The Complete Online Guide to Knifemaking BLADE TEXTURE

Blade texture is most often applied prior to heat treating. One exception is etching which can be done either before or after depending on the material and how dark you want the etched area to become. Etched areas of high carbon and tool steel will become darkened from carbonization during heat treating. Patinas and mirror polish finishes are done after heat treating.

Hammer Peened
This rugged texture is easily achieved by hammering the knife blank with a ball peened hammer. The peening can be done by heating the blade in a forge or directly onto a cold steel blank. Once heat treated, the deep areas are darkened due to carbonization or scale. The end result is always a one-of-a-kind creation. Another type of hammer peened texture is done with a crosscut hammer. The sledgehammer has grooves cut into its face. The design or pattern created from the grooves is transferred into the blade with each hammer strike. Make sure to check how flat the blade is after hammering. Blanks should be hammered flat again prior to bevel grinding and heat treating.

Thatched
Thatched or ground texture describes a variety of methods, each scratching or grinding grooves into the blade. Common types of grinding tools are Dremel grinders, small contact wheels of a 2x72 grinder or flap sanding wheels on an angle grinder. Much like hammer Peened texture on high carbon steel, the deep areas of each groove will become dark and more highlighted after heat treating. On stainless, those areas will not be as pronounced.

Etched
Etching encompasses a huge assortment of designs patterns and techniques. Etched textures can be done as a full blade texture or as smaller designs or patterns that are added to enhance the shape of the blade. Etching can even be done on a knife spine. Etching is most commonly done with acid or electrolysis but could also be done with a laser etching machine.

For this book, we are going to stick with the more common electro and acid etching. In either case, some type of resist is used to block or mask the areas of the blade that does not get etched. Self-adhesive vinyl works well. Designs can be hand cut with a razor knife or much more detailed patterns can be cut out with a craft vinyl cutting machine. The vinyl is then weeded. In other words, pick off all pieces that will not be adhered to the knife. A thin clear transfer film can then be applied to the vinyl and the paper backing removed. Using the transfer film helps to be able to visually position the stencil exactly where desired and adhered to the blade. We recommend trying clear contact paper instead of purchasing commercial transfer film. It’s less expensive and actually adheres a little better. Once the transfer film is removed the blade is ready to be etched. Every part of steel that is covered with vinyl will end up being shinny and every exposed area will get etched. We are big fans of etching high carbon and tool steel prior to heat treating. This is done because we like the dramatic dark background achieved through carbonization. When etching before heat treatment, the etch has to be deep enough to survive post heat treatment polishing.

For electro-etching, a machine can be purchased or you can use a 12-volt automotive battery charger or another 12-volt power source, and an electrolyte solution. The charger we have is 12 volts and set at 2 amps. The positive lead from the charger gets clipped to the blade. The negative lead gets clipped to a small section of angle iron that is then wrapped with gauze. We wrap the wire connection to the angle iron with electric and or duct tape to create a makeshift handle. Metal from the negative lead should never be in direct contact with the knife blade. At the same time, you should never be touching metal from both leads at the same time. The gauze is then dampened in the electrolyte solution. Warm salt water can be used as the electrolyte solution for high carbon and tool steel. A stainless electrolyte solution is available on eBay and provides much better results when etching stainless steel. The damp gauze is then applied over the vinyl stencil. Do not make the gauze too moist because if any of the solution drips onto exposed areas of the blade it will start to etch. We now suspend the blade between two scraps of wood to prevent any spilled solution or moisture on the table surface from etching the bottom of the blade. It’s recommended to only leave the gauze in place for 10 to 20 seconds at a time. Depending on the charger and material, it’s typical to etch every area of the blade for up to 2 to 3 minutes. This has to be done by slowly moving the gauze from spot to spot 10 to 20 seconds at a time. Check how warm the blade becomes and let it cool down if necessary. The rationale behind this is to avoid building up too much heat which may cause the vinyl to lose its adhesion. After the desired area is etched for the full time, the vinyl can be removed. Rinse off the electrolyte solution and lightly polish the blade with fine Emory cloth. Typically 400 to 1500 grit is used.

For stainless steel, we have not found a benefit to etching prior to heat treating. Stainless is therefore etched just prior to mounting bolsters or scales. The only exception is when etching a full blade pattern. For design purposes, it’s sometimes nice to grind the finished bevels after etching to create crisp bevel lines that act as a line of demarcation between the bevel and blade etching.

Acid Etched

We use Ferric Chloride for acid etching. We made a PVC container complete with a screw-on cap to hold the acid. Ours is actually mounted to a bucket filled with water. This not only prevents any spills but is less likely to get knocked over. Please use rubber gloves and eye protection whenever working with acid. Acid etching also uses a resist to block off areas not being etched. We use self- adhesive vinyl. Anything covered in the vinyl will stay shiny and any area exposed to the acid will get etched. Multiple tones can be achieved by exposing different areas to the acid for longer periods of time. Etching can range from just a couple of minutes to over half an hour depending on the material and desired darkness. The blade should be rinsed in a container of water mixed with baking powder to neutralize the acid.

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