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Hinges on flaps placement

Old 11-03-2020, 03:54 PM
  #1  
jangodog
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Default Hinges on flaps placement

My Viper had a minor crash and the flaps on my Eflite Viper came loose. I wan't to use nylon hinges instead the foam attached on the flaps so guess i have to install the hinges low near to the edge of the flaps. Don't think tape is secure enough.
Any suggestions?
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Old 11-03-2020, 06:23 PM
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firemanbill
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how do they attach originally? Not familiar with that plane.

If they are the type that are just molded in and cut thin you can make a hot glue hinge. Hold the pieces together and run a bead of hot glue along the seam. Then use a credit card to spread it thin and flat. It sounds ghetto but it does work.
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Old 11-03-2020, 07:09 PM
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I thought about the glue thing but not sure if it's strong enough? I have regular nylon hinges, small ones, but the flaps only goes down.
So should i install the nylon hinges in the middle or low near the edge of the flaps?
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Old 11-03-2020, 08:58 PM
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crxmanpat
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You could do one of two things:

1. Use the hinges you have (I assume these are standard pin hinges?) and install them along seam line where the flaps normally attach. It looks like the leading edges of the flaps are beveled so they should have no trouble moving.

2. Glue the flaps back on, then use Blenderm medical tape to make sure they stay secured.
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Old 11-03-2020, 10:15 PM
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Originally Posted by crxmanpat View Post
You could do one of two things:

1. Use the hinges you have (I assume these are standard pin hinges?) and install them along seam line where the flaps normally attach. It looks like the leading edges of the flaps are beveled so they should have no trouble moving.

2. Glue the flaps back on, then use Blenderm medical tape to make sure they stay secured.
Good info. I have Foamtac so guess itís okay.
Regarding the tape not sure what i should use.

Forgot to mention the nose broke off along with the wheel too. Planning to use foamtac and one or two carbon rods for strengthing/more stabel attachment.
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Old 11-04-2020, 09:57 AM
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solentlife
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Good advice above ...

My solution to split foam hingeing ....

Do not clean up the jagged split ... its a good indicator of when surface is back in place correct.
Take marker and mark both edges where you want to hinge - that way when closed up - you know where hinges are !!
Take sharp model knife and create slits for hinges .... I use thin narrow strips of plastic (mylar usually) or from packaging. Strips are about 1/3" (8mm) wide and about 15 - 20mm long. I mark the middle so I know when half is in slit.
Using foam safe CA or as I usually use - Epoxy ... I glue strips into one edge ... let cure - then glue into other ...

You should be able to close up the joint as original ... and once epoxy has cured ... you work the surface to ensure it moves and that epoxy hasn't locked it !!

Use of Tape to hinge is OK as long as :
1. Foam is not EPP ...
2. No typical factory paint - which just flakes off ..

I have used Hot Glue to hinge - but find it stiff and suspect on those hot summer days ... and in winter can be very stiff.

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Old 11-04-2020, 11:10 AM
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Originally Posted by solentlife View Post

My solution to split foam hingeing ....

Do not clean up the jagged split ... its a good indicator of when surface is back in place correct.
Take marker and mark both edges where you want to hinge - that way when closed up - you know where hinges are !!
Take sharp model knife and create slits for hinges .... I use thin narrow strips of plastic (mylar usually) or from packaging. Strips are about 1/3" (8mm) wide and about 15 - 20mm long. I mark the middle so I know when half is in slit.
Using foam safe CA or as I usually use - Epoxy ... I glue strips into one edge ... let cure - then glue into other ...

You should be able to close up the joint as original ... and once epoxy has cured ... you work the surface to ensure it moves and that epoxy hasn't locked it !!

Use of Tape to hinge is OK as long as :
1. Foam is not EPP ...
2. No typical factory paint - which just flakes off ..

I have used Hot Glue to hinge - but find it stiff and suspect on those hot summer days ... and in winter can be very stiff.
Good tips there I have both, packing strips and regular nylon hinges. Think itís better than glue/tape. The front with the nose wheel i have to glue back together as well.
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Old 11-04-2020, 12:35 PM
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solentlife
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Front ?

Trick there is to not beef it up too much - as then all you do is transfer all that stress further along and make any damage harder to fix.

My preferred way to fix this sort of damage is to use heat to straighten out the foam - being careful not to overheat and create crocodile skin ! Use of a jig such as a Workmate to hold all straight is good. Or to get wood battens and clamps / bands ...

I like to use Gorilla Glue or its generic form ... Polyurethane Glue ..... to fix this sort of thing. It foams into the cracks and holes filling the joint. It is light and strong. Can be sanded back ...

How ?

Materials ...... PU glue ... handful of cocktail sticks .... tape ..... clamping methods .... clingfilm or thin polythene sheet.

First remove heavy items from front piece (but only that which can be refitted back later).
Offer up front to model to ensure alignment and correct joint.
Get tape pieces and clamping ready.
Apply PU glue and bring model and front together into correct position.....
Using Cocktail stick and tape .... the sticks can be angled into the foam to bridge the joint and hold the two aligned. The tape can be applied to keep them together.
Clamping battens or in a Workmate with the plastic sheet preventing glue from sticking battens / Workmate to the model.

Once set - carefully cut the cocktail sticks and sand flush - no need to remove the part crossing the joint. Remove tape.

Any imperfection / gaps etc. can be filled ... sanded .... etc.

You should then be able to refit such as nose wheel gear etc.
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Old 11-04-2020, 06:29 PM
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Originally Posted by solentlife View Post
Front ?

Trick there is to not beef it up too much - as then all you do is transfer all that stress further along and make any damage harder to fix.

My preferred way to fix this sort of damage is to use heat to straighten out the foam - being careful not to overheat and create crocodile skin ! Use of a jig such as a Workmate to hold all straight is good. Or to get wood battens and clamps / bands ...

I like to use Gorilla Glue or its generic form ... Polyurethane Glue ..... to fix this sort of thing. It foams into the cracks and holes filling the joint. It is light and strong. Can be sanded back ...

How ?

Materials ...... PU glue ... handful of cocktail sticks .... tape ..... clamping methods .... clingfilm or thin polythene sheet.

First remove heavy items from front piece (but only that which can be refitted back later).
Offer up front to model to ensure alignment and correct joint.
Get tape pieces and clamping ready.
Apply PU glue and bring model and front together into correct position.....
Using Cocktail stick and tape .... the sticks can be angled into the foam to bridge the joint and hold the two aligned. The tape can be applied to keep them together.
Clamping battens or in a Workmate with the plastic sheet preventing glue from sticking battens / Workmate to the model.

Once set - carefully cut the cocktail sticks and sand flush - no need to remove the part crossing the joint. Remove tape.

Any imperfection / gaps etc. can be filled ... sanded .... etc.

You should then be able to refit such as nose wheel gear etc.
I know what you mean about ďbeefingĒ the front up but itís pretty fragile
to start with. And the fact that i had not installed the nosegear cover because
it got worn over time due to the many front gear repairs. Iím waiting for a new
cover but in the meantime iím gonna glue it together with foamtac and some
carbon rods. Your tips are very helpful with the cocktailsticks and tape etc
Still wondering why no one have mentioned carbon for the stronger attachment?
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Old 11-04-2020, 06:57 PM
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solentlife
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Carbon is great ... but in many cases overkill.

Carbon is best when its used as a long stiffener as in wing spars or longitudinal fuselage braces. But when used in short pieces in locaiised areas - it can create break points at its ends.

Cocktail sticks break easier than Carbon while still giving benefit till that point. Cheap ... easily obtained ...

I use cocktail sticks for so many things .... into fuselage sides to provide rubber band hold for hatches as example ... pin guides in joints ... many uses.
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Old 11-04-2020, 08:08 PM
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Good tip there too. Guess you are talking about the "longer" cocktail sticks for barbeque meat chuncks and so? The small ones are they big enough for the front part?
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Old 11-04-2020, 10:22 PM
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solentlife
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The short sticks used in Martini's ..... or as Toothpicks .... are more than enough to fix a joint while it sets.

The long BBQ skewers are used by me to inset into foam to provide longitudinal stiffening. With epoxy or PU ... the 'wood' absorbs part of the glue and itself is stiffened further ...
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Old 11-04-2020, 10:23 PM
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Okay, got it. Thank's
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