dieFluggeister

In the recent Model Avaiation magazine (pg 93-94) there is a mention of silicon glue being used as aileron hinges in a slope glider and is actually recommended by the manufacturer. Having never heard of that method, I was wondering if any of you have tried it, and how it would apply to 1/2A.

combatpigg

My Feedback: (3)

DF, I think it falls into the category of some ideas that work for some people IF done correctly and IF done for the right application. I can see no reason to try this idea though, the EZ hinges and one shot covering [with the covering pushed down into the hinge line] works so well, that I have no reason to try anything else. I also would like to learn to do skin hinges with kevlar, but that is a different subject.

dieFluggeister

[X(]

Sealed hinge line on a PU or dope finish.

KidEpoxy

it would take some real bead control to get just the right amount of rubber to avoid getting way to stiff, and it would be springy too, right, so high deflection would take more torque?

Clean

No bead control issues. Clean your surfaces completely with acetone or 98% proof alcohol (not rubbing-too much water in 81%) and lay your parts together on a clean table, lay a piece of scotch tape on the surfaces taping them together with a hairline of gap. Invert this, run a thin bead of silicon down the hinge and then come back with a round tip 1/8 diameter would be good, and scrape off the excess silicon leaving the leftover in a nice smooth, tight radius. leave it to setup overnight. Remove the tape and Voila, silicon hinge.

dieFluggeister

Clean, how would you judge the flexibility and the strength of the hinge?

Clean

I used it to seal up the hingeline on a 40 size plane, didn't seem to bother anything there but I had regular hinges on it. I was going to try it on an airplane someday as hinge alone. Haven't quite gotten there after, hmmm, 6 or 7 years.

combatpigg

My Feedback: (3)

You can seal a hinge line that uses painted parts by forcing clear tape down into the hinge line, then trimming off the excess. Silicone is not fuel proof and will eventially lift / fail.

Oldbob

Combatpigg, if silicon is not fuel proof than nothing is. You obviously don’t know much about silicon

Oldbob

Oldbob

Combatpigg, if silicon is not fuel proof than nothing is. You obviously don’t know much about silicon

Oldbob

Big Al-RCU

Gentlemen, although it may have no bearing on this discussion, I would like to take this opportunity to air a pet peeve. Silicon is an element and as such the term is ambiguous when referring to either an adhesive or a lubricant.
RTV (room temperature vulcanizing) rubber is made from synthetic (silicon) rubber and is usually identified as ‘RTV Silicon Sealer’.
However prior to RTV, ‘silicone’ commonly referred to silicon-based lubricants such as Dow Corning DC-55, a direct opposite of a sealer.
So asking for the application of ‘silicon’ may mean different things to different people, i.e., applying an adhesive or an adhesive repellant lubricant!
So I’m campaigning for the use of either ‘silicone lube’ or ‘RTV/silicone sealer’ for clarity.
Off soap box.
Al

Wayne C

I don't know so much about the lube side of silicon usage but on the adhesive/sealer side there are a wide variety of products intended for differing purposes. Some are sealer only; some are glue. Some are designed for different temperature ranges. Hot application silicon may become brittle when cold. Cold application products may turn to sticky goo or liquid when the heat rises. Some products are color coded for application. Some are color mathced to blend in with the surroundings. Some silicon adhesive products are not intended for wet applications. Some are great for sealing up that leaky fish bowl. Picking the right product for the purpose is much of the battle. Applying correctly is much more of the battle. I'm not offended by the general term silicon. I know it could refer to a variety of things just like the general terms glue, paint, oil, dirt, stickum and so forth.

combatpigg

My Feedback: (3)

Everytime I've ever used silicone to seal around fuel lines that pass through a firewall, or to seal covering seams, I get the same result, the silicone pulls away from the material it is supposed to be sealing and allows fuel to creep underneath. Of course we all know that silicone unto itself is fuel proof, but it is a lousy fuel proofer. Packing tape will survive much longer in a hinge line and offer less resistance to the servo.

Oldbob

Sorry guys, I guess I messed up. Silicon is not silicone. Funny how one letter can mess-up your mind. However the thread topic is SILICON / GOOP HINGES, not silicone/goop hinges, as it should have been. But no matter, we all know what was meant. Don’t we?

I have used silicone for many years in no, low, and high nitro fuel planes, and have never had it turn gummy or soft in any way when exposed to nitro fuels. I have had it come loose from some surfaces where the bond was poor to none. Silicone will not stick to pores surfaces or dirty surfaces for very long.

I have used clear silicone adhesive and clear silicone sealant to seal hinge line gaps, i.e. aileron, elevator, rudder. The trick is to form the silicone as thin as possible to minimize stiffness of the control surface. Try to squeeze it all out before it sets. The thin film that is left behind is all that is needed to seal the hinge line.

Oldbob

dieFluggeister

Alright, yes, I feel responsible for a misspelling, and the confusion that ensued. Sorry 'bout that. I meant silicone RTV sealant and related products and just missed the 'e'.

KidEpoxy

"The trick is to form the silicone as thin as possible to minimize stiffness of the control surface"

maybe we could use Silicon Spray Lube to un-stiff them Silicon Tube RTV rubber hinges.

combatpigg

My Feedback: (3)

AFAIK, GE makes the best silicone adhesive. I've used it in the past to fuel proof an entire batch of combat planes, where the engine mounts exit the wing, and around the fuel cell. I've also tried it, like I said before on RC related stuff. Same result every time, it lifts and peels away in the presence of fuel. Epoxy, and epoxy mixed with a tiny amount of spackle are still the best ways to fuel proof around iron on covering and bare or painted wood. The silicone hinges seem to show up with composite models, where the skin on both sides of the hinge line is at no risk of lifting or tearing away. On a typical monokote covered plane with silicone hinges, I would be concerned about the covering letting go.

treedog

ARE WE TALKING TUB CAULKING HERE OR SOMETHING ELSE I NEVER HEARD OF SILICONE HiNGES sorry for caps.
td

combatpigg

My Feedback: (3)

At least one kind of GE silicone was formulated to keep windows from popping out of a Chicago skyscraper. 1000s of windows had to be replaced in this building. They had people hired full time to stand on the sidewalk, look up and warn pedestrians that a window was falling. As it stands now with just a few EZ hinges on a typical plane, I get about 40 minutes of 2 channel flying from a 300 mil pack. With full length hinges made from caulk, the battery drain and strain on the servo has got to go up.