Jay Fisher - Fine Custom Knives

Plastics overview: Polymers

A quick overview is required here. In the United States, the word plastic means "to mold" or "capable of being molded." We also use the word plastic to describe polymers. There are three main classes of polymers: thermosets, thermoplastics, and elastomers. In the knife world, we mainly use thermosets. These are polymers that are hardened into a permanent shape in the manufacturing process, and are often cured from a monomer-polymer mixture into a long-chain molecular links. Once hardened, the thermoset polymers can not be restored to their original components.

Though there are dozens of types of plastics, and hundreds of variations on those types and thousands of trade names for the varieties, I'll try to keep it simple, in modern knife handle terms. The specific thermosets most commonly used in knife handle construction by handmade knife makers are epoxies, phenolics, and polyesters. I'll go into greater detail in my upcoming book. This page also lists some thermoplastics that I've used in knife handle construction.

Delrin (Acetyl Resin, Acetyl Plastic)

Delrin is a thermoplastic created by DuPont as a metal substitute. It is a friction reducing, tough, lightweight, wear-resistant plastic, and is approved for use in the food handling industry. I've used it before for chef's knives, where high temperatures, water resistance, and sterility are an issue. It is very tough, and has replaced other more brittle cellulose based plastics, and is used to make many things, including guitar picks. It's great for dive knives, as it cannot absorb gasses under pressures. The issue is bonding. Delrin has to be chemically etched before being bonded by epoxies or cyanoacrylates, but adhesive bonding with mechanical fasters can be effective. It is available in white, natural, and black.

Micarta® (Phenolics)

Micarta® is a registered trade name, and not all phenolics are Micarta. The phenolics I use on my knives originate from Norplex-Micarta®, so carry the name Micarta.

Phenolics are the mainstay for the custom knife manmade or synthetic handle material industry. Micarta® is a phenolic thermoset plastic originally developed as an electrical insulator. It is a great material, and is often called by knife makers the Cadillac of Plastics. Phenolics are moderately hard, though metals and abrasive compounds will scratch them. They are very tough (resistant to breakage). They do not bend easily. They can be injected into many fibrous materials, like woods, linen, fiberglass cloth, canvas, paper and just about any fiber and I imagine that you could make a phenolic with dead bugs as a substrate if you wanted (hey, neat marketing idea!). The fibers reinforce the phenolic, making it even tougher and more resistant to breakage, though in knife handles, particularly if supported by the metal tang of the knife handle, this is probably overkill. So the fibers, arrangement, and color are chosen mostly for two other reasons: appearance and texture.

I've read frequently here on the internet that Micarta phenolics scratch easily. Evidently this misconception, once posted, was simply copied and pasted over and over until people actually started to believe it. Micarta phenolic is relatively hard and scratch resistant. It is harder than most woods, and is absolutely harder than ivory, bone, horn  or antler. When doing a scratch test, you will find that the corner of a penny will not scratch Micarta, but a hardened steel pin, steel bolt, or steel knife blade will scratch it. The same hardened steel blade will also scratch G10 and Carbon Fiber Reinforced Polymers. When you see the phrase that Micarta easily scratches, this is a misconception and error. By the way, how often does a knife handle contact hardened steel edges and why? Another Internet fallacy.

My most commonly used Micarta phenolic is black canvas, and when bead blasted, takes on a gray appearance, going well with bead blasted stainless steel blades. Here are some examples:

There are obvious appearance properties of color choice, like a blue or red paper line in an ivory mass of Micarta® phenolic that looks neat. Camouflage colors or bright colors also have their appeal. Micarta phenolics come in just about any color, and here's a list of some that are available. The color is followed by the name of the reinforcing material (paper, fiber, linen, etc.) Not all colors come in all sizes.

See Accompanying Phenolic Color Chart Below

Though there are a whole rainbow of colors available, you won't see many on my site used in custom knives. My clients simply do not request odd colors that often. The most popular choice is black canvas, which is then bead blasted for a rough, gray color, and some tooth that can aid in gripping the knife in slimy environments, the most often being seawater. Micarta phenolics that have been bead blasted will darken with the oils of human hands, but can be restored by a cleaning with denatured alcohol, lacquer thinner (use carefully and sparingly) or even brake cleaner aerosol spray. A denser appearance with more vibrant color can be achieved after cleaning with a light coating of WD-40, wiped off.

Micarta® phenolics are waterproof, resistant to heat, a pretty much zero care phenolic.

Please note: Micarta phenolics are usually used on my tactical knives, and not used on knives with elaborate construction, destined for collector's grade finishing and accoutrements. Knives of this higher caliber usually include gemstone handles and exotic skin inlaid leather sheaths.

See Accompanying Color Chart Below

G-10 Composite

G-10 is a recent addition to the synthetic or man-made handle material group. G-10 is a glass (fiberglass) reinforced epoxy, and it is a very tough, hard, and durable handle material. Because it has fiberglass linen as reinforcement, it is physically stronger (more break resistant) than Micarta phenolic. It is scientifically manufactured, and the epoxy used is a specialized industrial grade which has heat resistance properties. It's also made with electrical grade, non-alkali glass cloth, and formed and catalyzed under heat and pressure.  It's waterproof, a little harder and slightly more brittle than Micarta, and has a more profound pattern when ground and finished, which is probably its greatest appeal. You'll notice in the photos below that the layered patterns vary in density and number of layers exposed in the curves of a knife. This is because different runs of the material have different layer numbers and thicknesses.

If you look around the web, you'll see guys trying to make G-10 or phenolics by hand. I've seen denim pants, with five minute discount store epoxy mixed together, I've seen jigs to try to press it all together. This may be a fun craft pursuit, but it is a poor substitute for professionally made materials like real G-10, Micarta® phenolic and Carbon Fiber. The industrial stuff is hard, tough, solid with no voids, and extremely durable. This is a zero-care, permanent, tough, and abrasion resistant waterproof handle material.

Like phenolics, G-10 that has been bead blasted will darken with the oils of human hands, but can be restored by a cleaning with denatured alcohol, lacquer thinner (use carefully and sparingly) or even brake cleaner aerosol spray. A denser appearance with more vibrant color can be achieved after cleaning with a light coating of WD-40, wiped off.

G-10 comes in many colors, and some of the newer types have several colors in folded patterns, sweeping patterns, or rolled patterns. Some of these are random, and some are called tortoiseshell, but it's all still the same stuff, laminated composite of fiberglass and epoxy. See them below:

Kevlar Reinforced Polymer
(Sometimes with metals)

This is a newer material, built along the same technical lines as G10 and Carbon Fiber. The polymer is an industrial polyepoxide thermoset, often cured under heat and pressure. The difference is in the reinforcing material.

Kevlar is the DuPont trade name (and the common name) for para-aramid synthetic fiber (Poly-paraphenylene terephthalamide), originally designed to reinforce racing tires. Kevlar has extremely high tensile strength per weight ratio, actually five times stronger than steel! But that's just the tensile strength measurement, and (of course) it can be abraded, cut, and worn, so the tensile strength is limited by exposure. I appreciate Kevlar in my cut-resistant gloves because it's harder for a piece of metal to punch through a woven web of the stuff; that's why it's used in body armor. There are many uses for the material that are too numerous to list here, and I encourage you to research this great material.

For manmade handle material use, our Kevlar is cast in a bed of epoxide thermoset, sometimes along with brass, bronze, or copper wires. This is tough, visually interesting stuff, and sure to be of interest in fine tactical knife handles.

Thunderstorm Kevlar

Thunderstorm Kevlar

Thunderstorm Kevlar

Carbon Fiber Reinforced Polymers
(also called "Graphite")

Carbon fiber is a blanket term given to a structure of typically woven strands of carbon in a polymer or thermoset plastic (epoxy). This material's actual name is carbon fiber reinforced polymer. Since it is molecularly close to graphite, the term graphite composite or just graphite is often used in objects built of carbon fiber reinforced polymers.

The advantages of carbon fiber when used for knife handles are hardness and appearance. Carbon fiber when finished creates a noticeable woven, braided appearance in the surface, an appearance some would call "techie" or even machine-like. Some call it futuristic and sophisticated. Carbon fiber reinforced polymers are somewhat brittle when compared to G10, but carbon fiber is harder overall. It's harder to machine, drill, and work with. This is a high durability and high toughness material and costs a premium to use. This is very pricey stuff. It's abrasive to machine, costlier to produce and comes in only a few colors. But when you want that certain look, it can deliver, and it is perhaps one of the hardest manmade materials to adorn a handmade knife, apart from ceramics (below).

Carbon Fiber

Carbon Fiber

Carbon Fiber

Carbon Fiber

Carbon Fiber

Color chart for Micarta® (phenolic) and G-10. (Thanks to Sheffield Knifemaking Supply)

Homemade "Micarta" (epoxy)

You'll see some handle material called "handmade micarta" or "homemade micarta." This is not Micarta®. Micarta phenolic is a professionally manufactured phenol-formaldehyde plastic. What these guys are calling Micarta is actually epoxy, a totally different thermoset, based on epichlorhydrin/bisphenol-A reaction.

Homemade epoxy products are usually made from quick-setting epoxy adhesives, coated on fibrous textiles (canvas, denim, and rope have been used) and left to cure. Using the word "Micarta" should not be done when referring to these materials as it is a registered, trademark name for a high quality industrially manufactured material. Any true phenolic is much harder, tougher, and much more resistant to heat than hardware store epoxy. Phenolics are structurally strong, of uniform density, as they are cured under heat and pressure. Handmade epoxies are not. Phenolics will not soften with heat, cheap epoxies will.

Please understand I'm not talking about the industrial epoxies used to create G10 and Carbon Fiber Reinforced Polymers. I'm talking about the over-the-counter hardware store epoxies. You'll see on this page that G-10 is a glass (fiberglass) reinforced epoxy, and it is a tough, hard, and durable handle material also, and will not soften with heat. Remember that the methods used to manufacture G -10 are industrial, and the epoxy used is a specialized industrial grade which has heat resistance properties. It's also made with electrical grade, non-alkali glass cloth, and manufactured under heat and pressure.

Don't get me wrong; I love my epoxies, jeweler's grade and high strength, when used for their proper adhesive purpose. But to form a handle from five minute epoxy and someone's old pants is not what you would expect to find on fine custom knives. In making these epoxy-based handles, there is no way to effectively remove air pockets, voids, and contamination as industrial process control is out of the reach of individual knife makers.

Phenolic Impregnated Woods: Dymondwood®

Sold under the brand names Pakkawood®, Staminawood®, and Dymondwood®, and Colorwood®, these are actually plywood products,  constructed from birch. Today, these products are made and sold by Rutland Plywood Corporation, who bought out Pakkawood years ago, and modified and updated their technology. The name Pakkawood is discontinued, and the name Staminawood is another name for the same product.

How it's made: Phenolic laminated wood is a densified, impregnated, hardwood composite with the mechanical properties of high density hardwoods, acrylics, polycarbonates, and even brass. Dyes are vacuum-impregnated into the wood, then the wood is put under vacuum to remove all moisture and then impregnated with phenolic resin at very high pressures. Then it is highly compressed into plywood blocks often at dozens of plies per inch. With the high compression rates and solid massing of the material, this creates a very dense, solid wood product, that is pretty much waterproof.

They can be a bit brittle when used in thin cross sections, though they hold up extremely well on knife handles. They're warp-free and stable. Though I don't use these often (some of the colors are garish), some clients request them and I'm happy to accommodate them. These stabilized laminates are very durable, polish brightly, and are long lived, some of the only waterproof wood products available. Great for clients who wish for a wood look, but require high moisture and exposure resistance typical in combat arms, tactical knives, kitchen knives, and hunting and specialty knives. Older color charts and descriptions are below.

Other Companies Currently Making Phenolic Laminate Birch

There are now other players in the laminate, impregnated phenolic plywood market. A popular company is Cousineau Wood Products, selling Dymalux® and Spectraply®. There are also many foreign suppliers of this product.

Nylon

Nylons are a group of thermoforming synthetic polymers. Nylon can sometimes outperform metals in applications like gears and rub plates, where high abrasion must be considered. Nylon 6/6 is the strongest over the widest range of temperatures, and has the highest melting point. Nylon has very high impact resistance, is very stable at a wide range of temperatures, and has good chemical resistance. A special use knife handle material, Nylon is available mostly in black, white, and natural. Though I've rarely used nylon for knife handle materials, I have used it in stands and displays as a strong, neutral component.

Pyralin and Cellulose: Alternative Mother of Pearl: (mother of toilet seat!)

Pyralin is one of the names for a manmade material that is used to imitate mother of pearl, or nacre. It is actually celluloid. Celluloid evolved from nitrocellulose and DuPont and the explosives industry in the early part of the 20th century. Naming cellulose Pyralin was an attempt to portray it as a more natural, not manmade material. DuPont pushed Pyralin in their use for "modern, stylized toilet ware" in the early 1930s, so many toilet seats were made of this material. After all, it looked pearly and expensive, and who wouldn't want to be reminded of the ocean while they're in the bathroom? Craftspeople would later cut up the toilet ware and use for musical instrument inlays, knife handles, and artwork to imitate the limited and expensive real mother of pearl. It is still used in some forms today for knife handles, mainly to imitate natural materials, and sometimes to create visual interest with garish colors and patterns.

I do not, nor will I ever use the stuff! No good maker in his right mind would; it is a tacky material typically found on foreign or poorly made knives. I just thought you might like to know the history.

Acrylics:  (mother of toilet seat revisited) Kirinite

 Not too much different than "polyester pearls" sold by knifemaking supply companies, this is the same sort of plastic you might see on a child's toy, a cheap trophy, bowling balls, fountain pens, picture frames, 1970's outer space furniture, costume jewelry, pool cues, guitar inlays, or anywhere that inexpensive plastic with overblown color is desired. Considered by many to be a "dandy" material, it rates right up there with pearlized toilet ware and gun grips. This stuff has gained popularity recently because knifemakers are constantly looking for something with color to add to their knives, that is cheap, easy to work with, and attention grabbing while being attached with simple tools and superglue. Typically, these materials are popular for a few years and then they fade away because people realize that they are just gaudy cheap plastic and of low value. Understand that no matter what, this is acrylic, which isn't even as durable as polyester, which is far less durable than any of the phenolics or epoxides. It's probably enough to know that acrylic is a thermoforming plastic, one that can be continually manipulated by heat, whereas polyester is a thermosetting plastic, that once it's set, it won't move. The acrylic (polymethyl acrylate) is actually transparent, but can be colored with dyes and various materials (like paper) for some "depth." Some even have small metal screens or grids cast in for visual interest. You might as well make a handle in Plexiglas®, it's the same stuff. How durable is that?

Oooh, how about some bugs in the pour? Do you remember the cute resin casting kits we had as kids? You could dry out a beetle or a spider, and pour the resin below, around, and above the critter and preserve him for posterity. Our parents dutifully accepted these paperweights as gifts, but I think they were just being kind... You can still buy these kits today, and they would be just as durable on the knife handle while allowing your creative juices to flow.

What about using these acrylic plastics (with a little bright orange or red or turquoise-colored dye) to soak into, around, and through a Cholla, Staghorn, or Ocotillo cactus branch? Or a pine cone? This is creative fare for many knifemakers, and they simply swoon at the romance of a desert night and alien life forms drawn to the garish (yet entirely natural) patterns...

Okay, so you know I don't like this plastic, but some do, and that's alright, as long as the knife it's on is as cheap as the plastic handle it has. It's just not right for a fine handmade knife to look like two-for-one drink night at the bowling alley. I'm sure I'll get some hate mail over this, but it's nothing I haven't heard before about Corian, Pyralin, or fiberglass. Even a shipping crate from China is made of tougher stuff!

Brand names for acrylic knife handle material? Kirinite, Acrylic Mother of Pearl, ALVS (Acrylic Laminated Shell Veneer), Decorative Acrylic, Synthetic Horn

The good news? In the future I hope to see more toilet seats made of this stuff; that I would buy for the bathroom in the shop (I don't think my wife would want it in the house).

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Fiberglass (Cast Polyester)

There are a few makers and manufacturers who claim to have "Fiberglass" handles on their knives. First, some background and clarity should be presented. The word fiberglass refers to glass cloth. Back in the 1970s, I worked in construction helping build an Owens-Corning fiberglass plant, and the process was quite interesting. The glass is made by melting rock and sand, essentially, into a liquid that is forced through a plate with tiny holes in it, like the spinnerets of a spider. The glass is cooled and collected by winding into a big bale.

You might think that the word "fiberglass" in a knife handle would mean a tough, hard, and durable handle material, but let's be very clear. The glass fiber (fiberglass) is a reinforcing agent for the resin that comprises the bulk of the cast knife handle, and that resin is polyester.

How it's supposed to work is that a rabbeted tang (chopped off and cut down) of a knife handle (nice, huh?) is held in a mold where polyester resin is poured. Hopefully, the fiberglass is in there somewhere, reinforcing the polyester. Then, it cures, the mold removed, and voila! Instant knife handle. This is no way to handle any (but the cheapest of) knives.

Polyester is a poor choice for any handle material. Just compare it with Micarta, G10 or epoxy thermosets in general and you'll see a substantial difference. Here is a simple chart below to let you know what the difference is.

Clearly, the epoxy thermosets, G10, and Micarta have greater strength, greater chemical resistance, and even greater heat resistance than cast polyester. The main consideration, the most important and dominating factor is the bonding strength. While both epoxies and polyesters bond mechanically to roughened surfaces, and their resins are very physically close to the bonding surface, the most significant distinction is that epoxies form an ionic bond at the atomic level with the surface of the steel, and polyester does not. This is why epoxies are so far and above cast polyester that polyester should never be used on any knife handle. Of course, you've probably noticed an important distinction in the table above, in the row titled "cost." Could this be why cast polyester is used on some inexpensive knives? Fine for a cheap knife, but what about the makers who use cast polyester and fiberglass who make a knife for thousands of dollars? Do you think that's money well spent?

VALOX: This is a polyester resin, used on a lot of factory knives. It's still polyester, no matter what name you give it, no matter how it's described, no matter what imagery is used by the sales department to write ad copy. It's a thermoforming plastic, so it can be heated and pressed into a mold. The outstanding characteristic that is claimed by the manufacturer of this plastic? "...exceptionally good processability and surface appearance." Which simply means cheap to make, cheap to use, cheap to mount, and a nice surface (like every other plastic surface ever made by man). It's polyester, revisited, renamed, resold to the unwary.

The knife handle is no place to save a buck or two, when you consider the tremendous forces applied to the knife tang through a supportive and solid handle. Long term durability, aging resistance, and abrasion resistance are also critical factors that cannot be met by polyester.

Alternative Ivory

Called Alternative Ivory, some this material is cast polyester. Though it may be an alternative to expensive or prohibited ivory, this is simply ivory-colored plastic. Polyester does not even approach the durability of phenolics or G-10. See the section just above. Another alternative ivory is based on dyed epoxy. I don't use it, and wouldn't expect to see it on finely made knives.

Corian®

Corian® is a registered trade name for an acrylic thermoplastic with alumina trihydrate. Since it is a thermoplastic, it can be formed, bent, shaped, and deformed by the application of mere 300°F heat. It is not heat-resistant like Micarta® phenolic or G-10, but I've seen some knives handled in this material. It is not abrasion-resistant, and even the manufacturer recommends sealing the surface with coatings to prevent staining. I don't use it, and don't expect to see it on finely made custom or handmade knives. There are other trade names for similar products, like Meganite®, LG-HIMACS®, Staron®, Wilsonart Gibraltar®, and Livingstone®. There are even countertops based on polyester-based plastics rather than acrylics, which should be much tougher, harder, and heat resistant. Still, do they belong on knife handles or on your kitchen or bathroom counter?