Make your own micarta : 1

Disclaimer: This tutorial is for entertainment purposes only. The author and/or publisher will not be liable for any use or misuse of this information. Use appropriate PPE, read and understand all product labeling and regard safety warnings.

Micarta
Micarta is a brand of synthetic board made from 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 we, as knifemakers, are interested in it.

Although most of us use the word Micarta loosely, technically it is a brand name. Micarta, BG10, Dymondwood are all materials from a similar genre, but the common theme to all of these products is: layers and resin.


The DIY Method
The 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.

Resin
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.

Hardener
The 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.

Fabric
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 coloured pieces if fabric e.g. brown, green, grey and black to make camoflauge 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 Process
The process is basically 90% preparation and 10 percent getting it done.

Supplies

• 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 sticks
• Scissors
• Tape
• 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.
• Rags

Optionally: Food wrap
Optionally: Stapler

SAFETY
Respirator (organic vapours 'OV' filter)
Safety glasses
Nitrile gloves
Ventilation

MSDS for product:
http://www.rustcheck.com/media/djcatalog/Rust Check- Polyester Resin - Part No 1993.pdf

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 Fabric
Cut 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 Press
Line 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.



Respirator time.
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.

 

(sorry post size limit reached)

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.



Saturate the fabric layer by layer. Put a little bit of resin on and spread it all over the surface. Go from side to side to side and get it everywhere. Then add the next layer and repeat. It's okay to have too much resin as it's going to splooge out when you press and clamp. Not enough resin or spotty coverage will be a problem.



Building up the layers.



Fit the top and start to clamp.



It's important that we DO NOT APPLY 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 an even, 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 Can
At 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 Unveiling
If 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 waxed paper releases really well.




The Camo Attempt
For giggles I tried a sort of camo type project.








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!

Casting Resin
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
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 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.

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I hope that you have found this to be enlightening. Please add your comments below and if you gave this a try, let us know.

Cheers!

Dan

 

that looks awesome-have to try

 

Do you have pictures of these used as handles, it'd be interesting to see them from start to finish. Very nice tutorial and thank you.

 

I'll be sure to post pics of some finished knives here showing the scales in action.

I did cut some pieces this morning and it is very hard. I have a 60 tooth carbide blade on my compound mitre saw and she was working to get through. I also buffed a piece the buffing wheel with some abrasive paste and the pieces polish up well. Just need to mount them up and give them some abuse.

 

Dan I'll take a set of your custom camo scales !!

 

re-post-
Dan I'll take a set of your custom camo scales !!

 

Report on Bondo brand polyester resin.

I made another batch, this time with Bondo brand resin. Check out the colour difference. It is much browner than the Rust Check brand resin I used in the first batch.



This time I made the scales with some layers of camo pattern cotton fabric.


These pieces are still oversized at about 2" wide by 5-1/2" long. I will trim them around the perimeter with the bandsaw. The piece on the right has had some treatment with the cotton wheel.

Dan

 

Hey Dan. Nice tutorial. I think I'll be giving this a try for sure. Which resin have you liked the best. I terms of how it set and the colour darkening. That second batch was really dark.

 

Although I have only tried the two brands; I like the Rust Check brand resin the best so far as it appears clearer and harder to cut with a carbide tipped blade.

I would like to try some clear casting resin and marine epoxy next. Stay tuned.

Dan

 

Thanks for the tutorial. I've been watching youtube videos about this all winter, looking forward to a warm enough day to work outside, given the stench.

It's warm enough now, and I've got an idea to work with fairly loose jute for a real grippy crosshatched pattern. I'll post some pics when I finish. Thanks again for your time and effort to put together a very easy to follow set of instructions.

-Matt

 

Update: Made some scales from the camo product:






I think they still need a bit of a polish with some finer sandpaper, but I like the results so far.

Dan

 

Here's the results with some 320/400 grit paperwork and a buff on the cotton wheel.


I had wished for more green. There is a speck to the between the pin and tube. That may have been purely in the randomness of the mix as I did it 33% black, 33% brown and 33% green with about 1% yarn.
Next time I'll add 50% more green, and maybe some lighter green. The coloured needle point yarn worked really well. It gives the "branches" look and finishes very smooth.

BTW, be careful with the heat from the buffing wheel. Friction can melt the resin. I did it too much (say boo-boo) and had to sand and rebuff that area.

Dan

 

Yeah I was wondering how that would turn out too. I specifically chose 100% cotton yard as opposed to wool or acrylic. I don't know if wool would make any difference though. It would be cool to try an experiment and chop up a whole bunch of different coloured yarn into a bucket and mix the resin in. The sky is the limit when it comes to being creative!

 

Nice knife Dan, I don't think you need much more green at all. Greens tend to go very dark when wet so it sometimes gets lost when close to black or dark brown. In the 2 photos under the one with your sanding spindle i can see a lot of green on both sides. So maybe instead of more green maybe less black or some light brown. Just a thought, but I like the camo!
Joel

 

Hey Dan, great tutorial! I like the camo stuff

One thing I noticed when I made some micarta was that I had better results when I used more clamping pressure. I clamped mine between two 1.5" thick steel plates in an 8" vice as hard as I could you'll never squeeze all of the resin out and the resin is brittle, less resin should yield a stronger product.

 

Thanks for feedback. It certainly makes sense. It stands to reason that as long as the fabric/fibre is saturated any excess resin would be weakening the product. If your fabric doesn't squish and slip out sideways under the high pressure you should be golden. In the case of the chopped fabric pieces (camo experiment), some sort of mould would be required to contain the mix as squeezing that hard between two plates would probably spooge most of it on to the floor.

I have another batch I am going to try with full fabric rectangles and multiple clamps cranked right up and see what the end result is.

Dan