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Sculpting more Rahm Kota armor


Koda Vonnor

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Yesterday I did the first pass at the weathering. 800 grit wet sanding of the darker top-coat. This is just to get the overall variegated patina seen in the CG references. This will be followed with some low-lighting and a wash of darker "dirt" that's a bit more color rich, then final screen-accurate scratching.

These photos show a test fitting. Note the main assembly still needs sand-off. I wanted to check spacing and clearances with the gloves on. I will need to open up both the elbow end and wrist clip about 1/8" diameter, but they both have enough allowance for that. It's a ton of hand-sanding though.

I had to add a non-accurate 6-32 hex-screw (just barely visible in one pic below) to clamp the wrist-clip to the main assembly.

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More to come.

~ Vonnor

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Lots of things at the same time! :D

First, I have started on the tunic. I am using stretch twill cotton that surprisingly takes a press very well and resists wrinkling. The sleeves will be cut off below the elbow and sewn to a brown spandex forearm that will hide under the gauntlets. The collar has yet to be engineered.

Second, I have decided to commission a much more accurate Rahm Kota lightsaber hilt. Don Close of Do-Clo Custom Sabers will hopefully be cutting the metals, and I will be doing the wrap. One major improvement will be the accuracy of the Tsuka-Ito. After thinking about the topology for three years I have finally figured out how to get a diamond pattern on just one side of the hilt rather than on both sides. I did a proof of concept with some scrap leather and it looks very nice. The 2D orthographic drawings below are sans-dimensions in deference to Mr. Close.

Third, I am still doing the first-cut weathering on the completed armor parts. It is going more slowly than I thought it would due to the darker iron metallic coat being too thick. I had said "live and learn" when I did that on the last project... Oh well, at least I'm still alive. ;)

Some pix:

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Hope to get the tunic finished next weekend. Stay tuned.

~ Vonnor

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This past weekend was spent sand-weathering the rest of the armor parts, casting the right gauntlet cross-straps in fiberglass, and putting a collar on the tunic.

Here is a small teaser (sorry for the blurry focus), Marek family crest by Jedi Leda:

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This costume might actually happen. :D

~ Vonnor

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Eighteen months those three fiberglass cross-straps for the right gauntlet sat on my shelf. Today I told some Starkiller costumers I would have this finished by CVIII, so sandpaper finally hit the bondo. It took a bit of grinding and shaping but here they are sitting nice and flush along the main body assembly. These will be bonded to the radius and ulna plates using polyester resin at the slots, and superglue at the edge trim as soon as the weather cooperates.

Like a book, the costume project waits patiently until you pick it up again, no matter how long you've been away.

Tick tock.

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~ vonnor

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No pictures this time but Saturday I attached the cross-straps using 50/50 Bondo/Polyester resin, then took off the temporary spacers, cut off the elbow end to the correct length, and dremeled down the ends of the straps that were run through the slots on the insides. Smoothed out the inside surfaces with sandpaper and tacked the upper two straps to the axial edge trim with superglue. The strap near the wrist I left un-tacked. I glued it tight to the edge trim on the left vambrace and opening the unit to get my hand in has caused hairline cracks (not visible past 1 metre). I hope to avoid this on the right vambrace by allowing the flex along most of the strap length.

Next up is to add the radial edge trim at the wrist and elbow, and fill the tiny gaps at the strap slots.

~ vonnor

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Today I got back to this, and carefully sanded around the epoxy fills I did a few weeks ago. Here is the first primer coat, there are only a few little scratches that I will fill in with styrene model putty and do one more primer coat. This one is cleaner, sharper and more screen accurate than the left vambrace, mostly due to lessons learned on the previous piece. Next up is the right forearm plate.

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~ vonnor

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This will be the right forearm guard junk model. The paper template will be aligned over these grooves, and the rigid model cut out. A silicone rubber mold will be made on the flat, and a urethane rubber flexible model will be cast. The flexible model will be laid over a plastic sheet wrapped around the main assembly, then a plaster backed silicone mold taken of the flexible model while it's in place. When the rigid production piece is cast in fiberglass it will hold the same contour as the flexible model while it was wrapped around the main assembly.

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~ vonnor

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I cast the flexible model for the right forearm plate using Smooth-On ReoFlexĀ® 40 urethane rubber then krazy-glued it to a .020 thick plastic sheet that I had taped tightly around the main assembly. Tomorrow evening I will make a silicone rubber mold of the thing. Hopefully I can get it in fiberglass on Sunday morning. This soft model was cut about 1/8" too big around the edges so I can dremel/sand it down to spec. The 1mm sintra edge trim will go on the fiberglass production casting.

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~ vonnor

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I brushed on a few layers of Smooth-On Rebound-40 silicone rubber and after it set up I under-cut the edges all around. This helps the rubber mold liner stay tight inside the plaster mold shell. I sprayed clear cote acrylic on some scrap cardboard then hot-glued an ugly but good enough bowl around the green rubber. Poured in some hobby plaster and now waiting for it to solidify enough to break it out. Note I carved a sorta flat bottom on the mold so it will sit better while I do the fiberglassing. I will bake the mold in the oven for a few hours at 180F to get rid of any moisture, then wax the mold liner a bit to help the fiberglass dry after I cast the production forearm plate in the morning.

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~ vonnor

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Flexible model of the right forearm plate on the left, cleaned up mold in the middle, production main vambrace assembly on the right:
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Finished fiberglass and rondo layup, still in the mold. 50/50 bondo/polyester resin gel-cote, 6 layer glass cloth, 60/40 bondo/resin finish coat:
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Production right forearm plate - freshly broken out of the mold:
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I had to do all this between 7 and 8am today. Even at that, it was freaking HOT out by the time I finished. :shock:

Next step is careful sanding then edge trim. The edges to be sanded down to meet the trim extents.

~ vonnor

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I cast a 2mm thick flexible elbow guard in the same mold I used for the left one, then took one of those plastic sheets you put over a bowl in the microwave to keep your soup from sputtering all over and tack-glued it inside the main assembly. I superglued the flexible model in place on the plastic sheet, then capped off the ends with clear-coat sealed cardboard and hot glue. Poured in some plaster to make a mandrel/mold. The plaster is baking in the toaster oven at the moment, but will be sealed and waxed this evening, and a 4-layer fiberglass production elbow guard will be cast in the morning tomorrow.

Ā 

Note the trimmed and shaped forearm plate in the background.

Stay tuned.

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~ vonnor

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I cut out 4 pieces of fiberglass cloth in the shape of the mold, and this morning laid them on with a couple rondo coats to top it all off. Had some difficulty with the Bondo mix and it started to gunk up real bad. But when in doubt, throw another layer on there. You can always sand it off.

She's kinda ugly on the surface, but underneath she's a beauty. :D

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~ vonnor

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See? A beauty. :)

Just a few battle-damage pock marks, but those will fill in with plastic model putty. Next up is the elbow guard edge trim and the magnetic closure system. I'll probably do that at the 501st armor party next Saturday.

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~ vonnor

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Three puzzle pieces. Just add magnets.

The squares will be milled out and 1/2" x 3/8" round neo-D magnets glued in the holes. 1/2" x 1/8" mates to these will be glued on the galvanized strip that's attached to the elbow guard. The other sintra pieces are guides that mesh with the edge trim on the main assembly and keep everything locked tight. This is the same closure system that was used for the left vambrace.

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I hope to have this ready to prime and test at the 501st armor party on Saturday.

~ vonnor

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Left one on the right, right one on the left. Symmetry is pretty good. The magnetic closure is in place but the glue has to set up before I can take it apart. I put epoxy filler on all the edges as well.

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~ vonnor

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Here is a rough cut of the right wrist clip sculpt. I still have to adjust the alignment a bit and smooth out the surfaces and edges. Just wanted to get the basic shape and volume on there. Shooting for fiberglass rigid model this weekend.

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~ vonnor

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This sculpt gave me a lot of trouble finding the correct thickness, edge cuts and symmetry. Every couple days for the past two weeks I worked on it but was never happy with the results. Finally in a moment of sanity today (or more accurately, functional insanity), I called it done. Any further adjustments I'll have to make on the rigid model.

Here it is ready for the mold. I will make that tomorrow.

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~ vonnor

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What this photo tells you: I made a mold of the right vambrace wrist clip using Smooth-On Rebound-40 and a plaster shell. While the vambrace assembly was wedged onto the armature, the elbow guard came apart. Originally I had used Loctite PL 8X construction adhesive to glue a galvanized steel strip to the fiberglass plate but for some reason the bond didn't hold. The glue did not stick to the galvanized steel. Likely there was some oil or other contaminant on the metal. I understand JB Weld is pretty good for metal to fiberglass so I used some for the repair (after cleaning the steel with acetone). Hopefully it holds.

What this photo doesn't tell you: The plaster mold shell broke in two places and had to be repaired with Elmers glue. I should have used Hydrocal but used White Art Plaster 'cause it was easier to get to in my storage closet (I have 5-Gal buckets of each). Also, the sides should have been thicker, and I should have softly pried up all round the edges instead of torquing the **** out of it on the breakout. Built-up clay mold walls would have helped as well. Live and learn.

I will lay fiberglass in the green rubber mold this weekend. Should be perfect weather for it.

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~ vonnor

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I stuffed the mold with rondo (60/40 Bondo/resin) and 6 layers of flberglass cloth/resin, topped off with another rondo gel coat. It was extremely difficult and frustrating stuffing the thin strips into the mold on the sides and the back-of-hand area with the semi-circular cutout. I should have built up mold walls in those areas so the return edge would be thinner. You can see I will need to thin out the edges quite a bit.

Here is the rough break-out with a little bit of sanding and edge trimming.Comparing the two hard-masters side by side shows some variance from mirror images of each other, but all in all it's not too bad. The right wrist-clip has a bit more twist to it, but as the sculpt aligned properly with the main assembly so should the rigid model.

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~ vonnor

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Side by side with the left vambrace shows pretty good symmetry. I should have tapered the sculpt more at the wrist, but there's not enough thickness to sand it down at this point. I'll try filling the insides a bit thicker on the palm/cutout side and tapering it on the production casting. It really needs to fade in about 3/16" (5mm) on the side with the rectangular cutout.

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I hope to put in the epoxy putty back-fill and alignment tracks tomorrow.

~ vonnor

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I decided it would be better to correct the taper on the wrist-clip hard master rather than on the production casting, so today I added a few more layers of fiberglass cloth and Bondo just to the palm side on the inside of the unit, then power-sanded the new exterior surface taper. Notice it is much thinner at the wrist and mostly follows the contour line of the main assembly all the way to the wrist opening. This is much more accurate to the references and mirrors the left vambrace dimensions. I also filled in some gaps, bubbles and Dremel slippages with PC-11 epoxy putty.

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~ vonnor

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This shows how I built the guide tracks for the vambrace mounting. The wrist clip has to squeeze the padded glove strap snug enough to keep the whole assembly from slipping down and encroaching on the hand guard while worn. It also has to withstand the normal torque from rotation/pronation of my wrist, and facilitate the rotation of the rest of the vambrace. In the CG model that is being replicated, there is only a small point of contact between the wrist clip and the main vambrace assembly. That small point will be subjected to a lot of torque in normal wear. These tracks will transfer to the production casting and lock everything in place. There will also be a 6-32 hex screw and an aluminum backing plate at the join point that will clamp the pieces tightly together. This will be one of only two screen inaccuracies on the costume that are necessary in order for it to be worn by a real person. :)

I tested this solution at CVII for a few hours with the left vambrace and it worked like a charm.

I first sprayed mold release on the contact area of the main assembly. I mixed up some epoxy putty and pressed it onto the inside of the wrist clip along the lines where it will mate with the edge trim of the main assembly, then just pressed it into place and clamped it for a few minutes. The mold release kept it from sticking to the main assembly and left nice neat tracks in the wrist clip.

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~ vonnor

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Sorry there's no photos of the mold making progress, but here is the production casting I poured last evening. One thing I did differently from the left wrist clip casting is I powdered the mold lightly with talc. This totally eliminated the surface bubble problem I had before. There was a little bit of bubbling up to the top, but it shouldn't affect the finish or the structural closure.

This casting used Smooth-On TaskĀ® 9 super-hard urethane resin with a splash of white coloring. The fit is tight and the alignment is decent. I'll clean up the flashing and surfaces and paint it later today.

The most technically difficult and tedious elements of this costume (the vambraces) are almost completed.

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~ vonnor

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