dehumidification kiln drying schedulesdehumidification kiln drying schedules

For a kiln temperature of 140 F, sterilization takes three to five hours. Reply. The MC ranges are chosen so that the loss of the first one-third of moisture, and the highest risk of checking and staining, will occur in the first step listed.). A bead of silicone caulking between the subfloor and sill plate will prevent air infiltration. For a small scale shed kiln, I recommend a maximum footprint of 200 square feet. So, if you have 100 bf in the kiln, every 12 hours you would extract (12 hours *100bf * .0061 SDR) = 7.3 pints of water. For a kiln temperature of 140 F, sterilization takes three to five hours. Appendix B . Recently, either Wood, or American Woodworker showed how to build a small version of a solar kiln. Many articles have been dedicated to solar lumber kilns: everything from a simple sheet of Visqueen over a stack of lumber in the sunshine to elaborate enclosures designed for solar gain. Staggering the seams between the sheathing and siding layers helps avoid air infiltration. In-service replacement of warped 2 by 4's as wall studs or truss members is costly. Taking moisture away at the rate the board will "safely" part with it . Website Content Copyright 2023 Nyle Systems |. 6. The velocity through the load is assumed to be between 275 and 350 fpm, except for the white woods (including maple, ash, basswood, hackberry) where higher velocities (up to 600 fpm) are desired and acceptable. My kiln uses four ceiling-mounted fans, each rated for 1,600 CFM. For the sterilization phase, air temperature needs to be around 140 F, for three to five hours. The thinner the stock, the more critical sticker placement becomes. Schedule for drying 4/4 and 5/4 upland red oak in a steam dry kiln. 906 0 obj << /Linearized 1 /O 908 /H [ 710 498 ] /L 501020 /E 6532 /N 45 /T 482781 >> endobj xref 906 12 0000000016 00000 n Table 1 shows a typical drying schedule for sugar maple. You could use the dehumidifier to dry wood but it would not be part of a "kiln." Just be a different process. For example, if you dry 7,500BF of fast drying Pine, youd select the 8MBF chamber with the HT18 Dehumidifier. On this order alone, I saved over $1,300 by drying the lumber myself. The four charges of lumber ranged from 600 to 700 board feet (bf), and a woodworker with no dry-kiln experience operated the kiln. For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. With a well-designed dehumidification kiln, hardwood lumber can be dried for mere pennies per board foot. An official website of the United States government. This problem is magnified if the lumber is thin or flatsawn. Any small building could work, as long as it has a minimum of 2 x 4 framing, and will seal out unwanted air. Items shipped directly from the manufacturer cannot be returned in store. I usually see a large volume of water in the DH each night when I check the kiln. . Kiln drying is almost always essential for wood intended for interior uses. I often buy from sawyers or homeowners at 40% to 50% of retail price. Attic fans are a perfect way to provide airflow over the stacks of lumber. Changing the position of the doorway in various kiln setups helps provide the best access to the stacks of lumber. 9. 0 \ Each layer of lumber is separated from the next by a series of "stickers" or spacer sticks. After seven to 10 days, I reverse the fan direction to make sure all stacks of lumber dry evenly. The fact is, most of my stacks of lumber air dry to 15% moisture content before entering the kiln. Kiln schedules are completely assembled and written out for easy use. Vote. Should a Moulding Mill Bring Sawmill Operations In-House? , , o* j=d It uses a simple humidistat to control the dehumidifier, and a remote bulb thermostat to control the heater, which is a couple of light bulbs. Once the flooring deck is constructed, think about sealing the shed framing at every opportunity. If for any reason you are not satisfied with the merchandise you ordered, just return it within 90 days to receive a refund in the manner of original payment for merchandise only. There are many types of kilns, but the most common are dehumidification kilns and conventional kilns. This makes lightweight baffles that can be easily moved and repositioned. I decided on a dehumidification kiln after reading an article in Fine Woodworking (1991). Phytosanitary heat treatments of Ceratocystis lukuohia and Ceratocystis huliohia-colonized Metrosideros polymorpha wood were evaluated using kilns. The schedules can also be formulated manually as follows. Every Nyle Dehumidification Dry Kiln System Example: If the WBT falls below the set parameter measures and regulates internal kiln conditions the system will turn on the spray system. %PDF-1.6 % For more capacity, consider a two stack kiln (12 x 12), or a three-stack kiln (12 x 16). A lazy Susan with 180 detents mounts the fan box to the ceiling. JavaScript seems to be disabled in your browser. temperature. Low Temperature Kiln Drying Systems (120F) 300BF - 4000BF Capacity . 3. Basically, you dont want all of the air rushing out under the stack, so find a way to redirect it. Your order will come with a return form with convenient instructions, or you may send your returns directly to Returns Department, Rockler Woodworking and Hardware, 4365 Willow Drive, Medina, MN 55340. This slows the end-grain drying and limits the severity of end checking. A locked padlock kiln/. Basically the idea seems to be to maintain a constant temperature, and to keep lowering the humidistat to maintain the SDR until the moisture content gets to the desired level. Thus, a drying program can be adapted according to the characteristics of the kiln load, e.g., species, dimensions, and moisture content. I found that brackets for mounting rigid metal electrical conduit work best. In vacuum kiln trials, logs were heated to 56C at 70 percent log radius depth and the temperature maintained for . I made a simple frame from plywood strips and attached theinsulation sheets to them with screws and fender washers. Thicker lumber like 5/4 or quartersawn lumber is naturally more stable. Culm parts with 2.0 and 2.2 m length after pressure treatment were dried in industrial kilns using three schedules with mild, severe and highly severe drying intensity. I use a Rockler steam generator, item #42826 (www.rockler.com). >> HT systems use 40-60% less energy than gas-fired or steam dry kilns. 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. This prevents dead spots inside the chamber that experience limited airflow. If required, look-up and write down the RH (sixth column) and EMC (seventh column) for each schedule step. Kiln Structure . Ignoring for a moment the merits of a homebrew DH kiln versus a Nyle, I was curious to see that rather than referencing the standard kiln schedules (e.g. Also check that air isnt escaping around the side baffles or under the stack of lumber. My aim was to develop a small dehumidification kiln for better control of the three key components of lumber drying: temperature, airflow and humidity. noun. A shed kiln has minimal venting (usually one or two gable vents) and sealed soffits. %PDF-1.4 % End baffles are also a good idea to prevent airflow from bypassing the stack entirely. Once all the lumber is stacked and stickered, place baffles over the lumber. I'm trying to find a timetable or drying schedule for the basic dehumidification kilns you see on youtube. These figures hold true for lumber up to 2" thick. Sign In Upload. ) or https:// means youve safely connected to the .gov website. For these reasons, I feel it is best to let the shed breathe, and forgo a plastic vapor barrier. (I have found that remotely monitoring the temperature and humidity with a WiFi sensor can be very helpful. Wood drying (also seasoning lumber or wood seasoning) reduces the moisture content of wood before its use. The sheetrock also helps to protect the fiberglass insulation. Total costs for the materials were $2,704 based on 2006 prices. I usually see a large volume of water in the DH each night when I check the kiln. 0000006297 00000 n In this paper, the effective schedules were further investigated for longer culm parts treated with boron. The store will not work correctly in the case when cookies are disabled. A lower RH setting will call for the DH to run more often. These figures hold true for lumber up to 2 thick. For 4/4 hard maple, with an initial temperature of 90F and an initial relative humidity of 81%, the SDR was given as .0061 pints per hour per board foot. Looking at the cost-benefit analysis of a shed kiln can be enlightening. 73. Without baffles, the top layers of lumber experience "potato chipping" with cupping, twisting or warping. I know mixed loads are taboo, but this one worked well, other than the horse chestnut. This kicker board will help distribute the airflow more evenly through all layers of lumber. 0000004213 00000 n %PDF-1.5 Dont even think of powering your kiln with an extension cord. Another common sticker size is 1 x 2, and these work fine as well. Align the stickers over the starter blocks on the first course. Low temperatures can be used for an extra safety margin on greener lumber. T8-C3 or similar for hard maple), the article instead provided a table showing the "safe drying rates" (SDR) for a number of species. A heavy-duty 1,500-watt space heater works fine. In the fourth column, write down the wet-bulb depressions (determined in #4 above), one for each Schedule Step, starting at the top (Schedule Step 1). Another common sticker size is 1" x 2", and these work fine as well. Place a sticker at each end, and every 16" along the stack for 4/4 stock. Hardwood kiln drying schedules typically keep the dry bulb temperature below 80 C (176 F). We are proud of the quality of our products, and we stand behind them 100%. For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. To hang the baffles, simply attach hooks to the plywood frame. As the MC drops and I crank the DH on more and more, the temp tends to rise up too high just from the heat the DH throws off, even though the light bulb heaters are not on at that point. Go to the first number designation (the temperature designation) and find the corresponding temperatures in the table below. Dr. Gene Wengert provides schedules for kiln drying hardwood lumber. 0000001186 00000 n Instead of using expensive electrically reversible fans designed for commercial kilns, I came up with a simple hardware solution. Unfortunately, little information is available regarding lumber drying technology and practices used, which is essential for the formulation of improvement strategies. After a short period of grumbling, they join me to lay down wood blocks for the first layer of lumber. This is because it needs to be dried to a lower moisture content than wood will air dry to outdoors. End baffles are also a good idea to prevent airflow from bypassing the stack entirely. Corners where walls meet should be sealed with expanding foam sealant. An anemometer confirms that your effort constructing baffles was worthwhile. The last step requires a short period of high humidity to relieve the drying stresses in the boards. This slows the end-grain drying and limits the severity of end checking. Delete from my manuals. A shed kiln is an attractive alternative for a couple of reasons. A higher humidity setting will run the unit sporadically to maintain that RH. Custom Doors, Drawers & Glass Accessories, Using a Small Scale Dehumidification Kiln, Learn Woodworking Tips & Tricks with Rockler, High-quality brands and products you can trust, Expert advice and free post-purchase support, Exclusive, innovative products that help you Create with Confidence, Detailed instructions, technical specs and guides to make the most of your purchases. I either use some cedar 3" x 5", or 4" x 4" stock. If you cannot find exact match, look at SG of same family species. Staff. A pre-hung steel exterior door is ideal in this situation, because it offers weatherstripping and is fully insulated. To hang the baffles, simply attach hooks to the plywood frame. Frequently, the lumber has already air-dried for several years in a barn or outbuilding. The kiln climate is controlled by venting the hot air and replacing it with ambient air. Installing a window in a kiln may seem counterintuitive at first, because windows lose more heat than an insulated wall. In a professional DH kiln, the final climate for oak is 120F and <40>t over-dry it at that rate. 7. Heat comes primarily from an integral dehumidification unit that also removes . -. 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. 0000003109 00000 n Then align each subsequent layer of stickers over the last. Wood Shrink/Swell estimator - A web-based program to estimate shrink/ swell in wood. A Checklist for Operators of Small Dry Kilns A companion to A Start-up Guide for Operators of Small Dry Kilns (FOR-132) Terry Conners, Forestry and Natural Resources /Height 2587 For sterilizing thicker lumber, additional time is required. Forum Responses That purchase was an average deal, and one I dont consider a particular bargain. %%EOF Different species should not be loaded simultaneously into the kiln due to often differing kiln schedules. With a 130 F kiln temperature, sterilization will take 10 to 12 hours ( Dry Kiln Operators Manual, 1991 ). This serves a dual purpose of supporting the rigid foam insulation as well as stiffening the floor framing. (Note: This letter designation is related to the green MC of the species. Insulation for walls and ceilings should be a minimum of R13. In contrast, a dehumidification kiln uses a sealed chamber, with only enough energy input to maintain the desired temperature. Most species of hardwood lumber can be safely dried this way, once the moisture content is 20% to 25% or less. What can you do to speed up drying time? In Fig. The velocity through the load is assumed to be between 275 and . 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. Always use adequate samples representing both the wettest and driest lumber in the dryer. Main thing is to not rush drying in first stages, as this will cause problems. txN.a!HQ)FmCw~{B1Aq_!+zN#+j Loading the kiln begins by rousing my sons and letting them know Ive planned a day of work. I recommend a 2 x 3 sliding window with bug screen. Electrical requirements for a DIY kiln are pretty straightforward, but hiring an electrician is still a good idea. Go to the second letter designation (the MC Class Designation) and find the corresponding MC ranges in the table below. I made a simple frame from plywood strips and attached the insulation sheets to them with screws and fender washers. Soon the DH won't show much water collected in the tray. All of these products were purchased at a local home center, except the remote hygrometer/thermometer which was purchased at a local electronics store. Joining end grain to long grain forms the king of joints. Apply foil tape to the edges of the main baffles to help protect the Styrofoam. Question Consider not only the space for the lumber stacks, but extra floor space to easily load and monitor the charge of lumber. The kiln humidity can be expressed as an EMC, relative humidity, or wet-bulb temperature. For 4/4 hard maple, with an initial temperature of 90F and an initial relative humidity of 81%, the SDR was given as .0061 pints per hour per board foot. So, with that lengthy introduction, here is my question. I have constructed a kiln using these plans. Select a heater with an adjustable thermostat and a tip-over shutoff. Not bragging or anything! For sterilizing thicker lumber, additional time is required. Standard kiln drying temperatures are low - around 120 degrees Fahrenheit or so, and drying times vary by wood size and moisture level. I opted not to install a true vapor barrier between the framing and sheetrock, because of potential condensation and mold issues with sheds constructed this way. endstream endobj 283 0 obj <>/Metadata 40 0 R/OCProperties<>/OCGs[294 0 R]>>/Outlines 53 0 R/PageLayout/SinglePage/Pages 280 0 R/StructTreeRoot 72 0 R/Type/Catalog>> endobj 284 0 obj <>/Font<>/Properties<>/XObject<>>>/Rotate 0/StructParents 0/Tabs/S/Type/Page>> endobj 285 0 obj <>stream The approach described in the article where you try to keep the water leaving at a steady rate is fine. Commercial scale steam kilns consume large amounts of energy. You can achieve top-quality results with incredible efficiency. Dehumidification kilns from Nyle Systems in Brewer, Maine. /Width 1628 )f7haRoMRhib5Sd|-=RBkBBN r-hzf+1\IFgk;v]3_, KxL$9oL "Qw#"BFGfk}>cT2g yP K|7@N*v9!Wy9jB. op(y"X)Fz"q]fQC/ha>7=k_p}}^VXQmj e'2fyXQ{~23X^H1,d>Hq|^KQ*cN=yF%z. Our next kiln charge is scheduled to begin around February 6, 2023. Lay down the bead of caulking before raising the walls. Abstract. The problems with solar kilns include limited control over temperature and limited solar exposure, depending on your region and site location. squares, handle stock, gunstock blanks) are given for many species. Then align each subsequent layer of stickers over the last. A better choice might be a solar kiln, as you can dry wood from "wet" to 6-8 percent MC in 6-8 weeks. However, if you kiln dry hardwood lumber that has already been air dried, the process is much more forgiving. 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). 0000000591 00000 n /BitsPerComponent 1 The Bolivian wood products industry was surveyed to determine lumber drying capacity, technology and. Operates at a temperature range from 80F - 160F (26 - 71C). /Name /ImagePart_0 I find that unplugging the DH is helpful during the sterilization phase so I can add a second heater, without overwhelming my electrical circuit. In smaller kilns, the heat generated by the fans and DH motor is sufficient to maintain temperatures in excess of 100 degrees. Nyle Systems dehumidification kiln packages are our best known product with nearly unlimited drying capabilities. USDA, 1991) . Air drying to 6 - 8% MC is a very long term proposition and I'm not a patient man so I wanted a means to finish dry lumber after air drying outside to the EMC of my area of around 12 - 14%. For these items, please call the store where you purchased them or our customer service department at 1-800-376-7856 so we can assist you. If MC readings still arent at the desired range, the heat may need to be increased for the remainder of the drying cycle. Schedules Dry Kiln Schedules for Commercial Woods However, the natural light and ventilation offered by a small window outweighs any disadvantages. 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. The order was 540 board feet (BF) of 5/4 white oak. My baffles hang from T-bar assemblies mounted to the ceiling. 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. . This makes lightweight baffles that can be easily moved and repositioned. Its a nice use of technology and adds a measure of safety as well.) Most species of hardwood lumber can be safely dried this way, once the moisture content is 20% to 25% or less. With two-stack and three stack kilns, it is better to have reversible fans to alter the direction of airflow mid-cycle. In the majority of cases, the drying schedules are from the world literature, with emphasis on U.S., Canadian, and British publications. The T-bars are made from 1/2 galvanized pipe and are attached to the rafters with threaded pipe flanges. I modified one of the Radio Shack combo units so it could measure the RH remotely as well as the temp. Rocky Mountain . Select a heater with an adjustable thermostat and a tip-over shutoff. The lumber was then measured for crook, bow, and twist. If MC readings still arent at the desired range, the heat may need to be increased for the remainder of the drying cycle. Check your local building codes for regionally specific requirements and electrical permits. I prefer to empty the water tray manually and record the volume of water collected. Such temperatures are high enough to kill insectsanother advantage of kiln drying over air drying. With a 130 F kiln temperature, sterilization will take 10 to 12 hours ( Dry Kiln Operators Manual, 1991 ). Built properly, a shed kiln may even increase the value of a property. /Length 7 0 R On the last load of lumber I purchased, I saved $2.50 per board foot compared to retail prices for kiln-dried lumber. The kiln operator sets the kiln controls based on the initial moisture of the lumber as it is loaded into the kiln. I know your kiln is absolutely tight and perfectly sealed, but it has to vent some or it would overheat. I have been reading & studying kiln schedules for years too. Once the core readings are 6% to 8% on a fresh cut, the lumber is dry and ready for sterilization. However, you may need more cycles depending on the species, moisture content, and size of the timber. Our capacities are 4,000 board feet in a kiln . A higher humidity setting will run the unit sporadically to maintain that RH. This prevents "dead spots" inside the chamber that experience limited airflow. Know how to choose and apply the correct schedule for the lumber. These well-known dehumidification kiln packages have been among our bestselling products for the past 30 years. (I use the Mini-Ligno MD/C from Lignomat, www.lignomatusa.com.) Dehumidification Kilns Loading the kiln begins by rousing my sons and letting them know Ive planned a day of work. 0000006274 00000 n More than 75 percent of the existing hardwood dry kilns in the United States are steam heated, are humidity controlled and have reversible fans inside the kiln. A free BASIC program to convert the designations into actual temperatures and humidities is available from the author. Enter the email address you signed up with and we'll email you a reset link. Whether to Wax Walnut Ends Before Steaming, Frequently Asked Questions about Widebelt Sanders. . Kiln drying is the process of drying wood in a controlled environment, where temperature, air circulation and humidity are monitored and stabilized. Dehumidification Kiln. . Secure .gov websites use HTTPS Leave an air space between the rigid foam and subfloor for additional insulating properties. 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. 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