Incorporating resins and epoxies into woodworking is becoming more and more prominent. But how do you know which type to use for your project? How do you mix it? How do you make a mold? Woodcraft is here with all the answers you need to create your own one-of-a-kind turning blanks, river tables and more!
Resins 101
What is Resin and How Do You Use It? Casting resin is the use or method of plastic casting using a liquid synthetic resin which hardens to a solid state. Urethane and epoxy resins are the two most commonly used in the woodworking and craft industries. Epoxy resins have a much lower viscosity and longer work time than urethane resins, making urethane resins an excellent choice where the resin will need to penetrate deep into cavities.
Resins can be used to create unique pen blanks, bottle stopper blanks, handle turning stock, knife scales, encapsulation pours, bar tops and river tables.
Mix and Pour
Most epoxy resins are measured by volume; others are measured by weight. Typically, the product is sold as two parts that harden when mixed together, often 1:1, but be sure to fully read and understand the manufacturer’s directions. An accurate scale, like the Precision Bench Gram Scale, is a good tool to get a proper mix.
Smaller projects like pen and bottle stopper blanks will only require are few supplies:
• Measuring And Mixing Containers
• Stir Stick
• Digital Scale
• Latex Free Gloves
For pouring river tables, bar tops and other large projects, you may also need:
• Plastic Drop Cloth
• Protective Eyewear
• Paper Towels
• Cutting Blade
• Palm Sander
• Disposable 2" Brush/Foam Applicator
• Propane Torch or A Fine Mist Spray Bottle with Isopropyl Alcohol 93%
What Resin Do I Use?
For casting pens and turned items, Woodcraft Product Manager Ben Bice recommends a urethane resin like Alumilite Clear (Slow) 12-Minute Casting Resin (available in 2-lb. or 16-lb. kits). Alumilite Clear Slow offers open/work time of 12 minutes before the curing process begins.
Epoxy resins are an excellent choice for bar tops, tabletops, encapsulation, and river tables because they have a much longer open time. Bigger items that require filling larger and deeper voids up to 1-1/2" are best poured by using Alumilite Amazing Clear Cast (available in 16-ounce and 2-gallon kits, mixes 1:1) or System Three Rivercast (1.5-gallon kit, mixes 2:1). “Both systems are clear epoxy-based resins designed to be tinted and/or mixed with colored powders for a pearlescent look,” Ben said.
System Three Rivercast - recommended for larger items like river tables and bar tops.
Do I Need a Pressure Pot?
For some epoxies like Alumilite Clear Slow, a pressure pot is not usually necessary. Gentle mixing allows any air bubbles to dissipate and evacuate on their own when used in small applications like turning blanks. “If used properly and by following manufacturer’s directions, pen blanks and bottle stopper size blanks can be cast with minimal bubbles when you aren’t using any additional materials like wood or pinecones,” Ben said.
“If you are looking to incorporate other items such as wood, metal fillings or cactus root, the use of a pressure pot will help ensure that the resin is pushed into every nook and cranny, creating a tight, bubble-free casting.” (See article referenced at the end of this blog for tips on preparing and stabilizing wood and other materials for cast resin turnings.)
When a pressure pot is needed, the Resin Casting Pressure Pot from California Air Tools is a great option. It features a Teflon® coated steel tank for easy cleanup, removable casters for added stability, and an on/off ball valve and pressure regulator for accurate pressure settings.
For deeper pours such as river tables and encapsulations, however, some heat may need to be applied to create a more flawless appearance when using epoxy resins like Clear Cast and Rivercast. To help pop bubbles at or near the surface, one tip is to spray a fine mist of isopropyl alcohol (93%) over the surface during the first hour after application. A second option is waving a propane torch over the surface. The flame should never come in contact with the resin, only the heat from the torch.
Jazz It Up
For a pop of color, dyes can be used to create opaque or translucent colors of resin. Most dyes are very concentrated, so a very small amount is all that’s needed to achieve the desired color.
Alumilite Dyes can be used in clear resin to make a translucent or pigmented color casting. Translucent colors include Green, Yellow, Red, Blue, Orange, Violet, and Ocean Blue. Opaque colors include White, Black, Fluorescent Red, Fluorescent Yellow, Fluorescent Green, and Fluorescent Pink.
Although primarily used to add a pearlescent quality, powders may also add color to the resin. Alumilite PolyClear™ Resin Powders can be mixed into resin to add shimmer and glitter for beautiful effects. The powders will actually change color based on how the light reflects off an object. Use by themselves or combine them with other colors to create various undertones of color. Available in Blue Pearl, Green Glow, Gold Metallic, Dark Bronze, Blue Glitter, Purple Metallic, Green Pearl, Yellow Gold, Green, Bronze Metallic, Black Glitter, Violet Pearl Metallic, Silver, Yellow Pearl, Pearl Metallic, Ocean Blue, Black Metallic, Dark Red Metallic, Bright Green, Blue Glow, Silver Glitter, Sky Blue, Copper Metallic, Crater Lake, Bronze Glitter, Gold Metallic, Purple, Cotton Candy, Copper Metallic, White Glitter, Blue-Green, Forest, Pewter, White Metallic and Red Pearl.
Dyes and powders can be used in both urethane and epoxy resins. They can be used by themselves or can be combined with other colors to create various undertones of color. Refer to manufacturer’s instructions for best results.
Creating Blanks
Woodcraft offers three sizes of Lizard Blanks Casting Molds to make creating custom castings, like pen blanks, bottle stoppers and knife blocks, a breeze. These easy-to-use and reusable molds are constructed from premium UHMW (ultra-high molecular weight) plastic, which offers high abrasion, wear resistance and a glossy surface to make removal easy – and no tools are necessary to use them.
Simply pour your resin into the mold and let it cure naturally, or place into a pressure pot if desired.
The use of an anti-stick lubricant like Stoner Mold Release will make the removal of castings even easier while also prolonging the life of your urethane molds. This release agent improves molding efficiency in many processes, including injection, compression, transfer, vacuum form, pour cast, die cast and extrusion molding.
Alumilite also offers Mold Putty, a two-part platinum base silicone mold putty that allows you to make a mold in less than 20 minutes. Simply mix equal amounts of the yellow and white putty together by hand until a uniform color is achieved. Then roll it over the item to be molded. Mold Putty will cure to a flexible rubber and reproduce all the exact detail of the original piece. Use Alumidust powders in combination with Mold Putty to achieve beautiful effects in your casting project.
More Resources
If you want to learn more about making resin-infused castings, a great resource is “Cast Resin Turning” by Keith Lackner, as featured in Woodcraft Magazine, April/May 2017 issue. Keith’s informative article discusses wood prep, making molds, estimating the volume needed, mixing the resin, curing under pressure and releasing the mold.
