CT Hobby uses, and sells, a wide variety of woods, plywoods, sublimation boards, acrylics and vinyls. But what are these made from, and what should I know about them?
Solid woods (“boards” or “glue-up panels”) are often used in high quality furniture and building materials. These can be milled to various thicknesses, but thinner boards become more expensive due to the higher end tools needed to resaw and plane thinner pieces. Thicker boards are more difficult to intricately cut, requiring either CNC (often a computer-controlled router) or longer focal length lenses to laser cut. Wider boards require cutting down larger trees, which in turn require longer growing time. The result is that wider boards cost more. Finding a single board big enough for a tabletop would require a single tree that was huge when cut down! Solid woods this large are normally made by gluing, side-by-side, multiple boards together in what then is called a “glue-up panel.”
To reduce the cost of larger boards, sometimes the tree can be “shaved” in a circular way, producing an extremely thin sheet of wood called a veneer. While this is not structurally usable, it can be glued over the top of other materials. Think about cardboard, for example.
No one would use the corrugated middle by itself. But glue flat, slightly thicker, pieces of thin wood to the front and back, and you have a useful material, consisting of several “plies.” An oversimplified definition of some plywoods might be, “two layers of veneer, with ‘nuclear waste’ in the middle.” Of course, it’s not actual nuclear waste. But nobody really knows what it is. It’s some kind of filler—maybe powdery sawdust, maybe glue filling knotholes. In some cases, it’s simply nothing. These are called, appropriately, “voids.” Since veneer covers both the top and the bottom, nobody knows if or where voids are present—unless the plywood happens to be cut where one of these holes is.
MDF, or Medium Density Fiberboard, in an oversimplified definition, is basically sawdust and glue, rolled out like a pizza crust. If you’ve ever seen piles of sawdust from different woods, you may have noticed how different colors appear in certain areas of both the wood, and the sawdust that comes from those woods. This can be due to a variety of factors.
“Heartwood” comes from the center of the tree, or it’s “heart,” and is often darker than outer areas of the tree. This is often noticeable in wood species like Redwood, Cedar, and Poplar.
Different species of wood also have naturally different colors. Pine even has names like “Yellow Pine” and “White Pine.” Walnut and Cherry are usually so dark that laser-engraving is hard to see without some kind of accentuation (such as a paint fill).
Lighter shades of MDF are generally made from softwoods such as Pine, Poplar, Acacia, and Rubberwood. These woods are easier to cut, and are suitable for RF tube lasers.
Darker shades of MDF are generally made from hardwoods, such as Oak, Cherry, Maple, Walnut, Birch, and Ash. These woods are denser, making them harder to cut for RF tube lasers. Cutting the denser wood requires slower speed and more power, often leave a heavier “char” when laser cut. This can often be cleaned with a rag or wipe, lightly moistened with alcohol. The alcohol will evaporate faster than water, reducing the damage to the workpiece from moisture.
MDF is at the core of sublimation boards such as Unisub. Usually made from hardwoods, these materials can be cleaned with an alcohol-moistened rag. The alcohol will evaporate faster than water, reducing the damage to the workpiece from moisture.
Sublimation boards often have a lightweight, clear or colored plastic protective film over the sublimation coating which can be laser cut as well. This film protects the sublimation coating during shipping and handling, and should be removed prior to the sublimation process. Edges can be wiped down with an alcohol rag prior to sublimating, removing much of the char left by laser cutting the denser hardwood based MDF.
Veneers are “sheets” of wood, cut or milled to 1/16 inch or less in thickness. Often these thin layers are glued to lesser quality (therefore less expensive) materials, such as MDF. These materials are then called “MDF Core” plywoods. Technically, this wood be a 3 layer (“ply”) material, so it can be called “Plywood.” These materials combine the denser core (virtually no voids), with the look and stainability of “real wood.”
Acrylic is a petroleum-based product, usually clear or colored. The material can be manufactured by either extruding or casting. Acrylic sheets come with a plastic or paper protective covering to reduce scratches during shipping, storage and handling.
Extruded acrylic does not engrave as well as cast, but either can be cut with a laser or CNC. Being petroleum-based, acrylic is flammable, and is often a source of laser fires. When laser cutting, the laser does not actually “cut” the material, it “melts” and “vaporizes” the acrylic. Air assist is critical, to get these flammable fumes removed from the heat of the laser quickly. As the vaporized acrylic cools, it condenses and may form a “ridge” along the cut. This can be gently scraped in the process of peeling the protective layer off the cut product.
Laser-cutting has the advantage over CNC cutting, in that the heat of the laser beam can effectively “flame-polish” the edge during the cut—a separate step required when cutting with a CNC. The disadvantage, as mentioned, is that this flame must be monitored carefully during cutting, to prevent it from getting out of hand and becoming a full-blown fire in the laser machine.
Extreme care must be taken to distinguish between acrylic, which can be lasered, and PVC–which can be easily confused with acrylics. PVC, more fully Polyvinyl Chloride, releases toxic chlorine gas when burned (such as with a laser). This can be fatal if inhaled, and causes rapid oxidation (rust) of equipment such as laser and exhaust machinery. DO NOT LASER PVC. If in doubt, ask the seller to furnish a Safety Data Sheet for your purchase.
CT Hobby carries the world’s best quality adhesive and heat transfer vinyl products, including Orafol Oracal and Stahls’ CAD-CUT. Ask your NFL friends what vinyl is used for the names and numbers on their game-day jerseys, and you’ll find that CT Hobby has this HTV in stock. YOU could be making the actual jerseys for your school or travel teams on your Cricut! And our exclusive Vinyl Club members get pricing so low, we’re not allowed (by contract) to advertise it!
CT Hobby is an officially licensed Reseller of Orafol products, and stocks Oracal adhesive vinyls such as Oracal 651. This is a permanent, solvent-based adhesive, rated for 6 years in outdoor use. The product can be easily cut by craft cutters such as Cricut, silhouette and others, but should NOT BE LASER-CUT.
Heat Transfer Vinyl
CT Hobby is an officially licensed Dealer of Stahls’ products, is part of the Stahl’s Reseller Network, and stocks CAD-CUT heat transfer vinyls for apparel decorating. These are (mostly) polyethylene products, and can be easily cut by craft cutters such as Cricut, silhouette and others. Many CAN be laser-cut, but some are PVC based. Contact CT Hobby for individual product use.