Lynch's Dune Fremen Crysknife and Sheath




About: I'm Mark and I run Ginton Forge! Ginton* Forge recreates the iconic pieces seen on film, video games or anime and placing said item in your hands. Because owning an item from the very thing you’re into i...

Idaho hesitated, then: "And, Sire, there's one other thing. One of the mercenaries we knocked over was trying to get this blade from our dead Fremen friend. The mercenary says there's a Harkonnen reward of a million Solaris for anyone who'll bring in a single crysknife."

Leto's chin came up in a movement of obvious surprise. "Why do they want one of those blades so badly?"

"The knife is ground from a sandworm's tooth; it's the mark of the Fremen, Sire. With it, a blue-eyed man could penetrate any sietch in the land. They'd question me unless I were known. I don't look Fremen. But . . . "
-Chapter VI, Dune by Frank Herbert

Thanks for checking out my first Instructable on the Fremen Crysknife and Sheath. It's based on a prop from the 1984 David Lynch movie, Dune.

I'm going to state the obvious: I'm a huge Dune fan. I attribute that to the fact that I’d first seen the movie when I was four and four year olds are all wont to deem epic the things they see at that age. When I read the book many years later, it was like ingesting spice--I loved the book and the universe Frank Herbert built.

Then, there’s the crysknife from the Lynch movie. To me, it’s the best version of the Fremen weapon made from the giant tooth of the desert sandworm. It’s has a very raw, spartan look that best represents the hardy, survivalist nature of the Fremen, while details like the handle blisters and uneven ridges along the edge make it look organic, like it really was made out of the fang of an enormous creature.

I wanted my own crysknife, and found that there were already existing resin casts for sale. I bought one from Reel Art, which was a recast of what's known as the Greyzon version of the knife. Though it wasn't exactly screen accurate (it was patterned after an early production sketch of the knife that wasn't used in the movie itself) I thought it was a fine version of the prop. At the same time, I noticed that the moulding itself wasn't polished and could use a huge improvement in terms of quality. It also appeared to have been made of a recast of a recast of a recast.

Still, I was content with the knife and that would have the end of it...

...till somehow my dog took it for a bone and ate it.

After that I thought of ordering another one as a replacement, but what I wanted to look for the second time around was a real, screen-accurate prop replica. There was one that claimed by the eBay seller to be an original prop which he said to have "found in the sands of Mexico". It was probably a third-generation recast of an actual prop but still it was the closest I could get to an actual replica. I didn't win the auctions though, so that was that.

Left with no options, that was when I decided to try and make my own screen-accurate replica of the crysknife, and why not a sheath as well? After all, one must keep the crysknife sheathed at all times. Ultimately, I created this project for the really hard-core Dune fans, like myself!

This Instructable puts together efforts I had in creating the crysknife. Most of the process is documented in the Ginton Forge website, and a limited number of pieces are actually available for order at the moment.

I'm only ever doing 30 of these* so if you're interested, kindly shoot me an email at or send me a message via my contact form.  

I hope you guys enjoy this post. Bi la kaifa!

*30 for a countdown to the 30th Anniversary of Dune's theatrical release on December 14, 1984! And I have to keep a limit on these handmade builds so I can start on other projects as well.  

Step 1: Materials and Safety

I chose resin to build the crysknife because it is the closest I could get to ivory; a tooth from a gigantic creature would more or less look and feel like an elephant tusk. Resin is also good for this project because it's very durable and has a very good weight to it. Because it starts out in liquid form, resin adheres to the shape of the container it is poured in, which means the very intricate details of my crysknife mould will be captured by the resin when it cures into a cast. Go resin!

A. Basic materials used for the crysknife are the following:

  1. A wooden crysknife mould.
  2. 1 kg silicone rubber moulding material + catalyst
  3. 1 liter R10 resin + MEKP hardener
  4. ivory toner for resin
  5. Plaster of Paris

B. Safety Measures (click here for full article)

Resin casting is fun but remember to protect yourself and your environment whenever you work!

  1. Proper ventilation. Some resins don’t give off a smell, but that doesn’t mean they’re non-toxic. Work outdoors and use and exhaust fan and don’t work when there are children in the environment. Make sure you have enough fresh air.
  2. Protect your hands. Nitrile gloves work best. If you like working with your bare hands though, wear barrier cream.
  3. Wear protective gear. People who mix large amounts of resin are advised to suit up–from aprons to goggles and full-faced gas masks, but since I only work with small amounts, the most I need is a decent respirator and goggles. When you’re sanding hardened resin, wear goggles to protect your eyes!
  4. Which respirator to use? I know of some people who have worked with resin for decades who now have weakened lungs because of the exposure. I started out with a cheap industrial respirator used for spray painting, but invested in a NIOSH-approved 3M 6300 for good measure; make sure yours fit snugly to keep the toxins out! (I didn’t quit smoking just to find out one day that my lungs were nonetheless damaged by my resin work!)
  5. Store away items you’ve used for resin. Plastic containers, moulds and mixing tools used for resin should never be used for food and should be kept away in storage. Track your stuff and store them properly.
  6. Establish a proper inventory of your equipment and materials. Your resin will have shelf-life so make sure you use it before it expires. Keep them in a cool dry place away from sunlight–or they’ll harden in their containers (what a waste!).
  7. Clean up spills right away. It’s a lot more difficult (sometimes near impossible) to clean up a spill after it cures, so clean up quickly! Keep your work area clean and uncluttered, with a lot of surface area to work on. Wash off resin that gets on your skin with soap and water.
  8. Dispose of spillage properly. The stuff heats up and hardens, so they might cause your trash to catch fire or clog your drainage when washed into the sink–designate a “resin-only” bin. I also cover my worktable with a thick, disposable plastic cover for an easy cleanup.

Step 2: The Crysknife Mould

Mouldmaking is not only the first part of the creating your own crysknife; it's also the most important part of the process. Every detail, down to every nick and imperfection will be captured in your resulting silicon mould and the casts youmake out of it.  That's why you have to finalize your master mould to eliminate any editing after the resin copy is made out of it.  Resin is very hard material that is difficult to edit, so better do your editing once with the master mould!

The crysknife and sheath master mould was carved from bitukling, locally known as ‘century wood’.  Century wood is a soft wood well suited for detail work.  The round blisters on the handle down to the uneven ridges along the bolster and heel of the knife, really gives the resulting wooden mould an organic appearance.

It took 3 attempts to create the crysknife mould and sheath as you'll see in the pics.  And prior to that hours upon hours of studying screenshots of the Extended Edition of Dune! The extended scenes were helpful particularly the one with Shadout Mapes and Jessica, where the crysknife is shown for the first time with an accompanying sheath.

Step 3: The Rubber Mould

Casting a rubber mould out of a master mould (also called the “male mould” or the “plug”) may be tedious and messy and time-consuming, but it’s certainly an important part of the process. You basically have to let the rubber capture the likeness of your plug (the wooden mould/model of a crysknife). The silicone rubber is initially liquid so it will flow over and around the plug and around into all its details.

When the rubber sets and when you remove the plug you’ll then have a negative imprint of your plug made out of rubber. That’s why it’s critical that you do the rubber moulding process properly or you won’t get the details right and mistakes you make at this point will show up on your subsequent casts.

I used a two part-mould for the crysknife, with each half backed with plaster of Paris for the rubber mould to retain its shape when the resin is poured in. Apply the same process for the sheath cast!

Step 4: Create a Resin Cast

After your rubber cast is done, all that's left to do is to pour resin into it.

I used R10-103 liquid resin for the crysknife. You'll need to catalyze the resin to turn into solid form by using MEKP hardener. Since I live in the tropics I use less hardener, around 2% of the amount of resin is mixed in. To achive a "bone" effect I mix in a bit of ivory toner, around 3-5%. The resin cooks in a little less than an hour, though I give it around 3-4 hours to set, especially towards the knife point--crysknife casts I took out of the silicone mould too early ended up bending a bit and setting that way!

In the top photo you can see three attempts to perfect the rubber and resin cast process; the bottom crysknife is the perfect iteration (it's white because it's been primed for painting).

Again, resin should be handled properly, please take note of these safety reminders.

Step 5: Sanding and Polishing

You’ll notice from the pictures that there are droplets all around; sanding resin produces a lot of resin dust, which is harmful to humans when inhaled. You can avoid dust particulates from occurring by doing the sanding underwater or under running water.

I started with a 60-grit sandpaper to edit out the course parts of the mould. I also cut out stray resin leavings with some hobby knives and carving tools. Then I ended up polishing the whole thing with 1500-grit sandpaper.

A friend who was into knives also told me that the crysknife I was making could count for a legit weapon since the mould had a strong spine that could make a powerful stab. I was reminded of this when I got carried away while sanding the knife edge–I wouldn’t call it a cutting tool but I wouldn’t run it through my skin!

I know the people ordering this knife from me just want it for aesthetics (I could see it being a fine display in anyone’s collection!), but while sanding I made a mental note to put in a warning or two that it isn’t a toy and that it has edges that can hurt people. I have of course, dulled the point and the blade edge since making that discovery.

Sanding and polishing makes a lot of difference–after the resin cooked, the surface was hardly smooth. But after polishing, the knife took on the look of these old Chinese ivory carvings. Also, whenever the tip of the knife hit a surface it would make a clean chiming sound that I find very similar to the sound of mahjong tiles washing against one another.

Step 6: Painting and Weathering

Nothing like acrylic paint and washes to bring out the detail of those handle blisters and detailing.

My best friend, one of the best scale modelers in the country, offered to do the first painting of the crysknife.
As a resin crafter, I thought mixing the proper values of ivory toner coupled with proper sanding would be sufficient to make the product look like bone. And to an extent I really thought it was enough–painting and weathering were just extras. After my buddy took a shot at it though, I have to admit this: I stand corrected. I’ll let the pictures speak for themselves; see the side by side comparison.

This is a whole different art form altogether.

Step 7: Cold Casting [OPTIONAL]

I'm trying out a new process that minimises painting. I'm of the belief that the ivory-toned resin already looks like bone and painting over it doesn't maximise the natural "bone" look of the crysknife. This is also why I'm experimenting on cold casting the knife guard and pommel; making these look metal, even without any paint applied.

Most people think moulding metal into a shape requires a furnace and bellows and basically high temperatures. Die-casting is done that way, but I’ve been researching the cold cast method, which incorporates real metal into a resin cast–without the need for high heat. The metal adds weight into the cast, and, when polished, really looks like metal. Which makes sense because it IS metal

As you can see in the pictures, the initial cold cast looks like muddy, grey clay. Results will only begin to show when you sand off the surface of the “muddy clay”. In the image below, you’ll see the metallic sheen beginning to emerge as it is further sanded.

While sanding the cold cast I find that the heated part that I’ve sanded takes a longer time to cool down, probably because of the actual metal in it! I'm still working on the technique and will update this Instructable when I've achieved the look that I want.

In the meantime I hope you enjoy the pics of the painted product on the next page

Step 8: Final Product: Dune Fremen Crysknife and Sheath!

I hope you enjoyed this Instructable! I'm already working on 15 sets for people interested in the knife (which was nice as I thought I was the only one!); although I'm still thinking of variations of the crysknife, like one that glows. How would you feel about a crysknife that faintly glows when you pick it up from the display stand? I haven't encountered a lot of people who were thrilled about it, but a crysknife that shimmers is my ultimate goal for this build!

Anyway enough of my meanderings! For any questions, suggestions or comments on the crysknife or on how to improve this Instructable, please shoot me an email at Or let's meet at the comments section :)


(Note: No Arrakis sandworms were harmed in the production of this crysknife replica)

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    72 Discussions


    1 year ago

    This one of the most epic props I have ever seen...your writing and the actual making of the knife is commendable.


    3 years ago

    I've seen one of the actual Crys Knife props (the one made to appear to draw blood) from one of the prop makers' personal collection, and I'd have to say you nailed it. Nice work.

    Spencer Jackson

    5 years ago on Step 4

    Your cat looks just like mine. Awesome work on the knife. If I had any artistic or wood-carving skills I would make myself one. Sadly I lack the much needed skills, So I'll just admire yours!

    6 replies

    Am really enjoying the comments related to my cat. He's a pure white coated (he's a bit dirty in the photo) tom with Fremen blue eyes. I love him to bits but he hates the smell and sounds of the workshop when I'm working.


    Here is mine, his name is Apollo. Named after the mission to the moon, as his fur reminded me of it.

    Where might I find Century Wood? A search online did not yeild many results.


    man, your cat knows how to keep himself clean! Vanilla Ice (am sure you know where I referenced THAT from) doesn't seem to know how to.

    "Century Wood" might be a misnomer because that's how it's known locally here in the Philippines--I don't know its international common name. The supply here can't be that high since the government listed "bitukling" in the list of tree species included in the nationwide log ban in 2012. I'll research the scientific name and post it here :)


    4 years ago on Introduction

    If you are still working on the shimmer or glowing effects you might want to look into casting with fiber optic fibers in the resin for the mild shimmer and/or using quartz for its piezoelectric/triboluminescent effects.

    1 reply

    hi! thanks for the suggestion! my efforts with an LED IC has so far been unsuccessful--I'll look into your input :)


    5 years ago on Introduction

    Excellent job on the movie prop reproduction. As for making a book version, thats sounds really tough. I don't remember a lot of detailed descriptions. But here is a picture of an actual knife made of Elk Bone. That reminded be a bit of a crysknife. It is curved but still (sort of) double edged. The marking or blisters shown on those prop knives are taken from the natural markings on real animal jaw bones, not actual teeth (see the gator jawbone pic below). The only animals on earth with a tooth long enough to make a knife from would be the Elephants, or Walrus tusk. The Walrus tusk being the closes. So design wise for making one from the book, it really depends on how you see the Worms teeth to start off with. With real bone you only shape the outer edge because if ground down to far you get into the soft inner layer. I realize this doesn't apply to casting something of course, but i thought I'd throw some info your way for realism sake... yes I'm using realism to describe a sci-fi knife from a giant worm.

    5 replies

    apologies for the late reply! i was away on a (much-needed) vacation. Having read your comment though got me on the lookout for bone/horn pieces on the weekend while I was travelling and I happened upon this water buffalo horn that was up for sale. this one was the best of the lot since the rest of the pieces were hollowed out; containing only the outer shell of the horn. this one's pretty solid.

    i have no idea what i'm making out of it (the shape won't fit a regular crysknife) but i'll keep you posted!


    Few places restrict water buffalo horn. Now if you had said you pick up some rhino horn that would be very different. I wonder if Tagua nuts come large enough to make a crysknife? Tagua nuts are also call Ivory nuts, once tried they carve and look like elephant ivory.


    Reply 5 years ago

    I've never seen tagua larger than 4" (10cm) in diameter, and that size is rare. Maybe if you did the blade and handle as separate pieces, and joined them?

    So design wise for making one from the book, it really depends on how you see the Worms teeth to start off with. With real bone you only shape the outer edge because if ground down to far you get into the soft inner layer. --> i gave this some thought and thought about the Lynch version of the knife and the sheath, which appeared in the extended edition held by the Shadout Mapes in the photo. the knife with sheath seems to be the whole tooth since the blisters extend up to the sheath itself, which mean the knife and the sheath is made from a single tooth. i think it's a great conceptualization of the crysknife by the prop designer. amazing amazing prop!


    5 years ago on Introduction

    been working really hard on crysknife orders so I haven't been able to post another How-To! these I keep the nifty Makerlympics medal nearby while I work--it gives me an extra boost for when I get tired :)

    i discovered a better way of painting the crysknife that maximises the look and feel of the resin; will post an Instructable on that when I get the chance! thanks for the support

    Ray from RI

    5 years ago on Introduction

    Great Job gintonforge...! However, I am still very curious about the wood you used to make the original knife from...??? When I looked/ goggled up the terms you used

    bitukling, locally known as ‘century wood’.

    I cannot find any reference to them on the internet...! Except for the term century wood which is a reference to wood reused from old mill flooring... but the term bitukling does not exist on the internet... except from a wood from the Philippines...

    So from what area of the USA or what part of the world do you come from???

    The only native hard woods in the USA that would be considered soft and relatively available to most areas of the USA are Bass wood and Cotton wood.... A common southern soft hard wood, would be Cypress tree wood which was used for flooring for a lot of southern mills....

    Needless to say many pine/ evergreen trees are found every where in the USA are soft as well.... but they may not hold the came kind of detailed carving as bass, cotton or cypress wood....

    Thanks for sharing such a great post...!!!


    1 reply

    Excellent Google-fu Ray! I am indeed born and raised in Manila, and bitukling is one of the native species of trees here in my country. It's called century wood colloquially and used to carve images of saints for Catholic churches (we've got a lot of those leftover from 300 years as a Spanish colony), but I'll research the scientific name (I sense a tree junkie here!).

    Another clue is that I've named my workshop after Ginton, who is a god of metallurgy of a tribe who lives way south in the Philippine islands. Many thanks for your comment!