the hinges in the control surface first rather than the wing or tail surface you can push the folded hinges against a flat surface and at least the hinge pins are lined up in a straight line then that epoxy dries like several hours later you can epoxy ( slow cure again) the hinges into the wing or stab . Of course watch to see if any epoxy squeezes out if the slot and wipe it off with a q tip ( just like Dan says) and the next day after it is all cured you have a perfect hinge job. . The vasoline seems to prevent the epoxy from entering the dreaded pin part. Hi Keith Varley

Keith's tip is a good one, not remembered because I don't use it. I have always been a little concerned about getting Vaseline on the leaves of the hinge. If one doesn't, no problem. But with all the care and attention to detail required, I'm not much interested in also having to worry about how the hinges themselves are being handled, where they are being touched.

I will tell you, however, that in the most complete and devastating crash of 2003--Keith's Saturn, pounded into asphalt during the PAC Annual in Vancouver, B.C.--that not a single hinge failed.

Will somebody puhlease change the subject so we can get Dr. Spark all wicked off at us for not being able to focus?

I just thought of a nice tool that i wouldnt be without. especially for this job.. An artists palet knife' wonderful for mixing epoxy and poking it in the hinge sockets. Keith ( my memory is failing) Varley

>I just thought of a nice tool that i wouldnt be without.
>especially for this job.. An artists palet knife' wonderful
>for mixing epoxy and poking it in the hinge sockets. Keith
>( my memory is failing) Varley

Keith,

Exactly. My stainless rule is good, your tool is better. (Do not be reading into that too much.)

I don't have much to add to what's already been said, but I do personally prefer to always lube the pin barrel before installation. I use an aviation lubricant called LPS 3. This stuff is thin, as sprayed from the can, and will wick instantly into the pin area when one end of the pin is dabbed into a small puddle of lube. Excess (if any)can be wiped away with a towel dampened with acetone, without removing the lube inside. After a few hours, the LPS thickens to the consistency of instrument grease, so I wait overnight before installing the hinges. Using the "stuff epoxy in the slot" method, I have never had a hinge get stuck after using LPS.

I also use LPS for all lubrication of the control bearings before sealing up the structure. The process I use for installing hinges is illustrated halfway down this (slow loading and unfinished...sorry) page from my web site:

http://www.classicaircraftmodels.com/CobraWing5.html

Bill Groman

Thanks to all. Dan, you really did well! I like the tissue trick to wick up the CA. But what would a person my age be doing with Vaseline in the house? So I think I will try some melted CRISCO instead. I remember using CRISCO to hold the loose roller bearings in place when I rebuilt my Mercedes transmission.

But what would a person my age be
>doing with Vaseline in the house?
>
>Floyd Carter

And you think the rest of us have a bad habit of switching from topic to topic!

Gotcha...