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Sculpting more Rahm Kota armor


Koda Vonnor

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I didn't get much done this week, due to the weather, but I did get the rear corner cut and edge trim build-up on the left shoulder bell and got both bells filled, smoothed, and primed. I had a ton of air bubbles in the right casting and hardly any in the left. Those are all filled and smooth. There are still some slight bumps and dips in the curved surfaces, but not readily noticeable.

 

Both are bright TK-white now and ready for the metallic. 8)

 

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~ Vonnor

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Weekend Update:

 

I got the shoulder bells covered in thick metallic silver and the left handguard hard model fiberglassed. For some reason no matter what I did with the lighting and camera, the pix all came out underexposed. I'm guessing all the shinyness confused the camera's brain. The silver is just stock metallic silver, very light in color tone. It's only the base coat for the weathering. Next is to hit it with one very light coat of a darker metallic for sand-weathering, paint the bird (dreading that - freehand masking yuk), then dry-brush in the crevasses and scrape the screen-accurate scuff pattern down to the white.

 

I used a slow mix on the resin/bondo catalyst today, and broke out the right handguard hard model before it had completely set up. This is because the hand lifecast I did had my thumb out unnaturally far, and I wanted to put some pressure on the hard model to kind of pull it bit tighter to the hand while it solidified. Note the strap in the photo.

 

More to come.

 

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~ Vonnor

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Today I finished putting the raised edging on the right handguard model and started on the production mold. I sprayed shiny clear stuff all over it then superglued a heavy paper flange on the back. This was to help delineate the halves of the rubber block mold. I hot-glued a sintra box and put the model in the box, then carefully filled up all the back side with clay. I had to put in a breathing tube for the thumb-side undercut and one near the pour hole. I also pressed in some registry keys although they probably weren't needed due to the funky shape of the mold. After I had a good seal all around I poured in some OOMOO 25 tin-cure silicone rubber and let it set up. I probably would use a platinum-cure like MoldStar 30 next time. It is a lot stronger and stretchier. I was looking at my money when I ordered it.

 

FYI, the OOMOO 25 spec sheet says 15min pot-life. Um, yeah, it'll POUR after 7min... but it won't self-level. Luckily I didn't mix quite enough the 1st pour so I hurried on the top-off mix and it came out nice.

 

I'll pour the other half tomorrow.

 

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~ Vonnor

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No, it's not a frowning Arcona. ;)

 

It's the finished right handguard block mold. The full block silicone mold should work very well, but I will look for another way to make the left handguard production mold, as what you see here is about $35 worth of rubber. It was good experience and practice though. I wanted to see if I could navigate the complex curves and undercuts of the piece. Thankfully none of the other armor elements have undercuts and the prod molds can be just rubber-lined plaster clamshells (much cheaper).

 

More to come.

 

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~ Vonnor

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I did a test pull of the right handguard today. I used Smooth-On Smooth-Cast® 45D semi-rigid urethane resin. One thing I learned was you can NOT pour into an unsupported rubber block mold. I should have built a box around the block to help hold the two halves in place. As a result, the resin started oozing out of the cracks and I had to stand there and hold in the sides a bit for 15 min until it kinda set up. You can see the major flashing on the piece where the resin seeped out.

 

I say test pour since there may have been some distortion from the loose mold, plus I got an air bubble in one of the thumb-side notches.

 

Also, I had a little 1/4"" thick disk left over from the bottom of the pouring cup. I wanted to show how flexible the cured resin is. This should work well for the handguards. :D They say you can finish-sand the material. I'll give it a try when it's fully cured.

 

Later.

 

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~ Vonnor

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I did some shaping and sanding on the handguard test pull today. I will not be wearing this as there were several flaws caused by problems with the mold, which have now been fixed. This test piece does allow the opportunity for experimentation though.

 

I plan on priming this and trying out Rub & Buff to see if that may be viable. You can see how soft and flexible the Smooth-Cast® 45D came out. It's what I was hoping for in the handguards. A material that would look rigid but flex when the hand flexes. Soft as it is, it still sands very nicely. The only concern may be if it can take the priming/finishing without cracking the paint. We'll see.

 

The advantage of a production block mold is I can try out different urethane materials.

 

Much more to come.

 

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~ Vonnor

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I think one of my favorite parts of your posts is that I'll always wonder something while I'm reading them, "would doing this work... will that be a problem... how will he work around this...", and invariably by the end of the post, you'll have posed the same question or mused about the same thing! (Can I claim that great minds think alike?)

 

I'm looking forward to hearing how the weathering comes out. I've used that same resin, but mine was cast and remained black and the pieces were thicker so they didn't have as much flex. I didn't try priming or weathering it, but now I'm curious. It will be interesting to see what you learn about it.

 

Fantastic work, as always, and thank you for continuing to share. (Though I must admit that I have something of a love/hate relationship with your posts. I enjoy them so much, but they also remind me that I'm not making nearly enough progress on my own CVI projects! It's like a weekly nudge to get a move on!)

 

Pam :-)

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I have the piece primed now Pam, and it doesn't lose anything in the flexibility. I'm thinking of hitting it with the same base color as the shoulder bells and the same scratch weathering just to keep the finished colors consistent. Even though the Smooth Cast 45D material at 3/16" thickness exhibits high flexibility, it won't get flexed to a great extent while worn. If the weathered paint finish holds up I'll just go that route. If the paint cracks, I'll likely try a 60D pull. It's the advantage of having a production rubber block mold in the can. 8)

 

~ Bill

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I started on the vambraces today, beginning with the hard model for the elbow guards. They are symmetrical so I only need one. I used Sintra 3mm for the base and 2mm for the edging, bonding the layers together with Azek PVC cement. Great stuff that Azek, water based and slow set allowing plenty of time to position the parts. I used the 3mm cutout as a jig to align the parts while I pressed them with a board and some iron weights. I painted the edge of the jig as it too was PVC and I didn't want it to stick to the finished model.

 

By tomorrow this will bond as if one piece of PVC and be easy to heat-bend to the curve of the arm. I already tested the bonding and thermal-forming on a scrap and it works fantastic. After this model is heat-bent to the proper curvature I will take a clam-shell mold and pour in some FeatherLite resin same as the shoulders.

 

One thing to note, although I had a plan to apply the slight waffle texture to the elbow guard and forearm plate models (see sketch below), two things dissuaded me. 1. The difficulty of scratch-weathering in the texture. 2. The machinist wanted over $250 just for the aluminum texture plate, due to having to fabricate a custom milling bit. I may explore the expense at a future revision. Just heat up the aluminum plate and the Sintra and press the texture into the plastic.

 

Stay tuned.

 

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~ Vonnor

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Sometimes the stuff you have to make is boring and ugly, but necessary to the project.

 

I show the test handguard partially weathered in place on the armequin. I spritzed it with dark bronze metallic over heavy silver, but sanded too much of the bronze off. Another spritz-n-sand should do the trick. The handguard's flexibility neither suffers from, nor seems to want to crack, the metallic paint job. I was glad of that since it will be easier to get all the pieces a consistent finish.

 

More when I get there.

 

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~ Vonnor

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Here is a photo-chop overlay of the vambrace armature with the game rendered model. I wanted to be sure I have a reference for scaling and fit. Notice the slight twisting of the armor as it goes up the forearm, which necessitates sculpting right and left separately.

 

Kota has skinny arms. :P

 

I hope to come close to this scaling but will need to leave a little rotational room from about 7cm above the wrist to the elbow bend, so they may be a bit fatter than the reference.

 

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~ Vonnor

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I just got the parts today and I have to say they came out brilliantly.

 

Here's the same layout from a couple pages back with some small parts. The filename of the image gives the formation away. :D

 

Also here's a showing of the saber holster frame for the back of the bando. It still needs the stiff leather lining shown on the game renders. Gonna see if fiberglass resin will soak into the thin brown lambskin I still have left over from the hilt wrap. 8)

 

Stay tuned.

 

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~ Vonnor

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I marked off the right ARM-ature for laying on the clay. The solid axial lines show the divide between vambrace halves and are opposite each other through the mass center of the arm. Notice they are skewed a bit toward the back of the body. The dashed axial lines show the vertical centerline as the arm is hanging at rest. I also marked the elbow pit and point and the top/bottom center of the wrist for reference and to help the alignment as the clay piles up.

 

There is a great deal of forward thinking involved in building rigid articles of clothing. The dimensions of body parts are never the same at rest as in motion, and especially at the full-range end of flexion and extension. I'm finding that compromises must be made to strike a balance between accuracy and wearability, to say nothing of comfort (which would shoot accuracy all to hell). As an example, I will have to cheat the inside arm a half-inch shorter to allow me to scratch my nose and eat a sandwich. :P

 

I'll post some rough sculpt pix tomorrow.

 

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~ Vonnor

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Some random thoughts on this stage of the project:

 

Up to this point, the armor pieces that have been built have been caps of a sort. The shoulders and handguards kind of just sit on or stand off of their respective body parts. The arms are the first to "wrap around" a body part. These and the torso armor have to leave some space between the plastic and the skin. If they don't, then the costume wearer (in this case, me) won't be able to move or breathe.

 

For the arms (and torso as well), I gave a lot of thought to several factors. First and foremost, the finished elements need to look like the game renders. Secondly, they need to look like the game renders while the wearer is moving. Third, the wearer needs to be able to move, preferrably the way the CG model moves or as close to that as possible. Lastly, the armor should not present any health hazards to the wearer for the duration of the 'cosplay' (used in its most literal definition).

 

I had some concerns that numbers one and two above might suffer for the other requirements (I still have some for the torso, but more on that later).

 

The CG game model armor elements have the luxury of being flexible along any axis. They can twist, stretch and contract as the body twists, stretches and contracts. The live armor parts cannot. This requires study of body motion for the part in question. For the arms, that means bending at the elbow and twisting at the wrist. It means paying attention to the limitations of the rigid part while wearing the armor. The key is knowing how far to limit the range of motion of the body. As the elbow bends, for example, it will reach a point beyond which if the rigid element is built to accommodate such a motion range, accuracy will fall below acceptable limits set by the costume crafter. On the other hand, preserving 100% accuracy may very well limit range of motion to a point where acceptable human functionality suffers.

 

It's finding the balance point between these two factors that's the trick.

 

For these vambraces, the plan is to have the main front & rear halves hold snug to the forearm at their lowest point just above where the wrist clip wraps around the wrist. To hold snug, I will have a soft neoprene band wrapped around the forearm and the plastic armor squeeze this band as snug as possible without cutting off circulation during normal wear. This is the key to the mounting system and can be spirit-gummed to the skin if necessary. The neoprene band will be a couple inches wide and 1/4" thick. Limiting the width of the band will allow for some twisting at the wrist, as the armor assembly will rotate around the forearm freely above the squeeze band. The assembly skew mentioned in the last post also allows for some forearm pronation while the elbow is bent. Without the skew twist the elbow guard would dig into the upper arm and prevent any bent-elbow pronation. Supination is no problem as you can see, since the elbow guard would rotate outward around the arm.

 

So given the necessary 1/4" squeeze band (and corresponding 1/4" spacing off the skin through the upper half of the assembly) and the approximate 1/4" thickness on the front/back vambrace halves, the sculpt for those parts should come off the armature about half inch. When I visualized that I was pretty sure that would make the scaling too thick, but after checking the ratio of the CG render to the dimensions marked on the armature, 1/2" off the arm looks just about perfect. I realize the elbow guard has to fit between the main vambrace halves and the skin, but I can cheat both parts thickness to 3/16" where they join and still be OK.

 

I also discovered that the circumference of the forearm just below the elbow increases as the elbow is bent, but I believe the above design allows enough room.

 

All this postulating may sound ridiculous, but it sure beats having to re-sculpt the pieces. I'm sure that "Durge" guy can attest to the benefits of such pre-build introspection. ;)

 

More pix to follow.

 

~ Vonnor

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I started on the right vambrace sculpt but rubbing a very thin layer of clay into the plaster so the heavier slabs would stick, then laying half-inch thick slabs around the whole arm between the previously marked wrist and elbow extents lines. This is just the first rough lay-on and appears a bit too thick at this stage. A lot of the bulk will come off as the final shape is refined. I will print out radial contour templates to help get the curves right (like I did on the shoulders). It also looks a little short, but according to scale it is OK. I believe the forearm plate and wrist clip will elongate the appearance of the overall assembly.

 

In order to get the shape and thickness of the wrist clip sculpt, the hard models of the front/rear main halves need to be completed first.

 

Keep it right here. 8)

 

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~ Vonnor

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Guest Anonymous

Wow, this has been a great read!

 

I'm so much less scientific when plotting out armor... I usually wrap paper / craft foam around my arm and trace out / trial and error my lines to make a template. The reminder on the geometry side of things was very useful!

 

I've started to dabble in making things out of rubber to better match how the Clone Wars CG models work. Taking a page from the people who make rubber molded bat suits, I'm playing around with trying to get a rubber that can either color match the white armor relatively well or at least hold paint well enough to do the job.

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It looked short because it was too thick. I put the sculpt on an after-Thanksgiving diet today. Shaved a lot of the bulk off using a flat-edge metal scraper then smoothed the surface and edges. I also added back the previous cut-outs, just so I could work on the overall contours. Remember this is just the two main vambrace halves for now. After these are in fiberglass I'll add the edging, then fit them back on the armature and sculpt the wrist clip and thermal-form the sintra forearm plate.

 

Also, the three straps on the underside of the arm will be 2mm Sintra, epoxied in place. I'll cut in the slots and file a lead-in taper for each slot on the hard model. The sintra will allow enough flexibility to get the armor on and off, and enough rigidity to hold the structure in place.

 

Gonna try to take molds and get these in fiberglass by tomorrow. May be the last decent poly-resin handling day I get until the springtime.

 

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~ Vonnor

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The project is moving forward once again after a brief time-out for family and some costume trooping last week. To make the skewed split cuts in the sculpt, and to insure they were straight and parallel, I laid a tailor's tape measure on the clay and scored down both edges. I scaled the overall length and cut in the curves on the underside at the wrist. I sprayed clear-coat on it and will take a plaster mold tomorrow. Notice the guide lines along the sides. Those are for the water-clay walls. I intend to cast the fiberglass/rondo hard model in one piece rather than two. It will be much easier to do the final shaping and smoothing before cutting the halves apart.

 

Like the shoulder bells, the edge trim will go on the hard model.

 

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~ Vonnor

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Here goes plus one mold, minus one scul... er... wait a sec... ;)

 

I cut cardboard end walls and hot-glued them onto the ARMature, then pressed on side mold walls using water-based clay. The clay walls were a bit flimsy so I reinforced them with "L" folded cardboard strips. You'd be surprised how strong of a structure you can put together with folded cardboard and hot glue.

 

After spraying the exposed surfaces with mold release I mixed up some Hydrocal very fat (heavy on the powder, light on the water) and blobbed it onto the sculpt. I had to do two layers of plaster for both sides since my mixing container wasn't very big. After pouring the first side I pulled off the clay walls and cleaned up the edges of the mold. I ground some divots into the edges for registry keys then painted vasolene along the exposed plaster before spraying more mold release and pouring (well more like sloshing and gooping) the second half.

 

After it set up a few minutes it came apart with just a little hand pressure.

 

I've never had a mold separate so cleanly! I was very happy. The original sculpt is almost salvageable even, just in case my one-piece mold cast idea fails. :mrgreen:

 

More to come.

 

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~ Vonnor

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Since the weather has turned cold and having no semi-indoor location to lay up fiberglass, I decided to work on the soft costume parts. I'll still do some sculpting and mold making but I do want to get the leather ordered and build the shirt and pants too before Springtime.

 

Here are the patterns and cutouts for the loin guard and hip pad. The floor shot shows the color very accurately (held the pieces up to the monitor). The leather is calfskin suede from Tandy Leather. The Kama is a first cut and will likely be re-done. I think it needs to be a bit fuller and more pointier at the bottom. The camera really washed it out too. It's a bit darker than it looks.

 

As a side note, that one photo clearly illustrates why I am on a diet to loose 30 before taking the torso cast. :shock:

 

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~ Vonnor

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Thanks Drac. 8)

 

Being blessed with a warm and calm winter day today, I laid up the fiberglass in the right vambrace mold. It was only 60°F so the resin and bondo needed a ton of hardener, for example I used 16 drops of MEKP for one ounce of resin where I'd normally use 8-10 during the summer. Even with the hot mix I still had 15-20 min working time per cup.

 

This is a [gel-coat / 3-layer-glass / gel-coat] laminate with a 50/50 bondo/resin gelcoat.

 

Having attempted a layup in a 360 wrap-around mold, I have to say I won't do it for the other arm. It was way too difficult to maneuver the brush and the fiberglass-cloth strips in the small opening. Upon breakout I noticed a lot of flaws. The gelcoat pulled away from the mold in a few places, and some of the edges had bad air bubbles. It will take a bit of effort to repair but I think it's workable.

 

Again I will add the edging to the hard model.

 

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~ Vonnor

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