Cutting Lumber

Cutting Lumber can be subject to cupping, twisting In this issue: and bowing. Often, dry boards will absorb moisture from the Cutting Lumber 1 atmosphere and will become distorted. Flat sawn lumber has a large variety of appearances based Drying Lumber 2 on the angle of the growth rings relative to the surface of the Show & Tell 4 board. The annular rings are generally 30 degrees or less to the Warren Johnson’s Saw Mill face of the board; this is often referred to as tangential grain. The resulting wood displays a cathedral Warren Johnson, VP and Program Director for CWA, recently pattern on the face of the board. Treasurer’s Report purchased a lumber mill and Q u a r t e r Closing Balance $3314 presented to the Association what sawing is Memberships 201 he knew of cutting and drying m o r e lumber. expensive than flat Warren made his presentation January’s Raffle sawn and based on what he knew prior to Prizes involves cutting the log radially into owning and operating a lumber mill four quarters. Once quartered, and what he has learned since. there are two different ways in 10” Irwin Trim Saw Blade Warren presented the processes which boards are extracted from CA Glue w/ Activator used for flat sawn, quarter sawn the log as shown in the photos. The Ryobi Sander and rift sawn lumber and compared upper method is more complex and Ridgid out feed support the relative advantages and labor intensive, but leaves far less disadvantages of each. waste from the log. The method on Irwin 12” Quick Grip clamps the right hand side can be executed Flat sawing is the most common, quickly, simply plain sawing the The CWA meeting least expensive quartered log. However, this lumber. Flat raffle could benefit from technique leaves large amounts of s a w i n g your donation. If you waste wood. In a quarter sawn (sometimes have any tools (old or board, the growth rings of the tree called plain are closer to perpendicular to the new) or shop supplies sawing) is the surface of the board than in most you would like to donate simplest method for milling a log flat sawn boards. In certain species to be raffled, please into planks and involves making a of wood, most notably Oak, this bring them to the series of parallel cuts through the creates a beautiful visual effect. log. This method is quick and meeting. These boards are more stable than leaves the least amount of waste. flat sawn, being less susceptible to Because of the directional tension distortion that comes with across the grain as the wood dries, expansion and contraction from ages and wears, flat sawn boards absorbing and releasing atmospheric moisture. Stable quarter sawn lumber is often recommend- ed when stability is important. Drying Lumber W a r r e n In the process, deliberate control Rift sawing is the most expensive and J o h n s o n least common as though it creates of temperature, relative humidity c o n t i n u e d the most and air circulation is provided to his presen- s t a b l e give conditions at various stages tation on boards, it (moisture contents or times) of dry- v a r i o u s is the ing the timber to achieve effective methods of drying lumber. Warren m o s t drying. Kiln drying provides a means presented air drying, fired kiln dry- wasteful. of overcoming the limitations im- ing, solar kiln drying, dehumidificai- Each of these boards is cut radially posed by erratic weather conditions. ton kiln drying and vacuum kiln dry- perpendicular to the growth rings of In kiln drying as in air drying, un- ing along with the advatanges and the tree. There are large triangles of saturated air is used as the drying waste left from between each board. disadgantages of each. medium. As a result, rift sawn lumber is costly Air drying is the drying of timber by Fired kiln uses directly induced to produce and therefore, the most exposing it to the air. The tech- heat through the use of a fueled or expensive type of planks available nique of air drying consists of stack- electric heater. These kilns are from a log. Rift sawn wood can be ing sawn timber with the boards sep- generally a masonry building, manufactured either as a compliment arated by stickers on raised founda- though other materials are used. to quarter sawn lumber or logs can be tions, in a clean, cool, dry and shady cut specifically as rift sawn. In rift Heating is usually carried out by place. Rate of drying largely de- sawn lumber the annual rings are typ- steam heat pends on climatic conditions, and on ically between 30-60 degrees, with 45 exchangers the air movement. For successful air degrees being optimum. Manufac- and pipes of drying, a continuous and uniform tured by milling perpendicular to the various config- flow of air throughout the pile of the log’s growth rings producing a linear urations (or by timber needs to be arranged. The grain pattern with no flecking. large flue rate of loss of moisture can be con- pipes through which hot gases from This method produces the most trolled by coating the planks with a wood burning furnace are passed. waste, increasing cost. Rift sawn any substance that is relatively im- Only occasionally is electricity or lumber is the most dimensionally sta- permeable to moisture. Coating the ble cut of lumber and has a unique gas employed for heating. Fans are ends of logs with oil or thick paint linear appearance. Rift sawn lumber then used for carrying the heat to improves their quality upon drying. is typically narrow with straight grain and the moisture away from all Benefits- Advantages/Disadvantages: pattern on the face of the board. The parts of a load. Least expensive drying method and annular rings or a rift sawn board are air drying often produces a higher A solar kiln is a cross between about 30-60 degrees to the face of quality, more easily workable wood kiln drying and air drying. These the board, but 45 degrees is opti- than with kiln drying, depending on kilns are generally a greenhouse mum. Similar to quarter sawn , rift climate, takes several months to a with a high-temperature fan and sawn is also referred to as radial number of years to air-dry the wood. either vents or a condensing sys- grain. Kiln drying, as listed above, takes tem. Advantages/Disadvantages: many forms. Not matter the type of Solar kilns are slower and variable kiln, kiln drying generally consists of due to the weather, low invest- introducing heat. Heat can be intro- ment, low operating costs, can con- duced directly, such as through a trol rate of drying, good quality of fueled heater, or indirectly, such as lumber, no sterilization. through solar energy. A dehumidification kiln is a This means that if capital outlay is closed loop (unvented) system involved, this capital is just sitting which uses a heat pump to con- there for a longer time when air dense moisture in the air and to drying is used. On the other hand, warm the dry air. Fans blow the air installing an industrial kiln, to say through the piles. These kilns oper- nothing of maintenance and opera- ate at about 120°F and use about tion, is expensive. half the energy of a conventional In addition, wood that is being air kiln. Advantages/Disadvantages: dried takes up space, which could Moderate investment, moderate also cost money. operating costs, produces good In air drying, there is little control quality lumber. over the drying elements, so drying degrade cannot be controlled. A vacuum kiln is a newer method The temperatures employed in kiln CWA Google Groups which uses reduced atmospheric drying typically kill all the fungi and Communicate with other CWA colleagues pressure to speed up the insects in the wood if a maximum on Google dry-bulb temperature of above drying process. A variety of vacu- With a single email you can let others know um the wood charge. By using vac- 130°F is used for the drying sched- what’s happening, share some information uum technologies the moisture in ule. This is not guaranteed in air or get an answer to a question. the wood can be evaporated at a drying. Note: You Can Join This Group on Your Own! lower temperature and thus faster. If air drying is done improperly (exposed to the sun), the rate of To join: Advantages/Disadvantages: Very drying may be overly rapid in the expensive typically due to the heat Create a Google account, if necessary dry (requires name, email and password). of vaporization being provided by summer months, causing cracking Please save your password in a secure electricity rather than local fossil and splitting, and too slow during place for future use. fuel or waste wood sources, pro- the cold winter months. Paste the entire line below in your web duces the highest quality wood, browser’s address bar The significant advantages of con- typically used for high value lumber http://groups.google.com/group/ ventional kiln drying include higher charlotte-woodworkers or projects. throughput and better control of “Sign in” Click the link "Join this Group" (on the right). A comparison of air drying, conven- the final moisture content. Conven- Once "signed in" select the radio button tional kiln and solar drying is given tional kiln and solar drying both "Email" at the bottom and enter a nick- below: enable wood to be dried to any name.

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