Build thread: Jinx' rocket launcher "Fishbones" from League of Legends

[Volpin]

I'll admit, I've never played League of Legends. The design of this thing is so cool looking though, I had to make it. Luckily my desire for a new project coincided with a potential client email, and I'm getting to build one!



Fishbones is a shark shaped rocket launcher. It's pretty damn big, and since this piece will be used as both a costume and display prop, I have to try to keep things lightweight, durable, but also replica quality. Gotta love a challenge. The gun will also be able to open and close the shark jaws with a pull handle and have illuminated eyes and barrel.

I've got a ton of progress done on this already but I'll break it up over a few posts so there isn't some monster brick of text in the first page. This post will just cover the sharketlauncer's jaws. Here's where I'm currently at as of about a week ago:

After mocking up some 2D blueprints, I set about sculpting the head. This is urethane tooling foam sculpted over plastic spines to mark the profiles, followed with a bit of bondo.

Same process for the lower jaw

Details were added with apoxie sculpt and layered sintra. Keep in mind these are just mold masters, so I'm not really concerned about weight at the moment.

Here's the head, ready for molding:

Molds were 2-part silicone brush on with Smooth-On's Rebound 25. The castings were done in layered epoxy with glass fiber backing to keep things lightweight. Here's the print coat, done in EpoxaCoat Red for the gel layer:

Cavities were filled with Free Form Air before layering with glass cloth and EpoxaMite epoxy. This makes sure there aren't any air bubbles or weaker areas from where the glass fiber can't curve around sharp corners.

The resulting casts are very lightweight and strong.

Also, happily, the jaws fit into one another perfectly! I was a little nervous sculpting them separately but it all worked out in the end. Whew.

More to come soon, thanks for reading!

 

[Crank729]

shark shaped rocket launcher.

Well, I'm sold.

Looks great so far, Harrison. Really like how well those jaw pieces lock together. Also looking forward to seeing your paint work on this.

 

[Volpin]

Woof, I need to remember to update more often.

So here's how I went about putting the body of the gun together. I need this to be as light as possible, and that'll be tough with a 40" long rocket launcher. The barrel that runs down the center is a myriad of intersecting pipe dimensions. This could be approximated with PVC pipe but it would result in a very heavy component. I decided to vac form mine.

This started out with a giant chunk or urethane tooling foam, chucked up on my wood lathe.

Urethane foam tools like butter, and I had this shape knocked out in a few minutes. If only everything could go so quick! I did a couple more pieces for the rear most components of the barrel too.

These were all pulled in .060" styrene sheet on my vac former.

Obviously, this leaves a bit of a seam. I pulled a third copy and used it as an interior lip to glue the halves together, then blended the seam with some bondo.

The resulting part is light, if a bit fragile.

I made an interior "sleeve" out of thin walled PVC to sit inside this vac formed part. All of the parts of the gun will eventually be anchored to this central spine so the thinner styrene doesn't take the brunt of any force. To save more weight, I cored out a ton of holes. This saves over a half pound with no noticeable reduction in strength.

The front barrel is a piece of 6" thin wall PVC with a few sintra spacers at the rear to align the rear barrel. The tapered muzzle is a piece of urethane resin turned on the lathe and secured to this front barrel.

This is all back log stuff to get this thread up to speed. I've made a ton more progress and should be going to paint in the next couple of weeks! More updates to come soon.

 

[cadu1990]

I've been following every update on this marvelous thing via Flickr and Facebook. Can't wait to see it done!

 

[Volpin]

I've been following every update on this marvelous thing via Flickr and Facebook. Can't wait to see it done!

Thanks! It's kind of an obscure one, but a fun project.

Onto the armor plates! The bulk of these are made from layered PVC sheet (sintra) because it's very easy to shape into simple curves and it carves easily. I made a bunch of mockups on several of the parts before going all out.

The beveled edges were added in sections to a base of bent PVC. I used my vac former oven to heat the whole sheet, then curled it around various diameter pipes for each plate until I got the radius I wanted.

To get the whole perimeter beveled, I started off with my grinder and a really rough bit to remove a lot of material very quickly. It's very easy to zip off way too much since the sintra offers very little resistance, so this is actually more of a delicate operation than it might seem.

This is followed by a pass with my dremel, then various grits of sandpaper and blocks until its niiiice and smooth.

That's the general process for pretty much all 4 armor plates. In the end, they're nice and lightweight but still quite rigid!

 

[Killtime]

Nice work Volpin, I too have been following the build on your Facebook page. Awesome work as usual

 

[Dragonmaster525]

Where do you get this type of tooling foam? Can it be bought in stores?

I've been looking for something similar to this to make Fallout props for a while now.

 

[Beer_Money_Props]

Would you mind showing the type of bit you used for this part? I'm guessing it's a metal cylinder rasp...

It looks like with enough finesse (and a light sanding), you could easily give PVC pipe a wood grain effect. Might be a godsend for people who make staff's and wooden sheild's out of plastic.

Awesome job as always sir!

 

[Volpin]

Where do you get this type of tooling foam? Can it be bought in stores?

I have a friend who gives me smaller scraps from time to time, they use mostly very large sheets for concept cars so anything under 10" cube is more or less trash. They drop me a big ol' box and I make my parts out of that. Several suppliers do sell it though, from eBay to people like The Engineer Guy here in Atlanta. Not sure if I've ever seen it in retail though.

Would you mind showing the type of bit you used for this part? I'm guessing it's a metal cylinder rasp...

Sounds right. It looks like this:

So, more updates! I need to get caught up since this project is nearing completion soon...

I've designed the jaws so they can open and close with a small trigger next to the handle. The first step was to create some anchorpoints inside the jaw for hinge pins. These are T-nuts epoxied in place. The post makes sure they're mounted in line with one another.

I eventually added a second pin to act as the pivot arm, since articulating the assembly on these threaded rods meant they were constantly backing out of the T-nuts.

This was the original set-up for the jaws:

But this proved to be problematic, so the pivot arms were added as well as a few return springs. Now the jaws clap closed with authority but pulling the trigger isn't too difficult or uncomfortable.

Here's a shot from the backside looking forward, where you can see the trigger and articulating cable routed through an aluminum plate.

The result of these efforts can be seen here!

More posting catching up needs to happen, I've already started on paint. Hope to be done before the end of the month. WOOOOOOOO

 

[robotboy]

Amazing work as usual

 

[Killtime]

Magnificent! The jaw mechanism works a treat and is so tidy!

 

[Silvercast]

This is INCREDIBLE!!! Do you have any plans to make any other league weapons?