Author Topic: Ball Joints  (Read 6205 times)

Titan-ex

  • Member
  • *
  • Posts: 74
  • Karma: 0
    • View Profile
Ball Joints
« on: July 12, 2006, 10:01:49 AM »
I've never used ball joints or any other kind of joints before and I was wondering what others would recommend for use on a HGUC gundam.

Articulation in:
feet and ankles
Hips
Shoulders
elbows
waist and neck

FichtenFoo

  • Model On!
  • Administrator
  • Member
  • *
  • Posts: 10399
  • Karma: 17
  • 16 bits of fun
    • View Profile
    • http://www.fichtenfoo.com
Ball Joints
« Reply #1 on: July 12, 2006, 10:06:48 AM »
Good topic question. This would be a great topic to get peoples techniques together in one place for future reference. 8) I don't replace many joints so I'm looking forward to the responses.
Rust is beautiful.

Titan-ex

  • Member
  • *
  • Posts: 74
  • Karma: 0
    • View Profile
Ball Joints
« Reply #2 on: July 12, 2006, 10:31:37 AM »
Guess I'll start off then,a few years back I came across a modeller's site where he would use SGT{first time I learned about this stuff} and toothpicks to build his own joints.

Gernerally he would build-up the SGT a little at a time on the end a toothpick,then sand it to smooth round shape.He did this with the neck,shoulders,knees,and ankle areas on most of his kits.

But where he would use standard polycaps I would make my own caps using a larger rubber ball-joint from a scrap kit to build the SGT around. Once dryed you can coat the inside with random things for stiffness when you insert the SGT ball in place.

Things you can use:
FFW
paint
paper
Plastic sheeting{the kind used to in folders}

Also if can find some scrap 10-gauge electrical wire,it can hold more weight and stress then the toothpick.Just cut some notches at the end to help the SGT hold better.

ronin4122000

  • Member
  • *
  • Posts: 32
  • Karma: 0
    • View Profile
Ball Joints
« Reply #3 on: July 12, 2006, 10:34:38 AM »
How about Erix93 tells us in more detail about the ball joint he made for The-o's waist? :D

Asmodeous

  • Member
  • *
  • Posts: 161
  • Karma: 0
    • View Profile
Ball Joints
« Reply #4 on: July 12, 2006, 04:56:52 PM »
When I work on joints I first off try to find a ball and socket or a polycap that accepts a rod and then try to match the two.  If the fit is not tight enough I coat the ball or the rod with super glue in thin layers until the joint is tight enough for my needs.  On my GM that I am working on I had to build a fixture for the polycap to set in.  I first set the pollycap in the stud of the foot too measurements and cut a box to house the polycap.  I then cut a circle out of thick pla plate, 1/8 inch thick or so, with a hole punch larger than the studs of the polycap. I then drilled a hole in the circles to accept the polycap studs.  These were then glued to the inside of the box.   I hope that makes sense.  Maybe the picture does.

Titan-ex

  • Member
  • *
  • Posts: 74
  • Karma: 0
    • View Profile
Ball Joints
« Reply #5 on: July 12, 2006, 06:55:26 PM »
Quote from: "Asmodeous"
  I hope that makes sense.  Maybe the picture does.



The top view does,still can't make heads or tails of the "inside" view though :?

Asmodeous

  • Member
  • *
  • Posts: 161
  • Karma: 0
    • View Profile
Ball Joints
« Reply #6 on: July 13, 2006, 01:27:14 PM »
That would be like sliceing it in half and then removeing one side.  So that you are looking at the inside of the "box".  The big black part is a side.  the "donut" looking part with the black center is where the polycap fits.  Clearer?

tetsujin

  • Builder of Zakus
  • Member
  • **
  • Posts: 395
  • Karma: 0
    • View Profile
    • Scope Eye.net
Re: Ball Joints
« Reply #7 on: July 13, 2006, 02:15:05 PM »
Quote from: "Titan-ex"
I've never used ball joints or any other kind of joints before and I was wondering what others would recommend for use on a HGUC gundam.

Articulation in:
feet and ankles
Hips
Shoulders
elbows
waist and neck


For some of this I gotta ask what you're hoping to accomplish.  The HGUC Gundam already has good posability in the shoulders and ankles, for instance.  How much farther do you want to push it?  This goes beyond simple "joint replacement" and into the realm of creating more elaborate joint systems, usually what I refer to as "self-extending joints" which reposition themselves as they turn in order to give the parts more clearance to move.  Often the problem isn't a matter of getting adequately posable joints, but finding someplace for all those bulky armor parts to move to and still look cool.  But anyway...

For elbows in 1:144 kits I highly recommend two parts: the first is the Kotobukiya Mecha Joint (small), the second is the Wave T-Shaft #1.  Both allow you to create a simple, small, double-hinge joint.  The T-Shaft is more suitable for the job out-of-box, it forms a nice little plastic (ABS? Styrene?) hinge block for the elbow with two (poly-vinyl) struts for mounting into other parts.  The Kotobukiya part is larger (but can be easily trimmed down) - the whole thing is made of poly-vinyl, too, so it's unpaintable unless you case it up in something.  The Kotobukiya part also has much better load-bearing capacity - it's a high-friction joint.  The Wave part is adequate to hold my Wing Zero's beam rifles, but in order to get it to perform that well I needed to clamp the plastic parts of the hinge until the glue dried.

My Strike: You can see the elbow joint part in the left arm, it's a Kotobukiya Mecha Joint that was trimmed down and then boxed up in styrene to make it paintable.

My Wing Zero: It's hard to see the elbow joints in this photo: unfortunately I don't think I have a better photo of that part of the model.  The elbows here are Wave T-Shaft, the only change I made to the parts was to bulk up the back side of the elbow with some styrene.

Those parts are great for replacing elbows in 1:144 kits - but there is another problem you must face.  Most 1:144 kits these days combine the elbow-swivel and the elbow-bend into one joint, usually a polycap mounted in the forearm.  If you replace your model's elbow joint with one of the above parts, you'll need to replace (or fix-pose) the arm's swivel-joint between the shoulder and bicep.  Usually this means installing a new strut in the shoulder and a matching polycap in the bicep part.


As for ball joints: they're sort of a tricky business in some ways...  The type with a polycap socket generally won't be very good at holding a pose, it's too hard to get adequate friction with them.  The strongest ball joints you can buy are the Yellow Submarine "Kansetsu Waza" ball joints.  They're made out of a clear acrylic material, like CD jewel cases or various transparent ballpoint pens.  Apart from being great for holding a pose, they're also paintable, which is something you can use to your advantage.

But one thing you need to bear in mind with any ball joint, but especially the Yellow Sub ones, is that the socket needs to be able to flex, particularly when inserting or removing the ball from the socket.  So you can't cut a hole, put a ball socket in, fill the gaps with SGT and then plug your ball strut in - there's a fair chance that you'll either be unable to get it in, or that the pressure will cause your installation to crack.  This is less of a problem with polycap sockets but still something to watch out for.

If you look at that picture of my Strike there's a Yellow Sub ball joint there between the torso and the arm: it's gray in the picture 'cause I painted it.  In that installation I actually installed the ball into the chest, and attached the socket to the arm, leaving space in the chest for the socket to move around the ball: that way, the back side of the ball socket is the part that's visible - it looks featureless and bland, but it doesn't look like a gray-painted clear ball joint with paint scraping off.  Plus I don't have to worry about pressure on the inside of the ball joint causing the chest block to crack apart: but most importantly, this design also features a polycap inside the chest block, so that ball joint can slide into and out of the chest, much like the MG Zaku F2's shoulder - so when I need more posability I can slide it outward, and when I want the arm to look more normal I can slide it back inward.  It's a very fiddly system but it's both good-looking and posable.


Another resource I must recommend is Bawoo's site.  Check out his Hi-Zack and Gaz R/L builds.  He tends to use Kotobukiya T-Joint polycaps to build his own hinge joints - these are a good, all-purpose polycap part, they're useful for all sorts of things.  For instance, check out his Gaz R/L elbow joints.  They look a bit bland IMO, but they're both simple and functional.
---GEC
Jabber ID: tetsujin@scope-eye.net

Titan-ex

  • Member
  • *
  • Posts: 74
  • Karma: 0
    • View Profile
Re: Ball Joints
« Reply #8 on: July 13, 2006, 05:15:01 PM »
Quote from: "tetsujin"
For some of this I gotta ask what you're hoping to accomplish.  The HGUC Gundam already has good posability in the shoulders and ankles, for instance.  How much farther do you want to push it?



Well I was looking to give some kits the same articulation in the shoulders as the Gundam seed destiny  Akatsuki kits,some like the double ball joint,not loose and not too tight.

More articulation in the feet/heel area for squating poses and such.Same with some of the MG 1/100 kits that lack this feature.


Thing is that I didn't know what some of those types of joint pieces were called,and most of what I found were just the round ball joints.

WhiteBase

  • Member
  • *
  • Posts: 176
  • Karma: 0
    • View Profile
Ball Joints
« Reply #9 on: July 25, 2006, 07:29:30 PM »
I use left over PC joints from my older kits, and I recast my own ball joints using milliput. I did a search around this forum ans realised that I did not post up my tutorial on this. Will do so shortly.  :wink:

EDIT : OK, the new thread has been added.
http://fichtenfoo.com/v-web/bulletin/bb/viewtopic.php?p=13955#13955

You can see from the first example on how I make my doublesided ball joints

David-GelgoogAce

  • Member
  • *
  • Posts: 11
  • Karma: 0
    • View Profile
Re: Ball Joints
« Reply #10 on: October 29, 2007, 05:23:56 PM »
The Polycaps i got on my model are stretched out. I'm trying to tighten them up. I will try the aforementioned super glue trick. I was also thinking some 2 part liquid Epoxy resin might work. Its really sticky, and a thin coat might stiffen up the joint a lot. I will try this and post my results.
Scratch Building Great things as we speak.

Still workin on that Damn Gelgoog. Will he ever finish.... Of course he will.

P.S

GOOOOOO STEELERS!!!!!

AnatoleFarmond

  • Fairly Useless
  • Help Editors
  • Member
  • **
  • Posts: 412
  • Karma: 1
    • View Profile
Re: Ball Joints
« Reply #11 on: January 31, 2008, 10:51:33 PM »
I dont know if this belongs here, but if anyone is into scrap building RC cars, they sell metal ball joint parts. I personally had some from someones trashed car, and I stole all the parts from, but the small metal ball joints are perfect size for 1/100 and 1/144 kits, I highly recommend them.

I did some searching around to see, they can be using in helicopters and nitro cars, from what I gathered... they are steel, so they cost a bit, but they are Fantastic! So if you have a really nice kit you want to put some extra money in, I recommend these.
http://www.wholesaletrains.com/Detail.asp?ID=200402892

"No matter how good you get, there will always be someone better than yourself." ~ Char Aznable

fredpekker

  • Member
  • **
  • Posts: 320
  • Karma: 2
    • View Profile
Re: Ball Joints
« Reply #12 on: February 01, 2008, 02:42:10 PM »
I bought some small pushrod connectors from the LHS and thought they would be pretty good, but they're not very tight and don't hold a pose very well.

oteebzo

  • Member
  • **
  • Posts: 428
  • Karma: 0
    • View Profile
Re: Ball Joints
« Reply #13 on: March 19, 2008, 08:30:34 PM »
The Polycaps i got on my model are stretched out. I'm trying to tighten them up. I will try the aforementioned super glue trick. I was also thinking some 2 part liquid Epoxy resin might work. Its really sticky, and a thin coat might stiffen up the joint a lot. I will try this and post my results.

Listn you can always wrap your joints in plastic wrap. ( the piece that goes in the other gets wraped) Then just cut the exposed from showing with a blae.