I dont think the same could be said for an old reefer truck converted into a kiln (no matter how well it dries lumber). Installing sheetrock and fire taping is a good idea for a heated room. For a small scale shed kiln, I recommend a maximum footprint of 200 square feet. This can create internal stress in the lumber that is released when sawing. Our capacities are 4,000 board feet in a kiln . noun. The store will not work correctly in the case when cookies are disabled. Temperatures inside the kiln range from 120 to 190 degrees F, depending on the stage of . Nyle. The company's small kilns can be configured for drying lumber, firewood, or heat-treating lumber or wood packaging. I'm trying to find a timetable or drying schedule for the basic dehumidification kilns you see on youtube. Warp in dimension lumber is a significant cause for loss in grade and value. KD150 Series dehumidifier pdf manual download. 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. By setting the relative humidity (RH) on the dehumidifier, you can control how often it runs. If you use a lot of lumber, and youre a decent hand at carpentry, a shed kiln will quickly pay for itself. Dr. Gene Wengert provides schedules for kiln drying hardwood lumber. 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%. An anemometer confirms that your effort constructing baffles was worthwhile. 1998. by Dr. Eugene Wengert. Also, since heat rises, ceiling-mounted fans have the added benefit of circulating the warmest air over the lumber. My four main baffles consist of sheets of 1 Styrofoam insulation. Excel Program for Modeling Lumber Dry Kiln Operations - a model for lumber dry kiln operation. 0000000591 00000 n Instead of using expensive electrically reversible fans designed for commercial kilns, I came up with a simple hardware solution. Dehumidification kiln schedules 145 Sterilizing, equalizing, and conditioning treatments 145 Sterilizing treatments 145 Mold 145 Fungal stain and decay 146 . After a short period of grumbling, they join me to lay down wood blocks for the first layer of lumber. Case hardening is a defect caused by the outer portion of a board drying quickly, while the inner portion dries more slowly. In exchange for building the shed myself, I wound up with a shed of higher quality, with more features. For the best experience on our site, be sure to turn on Javascript in your browser. For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. In contrast, a dehumidification kiln uses a sealed chamber, with only enough energy input to maintain the desired temperature. 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. My kiln uses four ceiling-mounted fans, each rated for 1,600 CFM. 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. 0000002536 00000 n USDA, 1991) . Staggering the seams between the sheathing and siding layers helps avoid air infiltration. A better choice might be a solar kiln, as you can dry wood from "wet" to 6-8 percent MC in 6-8 weeks. The first load was started with 60% and this load was started with 78%. /Length 7 0 R Also, since heat rises, ceiling-mounted fans have the added benefit of circulating the warmest air over the lumber. 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. The kiln operator sets the kiln controls based on the initial moisture of the lumber as it is loaded into the kiln. Low Temperature Kiln Drying Systems (120F) 300BF - 4000BF Capacity . Secure .gov websites use HTTPS building the dehumidification dry kiln. In larger kilns, the heater may be needed in the latter part of the drying cycle. %3.3 In larger kilns, the heater may be needed in the latter part of the drying cycle. Schedules for several thicknesses and specialty products (e.g. My kiln uses four ceiling-mounted fans, each rated for 1,600 CFM. The velocity through the load is assumed to be between 275 and . Additionally, a 12 air plenum is required between the walls and stacks of lumber. This shed will be essentially unheated for much of the year and very hot during the kiln-drying cycles. Sticker spacing can be increased to 24" apart for 5/4 or thicker hardwood. Perhaps the best part: you wont need to calculate your lumber needs down to the board foot. To browse Academia.edu and the wider internet faster and more securely, please take a few seconds toupgrade your browser. This will allow the DH to drain automatically without you needing to enter the kiln. There are two ways to remove water from the DH unit, and they both work well. The moisture loss, drying time and drying defects were determined. I also wrapped the shed with Tyvek HomeWrap. Place some sample boards in the stack that will be easy to pull out for moisture testing later. . Schedules Dry Kiln Schedules for Commercial Woods hbbd``b` $ &UD\q@u In-service replacement of warped 2 by 4's as wall studs or truss members is costly. hTn8>_l7h.&E:Bem=C9n\8]lMPc. . Typical . . Kiln drying is usually preceded by air drying to bring the moisture content of the wood down below 30%. I like these starter blocks to raise the lumber a few inches off the floor. Extruded polystyrene foam (blue or pink rigid foam) in this thickness has an R value of 10. Another great option is to convert an existing shed or outbuilding to a lumber kiln. I use a Rockler steam generator. Recently, either Wood, or American Woodworker showed how to build a small version of a solar kiln. Job Opportunities and Woodworking Services, Dust Collection, Safety and Plant Operation, Air-Drying and Kiln-Drying Methods for Wide Plank Flooring, Drying lumber - selecting the best method. _0e`bd\ p@ Once the core readings are 6% to 8% on a fresh cut, the lumber is dry and ready for sterilization. Difficult-to-dry species might not exceed 60 C (140 F). A kiln schedule is a set of temperatures and humidities that are used during kiln operation. Kiln dried wood typically sells for a third more than green lumber and eliminates the need for customers to incur costs associated with drying lumber . This would allow a stack of lumber four feet wide and 10 feet long. This kicker board will help distribute the airflow more evenly through all layers of lumber. (Note: This letter designation is related to the green MC of the species. Take the electronics out of the kiln, and continue operating the heater and fans during this phase. The DH is not needed at this time, as the lumber is already bone-dry. Official websites use .gov Air speed of 350 feet per minute is appropriate for common hardwoods such as oak and maple. A bead of silicone caulking between the subfloor and sill plate will prevent air infiltration. Omitting the sterilization phase can lead to costly losses from insect damage, so dont skip it. Changes in kiln temperatures and humidities are based on the MC of the lumber being dried, which in turn is determined from properly prepared kiln samples. /Subtype /Image For a kiln temperature of 140 F, sterilization takes three to five hours. The kiln humidity can be expressed as an EMC, relative humidity, or wet-bulb temperature. Ciencia y Tecnologia, Duygu Kocaefe, Ayhan Aytin, The Bolivian secondary forest products industry has experienced substantial growth during the last 10 years. Dehumidification Kiln. An outswing door can always be opened, regardless of shed contents. Once the lumber is sterilized, it is ready for the conditioning phase. Kiln Systems. I made a simple frame from plywood strips and attached the insulation sheets to them with screws and fender washers. This fact sheet summarizes the basics of kiln drying wood, the most commonly used methods, drying schedules and some drying defects. Exterior sheathing and siding type also factors into the heat-holding ability of the structure. I usually see a large volume of water in the DH each night when I check the kiln. 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 . Sorry, preview is currently unavailable. What can you do to speed up drying time? The schedule designations use the popular U.S. Forest Products Laboratory designations. For sterilizing thicker lumber, additional time is required. With a 130 F kiln temperature, sterilization will take 10 to 12 hours (Dry Kiln Operators Manual, 1991). Electrical requirements for a DIY kiln are pretty straightforward, but hiring an electrician is still a good idea. A dehumidification kiln continuously recycles the heat throughout the chamber, rather than . If severe enough, the lumber can develop honeycomb cracks throughout. Sign In Upload. Measure airflow over the stacks of lumber in various locations. 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. Once the lumber is sterilized, it is ready for the conditioning phase. Soon the DH wont show much water collected in the tray. Check out More On the Web for my complete calculations to figure savings. My number one priority was to build a kiln that was easy to load and easy to monitor. Formulating a Kiln Schedule A heavy-duty 1,500-watt space heater works fine. Once all the lumber is stacked and stickered, place baffles over the lumber. Dehumidification dry kilns operate at lower drying temperatures (typically below 150F) than do conventional kilns, which results in longer drying schedules. These figures hold true for lumber up to 2 thick. They are easy to use and give you precision control over your drying. Vote. 3. The problems with solar kilns include limited control over temperature and limited solar exposure, depending on your region and site location. Built properly, a shed kiln may even increase the value of a property. 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. For a kiln temperature of 140 F, sterilization takes three to five hours. After seven to 10 days, I reverse the fan direction to make sure all stacks of lumber dry evenly. 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 this system, moist air is not vented out of the kiln but is dehumidified, then recirculated . Many regions have increased the shed and outbuilding maximum allowable size without need for a permit. Select 3/4 conduit brackets for hanging baffles on 1/2 galvanized pipe. A lower RH setting will call for the DH to run more often. If your lumber stack is built on starter blocks, you will need to limit airflow there as well. November 1, 2020. 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? For equalizing, use an EMC 2% below the target MC at a dry-bulb of 170 F. For conditioning, use an EMC 4% above the target MC at a dry-bulb of 180 F. Professor Gene Wengert is Extension Specialist in Wood Processing at the Department of Forestry, University of Wisconsin-Madison. In addition, weight on top of the stack can be helpful, but nothing replaces baffles for the best lumber yield. Adjust the baffles or fan direction to achieve good airflow. Website Content Copyright 2023 Nyle Systems |. This listing incorporates current market requirements for the various species, as well as the current quality of the lumber resource itself. . Wood drying (also seasoning lumber or wood seasoning) reduces the moisture content of wood before its use. For sterilizing thicker lumber, additional time is required. Most species of hardwood lumber can be safely dried this way, once the moisture content is 20% to 25% or less. Vacuum Kiln Drying. Low temperatures can be used for an extra safety margin on greener lumber. Remove samples from the stack, and cut an inch or two off one end. They are easy to use and give you precision control over your drying. For single-stack kilns, stationary fans are adequate. Do not know just how the end point of moisture would compare. are generally kiln dried by time scheduleswhether the wood is intended for struc-tural lumber or for appearance uses, such as furniture or millwork. (Sawing and Drying Forum) The last step requires a short period of high humidity to relieve the drying stresses in the boards. With a 130 F kiln temperature, sterilization will take 10 to 12 hours (Dry Kiln Operators Manual, 1991). After four days, I decrease the RH setting on the DH to 30% and continue to run the fans. The dry kiln operator is fully in control, with the ability to make changes as the dry kiln schedule is executing. Hardwood lumber kiln drying schedules typically keep the dry bulb temperature below 180 F (82 C). For example, if you dry 7,500BF of fast drying Pine, youd select the 8MBF chamber with the HT18 Dehumidifier. 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. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. . It is a good idea to sterilize the lumber at the end of the kiln run. Drying small amounts of lumber using a dehumidification kiln is a suitable option for woodworkers even with limited knowledge of kilns. The delicate blue and white color scheme c I guess I am thinking that while I am seeing the wood's MC and the kiln's RH drop smoothly, the fact that the temperature jumps around a bit may mean that the drying rates are hard to control, hence my loss of horse chestnut. Abstract. Air speed of 350 feet per minute is appropriate for common hardwoods such as oak and maple. The baffles direct airflow over and through the stack and prevent the top layers from drying too quickly. 6. This plan allows . After seven to 10 days, I reverse the fan direction to make sure all stacks of lumber dry evenly. I prefer to empty the water tray manually and record the volume of water collected. From contributor D: 293 0 obj <>/Filter/FlateDecode/ID[<87A322ACC143C740A97F712BC6C2FBCD>]/Index[282 20]/Info 281 0 R/Length 68/Prev 378162/Root 283 0 R/Size 302/Type/XRef/W[1 2 1]>>stream The thinner the stock, the more critical sticker placement becomes. Hardwood lumber kiln drying schedules typically keep the dry bulb temperature below 180 F (82 C). 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. My four main baffles consist of sheets of 1" Styrofoam insulation. 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. John Baines Reply to Dann Barry 1 year ago This prevents "dead spots" inside the chamber that experience limited airflow. HDE small kilns feature all-aluminum construction for a long, maintenance-free life span . If the fans and dehumidifer generate enough heat to maintain a temperature of 100 to 120 F, then I wont use the auxiliary heater. 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. Soon the DH won't show much water collected in the tray. I hope that the sawyer coated the ends of the lumber with Anchor-Seal or oil-based paint when it was green. All of these products were purchased at a local home center, except the remote hygrometer/thermometer which was purchased at a local electronics store. A maximum 45 F depression often produces better lumber. (116 C) temperature. I either use some cedar 3" x 5", or 4" x 4" stock. 0000004213 00000 n Drying lumber too quickly can lead to deep end checking, warping and case hardening. Also check that air isnt escaping around the side baffles or under the stack of lumber. 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 . I decided on a dehumidification kiln after reading an article in Fine Woodworking (1991). Another common sticker size is 1" x 2", and these work fine as well. In vacuum kiln trials, logs were heated to 56C at 70 percent log radius depth and the temperature maintained for . I don't remember how the air flow was arranged in the kiln in the magazine, but it sounds like that could be a problem for you. Nyle Systems dehumidification kiln packages are our best known product with nearly unlimited drying capabilities. (In the original Dry Kiln Operators Manual written in the early 1950s, some species were not used in high quality products. I know mixed loads are taboo, but this one worked well, other than the horse chestnut. noun: kiln; plural noun: kilns. Apply foil tape to the edges of the main baffles to help protect the Styrofoam. << 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. However, you may need more cycles depending on the species, moisture content, and size of the timber.