Yang Xiao Long Post-Timeskip Prosthetic Arm Prop Worklog / Tutorial

This is my first time making a prosthetic type of prop in cosplay so the entire process is a little bit of a trial and error for me. There are a lot of things I could have changed to make it better but I am still very pleased with how it turned out.

This will be the start of my Yang Xiao Long Post-Timeskip cosplay worklog series. I'll be posting the entire costume worklog soon.

(Part 2 | Complete Worklog)

I also did Yang's first version cosplay. You can check out my complete worklog here.

Materials:

• Pattern paper (or any paper you can use to draw patterns)
• Form-fitting gloves (or you can make one yourself with a black stretch fabric)
• Cling wrap
• Masking/Duct tape
• 2mm Rubber Sheet/Craft foam (we mostly call it rubber sheets here so I'm going with that term)
• Super Glue
• Crack filler/Sealant
• Primer (I used wood glue mixed with water in 1:1/8 glue-water ratio)
• Spray Paint (or whatever you prefer)
• Metallic Gray (I know I used black here which was a mistake. I didn't double check my references when I went buying for materials)
• Yellow
• Velcro
• 0.5 cm elastic garter

The Arm

Using the reference, I tried sketching out the arm prosthetic first. By drawing it, I'd be able to understand the shapes that makes up the entire thing and makes it easier for me to design the patterns.

Starting first with the arm area, I came up with four main patterns:

• Pattern A - upper arm (I didn't revise the sketch here but the upper part of this pattern should be pointed)
• Pattern B - elbow
• Pattern C - Lower arm outer plate (the yellow part)
• Pattern D - Lower arm inner plate (the metallic gray part)

Starting with the lower arm piece, I used the cling wrap - tape method to get the base shape of my arm. To those who are not familiar with this technique, you first wrap a body part you wanted to pattern from with cling wrap and then cover it with duct tape. This will serve as a base where you can draw patterns that conforms to your size. (for a better picture)

I used masking tape here and although it still works, duct tape would probably be a better material for cover as the former loses its stickiness when you move around a lot.

Once I covered my entire arm, I divided the piece into two sides: left and right by drawing a line on the half of the top and another on the half of the bottom side.

I hope I made a clear picture

Then I carefully cut on one of the lines to dislodge the pattern off my arm and sealed the opening again with more masking tape and redraw the line.

Now I have a base to sketch my pattern.

img5: half of the outer plate pattern

Since the pattern pieces on the arm is symmetrical, I only need to draw one half of the pattern and just mirror the other side when I transfer it on paper. On one side, I'll be drawing the outer plate pattern and the inner plate pattern for the other side.

I didn't cut the base pattern in half yet before I'm done with the pattern sketch because I wanted to use each side as a reference to each other.

The dip in pattern D should be deeper than Pattern C. Pattern D covers the entire arm while pattern C is just a tad bit wider than half of pattern D's width.

img7: half of the inner plate pattern
The third piece(largest cut) should be the fold center once you transfer it on paper

Pattern D is divided into five parts to accommodate the curve of the arm. But it depends on how many parts you want. The more parts, the more it will conform to your arm shape.

I also drew marks on the cutting line as a guide when I glue them together so the parts will connect in the right places.

Once I'm satisfied with my patterns, I traced the drafts on pattern paper, and labeled them properly to avoid confusion. I also cleaned the curved edges with a french curve.

Then I transferred the final pattern to the 2mm rubber sheets and again making sure the pieces are marked properly including the guide lines on the edge for gluing.

I lost my progress a bit in this part because I forgot and accidentally closed the opening for the inner plate and my hand couldn't get through. I tried to cut a notch on the narrower opening but it just wouldn't work without making the notch really big and obvious so I had to redo the entire thing.

my hand still couldn't get through with a notch as wide as this

The lower arm pieces are primed and painted separately first and then added in the velcros before gluing the outer plate to the inner plate.

The Hand

First of all, my mistake here is that I should have done the gloves first so that I can pattern the hand pieces over it. The pieces fit perfectly on my naked fingers but over the gloves it was too tight and cutting off circulation. With so many pieces, it was exhausting to start all over again so I carefully used flame heat (because I'm too poor for a heat gun lol) to stretch the pieces a little bit wider. It was still a really tight fit but at least my fingers can breath properly now.

With that out of the way, I made the patterns for my hand the same way: with cling wrap and masking tape. For this I used my left hand instead of the right because it was easier, I just have to flip the pattern drafts later.

I didn't cover my entire hand, I used the reference as guide to only cover the parts that are needed.

Then I sketched the pattern with a marker. I marked the seams and lines where to cut and made sure the parts are properly labeled in order.

While drawing the patterns, I also keep on flexing my fingers every once in a while to make sure I didn't cover the joints area so that I can still have my finger movements when I put the finished product on.

After that is done, I carefully cut the pieces off my hand and transferred the patterns on paper.

don't forget to flip the final pattern if you used your left hand as base

For the fingertip-dome part(I don't know how to call it), it took me quite a while to figure out how I'm going to shape the dome. In the end I decided to just cut the base piece in half sideways and marked three notches (one on top and one for each side) on the curved edge of both sides (see img15 below).

After that is done, I traced the sample on paper. Then from the corner point of the notches, extend the line until the flat edge. These will be my cutting lines.

img15: I cleaned up the curved edges with a french curve

Each side consists of four pattern pieces so one fingertip would have eight in total.

Make sure each piece was labeled every pattern transfer

Then I cut the pattern out and transferred them to rubber sheets. It was a very tedious process but it's the best with what I got. lol.

I used superglue to connect the pieces together. I didn't exactly have to patience to wait with contact cement considering the amount of parts I had to deal with.

The dome piece was a little tough to put together but a little heat helped me make it pliant and easy to work on.

Testing... 

img19: All the dome pieces

For the palm area, the piece will cover both the palm and the back hand. There are two pieces glued together on the sides except the area below the thumb hole part(see img19). It needs to be open so that my hand can slide in and out easily. I used velcro the same way I did with the lower arm piece to keep it closed.

I cleaned the seams with sealant/filler and sandpaper to smooth the surface out.

test with gloves on

I forgot to take progress photos on this part but for the raised details on the back hand and lower arm, I just made a copy of the base pattern and drew the inner pattern on it so that i have a reference on size and placement. Then I transferred the final pattern to rubber sheet.

these details

Once the details are glued in place, I rounded out the straight edges a little bit with sandpaper for a smoother finish.

test fit

Elbow & upper arm piece

For the elbow and upper arm piece, I also used the cling wrap method. I slightly bent my arm so I can use the curve of my elbow as base and extended the coverage until the upper arm area.

I used the lower arm piece as reference to make sure the elbow piece fits nicely within its wedge and marked its position so that I have a guide to sketch my pattern.

Then I sketch the the elbow and the upper arm patterns simultaneously because they have to match in size and placement.

To form the dome-ish shape of the elbow piece, I divided the pattern into four parts so that I can lay the pieces flat for tracing and then marked the edges where the parts would meet.

Next I made two patterns for the upper arm part. One is for the main pattern, the second one the template guide for the inner yellow area.

Both ends will be glued together to form a cylinder.

Priming & painting

After the structure are done, I primed everything in three layers of wood glue and painted accordingly.

Then I added the final details after the paint is completely dried.

Assembly

Next I connected the pieces using 0.5cm black elastic garter and super glue. I didn't want to permanently put all the pieces together as one because I wanted it collapsible for easy storage/packing so I decided to put them into groups.

First, the finger pieces are connected with elastic on the inner palm part. Since I'm wearing black gloves underneath, the elastic will camouflage perfectly and can be barely seen.

I've also connected the elbow and the lower arm piece with two strips of elastic.

The upper arm will be a separate piece that can be connected to the elbow piece with velcro. That way it will also be easier to wear the parts a piece at a time rather that trying to cram in the entire thing at once. Also, the sleeves in my costume are a little bit tight so it's better for me if I wear the upper arm piece first before I put on my top.

And voila! it's done. I really regret using black paint instead of metallic silver so I'll probably do some repainting in the future. But all-in-all I really like how it turned out

Front and back view

compact for storage/packing
(the finger pieces, palm piece and gloves are neatly packed inside the arm piece)

It's been a while since I've written a cosplay tutorial so my format might be all over the place. Still, I hope I made everything clear and easy to understand. But for further questions, feel free to comment and I'll get back to you as soon as I can.

A post shared by Bianca Isabel (@fujo_trash) on Jun 5, 2018 at 1:42am PDT