Anyone who has encountered home repairs or just likes to make with their own hands is familiar with such material as plywood. In this article, we decided to tell you about different types of plywood, its purpose and some methods of use.
Plywood Manufacturing Process
Plywood is a sandwich of thin layers, or plies, of wood glued and compressed to form a very strong and dimensionally stable panel. Dimensionally stable methods that the panel doesn’t expand or contract much (as strong wood is extremely susceptible to doing) and you can depend on it having constant sizing and thickness throughout the material.
Production wood or softwood plywood undergo different procedures to guarantee the quality of the item produced. These approaches consist of selecting the log, debarking, cutting the logs, peeling the log, making a continuous ribbon of wood, cutting and stacking, gluing the wood, pressing the wood, trimming, sanding, and completing.
Picking the log
The preliminary step in making plywood is selecting the logs. Logs are selected according to its physical properties. Maturity, straightness, and roundness are the most critical elements to be thought about in selecting raw logs. Plywood manufacturers also guarantee that all raw logs used in plywood come from a legal source and sustainable forest concession.
Immersing logs in water over a period helps to peel and reduce logs into various sizes quickly. Some other mills, specifically in cold places use heat as a method to enhance the quality of peeling. These approaches are called hydrothermal processing.
The 2nd step is the debarking procedure. Logs are feed into a debarking machine. Just like shown in the picture. As the logs turn from the ridged wheels, the cutting head on the track is reversely turning with the log from end to end, causing the bark to be gotten rid of. The function of this is to peel the bark without harming the wood.
Cutting the logs
After the debarking process, the logs are cut into wanted lengths in step known as bucking. This procedure is done so that the next operation which is peeling the bark can be effectively carried out.
Peeling the logs
The next step is the peeling process. The markings in the log made by the debarking knives during the debarking procedure are eliminated using a considerable rotary lathe. The log revolves on the machine against a long blade cutter. The cutting procedure resembles sharpening a pencil except that the blade is parallel with the log at the time of cutting.
Making a continuous ribbon of wood
After peeling, the next approach to be done is creating a continuous ribbon of wood. The log turns and feeds towards the cutting edge of the lathe producing continuous and unwounded thin layers of wood. The thickness of the veneer depends upon how it is utilized.
Cutting and stacking
The piece of wood is cut to a basic size of 4′ x 8′. The ideal density of plywood range from 1/4″ to 3 1/4′, however the real density of the plywood after production is determined after the sheets are pressed and glued together. The sheets are automatically scanned as it turns up in the peeler. After scanning, it is stack in preparation for moving and drying utilizing drying ovens.
Gluing the wood
After cutting and stacking, the next step is sticking the sheets of veneer together. This is done to identify the wanted thickness of the plywood sheets. The frequently used adhesive in making plywood are those synthetic plastics such as phenol– formaldehyde or urea resins. The thin sheets of wood run through the gluing machine. As the sheet pass through, the glue is spread uniformly on the back and face of the veneer. The glued veneer is placed on top of unglued veneer, then followed by glued veneer. The process is alternating: glued, unglued, glued, unglued and so on.
Pressing the wood
After doing he glued and unglued alternating process, the sheets which are glued together is pressed utilizing a hot press machine to attain the desired thickness of plywood. An example of this pressing machine is the hydraulic or pneumatic pressing machine in which pressure, or sometimes heat and pressure are applied to the plies. When heat is used, the glue solidifies quickly and then solidifies as the combined veneer is pressed together. The plywood is thought about dry when the pressure is released.
Trimming, Sanding, and Finishing
The sheet will go through procedures to make it nice and commercial in the market. These methods include trimming, sanding, and finishing. Because of these processes, the sheets takes down into standard sizes which satisfy the requirements of the clients.
Types of Plywood
As a produced product, plywood is available in various types for various applications. These can be broken down into 2 main groups: plywood for construction and plywood for woodworking jobs, such as furnishings and cabinets. Building plywood typically is rougher and less appealing and has fewer plies than finish-type (often called cabinet-grade) plywood. Construction plywood typically is made just with common grades of softwood, such as Douglas fir, while surface plywood typically contains some hardwood. Almost all types of plywood can be purchased in the United States by ordering from an online store, such as https://plywood.market/.
A couple of common types of plywood and their uses consist of:
- Sheathing: Standard construction plywood used for wall sheathing, roof decking, flooring structures (subflooring) and general rough building where looks and surface area flaws aren’t important.
- Cabinet-grade: Also called furniture-grade or hardwood plywood, generally a higher-quality panel with attractive hardwood face veneers appropriate for staining. Lower grades have softwood interior plies; better grades have all-hardwood plies and face veneers. Utilized for all kinds of woodworking tasks where looks count.
- Marine: Premium plywood made with water resistant glue to prevent the plies from delaminating due to direct exposure to water. Typically misrepresented as “waterproof,” but the wood itself is not treated for rot-resistance. Developed for boatbuilding however also popular for outdoor furnishings jobs.
- Sanded plywood: General-purpose “project” plywood with decent-looking face veneers that have been sanded smooth. Good for standard tasks around your home, such as utility racks or workbench tops, and anything that will be painted.
- Subflooring: 3/4-inch-thick construction plywood with tongue-and-groove edges that lock together to develop a strong floor surface.
- Exterior: Various grades of construction plywood planned for outdoor use. Only pressure-treated exterior plywood is rot-resistant.
Plywood Grading and Exposure Ratings
Plywood grades normally refer to the quality and look of the face veneers. Each panel gets one grade for the front and one for the back. The majority of systems use grades A through D, with A being the best (if you see an “N” grade, it’s basically an A or better), but some use numbers 1 through 3 (1 is the best). Here’s what the grades suggest (keep in mind that grading standards differ by manufacturer):.
- A: Smooth, paintable surface area without any knots and no surface repairs.
- B: Similar to A however might consist of tight (not loose) knots up to 1 inch and may consist of repairs (made with wood putty or football-shaped wood spots).
- C: May contain tight knots as much as 1 1/2 inches, along with surface area repair work.
- D: May consist of big and/or loose knots, spaces without surface repair work, splits and other defects.
Exposure rating is a form of grading that shows suitability for outdoor direct exposure, and there are only 2 ratings: Exterior and Exposure 1. Both scores show the plywood is made with waterproof glue. Outside panels are rated for repeated wetting and drying cycles and internal moisture content that can be higher than 19 percent. Direct exposure 1 panels can be exposed to damp conditions only for a restricted time, such as during home building and construction, and ought to not surpass a moisture content of 19 percent for long periods.
A plywood grade consisting of the letter X, such as the typically sold CDX plywood, suggests Exposure 1 ranking. Plywood meant for ground contact should be pressure-treated. If a plywood panel does not carry an exposure rating, it is for indoor use.
The convenience of working with plywood is undeniable. By choosing the right type of plywood and using high-quality tools, you will not only achieve the desired result, but also enjoy working with such construction material.