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repair for my VF-19


jemC
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3 minutes ago, Froy said:

The old Yamato explodium.

Basically the upper arm part bellow the part that slides down for battroid mode just disintegrate. Happened to mine.

I just used some crazy glue.

Hi Froy,

Is crazy glue some kind of super glue?

 

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Hi all, 

This is the breakage 

1.thumb.jpg.57c6087d366feee21f59a9df8cbe5386.jpg

2.thumb.jpg.4bd4acda9726b2f176c0166aafaa0eca.jpg

 

As you can see, the breakage is on both hands. Just below the shoulder joint and at the hinge portion.

 

3.thumb.jpg.a906eea81e253d942c8b07513845a052.jpg

 

With the hand removed, on the side view, both hands have the plastic pieces broken. One from the top and the other from the bottom.

 

4.thumb.jpg.16742f3dbe4e105ccf2b053541bef134.jpg

The broken pieces are clean breaks. This caused the arms unable to remain on the body in fighter mode

 

5.thumb.jpg.9e427c5a23f524c3f454712ed61abeb3.jpg

 

This is where the broken pieces were supposed to be attached to the main body.

6.thumb.jpg.9d63838bb0f50499a2f30cd1390694d6.jpg

 

A closer look at how the breakage looks like.

 

Thus, I need some help.

1. From the above, is it recommended to just use Zap-a-Gap to paste them back or is it recommended to have additional internal support stabilizers before applying the super glue?

2. Should I use super glue or those epoxy glue like Permatex 84145 Permapoxy Black Plastic Weld? https://www.ebay.com/c/26014850560?

 

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21 minutes ago, Sanity is Optional said:

 

If you do glue it back together, I'd also glue the metal peg into the opposite side to help carry part of the load.

Could you help to explain a little more as to which opposite side?

Also, I just had a look again, a metal insert might not be possible. the area seemed too small. 

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So you see the pin that's already there, that goes from one side of the broken part to the other?

6.jpg.b3574d26e6a6d54b2c4df538f88c695f.thumb.jpg.8c701a0e353e82e2b84989779ee6c0ee.jpg

Glue it in on the other end, it'll help distribute the force across both sides, rather than just the side the pin's attached to.

As a mechanical engineer, the reason those both failed in the exact same way is that the force from the arm is concentrated on only one side of the hinge, specifically at the squared interior corner where it broke. There's a reason why putting a small radius in is a good idea.

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13 minutes ago, Sanity is Optional said:

So you see the pin that's already there, that goes from one side of the broken part to the other?

6.jpg.b3574d26e6a6d54b2c4df538f88c695f.thumb.jpg.8c701a0e353e82e2b84989779ee6c0ee.jpg

Glue it in on the other end, it'll help distribute the force across both sides, rather than just the side the pin's attached to.

As a mechanical engineer, the reason those both failed in the exact same way is that the force from the arm is concentrated on only one side of the hinge, specifically at the squared interior corner where it broke. There's a reason why putting a small radius in is a good idea.

I see what you mean. 

So, I'll just glue on the breakage point as well as the other side of the pin. 

It's something I've never thought of. Good point. 

Any idea if Zap A Gap works for this?

Will it causes the white fogging issues on these plastic parts?

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I'd expect anything you do to be more functional than aesthetic.

Personally I'd search for a good 3M A+B epoxy, one that will work with both plastic and metal, and has a low viscosity with a n appropriate set time (5-30min range?).

Might want a higher viscosity if there's a large gap between the metal pin and the hole, and if so check what the maximum bond thickness is.

 

Or just use some crazy glue and see if it falls apart again. I spend far too long researching appropriate glues for things at work...

 

[edit] This stuff seems like it'd do the job: https://www.mcmaster.com/74765A22/

Clear superglue, begins curing in 15sec, and full harden in 24 hours. Low viscosity, high maximum bond thickness. Bonds to most plastics and metals.

Edited by Sanity is Optional
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11 minutes ago, Sanity is Optional said:

I'd expect anything you do to be more functional than aesthetic.

Personally I'd search for a good 3M A+B epoxy, one that will work with both plastic and metal, and has a low viscosity with a n appropriate set time (5-30min range?).

Might want a higher viscosity if there's a large gap between the metal pin and the hole, and if so check what the maximum bond thickness is.

 

Or just use some crazy glue and see if it falls apart again. I spend far too long researching appropriate glues for things at work...

 

[edit] This stuff seems like it'd do the job: https://www.mcmaster.com/74765A22/

Clear superglue, begins curing in 15sec, and full harden in 24 hours. Low viscosity, high maximum bond thickness. Bonds to most plastics and metals.

Thanks mate. 

I'll have a look at both 3M A+B epoxy and mcmaster. 

 

 

 

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On 10/10/2020 at 1:24 AM, jemC said:

Thanks mate. 

I'll have a look at both 3M A+B epoxy and mcmaster. 

From a modeler's perspective:

I would drill 2 holes and pin each broken piece in place with some brass rod addition to even the epoxy.

I suggest you DEFINITELY pin it if you're going to try CA of any kind. Zap-a-gap should work as well as any other CA [crazy glue]. 

 

 

Pinning it may be time/trouble spent, but those breaks look like they could do with the extra re-enforcement, and I would expect a CA repair-job to crack under any appreciable stress.

Good luck with your fix!

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9 hours ago, slide said:

From a modeler's perspective:

I would drill 2 holes and pin each broken piece in place with some brass rod addition to even the epoxy.

I suggest you DEFINITELY pin it if you're going to try CA of any kind. Zap-a-gap should work as well as any other CA [crazy glue]. 

 

 

Pinning it may be time/trouble spent, but those breaks look like they could do with the extra re-enforcement, and I would expect a CA repair-job to crack under any appreciable stress.

Good luck with your fix!

Hi Slide

Can I assume that you would recommend a pin to be drilled in the middle here?

 

 7.thumb.jpg.12b81b6212b9a741ce3bbac6a2746cd9.jpg

The breakage is in an slanted position and when the shiny metal pin in the picture goes through the hole in the arm, it would be in an awkward position to have the additional pin. 

9.thumb.jpg.9ff08ebf2a8b4aae6a626e56d9df0631.jpg

 

Any solution for that?

 

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On 10/11/2020 at 10:20 PM, jemC said:

9.thumb.jpg.9ff08ebf2a8b4aae6a626e56d9df0631.jpg

 

Any solution for that?

 

I would use 1, maybe 2 pins if you have the physical space at a right angle to the part itself. normally I would recommend 90o to the break, but that'd make this even more complex/difficult 

something like this:

1282142766_YF19pin.thumb.png.2572a2865dd582cacc60d7c3302a7bd8.png

578191999_YF19pin2.thumb.png.5af0bbed2ae3d388d4bb366ee3082e5c.png

*this is dependent on the internal structure of the joint, of which I'm completely unaware, but if it's just a plastic-only part of the joint, I would use epoxy and 2 pins [because I'm type-A, and using two will give you extra stability to the repair] in the yellow locations above. 

this will keep the pins away from any actual moving portion or negative spaces required for mobility.

if you do not have a vice and some kind of drill-press, then doing it this way will be extremely difficult to get correct and not slip and mar/break the joint up even worse

 

Order of operations in my head: 

  1. A LIGHT scuffing with some sandpaper to the break itself will help give the epoxy something [texture] to bite onto and will hold better. Epoxy the broken joint-flange into place, making sure it's as square and tight as possible. let the epoxy dry. *note* you can stop at this point and test-out the joint's function/strength if you like. maybe you won't even need to pin it, but I suspect you will.
  2. I would then put the joint in a vice, and mark-out then drill the two pin-holes. I don't know if going all the way through is necessary, but I'd sink the pins at least half-way into the joint. The more 'meat' of the broken flange you can use, the better IMO
  3. Trim the pins so they are just a little bit countersunk into their holes [ever so slightly recessed] then drench the pins in epoxy, place them into the joint, and wipe off the excess. This should have the benefit of sealing the pins in all in one fell swoop.
  4. now you can fill/sand/paint if you feel you need to.

Once you've reached step 2, feel free to modify the angle of your pins if you like, perhaps perpendicular to the break itself would be best from a mechanical strength standpoint... but I'm not an engineer, I just play one in my hobbyroom!:D

 

WARNING: doing it my way will further damage the part before you make it better!! and stands a reasonable chance of outright failure!

I'm fully aware that doing it my way is NOT going to leave it pretty without additional work [filling, sanding, painting] and you need to know that too, before you start

But as a model-builder, that's how my brain immediately tackled the problem.

Shy of machining yourself a new piece, this is the most sturdy/long-lasting repair I can think to make.

My method may prove to be overkill, but overkill is under-rated and if you play with her at all, I would not trust an epoxy-only bond for any appreciable force on a repair surface-area of that size. 

 

Hope this either helps, or inspires a better/simpler solution. I like to overthink things like this so TIFWIW:unknw:

Good luck!

Edited by slide
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6 hours ago, slide said:

I would use 1, maybe 2 pins if you have the physical space at a right angle to the part itself. normally I would recommend 90o to the break, but that'd make this even more complex/difficult 

something like this:

1282142766_YF19pin.thumb.png.2572a2865dd582cacc60d7c3302a7bd8.png

578191999_YF19pin2.thumb.png.5af0bbed2ae3d388d4bb366ee3082e5c.png

*this is dependent on the internal structure of the joint, of which I'm completely unaware, but if it's just a plastic-only part of the joint, I would use epoxy and 2 pins [because I'm type-A, and using two will give you extra stability to the repair] in the yellow locations above. 

this will keep the pins away from any actual moving portion or negative spaces required for mobility.

if you do not have a vice and some kind of drill-press, then doing it this way will be extremely difficult to get correct and not slip and mar/break the joint up even worse

 

Order of operations in my head: 

  1. A LIGHT scuffing with some sandpaper to the break itself will help give the epoxy something [texture] to bite onto and will hold better. Epoxy the broken joint-flange into place, making sure it's as square and tight as possible. let the epoxy dry. *note* you can stop at this point and test-out the joint's function/strength if you like. maybe you won't even need to pin it, but I suspect you will.
  2. I would then put the joint in a vice, and mark-out then drill the two pin-holes. I don't know if going all the way through is necessary, but I'd sink the pins at least half-way into the joint. The more 'meat' of the broken flange you can use, the better IMO
  3. Trim the pins so they are just a little bit countersunk into their holes [ever so slightly recessed] then drench the pins in epoxy, place them into the joint, and wipe off the excess. This should have the benefit of sealing the pins in all in one fell swoop.
  4. now you can fill/sand/paint if you feel you need to.

Once you've reached step 2, feel free to modify the angle of your pins if you like, perhaps perpendicular to the break itself would be best from a mechanical strength standpoint... but I'm not an engineer, I just play one in my hobbyroom!:D

 

WARNING: doing it my way will further damage the part before you make it better!! and stands a reasonable chance of outright failure!

I'm fully aware that doing it my way is NOT going to leave it pretty without additional work [filling, sanding, painting] and you need to know that too, before you start

But as a model-builder, that's how my brain immediately tackled the problem.

Shy of machining yourself a new piece, this is the most sturdy/long-lasting repair I can think to make.

My method may prove to be overkill, but overkill is under-rated and if you play with her at all, I would not trust an epoxy-only bond for any appreciable force on a repair surface-area of that size. 

 

Hope this either helps, or inspires a better/simpler solution. I like to overthink things like this so TIFWIW:unknw:

Good luck!

wow! Thanks slide for the detailed explanation. 

Everything you said makes complete sense and well noted on the warning. 

I'll seriously consider your suggestions and once I've some free time, I will look to work on it.

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On 10/13/2020 at 9:01 PM, jemC said:

wow! Thanks slide for the detailed explanation. 

Everything you said makes complete sense and well noted on the warning. 

I'll seriously consider your suggestions and once I've some free time, I will look to work on it.

Did you have success with your repairs?

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I will second the person who said its worth your time to drill and pin.  I have repaired teeny tiny wrist joints on 1/25 Joy Toy figures using .020" brass rod where the figure was played with extensively and they have held up.  Straight glue repairs, however, have failed for me even on static 10mm ish connections.

If the joint is small, use a smaller drill and smaller pin.  I prefer thin brass so that if there's misalignment in the holes the pin has a bit of give.  You can also oversize the holes just a tiny bit and fill with a lower viscosity epoxy or superglue.

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On 11/1/2020 at 9:04 AM, Slave IV said:

I’ve used needles. I cut them with heavy duty wire cutters. 

You can also use piano wire. It’s super thin and extremely strong. Just note that you will have roughen the surface to make sure it adds bonded strength to your repair.

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