Making Damascus Micarta + Sunglasses

Micarta /mai-kar-tə/

noun

• A brand name for composites of linen, canvas, paper, fiberglass, carbon fiber or other fabric in a thermosetting plastic.

Damascus /dəˈmæskəs/

noun

• The forged steel of the blades of swords smithed in the Near East from ingots of Wootz steel.

These two iconic and unique materials are both examples of composites, whether it be textiles casted under pressure with a thermoset plastic, or a blend of forge-welded steels. We wanted to create something unique and maybe even a whole new process combining these two materials, then make something cool with it.

Follow along in this guide as we design and print our dies, lay up our micarta, and machine some cool sunglasses with it. Learn with us and make your own micarta at home for cool projects like knife scales, tool handles, and more! Check our video for more about our story making these, and some fun jokes and entertainment along the way.

For the Micarta:

• Melamine sheet for making a releasable mold box
• 3D printer and PLA filament
• Mold release wax or spray
• 100% cotton fabric - cut to the size of your mold box. ~200 layers results in about 1 1/8" thick finished micarta
• Heavy-duty "F" style clamps. We used a custom made steel screw clamp, but that isn't necessary.
• Epoxy Resin - we used TotalBoat ThickSet for its low viscosity and long working time/pot life
• Mixing pots and stir sticks
• Epoxy spreader
• Disposable paint tray liners
• Poly sheeting (to protect your work surface)
• Some friends - this layup will be difficult and time consuming to do solo.

For machining the sunglasses:

• Stock material - must be at least 3/4" thick
• Fusion 360 - CAD and CAM for making toolpaths
• CNC Router - we use an AvidCNC Pro 2448
• 1/4" flat 2 flute spiral upcut end mill - Part registration and roughing passes
• 1/8" ball end 2 flute spiral upcut end mill - Finishing passes
• 1/4" hardened steel dowel pins - for part registration
• T-Tracks and cantilever clamps - other workholding solutions will likely work fine
• Sandpaper
• Paste Wax
• Lenses
• Eyeglass Hinges (we were unable to source these domestically)

The first step in our project is to prep for our micarta layup.

You'll need to gather the supplies listed in the first section.

The 11"x11" dies were printed on our CR-10S Pro. We recommend printing with at least 20% infill or more with 3 wall, top, and bottom layers - as we'll be compressing these under a lot of force. Unfortunately the positive die file size is too large for instructables, but you can download all files related to this project here on our github repo. We did have to sand the die on its edge a little for it to fit in the mold box properly.

We've also attached a full parametric Fusion 360 archive for making a mold box if you want to cut one out on a CNC. You can adjust parameters for length, width, depth, headroom, and material thickness.

Cut your fabric into the dimensions of the final mold. It may be helpful to slightly undersize it to make alignment in the mold slightly easier. We happen to have a laser which made it super easy, but there's nothing wrong with good ol' scissors or rotary cutters. We used about 200 pieces in this layup.

The mold and dies were coated with a mold release wax, which helped - but we later had to destructively remove the dies, so if you plan to save them, we recommend using LOTS of mold release wax or spray.

Prep an assembly line with plastic drop cloths on your table in this order: One station for mixing new resin 1qt at a time, 1-2 stations with paint tray liners for wetting out fabric, and a final station with the mold box and dies.

Grab some friends, it's gonna be a while. If you're doing a layup this size and this many layers, I recommend having 3-4 people. Skip and Jeff were both wetting out fabric with resin while Graz was mixing new resin and Andrew was laying it in the mold. Even with all this help, this process took well over an hour.

We mixed up TotalBoat Thickset for this layup. While this is not a typical laminating resin, the extremely long pot life, working time, and low viscosity made it an excellent choice for this material. We used approximately a half gallon of resin for this layup.

Mix resin, and pour some into the paint tray(s). The paint trays are excellent for laying out and wetting fabric with resin while keeping your work surface somewhat clean.

Wet out the fabric in the resin, and lay it into the mold between the two dies. You may not need to fully wet out every single layer - some resin will pull through each layer. Communicate with the person in your assembly line laying out the fabric about when more or less resin is needed. A plastic epoxy spreader can be helpful to make sure the fabric and resin are spread evenly in the mold.

When all of your layers are done, place the top die and a lid/plate on top to clamp on. We used a custom made steel screw clamp; but F clamps will do just fine. Use at least one heavy duty or two standard F clamps on each side. You want to crank them down pretty good, but not so much that you squeeze out all the resin. There will be some squeeze out.

Wait AT LEAST 2-3 days for curing. Thickset can take as long as 5-7 days for a full cure depending on shop temperature and humidity.

After waiting for our micarta to cure sufficiently, it's finally time to break it out of its melamine prison.

We had a little trouble disassembling the mold, but nothing a spreader clamp, chisel, and mallet couldn't fix.

Unfortunately the dies were not removable. We don't think we used enough mold release. Additionally, the layer lines in a 3D print create an excellent mechanical bond with epoxy. We ran the block through our planer to remove the dies. We DO NOT recommend this in most planers, it will dull your knives quickly. If you have a helical cutting head, you should be fine.

Don't have a planer? You can surface with a CNC router, or even a handheld router with a flattening jig like you would use with a slab.

While it isn't required, we also ran it through a drum sander to get it perfectly flat.

Since we're machining this anyways, this step isn't necessary at all, but we really wanted to see how the colors would come out in the final product.

We sanded with a palm sander up to about 400 grit. After, we used a drill polishing pad with TotalBoat TotalBuff and TotalShine to bring out the colors in this. It's so pretty!

We took some time tweaking our model and testing the machining by cutting the parts out of a high density polyurethane tooling foam. This allowed us to test with faster machining feed rates and less risk to our CNC bits.

Our model files are attached here, with some additional files in our github repo.

Andrew is most fluent in Rhino, and prepared our model files there. We imported those files into Autodesk Fusion 360 where we modeled our stock, imported our Rhino files, and generated toolpaths.

In our stock, we created peck drilling toolpaths using a .25" upcut flat end mill to drill two holes through our stock and about .25" into our wasteboard to insert some steel dowel pins. These keep the stock registered in the same exact place after flipping it to continue machining the second side.

We used a 1/4" flat upcut bit for our roughing passes, and a 1/8" ball nose bit for our finishing passes. Our roughing passes left .050 stock to leave with up to a .25" stepdown, set to machine on the boundary. The finishing passes had a maximum roughing stepdown of .030 and a finishing stepdown of only .003", also set to machine on the boundary line. A couple thou of stock to leave would be a good idea to leave an onion skin so your parts don't fall out on you.

Starting with milling only using a small stepdown finishing pass took nearly 8 hours to machine these glasses. The addition of roughing passes, combined with REST machining (to account for stock removed in previous machining operations) allowed us to shave that time down to a cool 3 hours.

Make sure you have your patience cap on. Generating these toolpaths can take a LONG time.

There is likely a more efficient way to create these toolpaths and machine these glasses, but it worked for us.

We used our AvidCNC PRO2448 to mill these glasses with Bits&Bits astra coated tooling to handle the abrasive nature of micarta.

Use a small belt sander or even sand by hand to remove the onion skin and clean up any remaining tooling marks.

As it turns out, the lenses we got were not a great fit. We were able to heat the micarta and gently bend and form it into shape. While thermoset plastics like epoxy won't "melt", they will soften and become pliable with heat.

The recesses for the hinges weren't deep enough, but a little dremel work cleaned them up and helped us shape them. Learn from our mistakes so you don't have to make them :)

The glasses were finished with some simple paste wax. You'll have to wait a couple days for the solvent smell to dissipate, but it resulted in a great satin/burnished look.

Typically eyeglasses are made using methods and materials that would be better suited to holding lenses and hardware - often being injection molded right into the frames.

Without the ability to reliably "snap" the lenses into the frames, we resorted to carefully gluing them in with CA glue.

The hinges were a little hard to install, but using some very tiny hand twist drills, we were able to create some pilot holes for the tiny screws. With some patience, you may be able to screw them in without pre-drilling.

You've put a lot of hard work in, and you deserve to be a little vain. Take some cool selfies and enjoy the fruits of your labor!

We hope you enjoyed following along with our build. We'd love to see what you make using this process! Be sure to tag us or comment, we'd love to see it!

We'll also be running a giveaway for a short while when we launch this - you could win a piece of our damascus micarta to make something cool in your own shop!