Frozen horn

[Ken Culbertson]

Since we don't have a "What Stupid Thing Did You Do in your Shop Today" forum I will post this here.  I was plugging an access hole near my flap linkage when a small drop of CA decided to follow a crack and found my flap horn.   I have tired wiggling the horn and profanity but the horn is still stuck.  Is there a magic fix or am I faced with removing the horn.  I hesitate to try dissolving liquids but I will if someone else will admit to having done this and survived.

[James Holford]

Acetone

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[Dave_Trible]

It may depend on what is stuck to what.  If it's metal to metal the bond isn't usually that strong.  If it were me I'd roll the dice and grab the flaps at the root with a sandwich of lite ply or whatever and just pull......something will pop loose....hope it's the right thing!  Otherwise you may have to cut anyway.

Dave

[Massimo Rimoldi]

If possible, place the tip of an iron to weld.
Be careful not to breathe the vapors released when the CA heats up.

Massimo

[Ken Culbertson]

It may depend on what is stuck to what.  If it's metal to metal the bond isn't usually that strong.  If it were me I'd roll the dice and grab the flaps at the root with a sandwich of lite ply or whatever and just pull......something will pop loose....hope it's the right thing!  Otherwise you may have to cut anyway.

Dave

It was metal to metal.  For some reason I left the brass bushings on the horn and used them to mount it to the wing.  I have always used the clip type.  The ca flowed into the bushing.  It broke free but the residue has made the fit unacceptable.  Disconnected from the bellcrank and elevator the flaps should drop from their own weight.  These don't.  I will try a drop of acetone.  Lesson - NEVER USE CA near a bushing!

[Fredvon4]

TRUE That!

[Ken Culbertson]

If possible, place the tip of an iron to weld.
Be careful not to breathe the vapors released when the CA heats up.

Massimo

I will give that a try.  Good news - filler and sanding covers any number of stupid mistakes!

[Will Hinton]

The acetone is a great chance of caring for it.  But...it's gonna take more than just a drop.  Take heart in the fact that the acetone will completely evaporate over time and likely to not effect anything else.  You might need a couple of applications to totally free the action up, but keep after it and best of luck to ya!

[Mike Haverly]

Acetone didn't work for me.  MEK and heat worked, especially the heat.  Like was mentioned, get the heat as close as possible to the bushing.  Dip a cotton swab into MEK and let it wick in.  Do the same with WD-40.  It will loosen eventually.  Wear a mask!  Patience required.

[Fred Underwood]

The first drop or two of solvent makes a gummy mess.  It is a solvent and does not make the gum/goo vanish.  Several drops going through as a solvent and wash, and then lube as Mike suggests.  I added lacquer thinner as the acetone evaporates quickly and the thinner a bit slower.

[Dan McEntee]

  There is such a thing as debonder available where ever you buy your C/A glue at. I have read where pure nitro-methane works well also and quickly. Ans as already mentioned, what ever works will require a thorough flush to get it all out. Before using C/A in this situation, a thin coat of oil or light grease on the hone and bushings will help avoid this also.
  Type at you later,
   Dan McEntee

[Howard Rush]

Nitromethane may work better than acetone. Most debonder is at least part nitromethane. This, of course, reminds me of a story.

Late one night I CAed both hands to my workbench. I hollered to my wife, who was asleep in the bedroom above the shop. She came down, got the nitro, got me unstuck, and returned to bed as if the entire operation was routine.

[Mike Haverly]

  "She came down, got the nitro, got me unstuck, and returned to bed as if the entire operation was routine."

Probably more routine than confusing reducer for Prep Sol.

[Gary Dowler]

Nitromethane may work better than acetone. Most debonder is at least part nitromethane. This, of course, reminds me of a story.

Late one night I CAed both hands to my workbench. I hollered to my wife, who was asleep in the bedroom above the shop. She came down, got the nitro, got me unstuck, and returned to bed as if the entire operation was routine.

Funny. It's almost as if she had been around you enough to just not be surprised by anything anymore!  LOL!! 

Gary

[M Spencer]

Gas Torch . 

Might pay to apply Just One Finger Pressure to wherever ,

Freeing off a stuck engine brute force is often fatal . Where on the 10.000 th boiling magic happens .

So quietely a drop of disolver every two hours , like medicine . 

[Dan Berry]

I would dig it out.

[Dave Hull]

Good luck!

The best I can do is commiserate. I was trying to do some maintenance on an F2C model the night before a race. These planes are really light and use very light (and easily damaged) balsa in the wings. I touched a drop or two of CyA into the mid-wing line connection holes to keep the internal connection clips from chewing up the inside of the wing and damaging the fiberglass skins, or possibly catching on chewed up balsa and jamming the controls--and the glue wicked thru 3 inches of endgrain and glued the bellcrank into the holder, solid! We did not race the next day....

Lesson 1:  Balsa is like a collection of straws, and thin CyA has low viscosity! It is far safer to use thicker CyA when you can't control where it is going.

Lesson 2: Using straight nitromethane applied directly to the parts was useless. Applying it repeatedly over a period of days did nothing. break Soaking it in nitromethane did not reduce the strength enough to break the bellcrank loose with force.

Lesson 3: Same as lesson 2, but using acetone.

Lesson 4: The limiting factor is the exposure to the solvent/stripper/debonder.  If it only touches the edge of the glued-together-but-shouldn't be-seam, then it will take forever for any debonding to occur chemically. The seam will be deep; see Lesson 1 again.

Lesson 5: Sometimes you can't find good advice in the middle of the night (before a race) to start repairs with the least invasive approach. Even so, I would have been better off starting surgery immediately, cutting into the fuselage shell, grinding out the bellcrank mount and taking soldering iron and pliers to the bellcrank, then making new parts and reassembling the fuselage shell. As it was, I had to do all those steps anyway--I just wasted a week fooling with debonding attempts.

Lesson 6: You only know Lesson 5 is true in your specific case in hindsight.

Heat will work if you can do it without damaging anything, or if the only damage was to stuff that was easier to fix than any other repair technique. It wouldn't work for me because I had to tear out the plywood bellcrank mount to get at where the glue was not supposed to be. Machinists often use a "glue chuck" to hold material during machining using CyA. They hit the metal parts with a heat gun to pop it loose.

So again, good luck, but know that you aren't alone in having this kind of problem.

[Ken Culbertson]

Just want to thank everybody.  The patient is recovering from the surgery.  CA is our best friend but.....

[Gerald Arana]

CA is our best friend but.....

Boo Hisssss. I hate CA and only use it as liquid pins.

I recently purchased a model (Won't say which) that was built with CA and most of the joints just popped off when I tried to sand the surfaces. Yes, It was VERY hard balsa and the CA didn't work worth a damn. I had to re glue the joints with alaphetic resin and now they are stable. The plane is almost ready for Mono Coat.

Cheers, Jerry