Du-Bro hinges and messy work

[Matt Piatkowski]

Hello,
The flaps for my new model have five Du-Bro nylon hinges each.
 
I wonder how to glue them with epoxy to avoid mess and to make sure that the hinge pins are on a straight line.

I feel that such a subject had to be discussed before, therefore the thread is somewhere on the forum.
Where?

Thank you,
M

[Steve Scott]

Lots of videos for RC aircraft using these hinges.  Most techniques also apply to CL.

Use of the plastic straw is useful.

[Matt Piatkowski]

Hi Steve,
Thank you for the link.
Indeed, the trick with the straw is cool.
The length of the hinge line of the YouTube presented plane was relatively short, though.

In the case of my model, the wing's TE is 60.5" long, and the flaps are 28.5" each.
In such a case, every misalignment of hinges will increase the resistance when the flaps are deflecting.

Also, the 30 minutes epoxy, even heated, will start getting dense too soon. It was visible in the movie.

I do not want to rush. My airplane is large, and handling of it must be slow and careful.

Do you know how to delay the 30 minutes epoxy setting process without affecting its strength after setting?
Regards,
M

[Brett Buck]

Hello,
The flaps for my new model have five Du-Bro nylon hinges each.
 
I wonder how to glue them with epoxy to avoid mess and to make sure that the hinge pins are on a straight line.

   I don't use epoxy, I use Titebond, but the same issues should hold.

     I do them one at a time, from root to tip, put the hinge together with the pin through it, put glue on both leaves. Push it into the flap, and push it into the trailing edge, and line everything up. As soon as the glue grabs (a few minutes with titebond), pull out the hinge pin and remove the flap and the other leaf of the hinge, then clean up the hinge barrel. Once it is set well enough, move on to the next one, and use the first hinge with the pin through it to line everything up again. One at a time until you finish a side. You end up with all the hinge leaves in their surface, the pin pulled and all the barrels lined up. Clean and oil the pin, put it in, and then do the other side.

   The wire for the pin is nominally 1/32", and you should use that while installing it. When you are all done, replace it with the next side down (you can get either 0.029 or 0.025 straightened wire. That will give it a bit of slop and free it up. Retain the pin however you want, I put a right angle bend in the outer ends and use a small piece of tape, but you can make a groove for it with a small screw to hold it in the groove

    Brett

p.s. double-check the pin diameter when you are cutting them out, it has been a long time since I used DuBro hinges and I have enough Klett for a few more airplanes.

[M Spencer]

Accidently got a smear on a bit of one , pva . Didnt wanna come out without the scalple . Think stories of failure are mainly from gross negligance .

Best to setum up , leave trial fitted overknight. Minimum .

Use a 1/8 or 5/32 ( or both ) wire end for rebates in ailerons . Oh Er FLAPS > !  . IF Square wing / Tailplane T E .

Glueum first maybe to flaps / elevators . That way you can sit hinge edge on a flat thing , to gettum real flush , linear & so on, also sight along for twist .

Lotta dudes fit dual / twin - at extremeities . particularly TIPS , so you dont get aileron flutter . Or Flap Flutter . Or fatigue the end inge .

Vasiline , maybe heated liquid - with a toothpick . to pin. ----------------- A rag / paper towel with acetone to wipe pre adhesive .

Wipe glue on hinge , after useing say 1 mm x 10 mm alumn. strip to pre coat inside slots . then wipe edge . Push in 3/4 way then wipe excess ,
Fully seat & defelct , wipe excess from rebate .

Usefull to fit thin card 1/2 in od x gap between inges - and rubber band lightly across chord - locked neutral . To Tight & itll bind on the V flap L E . The LE knactually being

a RADIUS to match hinge pin barrel . 

ALSO  it takes a evening to sew thread hinges . and no less to fit Du Bro etc . Pehaps . Two Half Evenings for full job. slots rebates etc , if fitted in two drying steps . At Least.

So dont rush it , see they all fit aligned BEFORE reaching for the glue .

Maybe do a test for adheshives . Sure the selleys aquedhear would be fine . Tho aint tried it , Yet. I use 24 Hr Aryldite . Maybe warmed so runny . But can kick off early that way . 

[Vitalis Pilkionis]

I use low-expanding polyurethane glue Kleiberit 569. Work time is approx 10-15min, also one should prepare some cotton sticks and acetone to clean off the excess glue. Ready to use after 1-2 hours.


https://www.kleiberit.com/fileadmin/Content/Documents/EN/Info_Sheets/569_Supratac_GB_US.pdf

[Matt Piatkowski]

Hello Everyone,
Perhaps "Brett's Method"??

Hey Brett.
How do you " line everything up"? What exactly do you do?

I have found threads in which people use thin CA, Silkspan pieces around hinges' tabs and CA, and toothpicks and CA to secure all hinges simultaneously.
For example https://stunthanger.com/smf/building-techniques/'failure-proof'-hinge-pinning/msg514167/#msg514167.
These processes seem to be clean and guarantee that the hinges' pins are collinear.

Securing the pins, their removal, and/or replacement is another interesting issue.
Any suggestions?

The C/L devil is ALWAYS in the detail.

Stay Safe,
M

[Curare]

Hello Everyone,
Perhaps "Brett's Method"??

Hey Brett.
How do you " line everything up"? What exactly do you do?

I have found threads in which people use thin CA, Silkspan pieces around hinges' tabs and CA, and toothpicks and CA to secure all hinges simultaneously.
For example https://stunthanger.com/smf/building-techniques/'failure-proof'-hinge-pinning/msg514167/#msg514167.
These processes seem to be clean and guarantee that the hinges' pins are collinear.

Securing the pins, their removal, and/or replacement is another interesting issue.
Any suggestions?

The C/L devil is ALWAYS in the detail.

Stay Safe,
M

I've tried this method, I don't like it. If you make a mess with the CA, it's there for good.

[Avaiojet]

I've tried this method, I don't like it. If you make a mess with the CA, it's there for good.

There is a "release" agent that's used with CA.

Takes a bit of time and you may have to keep adding a few drops, but it does work.

I don't know which one of my builds, possibly a few of them, I show and mention hinge installation.

You have to have a drawn center line on both sides and pay strong attention this CL when removing material for the hinge. The Klett is a great hinge because you can separate the halves by removing the pin. I actually bend the hinge pin wire a true 90 degrees so it lays flat against the hinge edge.

You can oil the hinge wire after this is done and reassemble the hinge. I draw two vertical lines on each side of the TE or LE where the hinge is to be placed.

I uses a great tool designed just for the purpose of creating the hinge slots. This tool is a great asset and comes with accessories depending on the hinge size. Possibly made by Debro. It's a self-centering tool and aids in getting the slot cut on the CL.

I remove just enough material so the hinge is snug. I also "V" cut the area where the hinge center gets recessed. I hide the hinge 50% into each side plus eliminate the control surface gap as much as possible.

I never cut or notch a flap or elevator and expose a hinge.

I run a thin bead of Epoxy at the tip top and bottom, and by the time the hinge is in place there's little Epoxy to wipe if any. This fit is snug. I always place a toothpick pin on the outer hinge. I drill the end hinge before I place it in the model.

I've pinned control surfaces this way back in my R/C days flying pattern and I've never had a hinge pull out or loosen up once Epoxied in place. We all did our models this way. I now use 5 minute Epoxy because it's fast. I do a test fit before I "go for it!

BTW. The control horn wire also has to be recessed 50% on each side so everything is on center.