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Sculpting more Rahm Kota armor

Koda Vonnor

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Hi everybody. It's been a very long time since I've posted up here, but as I am starting in earnest tomorrow on the Force Unleashed II version of Rahm Kota, I'd like to once again borrow space at this excellent crafting community for the next few months. I hope to provide a bit more detailed observations and insights than on the last Rahm Kota project. Here are some references of Starkiller dressed up like the general:








Ninety-some odd more pix at my photobucket.


I have Daniel (JDOS Producciones) making the boots.


I will be making the arm and hands molds, and a shoulder armature tomorrow with my sister's help. I will be building the gauntlets first. Each piece of those will be a clay sculpt molded and cast in a fiberglass shell, then back-filled and clam-shell molded. My goal is to keep production quality molds as some of the pieces may need semi-rigid castings. That way I can try different materials if needed.


I have good ideas for every element except the belts. Hopefully I'll come up with something. 8)


I'll post some pix of the plaster body-mold process after tomorrow.


It's good to be back.


~ Vonnor

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I think I know just the thing for the bandolier construction;



That cracked me up, Maestro. :mrgreen:


Actually, I have a pretty good idea for the bandolier. You're not very far off.


After the breastplate and backplate are hard-modeled, I will do a vinyl contour template to get the curvature right (as I did on the TFU version). With the curve on paper I will fabricate 35 little sticks of polystyrene (or 6 of them, cast 6 times) and affix them along the curve, then take a rubber mold of that and cast it in rigid plastic. Then clean up the rigid master and take another rubber mold. Final casting to be poured in semi-rigid polyurethane and weathered with R&B. Then affix the flexible ribbed section to the leather bando strap.


I hope. :P


...and it is truly good to be in the zone once again. :D

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Yesterday with the help of my sister and niece, I built molds of my left arm and right hand. I will seal them up and pour plaster castings this weekend. I made a few observations, this being the 2nd time on such an endeavor.


First, I can give a true unsolicited endorsement for Gypsona plaster bandages. I used Pop-Art bandages on the last project and the difference was like night and day. The Gypsona was much easier to smooth down and it blended into a cream much easier with less lumps than the Pop-Art.


Second, we used very warm water (because my sister doesn't like cold hands, I found out after), and it really helped the mold set up more quickly. This helped me keep my arm still for the duration.


Used a toothbrush to clean up the caked-on plaster crud, as I did not want to remove the back half to clean my arm off then try to re-attach the mold before doing the front. Also of note was I shaved my arm and hand and used no mold release (cold-cream) on my skin. This really helped the mold bandages stick to my arm all around.


Note the "line" from the widest part of my elbow to the widest part of my wrist is a bit twisted. This is due to the natural pronation of the forearm when dangling at rest. You need to run the seams like this if you want to take an arm mold. I found this interesting but it was discovered by the mold-maker (my sister) and came out very nice.


The mean thickness of the arm mold is 3/16" to 1/4"". The seam overlap is about the same (kudos to my sister for her precision).


We used a blow drier to keep the heat on the mold for about 30 min before doing the front half, then the same before attempting to crack open the mold. The light layer of Vaseline brushed on the edges was well enough to allow for clean separation.


We attempted a shoulder mandrel as well, but a miscalculation on my part rendered it unusable. We will do another one when we build the torso mold.


I was originally going to take a separate arm mold and two hand molds, but decided it might be easier to get all 5 gauntlet parts to mesh with the hand-guard if I could sculpt them all on one cast (sequentially, not simultaneously).


Some sample pix (31 total in my bucket):

















~ Vonnor

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Weekend update.


I dry-brushed the hand mold to get any loose plaster off it, then painted the insides with a mixture of half water and half Murphy's Oil Soap (see pix). They say Tincture of Green Soap (tattoo wash) is best but Murphy's was all I had on hand. This is to waterproof the mold so the casting doesn't stick. The first coat took a lot of the mixture as most of it sunk in to the plaster. The second and third coats were much easier and just glided right on.




After taking a blow dryer to that, I checked one final time for loose bits of plaster in the mold, then reconnected the two halves and sealed the seams with hot glue. I used little round corrugated cardboard plugs that I sprayed with Krylon Crystal Clear acrylic to plug the finger and thumb holes and hot glued them in place.


To figure out how much plaster I needed, I filled a measuring bucket with water and set it inside a cake pan. Then I stuck my hand in the bucket up to my wrist and measured how much water my hand displaced (about 20oz). I mixed up the HydroCal per instructions and poured it into the mold. No leaks! :) I tapped it lightly against the table to help settle the plaster and pull up any bubbles, then waited about 30 min to extricate the casting from the mold.









Notice the Gypsona bandages captured enough detail to make out fingerprints. 8) After filing down the sharp edges and smoothing out the seams a bit, I set it under two 75watt light bulbs for about 4 hours. This helps it harden during the "cold & clammy" phase. It's important to note that if you want to do any edge filing or seam smoothing on HydroCal or UltraCal, you need to do it before the "cold & clammy" phase. I did my tooling between about 30min and 60min after the pour.





I did not do the arm as I wanted to see how the Murphy's would perform as a mold release. I will do the arm tomorrow, time permitting.


~ Vonnor

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As a way of a bump, I had been keeping my eye open for the right color leather to use for the loin-guard and hip pad. I just ordered this off ebay.


Looks like a very good match to me. I will use it for the facing surfaces with cotton backing and some thin polyester quilt batting in between. I can highlight the top-seams with dye.


http://pictures.kyozou.com/pictures.asp ... et=6352666


The CVI announcement was a wake-up call for this project. Updates will come a bit more regularly now.


~ Vonnor

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Did the first cut at the right handguard sculpt today. Just getting the basic shape down. Most of the bulk thickness will get shaved off as I put in the surface contours. Still have to do the thumb-side cutouts and the edge bead, which will come last.








I hope to have this in fiberglass by next weekend. Eventually I will back-fill that, leaving a slight depression on the underside for the thickness of the Velcro, and make a clamshell mold with silicone and plaster-backed. Depending on how good the first hard-model comes out, I may make another with a rigid resin pour to do the final shaping and smoothing. Ultimately the production piece (and it's left counterpart) will be poured in a semi-rigid resin, something near Shore 65-80A hardness. A bit softer than a rollerblade wheel. That way it will flex when my thumb moves.


Stay tuned.


~ Vonnor

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Weekend update:


I didn't get to the fiberglass stage (woulda been too hot to mix the resin anyway), but I did put the sculpt on a bit of a diet. Thinned the edges and did a little bit of smoothing. I also cut out the thumb-side notches and sprayed the whole mess with clear-cote. Normally you'd want to do a lot more smoothing of the clay before taking the first mold, but I'm finding that my eyes are not as sharp nor my hand as steady as they were a few years ago. It will be easier for me (but take longer) to sand and smooth the plastic hard model before I make the production mold.


Samples (more in my PhotoBucket):







Next is to pop this in the fridge for a while to harden up the clay, then put the mold wall barrier on it and some cardboard walls around it to make a 2-piece junk mold (one piece on the pinky side and one on the thumb side).


I will put the edge beading on the hard model.


Stay tuned.


~ Vonnor

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I was sculpting some parts for my niece's Princess Zelda costume this past month. Finally got back to Kota.


I put up cardboard walls all around the sculpt, with some "ceiling" panels on the ends to form little pockets around the undercuts at the thumb and pinky sides of the hand. I sprayed clear-coat acrylic on the whole mess, then pushed in a water-clay barricade down the middle and kept it very wet while smoothing the edges with a shaping tool.


The mold had to be in two pieces as the undercuts would prevent removal of a one-piece mold.


I poured in Hydrocal in the little pocket and rolled it a bit to prevent bubbles in the undercut, then sort of dribbled the plaster in little by little. As the mix in the cup started to thicken I scooped it out by hand and mounded it up in the middle. I let that set up for about 30 min then carefully pulled off the clay center-wall. You can see the residue from that in the pix.


I cleaned up the plaster join surface and the keys (dimples and ridge) with a metal tool and brushed a coat of Vaseline on the plaster so the fresh pour wouldn't stick, then basically repeated the mix/pour for the other side. I'll use some acetone to clean up the Vaseline and glue the two halves together for the fiberglass lay-in.









More to come...


~ Vonnor

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Thanks Maestro. 8)


Some focused thoughts:


The build path in my mind is follows:

- R-handguard hard model

- L-handguard sculpt/mold/hardModel (using contour gauge / measures from R model

- Wrist-clip sculpt/mold/hardModel (only one needed as this is symmetrical)

- L forearm...

...was going to build the arms symmetrical, but upon closer inspection will need separate builds for L/R. The natural rotation of the arm at rest is quite apparent in the 3D images and without a bit of a skew in each armor set it would severely restrict normal arm rotation. The gauntlets must hold snug at the wrists (oval x-section) and taper to a circular section near the elbow because of the relationship between hand guard, wrist-clip, and gauntlet. This would cause the elbow guard to bite into my upper arm when the palm is rotated inward without that slight twist in the design. It is more work but will also be more accurate. I am looking at clay sculpts for just the two main gauntlet halves. The elbow-point guard and back-of-forearm plate will likely be heat-formed Sintra for the hard-model. I have a grid frame already set up to sand in the waffle pattern on those before I bend them to shape. :mrgreen: The production pieces will be semi-rigid urethane resin pour from a rubber clamshell mold.

- Shoulder sculpt/mold/hardModel...

...will do one symmetrical bell w/o the rear corner cutout. At the hard model I will add the edging and take two additional interim casts, each will have the respective R/L corners cut off and the edging built back up w/Bondo. Then will take two prod clamshell molds.

- Leatherwork/belts...

...will likely do the soft parts at this stage. I need to see where the main belt will ride in order to scale the belly plates which in turn determine the scaling for the breastplate/backplate... Mel Matson will build the main belt and top half of the bandoleer. I will make the loin and hip pads from pull-up leather layered with thin batting and stretch twill backing.

One challenge for the torso bust will be seeing that the belly-plates wrap around it smoothly. I can squish the flesh-rolls a bit with the Sintra wrap (which will snap-closure at the spine) on my body, but the non-squishy rolls reproduced by the Hydrocal will not be as yielding. I may have to build the belly-plate and wrap up in it before making the torso bust. Then the belly-plate will be already in the bust and I can sculpt the chest/back right on that... still figuring it out.


I'll add more thoughts later ... am out of time for now.




- Belly plate(s)...

...measure circumference of my waist at top of leather belt and again at a point high enough on ribs to insure belly coverage upon shoulder shrug/arm raise. Build tin mandrel (like for the Kota1 gaunts) and heat-form sintra around the mandrel. May be a complex curve cut on the sintra depending on torso taper from waist to ribs, will use poster board for template. Belly plate(s) ends will join at spine and be held with a snap panel. Needs to hold considerable shear force when worn so will epoxy snaps to another sintra strip. Entire piece to be padded with soft 6mm neoprene backing.

- Belly control box, bandoleer buckles to be machined PVC.

- Breastplate/Backplate...

...clay sculpt. Torso bust to have belly-plates already cast into it. Leave space for 12mm foam padding at bottom edge and shoulder tops. Allow for slight foam compression at shoulders when scaling height. Armor assembly to float above belly-plate(s) to allow some bending/twisting. Sculpt as one piece joined flush at shoulder tops. Two-piece Hydrocal junk mold for fiberglass lay-in. Hard model to be cut in two at shoulders. Prod pieces to be poured semi-rigid urethane with snap-panel joins at top of shoulders (may need to do fiberglass prod pieces for thinness and weight). Side panels will be either cut corrugated rubber floor matting, or silicone rubber casting of same. Make texture-matching "V"-cut slot clips on sides of breastplate/backplate that soft panels will slide into to close.

- Bandoleer...

...Top half will be black leather and run between the two square-ish buckles and over the shoulder. Metal cylinders to be machined (ElvisTrooper?) and held w/ leather strap. Will make shoulder strap-pad from neoprene. Saber holster frame - not sure yet. May be bent sheet-metal with some machined parts, or sheet plastic with some sculpted/cast parts. Holster lining - sculpt contours on a tube and lay-up thin FG over hard-casting of contour. Finish like weathered leather and lace up with string or floss then paint string with resin. Lower sections - template the curves then glue small cut strips (the Maestro's Q-tips above) side-by-side along templates. Take molds, cast hard-models, shape/smooth models, make rubber molds, pour prod pieces in semi-flexible urethane. Glue to square-ish buckles. Leather connector strap at waist.

- Leg Strap...

...Because the leg strap positioning is not at the narrowest point of the thigh it is not likely to stay in position on its own through normal movement, and because there is some fabric looseness shown above the strap it cannot be attached directly to the pants fabric. Attach magnetic strip (fridge-magnet stuff) to back of leather leg strap. Doctor up a pair of "bike" style UA shorts with a slot holding matching magnetic strip. Wear bike shorts under costume. Magnet sticks to magnet through pants fabric.


~ Vonnor

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Small update:


I went over the reference pix looking at the shoulder bells today. Although they are definitely not symmetrical I chose to make them such. This will save a bit on sculpting (one sculpt instead of two). In scaling them I went a half inch bigger than the references suggest, and will "buldge" the side curvature out a fraction more than the references show.


Here is the template sketch, scaled to my own height.




Clay to be laid up this weekend.


~ Vonnor

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I laid some clay onto a plaster cast of my shoulder, just to rough-in the contours. I printed out templates from Turbo-Cad to check the curves. No edge bead yet.


The original scaling was based on the length of the 3D model's arm compared to my own. Note the bottom corners come very close to the curve of my chest and back. and the bottom side is even farther off the arm than the 3D model. I will likely have to rescale the sizing a bit to allow clearance off the breastplate and backplate, while preserving the "floating" distance off the arm. This will not be too difficult as most of the clay is already on the armature.


These are things you sometimes have to adjust for during a build. :oops:








I will rescale the blueprints and contour templates and add more clay tomorrow. Still need to do 4-5 cross-section templates as well.


Project's finally got some "Mo." 8)


~ Vonnor

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Took a couple pix of the shoulder sculpt with the final edge cuts to check the symmetry, and a size comparison to the TFU Kota bell. Just have to do some final smoothing with rubbing alcohol and will be ready to take a mold.


I'm going to put the edge bead on the hard model.






~ Vonnor

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Whenever someone asks me about finding proportions or creating symmetry while they're designing armor sculpts, I always send them to your threads. You have developed those skills into a true art. And, I grin every time I see the word "ratio" in your posts... after all the years of my students asking me if they'll ever use math skills in real life, I can reply, "Well, yeah, if you make Rham Kota armor." (If they know who Kota is, they get an automatic A in my class!)


Thank you again for continuing to share your work! As usual, it's one of my favorite threads.


Pam :-)

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Thanks Pam! :D


I was always meh about Math in school too, and didn't think I'd use any of that IRL.


Now I find myself doing the "(size-of-blah-on-me X size-of-unknown-on-reference) ÷ size-of-blah-on-reference = size-of-unknown-on-me" in my sleep.


Doesn't always work verbatim though, since I had to adjust this piece a half inch for my own body, but it's still the best starting point in town. 8)


~ Bill

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I smoothed out the surface a bit using isopropyl alcohol and added mold walls around the edges, flaring them outward a little to make accessing the undercuts easier when I do the fiberglassing. Hot-glued a cardboard wall around the whole thing and sprayed it with Krylon Crystal Clear acrylic. I supported it with one end higher to help keep bubbles from forming in the undercuts as I poured the plaster in (I did get a bubble but not too bad).


Mixed up some Hydrocal White a little thicker than normal and poured it into the walled-off area.


It came out pretty clean and smooth. I'm going to wait on the fiberglassing until the weather cools down some.


That's enough for today. Tomorrow I start on the arms.







~ Vonnor

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Since today was supposed to be cooler and no wind or rain (10%) I decided to lay up the fiberglass hard models for the R handguard and the shoulder bell. Right now it's 10am EDT and I should be doing the bell, but even 10% hits the dice roll once in a while. It's raining steadily and while I wait for the unforecasted rain clouds to go somewhere else, I took a couple pix of the handguard layup.


This is a homemade gel-coat of 50% bondo and 50% resin dabbed in the mold (after mold-release applied to the mold) with a brush and kinda rolled the mold around so it didn't pool in any particular spot. The gel-coat kinda rounds off the hard angles a bit and helps the cloth fit into corners. After the gel got tacky (about 10 min) I brushed in some mixed resin/hardener (I used about 6 drops in one ounce) and pushed in a scrap of fiberglass cloth. Continued laying in the cloth pieces overlapping the previous piece a bit and overlapping the edges as seen. Did only three layers total as this is just a hard model and will not be used in production.


Lesson learned: I first tried to push in a big piece of cloth but it was too hard to press it into the corners without pulling it away from an opposite corner. Luckily the resin mix was "cold" (slow-set / less drops of hardener) on the first layer so I had time to rip out the big mess and cut smaller cloth pieces before the resin got goopy.


After three layers of resin/cloth I mixed a little more homemade gel-coat and brushed that into the edges and back, to kinda reinforce the model. Notice the big glob in one spot? That's 'cause I mixed that coat "hot" and it started to harden before I was finished brushing it in.


Hopefully the rain will let up and I can do the shoulder in a few minutes.





~ Vonnor

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I had a window from 10am to 12noon in which to do the shoulder bell, as once again the skies opened and clear odorless liquid fell.


This is the same method as the handguard above:


- Gel-coat (50/50 Bondo/resin - "Rondo" in some circles)

- 3 layers of fiberglass cloth

- Gel-coat


Was a little bit harder to get the initial gel-coat to stay up in the undercuts, but I can always do some edge filling after I crack it out later tonight.





~ Vonnor

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