Perhaps the best part: you wont need to calculate your lumber needs down to the board foot. A heavy-duty 1,500-watt space heater works fine. However, if you kiln dry hardwood lumber that has already been air dried, the process is much more forgiving. Most species of hardwood lumber can be safely dried this way, once the moisture content is 20% to 25% or less. Forum Responses If you use a lot of lumber, and youre a decent hand at carpentry, a shed kiln will quickly pay for itself. These figures hold true for lumber up to 2 thick. I decided on a dehumidification kiln after reading an article in Fine Woodworking (1991). 0000001417 00000 n Soon the DH won't show much water collected in the tray. %PDF-1.4 % This makes lightweight baffles that can be easily moved and repositioned. My shed kiln was stick-built from standard building material, and sized to take advantage of typical 4 x 8 sheet goods. (Note: This letter designation is related to the green MC of the species. Place some sample boards in the stack that will be easy to pull out for moisture testing later. 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. In this paper, the effective schedules were further investigated for longer culm parts treated with boron. Table 1 shows a typical drying schedule for sugar maple. I am using a household . The column on the right I added part way through is the kiln's internal RH. A bead of silicone caulking between the subfloor and sill plate will prevent air infiltration. Basically, you don't want all of the air rushing out under the stack, so find a way to redirect it. This fact sheet summarizes the basics of kiln drying wood, the most commonly used methods, drying schedules and some drying defects. A household dehumidifier (DH) removes moisture from the kiln chamber. Drying lumber too quickly can lead to deep end checking, warping and case hardening. We are proud of the quality of our products, and we stand behind them 100%. 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. With advances in spray foam insulation, it may be possible to seal older, drafty structures as well. The schedule designations use the popular U.S. Forest Products Laboratory designations. Nyle Systems dehumidification kiln packages are our best known product with nearly unlimited drying capabilities. . The baffles do not need insulating properties, and plywood would work just as well. This will allow the heater to cycle on and off automatically, according to the kiln operators setting. noun: kiln; plural noun: kilns. 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. Electrical requirements for a DIY kiln are pretty straightforward, but hiring an electrician is still a good idea. I'd like to know for my own curiosity, as well as to be able to generate SDR schedules for other species not given in the American Woodworker article, like the 6 foot long 24" wide slabs of 8/4 madrone I got this summer. After a short period of grumbling, they join me to lay down wood blocks for the first layer of lumber. Question Dehumidification kilns from Nyle Systems in Brewer, Maine. Sears Canada 70 Pint Dehumidifier. Design and Operate a Small-Scale Dehumidification Kiln (In the original Dry Kiln Operators Manual written in the early 1950s, some species were not used in high quality products. Thicker lumber like 5/4 or quartersawn lumber is naturally more stable. Main thing is to not rush drying in first stages, as this will cause problems. In vacuum kiln trials, logs were heated to 56C at 70 percent log radius depth and the temperature maintained for . A lazy Susan with 180 detents mounts the fan box to the ceiling. End baffles are also a good idea to prevent airflow from bypassing the stack entirely. For sterilizing thicker lumber, additional time is required. Make sure the total amp draw is well within the limit of your electrical circuit. My baffles hang from T-bar assemblies mounted to the ceiling. If MC readings still arent at the desired range, the heat may need to be increased for the remainder of the drying cycle. T8-C3 or similar for hard maple), the article instead provided a table showing the "safe drying rates" (SDR) for a number of species. Reply. A low temperature heat treatment chamber and/or dehumidification kiln is identified as operating between approximately 43C (110F) and 56C (133F) for an extended period during the kiln drying cycle. Dehumidification Kilns INDUSTRIAL DEHUMIDIFICATION DRYING OF SOFTWOODS - Oregon State University %PDF-1.5 The lumber was then measured for crook, bow, and twist. This shed will be essentially unheated for much of the year and very hot during the kiln-drying cycles. Built properly, a shed kiln may even increase the value of a property. A 1.5-kW dehumidifier was installed in the solar dryer to determine the performance of a combined solar-dehumidification dryer. With a 130 F kiln temperature, sterilization will take 10 to 12 hours (Dry Kiln Operators Manual, 1991). 3. Our capacities are 4,000 board feet in a kiln . Once the core readings are 6% to 8% on a fresh cut, the lumber is dry and ready for sterilization. Regardless of size, allow for a 36 door that opens to a hallway of open space. 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. I then manually rotate the fan boxes halfway through the drying cycle. Always avoid conditions that add moisture back to the lumber, especially during start-up. These kilns will typically hold several thousand board foot of lumber. Check your local building codes for regionally specific requirements and electrical permits. The T-bars are made from 1/2 galvanized pipe and are attached to the rafters with threaded pipe flanges. . Place some sample boards in the stack that will be easy to pull out for moisture testing later. 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? Add to my manuals. I find that unplugging the DH is helpful during the sterilization phase so I can add a second heater, without overwhelming my electrical circuit. By setting the relative humidity (RH) on the dehumidifier, you can control how often it runs. 158 p. Dry kiln schedules for commercial woods : temperate and tropical. For these reasons, I feel it is best to let the shed breathe, and forgo a plastic vapor barrier. 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. After seven to 10 days, I reverse the fan direction to make sure all stacks of lumber dry evenly. Different species should not be loaded simultaneously into the kiln due to often differing kiln schedules. Loading the kiln begins by rousing my sons and letting them know Ive planned a day of work. Difficult-to-dry species might not exceed 60 C (140 F). 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. The stickers are uniform in size and usually 3/4" or 1" square. Also check that air isnt escaping around the side baffles or under the stack of lumber. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. Featuring lower cost drying at speeds equal to gas & steam, these kilns are continuously exceeding industry standards and changing the game. Hardwood lumber kiln drying schedules typically keep the dry bulb temperature below 180 F (82 C). Chinese, Korean or Japanese kilns have an arch roof. 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. Page 30 Wood-Mizer Figure 3-4 Drying Schedules Normal Schedule Alternate Schedule Moisture Content Dry Bulb Wet Bulb Dry Bulb Wet Bulb Group 2 Above 45% 90F 85F 100F 97F . Application of Heat Pump Dehumidification : A Case Study : Drying Job Opportunities and Woodworking Services, Dust Collection, Safety and Plant Operation. Farm Forestry timbers - Drying (Seasoning) Timber Unlike general shop space, bigger is not always better for kiln design. By. 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. The kiln configuration and a drying schedule can be input and the code in the Excel file will simulate . in the kiln to dry specific wood products at a satisfactory rate without causing objectionable drying defects. Apply foil tape to the edges of the main baffles to help protect the Styrofoam. I have sensors in the kiln for moisture levels & probes in the center of the wood attached to a lignomat moisture meter. In this system, moist air is not vented out of the kiln but is dehumidified, then recirculated . Determine the correct designation, such as T3-D2 for 4/4 red oak. All of these products were purchased at a local home center, except the remote hygrometer/thermometer which was purchased at a local electronics store. Using a Kiln Schedule Dehumidification drying system. Fundamental Aspects of Kiln Drying Lumber - Academia.edu With a well-designed dehumidification kiln, hardwood lumber can be dried for mere pennies per board foot. I prefer to empty the water tray manually and record the volume of water collected. PDF An Overview of Drying Hardwood Lumber Typical dehumidification kiln (FPL 1999 p. 12-10). This can be done by heating above 133F for 4 hours (measured at the core of the wood), or at 120F for about 7 - 10 days. This slows the end-grain drying and limits the severity of end checking. My baffles hang from T-bar assemblies mounted to the ceiling. At what temperature is wood kiln dried? At the end of the cycle I have the opposite problem. The DH is not needed at this time, as the lumber is already bone-dry. I cannot stress the importance of baffles enough. Go to the first number designation (the temperature designation) and find the corresponding temperatures in the table below. This procedure is discussed in a following section. Add up the amp draw on all the equipment you plan to use in the kiln, including a heater, dehumidifier, fans and steam generator. An Overview. PDF FOR-131: A Checklist for Operators of Small Dry Kilns Also, since heat rises, ceiling-mounted fans have the added benefit of circulating the warmest air over the lumber. Attic fans are a perfect way to provide airflow over the stacks of lumber. A shed kiln is an attractive alternative for a couple of reasons. My kiln uses four ceiling-mounted fans, each rated for 1,600 CFM. Not bragging or anything! Appendix B . In this research, a drying restraint system was evaluated as a means of warp reduction in 8- and 16-foot-long SYP lumber. Items shipped directly from the manufacturer cannot be returned in store. A pre-hung steel exterior door is ideal in this situation, because it offers weatherstripping and is fully insulated. Wood boiler for Lumber Kiln | Hearth.com Forums Home Dehumidification Kiln. . This would allow a stack of lumber four feet wide and 10 feet long. Hardwood Lumber Kiln Schedules 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 A small electric heater supplies auxiliary heat to maintain adequate kiln temperature. A small "m" after the designation indicates that the wet-bulb temperatures should be adjusted to avoid temperatures below 90 F. See the above mentioned publication for details. Heat comes primarily from an integral dehumidification unit that also removes . With a 130 F kiln temperature, sterilization will take 10 to 12 hours ( Dry Kiln Operators Manual, 1991 ). Dehumidifier suggestion: http://amzn.to/2iYZqVZThis is the first in a series of videos showing how I built a kiln for drying lumber. Sorry, preview is currently unavailable. >> Dehumidification drying equipment is available, but an enclosure must be built to house the equipment and dry the lumber. 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 In exchange for building the shed myself, I wound up with a shed of higher quality, with more features. As a result, the kiln schedules were too severe. For example, if you dry 7,500BF of fast drying Pine, you'd select the 8MBF chamber with the HT18 . John Baines Reply to Dann Barry 1 year ago Schedules Dry Kiln Schedules for Commercial Woods Technical Heat Treatment Guidelines and Operating Conditions Manual 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.. Initially, I set the DH to 40% RH, because I dont want to remove moisture too quickly. The last step requires a short period of high humidity to relieve the drying stresses in the boards. 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 four main baffles consist of sheets of 1" Styrofoam insulation. Building a dehumidifier wood kiln - part 1 - YouTube In larger kilns, the heater may be needed in the latter part of the drying cycle. I am removing water about 50% below the SDR. This allows for a more gentle kiln schedule to fully dry the timber. For DH kilns, use the same RH, but lower the temperature to the typical operating temperature for the compressor; raise temperature to steam values when convenient and possible. With a 130 F kiln temperature, sterilization will take 10 to 12 hours (Dry Kiln Operators Manual, 1991). I modified one of the Radio Shack combo units so it could measure the RH remotely as well as the temp. I was hoping someone could point me in the right direction or share experience. Particularly, important investment has taken place in lumber drying capacity. It is a meaningless exercise to try to convert those schedules for the kiln you built. Each layer of lumber is separated from the next by a series of stickers or spacer sticks. Another common sticker size is 1" x 2", and these work fine as well. Dr. Gene Wengert provides schedules for kiln drying hardwood lumber. (See the following sections for a discussion of how to develop a schedule from these designations.) I either use some cedar 3 x 5, or 4 x 4 stock. Website Content Copyright 2023 Nyle Systems |. 5. I had these custom cut and I air dried them outside under a tarp for 6 to 18 months (depending on which load they came in on) and then I kiln dried them in a Nyle dehumidification kiln for 3 months. A lower RH setting will call for the DH to run more often. 1. a furnace or oven for burning, baking, or drying, especially one for calcining lime or firing pottery. Installing sheetrock and fire taping is a good idea for a heated room. Although I can maintain the 90 degree temperature, I could not start at the recommended humidity level unless I added humidity. In addition, wood can be dried by special methods that include solar drying (use of greenhouse-type dryers or those equipped with solar collectors . Download Table of Contents. Figure 3-4 Drying Schedules Normal Schedule Alternate Schedule Moisture Content Dry Bulb Wet Bulb Dry Bulb Wet Bulb Group 2 Above 45% 90F 85F 100F 97F . However, if you kiln dry hardwood lumber that has already been air dried, the process is much more forgiving. A lock ( These are rough-saw red oak. Dehumidification Kiln - Sawmill Creek For international returns, please click here. Difficult-to-dry species might not exceed 140 degrees F. Dehumidification kilns are very . Abstract. the Dry Kiln Operator's Manual (Simpson, 1991). Corrosion resistant epoxy coated aluminum cabinets and specially coated dehumidification coils for an extra long life. Air speed of 350 feet per minute is appropriate for common hardwoods such as oak and maple. With two-stack and three stack kilns, it is better to have reversible fans to alter the direction of airflow mid-cycle. To hang the baffles, simply attach hooks to the plywood frame. Using a dehumidifier for home made kiln? | Woodworking Talk Loading the kiln begins by rousing my sons and letting them know Ive planned a day of work. Hardwood lumber kiln drying schedules typically keep the dry bulb temperature below 180 F (82 C). The common lumber name is used throughout. 44. An outswing door can always be opened, regardless of shed contents. This kicker board will help distribute the airflow more evenly through all layers of lumber. Dehumidification Kilns Low temperatures can be used for an extra safety margin on greener lumber. 0000004213 00000 n Small, complete dehumidification dry kilns under 5,000 board-foot capacity are not available for sale. This gives me a secondary method of tracking the drying process, using both water volume and moisture content (MC) readings. Just walk out to the shed kiln and grab what you need from your custom-dried supply. 0000001208 00000 n A locked padlock I usually see a large volume of water in the DH each night when I check the kiln. ) or https:// means youve safely connected to the .gov website. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. HT systems use 40-60% less energy than gas-fired or steam dry kilns. Kiln - Wikipedia I have constructed a kiln using these plans. These well-known dehumidification kiln packages have been among our bestselling products for the past 30 years. Diy dehumidifier kiln time table. squares, handle stock, gunstock blanks) are given for many species. I use a Rockler steam generator. For single-stack kilns, stationary fans are adequate. Additionally, a 12 air plenum is required between the walls and stacks of lumber. Detailed design and custom manufacture of dehumidification and chiller systems for food processing, lumber drying and industrial applications. Omitting the sterilization phase can lead to costly losses from insect damage, so dont skip it. I know mixed loads are taboo, but this one worked well, other than the horse chestnut. For end baffles, I use 2"-thick rigid foam insulation screwed to the main baffles. To condition the lumber, I introduce steam into the kiln for about two hours. A higher humidity setting will run the unit sporadically to maintain that RH. Cost and operation of a Small dehumidification dry kiln - ResearchGate I have been reading & studying kiln schedules for years too. Minus the drying equipment, a shed kiln is just an insulated storage space, with a host of possible uses. 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. I then manually rotate the fan boxes halfway through the drying cycle. Low Temperature Kiln Drying Systems (120F) 300BF - 4000BF Capacity . This is because it needs to be dried to a lower moisture content than wood will air dry to outdoors. 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 . PDF Kiln Schedules Chapter 7 I use a Rockler steam generator, item #42826 (www.rockler.com). However, because wood from Contractors work on a tight schedule, and that may not allow much time for curing and drying concrete. , , o* j=d 8. This report contains suggested dry kiln schedules for over 500 commercial woods, both temperate and tropical. This prevents "dead spots" inside the chamber that experience limited airflow. High Temperature Kiln Drying Systems (160F) Loads up to 350,000 BF; Pull up to 20,000 pounds of water daily; Use standard drying schedule; Precision temperature and RH . Wood Drying | Oregon Wood Innovation Center - Oregon State University This returns some moisture to the very dry exterior of the lumber, while not affecting the core moisture level. Nyle. Operation and cost of a small dehumidification dry kiln Temps are in Celsius (20C = 70F, 40C = 105F). The kiln process involves the drying of wood in a chamber where air circulation, relative humidity and temperature can be controlled so that the moisture content of wood can be reduced to a target . Use the gridded drawings provided on the PDF, Woodworking | Blog | Videos | Plans | How To. Each layer of lumber is separated from the next by a series of "stickers" or spacer sticks. Its a nice use of technology and adds a measure of safety as well.) Whether to Wax Walnut Ends Before Steaming, Frequently Asked Questions about Widebelt Sanders. NYLE SYSTEMS L200 SERIES USER MANUAL Pdf Download In time schedules, dry- and wet . Dehumidifier Kiln Schedule | Dehumidifier Supply When that is the case, I know Ill have usable lumber in just a few weeks. There may be more depression values than required; ignore the extra depression values in this table. Drying lumber too quickly can lead to deep end checking, warping and case hardening. Manufacturer guarantees/warranties for power tools, CNC and laser products will supersede the Rockler Guarantee if these items are damaged or defective. Blue&White Ginger Jar - L - Dyag East Anyway, I included my log of a load I did in Nov '06 for everyone's amusement. 0000002827 00000 n For the sterilization phase, air temperature needs to be around 140 F, for three to five hours. We proudly stand behind all of our products. This returns some moisture to the very dry exterior of the lumber, while not affecting the core moisture level. A shed kiln has minimal venting (usually one or two gable vents) and sealed soffits. In larger kilns, the heater may be needed in the latter part of the drying cycle. 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. Our next kiln charge is scheduled to begin around February 6, 2023. 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 Choosing a Kiln Schedule Check out More On the Web for my complete calculations to figure savings. If you cannot find exact match, look at SG of same family species. End baffles are also a good idea to prevent airflow from bypassing the stack entirely. You can download the paper by clicking the button above. The order was 540 board feet (BF) of 5/4 white oak.