Thread for Resin Casting Toy Parts

[Mr. Ginrai]

Tony,

Be careful with getting figures open. Some figures will come apart easily but there are some toys that had bodies which were originally sonic welded rather than glued (vintage thundercats). Basically they use high frequency sound vibrations to vibrate and heat the plastic and it fuses the two halves of the body together. Pretty much impossible to get those open without some form of damage.

[magengar]

I guess that is the case with my DC Batman figure, it's a Sonic weld.

A typical two-part molded object will show some physical attempt to
smooth out the seam by hand or machine, and it varies from figure to figure.
The whole object is cast inside a two-part mold.

Sonic welds treat all units the same, so the body appears perfect in
every unit coming off the production line,
with the seam smoothed away so fine it's almost "invisible".
It's a faster process than two-part molding...
The parts and halves are cast separately (rather than casting them
together as whole objects inside a two-part mold),
then the parts and halves are sonic-welded.

Now here's my theory:
The action figure's main body isn't completely solid to the core.
The arms and legs are attached to the main body with pins for articulation;
therefore the main body Has to have hollow areas where the
limbs get attached.

Instead of using a flat screwdriver, I could try using a heated Exacto knife
attached to a soldering iron and gradually cut my way into the main body.
If the main body starts to give into being gradually pried open, I can
remove the limbs and then continue splitting the main body along
the weld seam.

My DC Batman figure isn't articulated at the waist (ie: separate abdominal
from the upper bust), it's one whole welded object from the neck
down to the groin; I'll be safe splitting the main body in half along the
weld seam all the way from top to bottom using a tight heated E6 guitar string
attached to a controllable AC power source (like a home-made Styrofoam cutter).
I would have to build such a cutting tool for this project.
Damn... a project Within a project!  The sh*t-show just Never ends!

zozo-mag

Jun 24, 2013 1:54:04 GMT -5 Mr. Ginrai said:

Tony,

Be careful with getting figures open. Some figures will come apart easily but there are some toys that had bodies which were originally sonic welded rather than glued (vintage thundercats). Basically they use high frequency sound vibrations to vibrate and heat the plastic and it fuses the two halves of the body together. Pretty much impossible to get those open without some form of damage.

[TheMazingerZ]

That is the problem with using new figures for customizing. It is hard to start tearing into them without experiencing some sort of guilt...

}D

[magengar]

I agree with you on That one.  I don't wanna wreck this DC Batman.
That's why I'd rather copy it and use the resin copies.

After I've made my Batman body-part copies I can put the original figure
back together, coz it's still a very nice figure.

zozo-mag

Jun 25, 2013 13:42:15 GMT -5 TheMazingerZ said:

That is the problem with using new figures for customizing. It is hard to start tearing into them without experiencing some sort of guilt...

}D

[TheMazingerZ]

Have you tried making "blank" bodies out of putty? I've been meaning to do it, but just haven't had the time yet.

}D

[magengar]

That may be the safer thing to do, I'll try that idea
rather than risking damage to the Batman figure.

If I can sculpt a penny-sized resin figure, I should be able
to sculpt an almost exact putty copy of the Batman figure.

zozo-mag

Jun 25, 2013 17:09:16 GMT -5 TheMazingerZ said:

Have you tried making "blank" bodies out of putty? I've been meaning to do it, but just haven't had the time yet.

}D

[magengar]

I recommend this book

www.barnesandnoble.com/w/how-to-cast-small-metal-and-rubber-parts-william-a-cannon/1000701671

.....and it's also available online at Walmart's website.

zozo-mag

[magengar]

"Composimold" re-usable rubber mold...

www.composimold.com/index.php

...melt it in the microwave oven, pour it over your master object,
it cures into a mold, remove your object from the mold.
To re-use the mold, put it back in the microwave and melt it.
Ready to use for the next project, and again project after project!
Saves you money from having to buy silicone mold making materials

Searched for it at eBay, you wanna purchase it under B.I.N. with FREE SHIPPING.
www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313.TR11.TRC1.A0.XCOMPOSIMOLD.TRS0&_nkw=COMPOSIMOLD&_sacat=0&_from=R40


Here's a quick video demo for Composimold...




Enjoy, and have fun!


zozo-mag

[ryomakabuto]

I tried that composimold years ago. it is good for simple castings of solid objects without much detail, but since you have to heat it to at least 120 degrees to make it flow, forget about using it on thin plastic parts or wax model prototypes, as it will melt them. it is not very strong so when you pull the part off from it it may tear small chunks of composimold with it and the mold will be worthless.

[magengar]

I didn't know that. 
This would be the first time I'll be using it, for simple parts.

I've got a sculpt made with Balsa and I'm gonna coat it with shelac
or polyurethane before I give it the Composimold treatment.
If the Balsa sculpt fails, I'll sculpt the piece from a chunk of 2x4
or pressure-treated lumber.

zozo-mag

Jul 5, 2013 10:46:33 GMT -5 ryomakabuto said:

I tried that composimold years ago. it is good for simple castings of solid objects without much detail, but since you have to heat it to at least 120 degrees to make it flow, forget about using it on thin plastic parts or wax model prototypes, as it will melt them. it is not very strong so when you pull the part off from it it may tear small chunks of composimold with it and the mold will be worthless.

[magengar]

DIY HOME-MADE ROTATION CASTING MACHINE
For those of you looking to cast hollow parts...



He built the rotation machine frames with wood, gears, bearings,
and what looks like a bicycle chain... an ordinary electric drill is attached
to it, to do the turning, at slow speed, as the resin is curing.

...for hollow castings, especially parts for jumbos, you need This!

zozo-mag

[magengar]

Here's something interesting... an alternative to silicone rubber, Sugru.

sugru.com/

...I'm curious to try this substance as an alternative to silicone rubber
for making molds.
Has anyone here ever used sugru?





zozo-mag

[magengar]

Moving right along.........

I'm trying to brainstorm ideas on how to hinge the
wings on my custom Hover Pilder when the time comes
to assemble the wings...

...I found this to be a nice idea........
www.tailiglassesparts.com/hinges-buy/nickel-hinge-for-sunglasses-8.0mm-width.html



...Of course these eyeglass hinges might have to be sanded and lightly painted
to match the red color of the Hover Pilder.
I haven't thoroughly checked that website to see if they manufacture
ABS plastic colored hinges, then perhaps I can find a set of red hinges.

zozo-mag

[xiombarg]

The problem with hinges is having tension and not having a hinge that strips when you tighten it. This is why I like using pre-made ball joints because if they get loose you can always brush on a little bit of super glue.

[magengar]

I agree with you about the ball joints, I would use such joints as well.

But in the case of the Hover Pilder's wings, I'd have to use hinges;
because the wings are flat...
...when the wings fold upwards (docking into MZ's head) the wings
are jointed by a mechanical hinge that spans the full width of the wing.






......a hinge is the closest method I can use to articulate the wing.
A ball joint would look weird on the wing surface.

zozo-mag

[xiombarg]

Oh yeah, my bad. I don't know what I was thinking.

For that it seems like a regular hinge would work.

[magengar]

LOL... that's okay, it's one of those minor details we hardly notice
on these toys until we get to that detailed area.

I came to this conclusion of using hinges, because my custom Pilder wing
is about a hair less than 1/16th" thick and 3/4" wide... I would have to drill
all the way through the wing in and out without letting the drill bit trespass
the surface of the wing...

I'd have to use a long drill bit, bit it's not guaranteed that the drill bit will
spin solid perfect center on its axis... ever notice how the tip of the bit
"vibrates" more at the end than at the base of the shaft?

...if I try to drill holes (with a Dremel) through the width of the wing
to "hinge" the folding wing parts, the resin could melt from the friction of
the hot drill bit as it goes through the material.
...if I try to drill by hand (spinning the drill bit with my fingers) I could
end up wrestling the bit which could then break the wing.

Using an outside hinge on the surface of the wing parts will allow the wing
to pivot upwards as the Pilder is docked inside Mazinger's head.
When the Pilder is on the ground, the wing will be pivoted downwards
in Landing mode and will lock in its straight horizontal position without
flopping further downwards.
(My custom Pilder will have engines underneath, to take the weight of
the ship Off of the hover drums that are at the end of the wings).

I'm tied up distracted with other projects during this Christmas holiday rush,
but I will try to squeeze time in to get more work done on my Pilder
hopefully this week so that I can make some significant progress with it.

zozo-mag

Dec 8, 2013 13:46:16 GMT -5 xiombarg said:

Oh yeah, my bad. I don't know what I was thinking.

For that it seems like a regular hinge would work.

[xiombarg]

Yeah, I would use an outside hinge. Drilling your own holes for a custom pinned hinge is practically impossible to get it straight without a drill press.

You will probably have to put the hinge on the top for it to close correctly.

[magengar]

Yep, so that it will close like this...



You can see how the PX-04 has its wings jointed straight through.
And then there's a mechanical lever over the top of the wing to
spring it when a button is pushed.

This sun-glass frame (pic below) shows the simple hinge function
that I want to use for my Pilder wings...



zozo-mag

Dec 9, 2013 12:23:36 GMT -5 xiombarg said:

Yeah, I would use an outside hinge. Drilling your own holes for a custom pinned hinge is practically impossible to get it straight without a drill press.

You will probably have to put the hinge on the top for it to close correctly.

[magengar]

One of the major tools I needed for my casting supplies
is Modeling Clay, and I didn't have any until now...

A while ago I bought two 1lb packs of Crayola Modeling Clay...



I was lucky to score the last two packs off the shelf at my
local CVS Pharmacy store... I paid full price for one pack ($4.99 USD)
and got the second pack for half-price ($2.49 USD)...yaaaay!

You'll also find this clay sold at Walmart, in the same aisle with the
School supplies/crafts section... yaaaay!

This clay will never dry, and is a medium density which is good for
modeling and sculpting. But it is not made for baking nor for ovens and kilns.
I use this to make a mold for rough mock prototypes by just pressing
the original object inside a slab of the clay, and gently pulling the object away
thus leaving a detailed imprint ("inwards embossed print"), and then pouring
the resin mixture into the imprint.

You must pull the object away GENTLY (do not wiggle the object out
of the imprint) or else you'll warp and bend the imprint out of shape and
your resin casting will come out warped as well.

The resin casting will result in a rough texture, but it can be sanded smooth.
A release agent for the clay mold is optional, but you can cast the resin
directly into the clay since the clay has some oily chemical composites.
Any clay residue on the resin can be cleaned off after the resin has cured
and de-molded from the clay.

You can only create a half mold with the clay; but this will also lend itself
to making a two-part silicone rubber mold by leaving the object embedded
half-way inside the clay and embedding 2 to 4 small marbles or ball bearings
inside the clay to form mold "locks", then slowly pour the silicone rubber mixture
over the object until it is covered and let it sit overnight or maximum time
for the silicone to cure.

But, FIRST, you must make a mold box around the object; and seal the bottom
edges and of the mold box down to a smooth flat surface with hot glue,
and seal the seam with clay.  A strip of corrugated plastic cut to twice
the height of the object will work... bend and form the corrugated plastic
around the object, leaving some space around the object, and tape the
corrugated plastic closed and seal that seam with clay.
The mold box will keep the silicone from spilling all over the place.

Then after the silicone is cured, flip the entire mold box over and pull the clay
away from the object... then clean off any clay residue from the object,
and seal the mold box down to a flat surface again with the hot glue.
Then apply some release agent to the object and the first part silicone mold,
then pour the next batch of silicone rubber over the object and let it cure.
After the second part of the silicone rubber mold is cured, you can open the mold
and pull the object out and BAM! you'll then have your two-part mold for
casting a resin copy of the object.

I can't have enough modeling clay, for big jobs and minor jobs.
So, later this week I'll buy a couple more packs of this Crayola clay
to keep it in my stock.

Do NOT try these tips with Play-Dough, because the play-dough will
leave a powdery residue on your castings.

Have fun!

zozo-mag