Disclaimer: This tutorial is for entertainment purposes only. The author and publisher will not be liable for any use or misuse of this information. Read and understand all product labelling and regard safety warnings.
Micarta is a brand of synthetic board made from phenolic resin and fabric. The original micarta was made by Westinghouse over 100 years ago as an electrical insulator. The product is made of a thin flat material such as paper or fabric that is saturated with a resin and layered to form a laminate. When the resin hardens, the result is a super durable reinforced material. Micarta can be used for tough, water resistant knife handles and that is why I am interested in it.
Although us knifemakers use the word Micarta loosely, technically it is a brand name. Micarta, G10, Dymondwood are all materials from a similar genre, but the common theme to all of these products is: layers and resin.
The DIY MethodThe following is how I made some laminate. I warn you in advance, this may not necessarily be the best way.
Most Do-It-Yourselfers will use a readily available polyester resin (automotive type) and some selected fabrics to make their own micarta. This process is fairly easy, but messy and definitely stinky. If you've ever known someone that was building a boat or doing body work on a car, you know that smell.
Polyester Resin is available in such brands as Bondo (3M), Rust Check and a dozen more names. There are two parts to the product: a resin and a hardener. The resin will be in a can and the hardener will be in a small plastic tube. If you want to try this, be sure to by resin, not body filler. Clear and colourless is ideal, but expect some tint, pink, blue, brown in the end product if you are using automotive grade resin. In my example, I'll be using Rust Check brand polyester resin. It's about $17 for a US quart or 946ml for us Canucks. You will be able to see its colour here.
HardenerThe typical hardener that comes in resin kits is a super-toxic chemical combination known as Methyl Ethyl Keytone Peroxide. That's a mouthful, but you never want to get this nasty stuff in your mouth. It's an explosive to boot, so read the product labeling very carefully. The hardener will chemically react with the base resin and solidify into a hard material, much like how epoxy works.
The fabric acts as reinforcement. Similar to fiberglass, Kevlar or carbon fibre, our fabric will bind the resin into a sturdy mechanical structure. I am using 100% cotton bandanas I bought at a surplus store. The colours and prints are accessory only. Any fabric that can hold the resin on a microscopic level will work.
Really cool patterns can be made by alternating coloured layer, chopping up random colours e.g. brown, green and black to make camo effect.
Coloured paper can be used and I don't see why straw, leaves or moss couldn't be used as long as these are fully dried before use.
The ProcessThe process is basically 90% preparation and 10 percent getting it done.
- Polyester resin kit - 1 quart will do about 18 or more 1/4" thick knife scales
- Plastic cup, say 500ml to 1 litre. Flat bottomed is better for mixing.
- Stir stick
- Waxed paper
- Fabric of your choice - (size of fabric depends on how much, how thick, what layers etc.)
- Two pieces of very flat wood to make a press. Scrapped MDF shelving. I have made a simple mold out of this stuff to help keep the shape.
- Clamps, 4 to 6 depending on the size of your press.
- Respirator (organic vapours 'OV' filter)
- Safety glasses
- Nitrile gloves
You'll always want to open up the doors and windows and make a bench top from old scrap wood or something. This stuff drips and then becomes rock hard, so DO NOT DO THIS IN YOUR KITCHEN!
Cutting FabricCut your fabric into pieces of a consistent size. I am making 4 scales and will use fabric that is 4" x 11". I cut all the pieces roughly the same size with the scissors. For me, 4" x 11" will make 4 pieces approximately 2" x 5-1/2". Allows some room for error when cutting and if the pressed edges are not perfectly straight. My real finished dimensions are to be 1-1/2" x 5". Make a stack of the material at least 3/8" thick.
Prepare the PressLine the press, MDF or what-have-you with waxed paper. If you tape this down it will stay in place. Packing or masking tape will work just fine. In my little press, I wrapped the waxed paper around like I was wrapping a present.
For 4 scales, I am using 4 oz (118ml) of resin and 12x4 drops of hardener in a 500 ml plastic cup. Using a wooden stick, tongue depressor, paint stirrer etc. work the hardener into the resin for at least 30 seconds. Mix all the way through, down to the bottom of the cup and around the sides. Don't scrimp here. You've got at least 10 minutes to work with it.
Note the colour of the resin before the hardener is applied.
Now check out the colour of the resin after the hardener is mixed in. This is a sign that the chemical reaction has started. If we were doing a white cotton, we'd be getting a brown cotton scales folks.
Now is a good time to take a look at the clock and make a mental note of when the curing process has started.
It's important that we APPLY ENOUGH, BUT NOT TOO MUCH PRESSURE with the clamps as we want some of the resin to stay in. We're trying to get the right pressure to ensure a flat product, but not squeeze all the resin out.
In my first set of scales, I found that 4 oz of resin was more than ample to do this particular batch. In reality, 3 oz would have been enough. Trial and error I guess. Note the the expired paint tray is catching the excess.
Take it Outside if You CanAt this point the resin is dripping and stinking like a body shop as predicted. I moved the whole mess outside AMEN! In hindsight, doing this outside on a couple of saw horses on a warmer day would have been best. It should be noted that the manufacturer does not recommending working the resin in direct sunlight.
The UnveilingIf you've got your hardener ratio right (I did mine in drops per oz) and the room temperature is above 15°C, the resin should be getting very tacky in 15 minutes and hard in about two hours. In 6 to 12 hours it should be fully cured. So let's go and take a look.
The Camo ProjectFor giggles I tried a sort of camo project.
Here are some photos of working the camo scales into a build.
Tips:Premarked Measuring Cups
If 4 oz works for your batches, take a measuring cup and fill it with 4 oz of water. Now take some plastic drink cups and pour the 4 oz of water in. Using a Sharpie, mark the water line on the inside of the cup. Repeat and make a few extra cups for your shop.
Measure By Weight
The specific gravity of polyester resin is 1.09 to 1.15, which means a fluid oz should weigh about 10% to 15% more than water. So 4 fluid oz would weigh about 4.5 oz. Using a scale would be a good way to accurately measure the resin.
Find Some Old Clamps
Clamps will be gooped in a short time. Old bar clamps or C clamps could be dedicated just for pressing.
Keep it Warm
Resin cures much slower at cooler temperatures. 15 to 30 degrees C is ideal. My garage doesn't always stay that warm especially in the winter time. If you cannot keep the temperatures up, consider making a few extra batches in the summer time so you don't have to make any in the winter months. As a heat source it is recommended to use a heat lamp approximately 18" to 24" away. Do not use an open flame!
Super clear polyester casting resin is available, although it's more expensive than automotive grade resin. It's the same process and principles, only this stuff is clear as glass. If you want to make white scales, you'd be wanting to use clear casting resin. An hey, what if you wanted to cast a butterfly or other insect into your knife scales? Too cool!
Epoxy resin offers superior performance to polyester resin in almost all aspects. If you can get some epoxy from a marine supply shop, this would be better than polyester.
Make a Press
I made a press of a specific size to make 4 typical knife scales.You could make a proper press with a sort of mold and built in clamps so you don't get your best Besseys covered in gloop.
Press Gauge or Stop
It's difficult to get the clamping pressure and height uniform. A stop or gauge would help produce a board of uniform thickness. Something as simple as little pieces of 3/8" plywood around the edges to prevent over clamping.
Another batch with Bondo brand resin:
Hopefully you have found this useful. I will add more notes here as I get more experience under my belt with commentary on different resins, materials and jigs.