Mokume Gane, Japanese for "wood-grain metal" or "burl metal" is a technique of metal-working developed by Denbei Shoami in 17th century Japan for the adornment of the guards (tsuba) of Samurai swords. The wood-grained effect is achieved by working diffusion bonded stacks of dissimilar metal plates. The contrast between the metals can then be accentuated with chemical treatments called patinas. It has more recently found use in the west to create beautiful jewelry. Although mokume gane can be made at home by the DIY'er, it takes some pretty heavy equipment to make it happen. Wouldn't it be nice to be able to achieve a similar wood-grained effect with simpler techniques? Enter our old friend the composite.
Back in 1910, Westinghouse developed a composite of resin-impregnated fabric trademarked as MIcarta® (now a registered trademark of the Norplex-Micarta company). The name micarta (with a small "m") is sometimes used as a generic term for any resin impregnated laminate of linen, canvas, paper, carbon fiber, or glass fiber. These composites are generally strong, waterproof, resistant to many solvents, and are great electrical insulators. They have been used as knife handles, grips for firearms, printed circuit boards, electrical insulators, pool cues, and guitar fretboards.
In this instructable, we'll use simple techniques to produce micarta-like laminates with Mokume Gane style patterns out of cheap bed sheets and epoxy resin. You can use these laminates for computer case modding, steampunk projects, costume jewelry, knife handles, and a host of other things. I call these laminates Mokume Kireji (wood grained fabric).
Step 1: Gather Your Materials
Respirator or Mask: Sanding, filing, or grinding on composites generates nasty fumes, smells, and dusts. You must wear respiratory protection when working with composites.
Gloves: I used cheapo disposable nitrile gloves to keep the epoxy off of my skin
Eye protection: You know better than to use chemicals and tools without eye protection. Foresight is better than no sight.
Clothes you don't mind ruining: No matter how OCD you are, you will almost certainly get epoxy on your clothes. Wear something you don't mind messing-up.
Resin: I used West Systems 2-part epoxy. This stuff cures slowly (hours) which gives me more time to work. Do not use quick curing resins like "30 minute epoxy" because they will harden before you have a chance to finish your work.
Plastic Wrap: I used Saran Wrap. Epoxy does not like to stick to Saran Wrap and this will be used to your advantage.
Fabric: I used cheap cotton bed sheets from Wal-Mart. Select at least 2 contrasting colors (more is ok).
Scissors and/or a paper cutter: Something to cut the fabric with
Clamps and/or a press: You need to compress the layers of fabric together. If you don't have a shop press, don't sweat it; you can use some inexpensive C-Clamps and wood to make a functional press for small projects. Some of my examples are made using a 20-ton shop press; the others are made using four 5 inch c-clamps (about 5 bucks each) and 2 planks of 1 inch thick wood. No need to buy fancy/expensive equipment if you don't really need it.
Sander/files/sandpaper: You will need to sand, file, or grind away parts of your composite. You can do it by hand, but it will take some time. A small power sander will make the work go faster. Use coarse grit paper to "hog out" larger amounts of material and fine grit paper to smooth out the surface and make it all pretty.
Advanced technology resin application devices: to mix/apply the resin. Wooden popsicle sticks or tongue depressors work just fine
Mixing containers for epoxy: I used GladWare disposable soup and salad containers; epoxy doesn't like to stick to these either; when the residual epoxy cures, pop it out of the container and you can reuse it (for more epoxy, not for food please).
Patterning material: This can be anything from dried beans to toothpicks. You'll see what I mean in just a few steps.
Step 2: Get to the Chopper!
Using a paper chopper or scissors, cut your fabric into appropriately sized pieces. Keep in mind that the edges of your composite will be wonked up by excess resin, so you should plan on making your fabric slices at least 10 to 15% larger in area than what you need for your final size. It will also need to be thicker. How much thicker? That depends on what you use to create your pattern. The thicker the patterning material, the more material you will have to remove to get both surfaces flat and parallel. This will make much more sense in the following steps. In any event, it is a good idea to make a small test piece in order to get your measurements the way you want them.
This is also when you need to decide what your color scheme will be. Will it be alternating layers of black and white? Three layers of red to every one layer of brown? How about red, white, and blue? How many layers thick do you want your composite to be? Figure this out now and cut enough fabric for your project. Also keep in mind, that the tint of your resin will slightly alter the color of your fabric. My resin had a bit of a yellow cast to it, and this tended to give my white fabric a bit of an olive tint. When in doubt, make a small test piece to ensure you're going to get the results you really want.
Step 3: Lay Up Your Composite: Birdseye and Ladder Patterns
Now lets put the components to work. Let's make a single piece of composite with two different patterns: The birdseye pattern, and the ladder pattern. This one will be made out of 15 pieces of black fabric alternating with 15 pieces of white fabric.
- If you're using a press, wrap your press-plates in saran wrap. If you're using c-clamps, wrap your pieces of 1 inch thick wood in saran wrap. This will keep your press plates from sticking to your work.
- Place a single sheet of your fabric down on the press plate. This will serve as a template to help you place your patterning materials accurately.
- Arrange your patterning materials on the template sheet. For the ladder pattern mokume, I used several pieces of plastic filament about 3mm in diameter, lined up in a row (toothpicks would have worked too). For the birdseye pattern, I used steel BB's (4.5mm diameter) arranged randomly.
- Cover your patterning materials with a sheet of saran wrap so that they don't become glued to your composite.
- Mix a batch of epoxy resin according to the manufacturer's instructions
- Place your first sheet of black fabric on top of your patterning material and coat it with a thin layer of freshly-mixed epoxy resin. The entire sheet should be lightly coated.
- Now add a sheet of white fabric and gently apply another thin layer of epoxy.
- Continue this process: black sheet, epoxy, white sheet, epoxy, etc until you have used up your fabric (30 pieces in this example)
- Take your other press plate (make sure it's covered with saran wrap) and lay it on top of your stack of epoxy-coated fabric.
- Clamp tightly and evenly using your c-clamps (or press in your shop press)
- Wait for the epoxy to fully cure
Words of wisdom:
-Make sure you let the epoxy fully cure, or the next step will be a disaster
-When you clamp your press plates down, excess epoxy will come smooshing out the sides of the press. Make sure you lay down some plastic to catch the excess resin, or you will have one heck of a mess.
-Don't rely on paper towels or newspaper to catch the excess resin. Just enough will bleed through to permanently fuse the paper to your floor and/or work surface. You must never ask me how I know this.
Step 4: Reveal the Pattern: Ladder and Birdseye
Once the epoxy has cured, remove your masterpiece from the press/clamps to reveal: a turd. Your composite will look ugly, with chunks of resin hanging off the edges and no signs of the beautiful woodgrain pattern that you were expecting. Don't sweat it, you're not done yet. Using files, a power sander, a saw, etc, remove the ugly tattered edges, leaving behind the nice uniform center. Now using a sander or files, begin to slowly remove material from the surface of your slab of composite. Note that in the pictures below, the ladder-pattern part of the composite was cut away from the birdseye-pattern part for greater clarity. Also note that the BB's you see stuck in the composite were wedged into the composite but were not epoxied to the slab thanks to that piece of saran wrap. The stuck BB's were easily pried out prior to sanding.
As you sand down the surface, you will begin to see the pattern appear. The patterned surface will appear dull and matte, but we'll fix that shortly.
Now is probably a good time to fashion your piece of composite into your project of choice. Cut out a piece in the center and make an uber cool picture frame. Maybe an escutcheon plate for computer case modding? Perhaps a component of your next steampunk creation? This stuff cuts like wood, with simple hand tools. Don't worry about making sharp 90 degree cuts, if you radius the the edges with files or sanding (instead of leaving them sharp) the mokume pattern will become even more dramatic.
Step 5: Finish the Surface: Ladder and Birdseye Patterns
Now to bring out the shine.
Prepare a small batch of epoxy and apply a coat to the sanded surface and allow it to cure.
Any irregularities in this clear coat can be sanded out, and the surface re-coated with fresh epoxy.
Polish as desired. Admire your work, as you are indeed "all that".
Step 6: Bonus Pattern: Grid Pattern
But wait, there's more!
Sure, you can come up with all kinds of patterns on your own, but isn't nice to start with a palette of basics?
This grid pattern was created with a piece of the brittle plastic sheet that is used to cover fluorescent light fixtures. A 2x4 foot sheet of the stuff set me back about 6 bucks at a home improvement store.
This is a really fun one as it serves a double purpose. The demo piece below was created using alternating sheets of black and white fabric (again, cheep cotton sheets from Wal-Mart) with a piece of the textured light-fixture plastic as a patterning layer.
The left side of the piece has not been sanded and has a beautiful "quilted" appearance. It could be used as-is. The right side of the slab has been sanded and then re-coated with epoxy to reveal the white layers underneath.
Step 7: Bonus Pattern #2: Twist Pattern
But wait, there's STILL more (please excuse me, I seem to have misplaced my dignity...)
Here is one more pattern you steampunk types might particularly appreciate. The twist pattern can really look an awful lot like wood if done well. The sample below was done with black and chocolate brown cotton bedsheet material in a 1 to 1 ratio. In hindsight, a 4 sheets of brown to 1 sheet of black probably would have worked better. I could not photograph this technique due to the sloppiness involved therein, so I will describe it as best I can.
- Wrap your press plates in saran wrap
- Place a large sheet of saran wrap on your work surface
- Put your first sheet of fabric on the saran wrap, and apply a light coat of epoxy
- Continue adding fabric/epoxy until your stack is complete
- Tightly roll your fabric stack into a cylinder
- Wrap the cylinder in saran wrap
- Twist the cylinder firmly, and be ready for the excess epoxy to ooze out one or both ends
- Keeping the whole mess tightly twisted, put it between the two press-plates, and clamp tightly
- Allow the epoxy to cure completely
- Remove the piece from the press, and peel away as much of the saran wrap as you easily can
- Grind/sand/file down the surface to reveal the pattern below.
- Apply a finish coat of epoxy to bring back the shine.
- Not too shabby...
I hope you've enjoyed my first Instructable and hope it helps you in your quest to build cool things. These low-tech composites have been around for over a hundred years and while I didn't invent these techniques, I so rarely see them used, that I felt I should share the fun. If you liked this Instructable, please vote for me in the Epilogue Laser Cutter contest.