Stiff hinges

[Curare]

Hey guys, I just installed a bunch of du-bro style hinges into my latest dog, and loe and behold, they're stiff to move. 

Any ideas on how to free them up?

I used Pacer hinge glue, and cleaned up every bit I could see with a q-tip, but I obviously didn't get all of it.

[Mike Haverly]

Drizzle some WD-40 on them with a Q-tip.  It may take more than one application, but it usually helps.

[Curare]

Thanks, I'll give that a try.

I have to say this has been an ABSOLUTE NIGHTMARE.

1. I cut the slots for the hinges assuming (stupidly) that I'd be able to buy the large du-bro hinges from my LHS. I had about 4 laying around but that's enough to do one flap.

I went to the LHS and they had NO large Du-bro hinges, instead they had MP JET hinges, which click across centre. It took 5 minutes each hinge to get them to rotate smoothly.

Now the ones that I've used in the flaps are stiff!

I'm tempted to just cut them off and do a monokote hinge!

[Chris Wilson]

Are we talking about the flex one piece hinge or the type with a separate hinge pin here?

[Curare]

Pinned "Klett" style hinges.

I may be an idiot but I know those hinges and C/L do not mix. Hell, for me they don't even mix for RC!

If you wanna get technical, those bendy hinges aren't hinges, they're flexures.

[Will Hinton]

Greg, before you cut those hinges, try some acetone on the pins and just keep moving them for a few minutes for each hinge.  Do them one at a time.  That has worked for me in the past when I got careless during installation.
Now I use the trick someone on here showed us a long time back of melting Vaseline and then folding the hinge and dipping the pin area in the Vaseline and letting it set up.  I haven't had a problem since.

[Curare]

Oooh, good trick, I'll use than on the others:)

[Chris Wilson]

Hmm, protecting pinned hinge lines from glue ingress can be easily done by doubling the hinge over upon itself and dipping only the hinge barrel into melted candle wax.
The wax hardens in a split second and when inserted for use will not unduly bleed into the hinge tab or the wing slot.

Once the model is completed simply hit it lightly with a heat gun if it gums up the movement too much.

That's about the best protective method for hinge lines that I have heard of!

[john e. holliday]

I myself have had pinned hinges come up stiff on completing a model.   But, I don't use glue to put them in.   I insert the hinge and then drill a hole for a round toothpick or a bamboo skewer.    Usually after several flights they loosen up quite a bit.   

[MarcusCordeiro]

Stiffness could be caused by hinge barrel misalignment...
But it seems that is not the problem here...
I used to do the pin trick like Doc, but now I want to be able to paint stuff separated, so I haven't been doing that.
The hinges are usually a little stiff, but loose up after a few drops of alcohol on the barrel. I use epóxi to glue them.

Marcus

[FLOYD CARTER]

Any pin-type hinge will bind if the slots are all not exactly in line with each other.  None of the commercial hinge slot cutting tools are good enough.  I cut hinge slots with the drill press and a Dremel cut-off wheel.  Of course, this is best done before the trailing edge piece is assembled on a wing, or stab.

Just make sure the drill press table is exactly parallel with the cut-off wheel.

I put Nylon hinges in using epoxy.  If epoxy is worked into the slot and excess wiped off, then pushing the hinges in will push the epoxy down, and not into the hinge.

Floyd

[55chevr]

RC56 is good adhesive for nylon and plastic ... has body and doesn't run.  I always scuffed the hinges to give the nylon "tooth".


Joe

[John Craig]

Let me second the R/C 56 or other canopy glues!    I looked up those hinges that you used.  They look particularly difficult to keep in line.  2-3 degrees off on one hinge then the next 2-3 degrees the other way & you have a row of binding hinges.  Since I am acutely lazy, I would look for that one hinge that is way out of line. If that fails, I like your  Moneycote idea.

[Randy Cuberly]

This may sound a little strange at first, especially to those of the liberal persuasion, but I've been very successful in freeing up stiff hinges (and believe me I've tried all the mentioned methods) using RemOil.  Yes Gun Oil marketed by Remington Arms.  It's basically a light grade machine oil in a fairly stron solvent base...No it won't harm a dope finish but I wouldn't leave it on there forever.  It comes in a spray can and can be carefully sprayed on the hinge barrel  and left to sit for a few minutes then given a second blast and work the control surface using the leadouts and I think you'll be amazed!
RemOil is available at your local gun shop or at WalMart!

I would also wonder about ball links if you have used them!  They can sometimes stiffen and give the same effect as stif hinges...unfortunately there's no quick fix for them aside from cutting in!!!

Randy Cuberly

[Curare]

Thanks for the input guys,

Lets go through this.

Floyd, the hinges are set into the trailing edge, but no flap is fitted so each hinge can be tested indivually. I do line them using a straight edge, but even so, some misaligment may have crept in. I'll know when I hang the flap I suppose.

By the way guys, RC-56 is very similar (at least in my experiences) to Pacer Hinge Glue, it's some form of aliphatic, and is cleaned up with water.