raron455

My Feedback: (38)

I have had a couple questions and had plenty of help from all, and Isay thank you for that,, I have another question that someone can help me with,,, it concerns applying epoxy,, How do you epoxy a robart hing in without getting it all over the pivot point,, I dont know howTo get any epoxy in the hole that the hinge goes in,,If I just brush epoxy on the hinge when I insert it The epoxy is going to push up the hinge as I insert it, and get in the pivot,, I have done this before and it did not go too well, had to tear the hinges out and use CA,, Ihave been told epoxying the hinges in is the best and strongest way to do it,, and the plane I am building is a 50cc model,,So here I am again,, asking for advice,,sure its simple to alot of you, but I have only been in the hobby less than a year, and want to do everything Ican to do it right,,, Thanks fellas

Fleet

Dab it DEEP into the hole with a toothpick or simular device and keep it away from the hinge area with some sort of grease or equiv.   Someone used a chap stick others use light machine oil. 

Hope this helps

Ray W.

nute12

My Feedback: (14)

put a drop of oil on the hinge pin area.(I just use 3 in one) do not be chincy with the glue. if a little does not show when you insert the hinge, how do you know its actually bonded? real pain to pull the surface later and re bond a hinge. little alcohol on a paper towel cleans up whatever squishes out. as the glue sets deflect the surface occasionally to max deflection both directions. has always worked for me.

sensei

Actually Gorilla glue is the strongest way to install them.

Bob

acdii

See if you can find a syringe. I found a 3 pack at my LHS and they work great. I haven't used it for epoxy, just aliphatic, so it cleans up nice. I should be resistant to alcohol, but not acetone, so cleaning the epoxy out will be a pain.

rafeeki

My Feedback: (11)

What do type of Gorilla glue do you use as there are several.

I use 30 min epoxy, dap it on the hole and as it takes time to set it seeps down the hole. I also apply epoxy on the hinge stem and push it carefully down thehole, not much epoxy oozes out this way.


Thanks

Rafeek

CK1

My Feedback: (60)

Put some vaseline on the hinge knuckle and work it into the joint,also put some vaseline around the opening for the hinge on both surfaces . This will prevent epoxy or glue from entering the hinge . I also use monoject syringes for getting the epoxy inside the hole for the hinge .

nute12

My Feedback: (14)

never used GG... but i have seen the caliber of sensei's building. I will try it on the next. My advice is to listen to him.

sensei

[quote]ORIGINAL: rafeeki


What do type of Gorilla glue do you use as there are several.

I use 30 min epoxy, dap it on the hole and as it takes time to set it seeps down the hole. I also apply epoxy on the hinge stem and push it carefully down the hole, not much epoxy oozes out this way.


Thanks

Rafeek

As several have stated; place a drop of lubricant on the hinge prior to installation. I never start the hinging job unless I have plenty of time to tend the post cleanup process lasting upwards of an hour per process. I start with a Monoject 412 filled with water and one with original formula G/G. I inject a little water into each hinge hole, then G/G and finally the hinge, you can do one at a time or several. The post cleanup starts around 6-8 minutes after the last hinge is installed. Generally I will perform this process in four stages; the aileron hinges into the wings and then the tail feather hinges into the vertical and horizontal group. once all is cured I will install the ailerons and then move on to the elevators and rudder. The post clean consist of having plenty of paper towels and acitone; as the G/G swells I simply dampen the P/T with acitone and continually remove the expanding G/G until it stops. The reason I go to this much effort is as follows, The G/G expands around the barbs on the Robart hinges making them well bonded in place, it is that simple. I performed a test and you can do the same. I bonded several hinges in hardwood with G/G and pull tested them individually to failure, they wound up failing the pull test once the pull exceeded 55 lbs. in tension and the bond line did not fail, rather the metal pins in the hinge finally pulled through the plastic knuckles molded on the hinges.

Bob

gravityking

My Feedback: (19)

Here's the method I use and won't ever go another way! This is part 3 and directly answers your concerns but I would watch all 3 parts if I were you.

[youtube]http://www.youtube.com/watch?v=sny6BT14Zwo[/youtube]

http://www.youtube.com/watch?v=sny6BT14Zwo

airbusdrvr

This post is not to get a spat going over which type glue to use, but to share an alternative approach. To alleviate the glue in the hinge problem I did a test using wood glue. A test section of rear wing spar and a test section of aileron stock were used along with a hinge glued in place with wood glue. The glue that squeezed out onto the hinge was easily wiped away with a wet Q-Tip. Next day when the pull test was conducted, the wood splintered with hinge attached. The glue joint did not fail. I have since used this method on all non-CA hinge installs and had never a failure.

sensei

LOL

Bob

Tluu

My Feedback: (85)

+1

gravityking

My Feedback: (19)

I hope I didn't appear to start a spat! Seems hard to do by offering advise on what works for me.

I'm just glad we all have different ways of accomplishing it that work and can share our ideas.

Gray Beard

My Feedback: (-1)

The drug stores will give you a graduated syringe for free, I try to get as many as they will give me. I ask at every drug store I go into. To get the Epoxy OR Gorilla glue into the slot or hole is easy with one. On slots I always drill a hole, about a 3/32 or so into the center of the slot and using the syringe I just squish it in the center hole. I can see when it flows out to the sides of the slot. Hinge pins I just squish it into the hole. If from trial fitting my controls the pin holes get sloppy then I use the Gorilla glue, it they are nice and tight I use epoxy. The expanding Gorilla glue is great on any of the over size holes.
Those are great videos by the way. I do have some small syringes diabetics use for adding just a drop of oil onto the hinge center pin.

sweatybetty

local farm supply should have syringes fairly cheap. i use the ones with a 16ga needle, but file the pointed end down smooth first.

Zor

Well ___no one mentioned my method.

I have no glue coming to the hinge at all.

I drill the hole right through. If it has to be a dead end like in all solid wood then I also drill a 1/16" dia hole at the bottom of the hinge hole.
The idea is to have an outlet for the glue.

I apply the glue into the hole like someone said with a small rod. I do not use toothpicks that breaks. I use a smal wire or a straightened paper clip and swirl the glue all around the inside of the drilled hole. I then apply glue on the stem of the hinge to about 1/8" away from the pin (axis) and remove all surplus on the hinge.

When inserting the hinge the surplus goes out the vent hole or the open end if drilled through.
Careful using oil ___oil has the affinity to spread rapidly and you may end up with a shaped glue around the saw tooths without adhesion.
If the wood expands a bit then the hinge can slip right out. Vaseline is better but may not penetrate well intothe hinge.

I figure a method without any lubricant and without any glue squeezing out at the hinge axis is preferable.

Zor

JPMacG

My Feedback: (2)

+1 on the syringe method. I use a syringe with a glue applicator tip for applying epoxy in tight areas and making fillets. This works really well and the results are very nice looking.

Only thing is that I haven't been successful at cleaning the syringe afterwards, so I have to use a new syringe and applicator each time.

Zor

I just watched both videos by Jim and was disappointed.

After inserting the hinges in the movable control surface he held the surface vertical between two weights.
He had no assurance that the hinges axis were in an absolute straight line.

What I do is first make sure the hinges are rotating exacly 90 degrees with the surfaces then sit the surface horizontal and place the hinge halfs unto a known absolute straight surface and put weight on them. This assures me that they will be on a straight line when the glue (epoxy) has cured..

I then insert the control surface into their support and make sure that the surfaces fall to their full travel just by their own weight no matter how light weight they may be.

After proceeding with the gluing into the supporting surfaces I repeat that test.
When all is finished and the glue is all cured I want these surfaces to freely fall to their full travel in both directions due to their own weight.

I noticed that this did not happen with Jim's surface when it was horizontal in line with the wing and he was not flipping it back and forth.

I am not crticising Jim and I am not claiming he does it wrong.

I am just explaining what I do to assure that the servos are not working any stiffness in the hinges, nor working on misaligned hinges trying to warp the spar even if just very little.

Zor

Edited to change "stffness" to "stiffness".

sensei

I actually welcome the G/G pushing it's way to the hinge line, this way I know the G/G has swelled around all the barbs and I can rest assure that I won't lose a surface during a high energy maneuver. Most of the stuff I design, build, and fly is very large with top speeds of over 115 mph, and with some flight control surfaces exceeding 300 sq. in. The ganged servos driving these large surfaces are applying upwards of 1800 oz. of torque per surface so I cannot afford to hope I have enough adhesive on any bond line area, I must to know for a fact. As I stated in an earlier post; I have performed pull testing to failure utilizing Robart hinges G/G and the methods of installation I specified in that earlier post. If those that are going to fly slow lazy relaxing type aircraft then just about any method of installation will work just fine and there is nothing wrong with that at all, but if you are going to fly high performance...

Bob

RBACONS

My Feedback: (3)

I use vaseline on the hinge but not straight from the jar. I put a little blob on a piece of tin foil and melt it (heat gun, light bulb, lighter, etc) and then fold the hinge in half and dip it in the vaseline, flex it the other way, and repeat. This get the vaseline into the hinge pin and all of the little finger joints. It re-solidifies quickly and you don't have to worry about it spreading to the barbed areas like you do with oil.

And I agree that any type of glue will work fine. They all produce a bond that is stronger than the surrounding wood. Canopy glue (RC56) is also excellent for installing Robarts and is water clean up like the wood glue.

Zor

Good morning Bob,

I am sure that many readers appreciate to read about your method of installing Robarts' hinges.
No doubt many folks like to use swelling G/G (Gorilla Glue) like you do.

Visualizing "what is going on" we must make sure the holes are not drilled oversize. The hinge should slip in the hole wihout any looseness. Then the G/G can expand only along the length of the drilled hinge hole. If there is no vent as I described in my method then the glue can only come back toward the rotation axis and for sure you need "anti adhesive" to prevent solidly jamming the hinge. You still have to clean up any glue that has swelled or simply been forced out of the dead end hole when inserting the hinge(s). I saw Jim in the video having to do that.

I do not have this situation by providing for the glue to come out of the vent and do not have to clean up at the hinge line. I still have glue curing all the way to the edge of the drilled hole but not on the swiveling part. No cleaning of cured glue needed.

Of course when applying the glue in the holes we have to make sure there is glue everywhere on the walls of the drilled holes and on the whole surface of the hinge stem but remove any surplus on the stems and keep away about 1/8" from the hinge rotation axis.

Personally I have never used G/G. I use 30 min epoxy that gives me plenty of time to do the work.
I also wipe the hinges stems with solvent to remove any dirt or oily substance like finger grease from handling just before applying the glue on the stems.

There is more than one method suitable to do many jobs.
The readers can choose their own.

Have a great day . . .

Zor

Gray Beard

My Feedback: (-1)

I use Gorilla glue often with hinge pins too and I wipe the covering on the LE and TE being hinged, this just eases the removing of the over flow. I go out to the shop about every half houe and use alcohol to remove the over flow until it starts setting up and expanding. Flat hinges I use epoxy more often. If you drill the holes all the way through the wood as Zor mentioned then most of the glue expands into the inside of the covered sections taking the path of least resistance.
Both types of glue seem to work very well but I would like to see Pacer come back out with there hinge glue. Looked a lot like wood glue, flowed well and you could get it into tight places and it stuck very well to both plastic and wood. I still have a little of it left. I ran tests with it against titebond II and the titebond didn't work very well. The Pacer you had to break the wood apart to remove the hinge. I liked it for the flat hinges better then hinge pins though. I always use some type of oil in the hinge center because I always seem to get glue of any type sloped onto the hinges center. The Pacer would just break loose with flexing. My Kingdom for a case of the old Pacer Hinge Glue!!!

Zor

Please note that I said "I never used G/G and still do not.
I use 30 min epoxy and there is not a lot coming out of the venting holes.

We have to make sure that the whole inside surface of the drilled holes is covered with epoxy without any excess. Same on the stems of the hinges; no excess.

Make sure you can see the glue at the hole and if there is some coming out, wipe it off before the final push in of the hinges. Rarely is there any if the glue application was not excessive. Many tests have proven that.

Like any other types of gluing, gluing is an art and a dexterity to be learned.

NOTE:
Someone mentioned that he has 1800 oz of torque on his servos which I figure is a reason for solid control surfaces hinge gluing.

Anyone can have 1800 oz force (that is 112.5 lbs-force) even on mini-servos if the moment arm is short.

Torque ISNOT mesured in oz or pounds-force.

Any force trying to pull out a hinge would come from the aerodynamic forces on the control surfaces; not from the capability of the servo(s).

Zor

sensei

You completely evaded my statement that the surfaces are over 300 sq. in. of area each and when deflected at the air speeds I stated there are all kinds of aerodynamic loads... Hello I gave the torque values only to show what it takes to deflect and maintain a given throw on surfaces this large while at speeds this high.

NOTE: You pulled just a portion of what I stated and through some poor engineering Bla, Bla, Bla, out there that means nothing of any value...

Bob