Another common sticker size is 1 x 2, and these work fine as well. In the third column, write down the appropriate dry-bulb temperatures. The water tray can be removed and emptied manually, or a hole can be drilled through the wall of the shed to pass a drain tube. My baffles hang from T-bar assemblies mounted to the ceiling. Secure .gov websites use HTTPS If you intend to kiln dry lumber from a green state, right off the sawmill, you will need to be well-versed in airflow rates and follow a detailed drying schedule. How do I convert from the standard kiln schedules in the USDA's "Dry Kiln Schedules for Commercial Woods" and "Drying Hardwood Lumber" to an SDR-type schedule? Our approach was to build and operate a small dehumidification dry kiln. My kiln uses four ceiling-mounted fans, each rated for 1,600 CFM. Add up the amp draw on all the equipment you plan to use in the kiln, including a heater, dehumidifier, fans and steam generator. This report contains suggested dry kiln schedules for over 500 commercial woods, both temperate and tropical. After a short period of grumbling, they join me to lay down wood blocks for the first layer of lumber. %3.3 Each layer of lumber is separated from the next by a series of stickers or spacer sticks. This problem is magnified if the lumber is thin or flatsawn. Reply. The four charges of lumber ranged from 600 to 700 board feet (bf), and a woodworker with no dry-kiln experience operated the kiln. The water tray can be removed and emptied manually, or a hole can be drilled through the wall of the shed to pass a drain tube. These well-known dehumidification kiln packages have been among our bestselling products for the past 30 years. The kiln configuration and a drying schedule can be input and the code in the Excel file will simulate . If the temperature is below this range, I start the heater and adjust the thermostat accordingly. Its a nice use of technology and adds a measure of safety as well.) In Fig. Thicker lumber like 5/4 or quartersawn lumber is naturally more stable. My question focuses on the initial relative humidity featured in the Safe Drying Rate table. Each layer adds approximately .81 R value. I either use some cedar 3" x 5", or 4" x 4" stock. Loading the kiln begins by rousing my sons and letting them know Ive planned a day of work. The DH is not needed at this time, as the lumber is already bone-dry. A lower RH setting will call for the DH to run more often. Detailed design and custom manufacture of dehumidification and chiller systems for food processing, lumber drying and industrial applications. John Baines Reply to Dann Barry 1 year ago In exchange for building the shed myself, I wound up with a shed of higher quality, with more features. You could use the dehumidifier to dry wood but it would not be part of a "kiln." Just be a different process. For a kiln temperature of 140 F, sterilization takes three to five hours. Schedules for several thicknesses and specialty products (e.g. Take the electronics out of the kiln, and continue operating the heater and fans during this phase. Use the gridded drawings provided on the PDF, Woodworking | Blog | Videos | Plans | How To. The kiln schedule information in the tables below has been assembled from many different sources, including drying texts and industrial contacts. Among the various sizes of southern yellow pine (SYP) dimension lumber, 2 by 4 is produced in the greatest volume. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. Many regions have increased the shed and outbuilding maximum allowable size without need for a permit. Apply foil tape to the edges of the main baffles to help protect the Styrofoam. Kiln schedules are completely assembled and written out for easy use. For the best experience on our site, be sure to turn on Javascript in your browser. 1998. by Dr. Eugene Wengert. That purchase was an average deal, and one I dont consider a particular bargain. Vote. Inexpensive Dehumidification KilnIn this video we'll build and load a 14' long 4' by 4' wood kiln that dries wood by heat and dehumidification.We had quite a. The stickers are uniform in size and usually 3/4" or 1" square. I find that unplugging the DH is helpful during the sterilization phase so I can add a second heater, without overwhelming my electrical circuit. If you dry 9,500BF of slower drying Oak, youd use the 10MBF chamber with the HT8 Dehumidifier. To hang the baffles, simply attach hooks to the plywood frame. Measure airflow over the stacks of lumber in various locations. The baffles direct airflow over and through the stack and prevent the top layers from drying too quickly. This returns some moisture to the very dry exterior of the lumber, while not affecting the core moisture level. The kiln humidity can be expressed as an EMC, relative humidity, or wet-bulb temperature. For end baffles, I use 2"-thick rigid foam insulation screwed to the main baffles. Its a nice use of technology and adds a measure of safety as well.) For a small scale shed kiln, I recommend a maximum footprint of 200 square feet. Determine the correct designation, such as T3-D2 for 4/4 red oak. I like these "starter blocks" to raise the lumber a few inches off the floor. Once all the lumber is stacked and stickered, place baffles over the lumber. Official websites use .gov Once the core readings are 6% to 8% on a fresh cut, the lumber is dry and ready for sterilization. After seven to 10 days, I reverse the fan direction to make sure all stacks of lumber dry evenly. This will allow the heater to cycle on and off automatically, according to the kiln operators setting. I was hoping someone could point me in the right direction or share experience. Soon the DH won't show much water collected in the tray. However, you may need more cycles depending on the species, moisture content, and size of the timber. 1998. To accommodate the floor insulation, blocking between joists is oriented horizontally instead of the normal vertical position. Kiln drying lumber is a simple, cost effective method recommended for anyone who wants to increase profits by selling dried lumber. A typical home center sheds floors are underbuilt for the weight of a load of lumber. The approach described in the article where you try to keep the water leaving at a steady rate is fine. Most species of hardwood lumber can be safely dried this way, once the moisture content is 20% to 25% or less. Question 158 p. Dry kiln schedules for commercial woods : temperate and tropical. Once all the lumber is stacked and stickered, place baffles over the lumber. Just walk out to the shed kiln and grab what you need from your custom-dried supply. We proudly stand behind all of our products. Table 1 shows a typical drying schedule for sugar maple. For single-stack kilns, stationary fans are adequate. trailer << /Size 918 /Info 891 0 R /Root 907 0 R /Prev 482770 /ID[<67858f68421814977b05bc7913f6cc23><4073af979fbabe8f1c016146fd1c21ef>] >> startxref 0 %%EOF 907 0 obj << /Pages 902 0 R /Type /Catalog /DefaultGray 903 0 R /DefaultRGB 904 0 R /Metadata 905 0 R >> endobj 916 0 obj << /S 499 /Filter /FlateDecode /Length 917 0 R >> stream The moisture loss, drying time and drying defects were determined. For sterilizing thicker lumber, additional time is required. January 27, 2007. They are normally mounted in the gable of household attics, and they are designed to be used in high temperature environments. The membrane was taped and lapped to the weather so if the tape ever fails, any rain that gets behind the siding would still be shed down and away by the HomeWrap. I selected a 36 outswing exterior door. My shed kiln was stick-built from standard building material, and sized to take advantage of typical 4 x 8 sheet goods. Made in China, it exudes the classic style of Asian and Chinese cultures, featuring a unique shape that sets it apart from traditional jars. Low Temperature Kiln Drying Systems (120F), High Temperature Kiln Drying Systems (160F), Very High Temperature Kiln Drying Systems (220F), Website Content Copyright 2023 Nyle Systems |, Affordable and easy method to accomplish top quality lumber drying, Designed specifically for any sized operation, Modular based systems for unlimited capacity, No boiler or steam required with gas furnace, Can be installed along side existing kilns, Chambers are sized with our DH systems to meet your lumber drying requirements. . Installing a window in a kiln may seem counterintuitive at first, because windows lose more heat than an insulated wall. This would allow a stack of lumber four feet wide and 10 feet long. If we revisit the example of a $1,300 gross savings from a load of 540 BF of white oak lumber, and we subtract the estimated cost of $62 to kiln dry the lumber, we arrive at a net savings of $1,238 less than retail. (Note: This letter designation is related to the green MC of the species. For example, if you dry 7,500BF of fast drying Pine, youd select the 8MBF chamber with the HT18 Dehumidifier. For these reasons, I feel it is best to let the shed breathe, and forgo a plastic vapor barrier. There may be more depression values than required; ignore the extra depression values in this table. of this publication is to make available to dry kiln operators and others interested in kiln-drying wood, kiln schedules that are completely assembled and written out for ready reference and easy use. For single-stack kilns, stationary fans are adequate. End baffles are also a good idea to prevent airflow from bypassing the stack entirely. %%EOF A.gov website belongs to an official government It is a meaningless exercise to try to convert those schedules for the kiln you built. Adjust the baffles or fan direction to achieve good airflow. A typical kiln schedule is a series of temperatures and relative humidities, which are applied at various stages of drying as can be seen in Table 1. . Soon the DH wont show much water collected in the tray. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. Share sensitive information only on official, secure websites. My baffles hang from T-bar assemblies mounted to the ceiling. Solar kiln drying was most effective in the summer and early fall, when kiln efficiencies were 90% to 67%, respectively, and drying times were 2 to 3/one-half/ times faster than air drying. So, with that lengthy introduction, here is my question. This slows the end-grain drying and limits the severity of end checking. If you use a lot of lumber, and youre a decent hand at carpentry, a shed kiln will quickly pay for itself. The kiln humidity can be expressed as an EMC, relative humidity, or wet-bulb temperature. A discussion of how to apply "safe drying rate" calibrations with a home-built dehumidifying kiln. The T-bars are made from 1/2" galvanized pipe and are attached to the rafters with threaded pipe flanges. Should I? A higher humidity setting will run the unit sporadically to maintain that RH. I either use some cedar 3 x 5, or 4 x 4 stock. /Height 2587 3, a simplified transverse section of a kiln chamber with an energy recovery and dehumidification system is shown. For sterilizing thicker lumber, additional time is required. Willie Sandry is a furniture maker and a lumber kiln operator in Camas, Washington. Kiln Structure . Saving money by drying your lumber may not be the answer for every woodworker, but the basics shown here demonstrate that it is within the reach and skills of the average person. The air flow rate through your stacks should be about 350FPM. What can you do to speed up drying time? 4. In addition, weight on top of the stack can be helpful, but nothing replaces baffles for the best lumber yield. With a 130 F kiln temperature, sterilization will take 10 to 12 hours (Dry Kiln Operators Manual, 1991). (A major source was Dry Kiln Schedules for Commercial Woods which is available from the Forest Products Society in Madison, WI.) Can also be used on any mobile device! Windows and doors are also sealed, as well as any holes cut for electrical service. Nyle. I found that brackets for mounting rigid metal electrical conduit work best. In larger kilns, the heater may be needed in the latter part of the drying cycle. If you intend to kiln dry lumber from a green state, right off the sawmill, you will need to be well-versed in airflow rates and follow a detailed drying schedule. You may also return purchases to a Rockler store near you for store credit. Regardless of size, allow for a 36 door that opens to a hallway of open space. These figures hold true for lumber up to 2 thick. Staff. I use a Rockler steam generator. When the drying is done in a kiln, the product is known as kiln-dried timber or lumber, whereas air drying is the more traditional method.. 8. This returns some moisture to the very dry exterior of the lumber, while not affecting the core moisture level. For example, if you dry 7,500BF of fast drying Pine, you'd select the 8MBF chamber with the HT18 . /Name /ImagePart_0 Basically, you don't want all of the air rushing out under the stack, so find a way to redirect it. The conversion method described in the Dry Kiln Operator's Manual is not really accurate, but it is safe. If your lumber stack is built on starter blocks, you will need to limit airflow there as well. Always avoid conditions that add moisture back to the lumber, especially during start-up. I have sensors in the kiln for moisture levels & probes in the center of the wood attached to a lignomat moisture meter. 0 . Place a sticker at each end, and every 16 along the stack for 4/4 stock. My kiln schedule starts with running all fans and the dehumidifier for two days, measuring and removing water as it accumulates. This will allow the DH to drain automatically without you needing to enter the kiln. A dry kiln needs to be operated when it is filled with lumber and forces airflow through the tiers of lumber instead of around the ends or over the top of the stack(s). (Dry Kiln Operator's Manual. Two-by-four material sawn from young trees, thinnings, and stem tops contains a significant proportion of juvenile wood and is particularly notorious for warp. Equalizing and conditioning are required for almost all hardwood lumber. This is because it needs to be dried to a lower moisture content than wood will air dry to outdoors. Unfortunately, little information is available regarding lumber drying technology and practices used, which is essential for the formulation of improvement strategies. The first load was started with 60% and this load was started with 78%. Dehumidification Kilns During the conditioning process, the only equipment operating are the fans, heater and the steam generator no dehumidifier. Consider not only the space for the lumber stacks, but extra floor space to easily load and monitor the charge of lumber. WOODWEB is a registered trademark of Woodweb.com. If the temperature is below this range, I start the heater and adjust the thermostat accordingly. To condition the lumber, I introduce steam into the kiln for about two hours. The common lumber name is used throughout. A heavy-duty 1,500-watt space heater works fine. If it isn't overheating, it is leaking. The problems with solar kilns include limited control over temperature and limited solar exposure, depending on your region and site location. Know how to choose and apply the correct schedule for the lumber. Heres a classic project that both steps up and provides overflow seating. The company's small kilns can be configured for drying lumber, firewood, or heat-treating lumber or wood packaging. Items shipped directly from the manufacturer cannot be returned in store. Wood drying (also seasoning lumber or wood seasoning) reduces the moisture content of wood before its use. A 1.5-kW dehumidifier was installed in the solar dryer to determine the performance of a combined solar-dehumidification dryer. This shed will be essentially unheated for much of the year and very hot during the kiln-drying cycles. Temps are in Celsius (20C = 70F, 40C = 105F). The first thing to consider when designing a shed kiln is size. Construction of a kiln chamber is very similar to building a small house. A dehumidification kiln continuously recycles the heat throughout the chamber, rather than . Omitting the sterilization phase can lead to costly losses from insect damage, so dont skip it. Select a heater with an adjustable thermostat and a tip-over shutoff. Place some sample boards in the stack that will be easy to pull out for moisture testing later. 3. The first charge of mixed air-dried 4/4 hardwoods and softwoods was kiln-dried from 18.4% to 7.3% moisture content (MC) in 15 days with no . 0000006297 00000 n A free BASIC program to convert the designations into actual temperatures and humidities is available from the author. Dehumidification Kiln Drying. Moisture Content Dry Bulb Wet Bulb Depression percent degree F degree F degree F Above 50 110 106 4 50 to 40 110 105 5 40 to 35 110 102 8 35 to 30 110 96 14 30 to 25 120 90 30 Insulation for walls and ceilings should be a minimum of R13. Omitting the sterilization phase can lead to costly losses from insect damage, so don't skip it. Any small building could work, as long as it has a minimum of 2 x 4 framing, and will seal out unwanted air. Instead of using expensive electrically reversible fans designed for commercial kilns, I came up with a simple hardware solution. Joining end grain to long grain forms the king of joints. They are easy to use and give you precision control over your drying. I cannot stress the importance of baffles enough. In contrast, a dehumidification kiln uses a sealed chamber, with only enough energy input to maintain the desired temperature. Place the sample board in the lumber stack in a location where it will dry at the same rate as the rest of the lumber in the dryer (see Figure C). The baffles do not need insulating properties, and plywood would work just as well. Exterior sheathing and siding type also factors into the heat-holding ability of the structure. Chinese, Korean or Japanese kilns have an arch roof. The four charges of lumber ranged from 600 to 700 board feet (bf), and a woodworker with no dry-kiln experience operated the kiln. I hope that the sawyer coated the ends of the lumber with Anchor-Seal or oil-based paint when it was green. If you cannot find exact match, look at SG of same family species. Hardwood kiln drying schedules typically keep the dry bulb temperature below 80 C (176 F). Wood-Mizer dehumidification and solar wood kilns range from 300 to 35,000 board feet capacity for drying lumber. For more capacity, consider a two stack kiln (12 x 12), or a three-stack kiln (12 x 16). A heavy-duty 1,500-watt space heater works fine. I'm thinking I could vent it manually, but with the RH so high externally I am not sure if that is the right thing to do. txN.a!HQ)FmCw~{B1Aq_!+zN#+j Bring your moisture meter to confirm. Milling the stickers square is advantageous over a rectangular cross-section, because no matter how you place the stickers they will form a level stack. Seems like a pretty simple way to run the kiln - once or twice a day just measure the amount of water extracted, and turn down the humidity a bit as needed. Khmer Kiln: quite similar to the Anagama kiln however, traditional Khmer Kilns had a flat roof. There is a way to do the conversions and there is a chart published by Nyle to do it, if you want to do some academic exercise. Any info or advice on using dehumidification equipment to dry out chainsaw milled lumber. For the sterilization phase, air temperature needs to be around 140 F, for three to five hours. In time schedules, dry- and wet . Oregon-based HDE Dry Kilns has launched a new line of small kilns ranging from 2,000 to 12,000 board feet. Instead of using expensive electrically reversible fans designed for commercial kilns, I came up with a simple hardware solution.

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