dehumidification kiln drying schedules

The delicate blue and white color scheme c A locked padlock A household dehumidifier (DH) removes moisture from the kiln chamber. Also, since heat rises, ceiling-mounted fans have the added benefit of circulating the warmest air over the lumber. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. My aim was to develop a small dehumidification kiln for better control of the three key components of lumber drying: temperature, airflow and humidity. 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. . the Dry Kiln Operator's Manual (Simpson, 1991). Leave an air space between the rigid foam and subfloor for additional insulating properties. I prefer to empty the water tray manually and record the volume of water collected. All of these products were purchased at a local home center, except the remote hygrometer/thermometer which was purchased at a local electronics store. This shed will be essentially unheated for much of the year and very hot during the kiln-drying cycles. 282 0 obj <> endobj After a short period of grumbling, they join me to lay down wood blocks for the first layer of lumber. Place some sample boards in the stack that will be easy to pull out for moisture testing later. 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 . The DH is not needed at this time, as the lumber is already bone-dry. However, the natural light and ventilation offered by a small window outweighs any disadvantages. Be sure that all of the kiln equipment is working prop-erly before lumber is loaded into the kiln. 3. . I often buy from sawyers or homeowners at 40% to 50% of retail price. A heavy-duty 1,500-watt space heater works fine. Select 3/4" conduit brackets for hanging baffles on 1/2" galvanized pipe. Remove samples from the stack, and cut an inch or two off one end. Kiln Structure . Another common sticker size is 1" x 2", and these work fine as well. 3, a simplified transverse section of a kiln chamber with an energy recovery and dehumidification system is shown. /Subtype /Image . My four main baffles consist of sheets of 1 Styrofoam insulation. The air flow rate through your stacks should be about 350FPM. The thinner the stock, the more critical sticker placement becomes. A lazy Susan with 180 detents mounts the fan box to the ceiling. Hardwood lumber kiln drying schedules typically keep the dry bulb temperature below 180 F (82 C). 73. stream Select a heater with an adjustable thermostat and a tip-over shutoff. Small, complete dehumidification dry kilns under 5,000 board-foot capacity are not available for sale. 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. I can show you the kiln schedules and data. Take the electronics out of the kiln, and continue operating the heater and fans during this phase. After seven to 10 days, I reverse the fan direction to make sure all stacks of lumber dry evenly. My shed kiln was stick-built from standard building material, and sized to take advantage of typical 4 x 8 sheet goods. They are based on different air flow rates, etc. Soon the DH won't show much water collected in the tray. After four days, I decrease the RH setting on the DH to 30% and continue to run the fans. /Name /ImagePart_0 Particularly, important investment has taken place in lumber drying capacity. 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. I either use some cedar 3" x 5", or 4" x 4" stock. 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. A small electric heater supplies auxiliary heat to maintain adequate kiln temperature. 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 ). Bring your moisture meter to confirm. The starter blocks should be as long as the stack is wide. The common lumber name is used throughout. This helps keep the lumber straight during the drying cycle; in fact, improper placement of stickers can permanently deform lumber. The cost associated with shed construction was similar to buying a prefabricated kit. Installing sheetrock and fire taping is a good idea for a heated room. For international returns, please click here. 301 0 obj <>stream Lock 0000003109 00000 n Take the electronics out of the kiln, and continue operating the heater and fans during this phase. Dr. Gene Wengert provides schedules for kiln drying hardwood lumber. In the majority of cases, the drying schedules are from the world literature, with emphasis on U.S., Canadian, and British publications. The four charges of lumber ranged from 600 to 700 board feet (bf), and a woodworker with no dry-kiln experience operated the kiln. Detailed design and custom manufacture of dehumidification and chiller systems for food processing, lumber drying and industrial applications. I usually see a large volume of water in the DH each night when I check the kiln. Size and placement of the access door are critical as well. Place a 1x6 board on the floor behind the stack, tilted to a 45 angle. hb```[@9p(T-3jO:g)@S 4Y]g7l\V!c!$Bf J B@&xcEz8PH@ZHs1/X$qOq,x'x$0.rWg*d XAT10 );9 Place the one inch sections in an oven 215F to 218F (102C to 103C) and dry - usually 18 to 36 hours depending on the oven. There are many types of kilns, but the most common are dehumidification kilns and conventional kilns. Any info or advice on using dehumidification equipment to dry out chainsaw milled lumber. A lock ( With two-stack and three stack kilns, it is better to have reversible fans to alter the direction of airflow mid-cycle. 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. January 27, 2007. The last step requires a short period of high humidity to relieve the drying stresses in the boards. Gen. Tech. A heavy-duty 1,500-watt space heater works fine. Remote operation and networking is optional. Go to the second number designation (the wet-bulb depression designation) and find the corresponding depressions in the table below. KD150 Series dehumidifier pdf manual download. If you cannot find exact match, look at SG of same family species. Usually, you need anywhere between five to eight kiln schedules to complete the process. November 1, 2020. Corrosion resistant epoxy coated aluminum cabinets and specially coated dehumidification coils for an extra long life. Made in China, it exudes the classic style of Asian and Chinese cultures, featuring a unique shape that sets it apart from traditional jars. Created and Presented by: Henco Viljoen and Elijah McCarty with Nyle Dry Kilns. A household dehumidifier (DH) removes moisture from the kiln chamber. I made a simple frame from plywood strips and attached theinsulation sheets to them with screws and fender washers. The stickers are uniform in size and usually 3/4 or 1 square. Joining end grain to long grain forms the king of joints. 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. Select 3/4 conduit brackets for hanging baffles on 1/2 galvanized pipe. 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. This makes lightweight baffles that can be easily moved and repositioned. On this order alone, I saved over $1,300 by drying the lumber myself. Schedules. Attic fans are a perfect way to provide airflow over the stacks of lumber. With each load I did not have the initial relative humidity rate. Temperatures inside the kiln range from 120 to 190 degrees F, depending on the stage of . If severe enough, the lumber can develop honeycomb cracks throughout. 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. I cannot stress the importance of baffles enough. 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). To hang the baffles, simply attach hooks to the plywood frame. Align the stickers over the starter blocks on the first course. Attic fans are a perfect way to provide airflow over the stacks of lumber. I then manually rotate the fan boxes halfway through the drying cycle. Dehumidification: This kiln-drying process requires the use of a heat pump system to remove water from the wood. I usually see a large volume of water in the DH each night when I check the kiln. Measure airflow over the stacks of lumber in various locations. This problem is magnified if the lumber is thin or flatsawn. << Although dehumidification kilns are slower than conventional kilns for drying, the lower drying temperature has the reported advantage of less degrade and less shrinkage. Wood drying (also seasoning lumber or wood seasoning) reduces the moisture content of wood before its use. /BitsPerComponent 1 HWn8gXA N,[mKJr2"Ec9,t Equalizing and Conditioning Job Opportunities and Woodworking Services, Dust Collection, Safety and Plant Operation. Reweigh and obtain the oven dry weight. %3.3 noun: kiln; plural noun: kilns. Most species of hardwood lumber can be safely dried this way, once the moisture content is 20% to 25% or less. A lower RH setting will call for the DH to run more often. This helps keep the lumber straight during the drying cycle; in fact, improper placement of stickers can permanently deform lumber. This plan allows . /Length 7 0 R I was hoping someone could point me in the right direction or share experience. 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 . After four days, I decrease the RH setting on the DH to 30% and continue to run the fans. Enter the email address you signed up with and we'll email you a reset link. I'm trying to find a timetable or drying schedule for the basic dehumidification kilns you see on youtube. In a professional DH kiln, the final climate for oak is 120F and <40>t over-dry it at that rate. I selected a 36 outswing exterior door. 3.24 solar-dehumidification drying kiln Basically the idea seems to be to maintain a constant temperature, and . Unlike general shop space, bigger is not always better for kiln design. Measure airflow over the stacks of lumber in various locations. Apply foil tape to the edges of the main baffles to help protect the Styrofoam. . In the third column, write down the appropriate dry-bulb temperatures. My kiln schedule starts with running all fans and the dehumidifier for two days, measuring and removing water as it accumulates. https://www.fs.usda.gov/research/treesearch/9635, International Institute of Tropical Forestry, Eastern Forest Environmental Threat Assessment Center, Northern Institute of Applied Climate Science, Western Wildland Environmental Threat Assessment Center, conventional-temperature (< 180 F) schedules, elevated-temperature (180-212 F) schedules, R. Sidney Boone, Charles J. Kozlik, Paul J. Bois, Eugene M. Wengert. These well-known dehumidification kiln packages have been among our bestselling products for the past 30 years. Looking at the cost-benefit analysis of a shed kiln can be enlightening. (I have found that remotely monitoring the temperature and humidity with a WiFi sensor can be very helpful. . With a 130 F kiln temperature, sterilization will take 10 to 12 hours ( Dry Kiln Operators Manual, 1991 ). Sorry, preview is currently unavailable. This is because it needs to be dried to a lower moisture content than wood will air dry to outdoors. Select a heater with an adjustable thermostat and a tip-over shutoff. 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. ) or https:// means youve safely connected to the .gov website. I dont think the same could be said for an old reefer truck converted into a kiln (no matter how well it dries lumber). To condition the lumber, I introduce steam into the kiln for about two hours. Matched to one of our L-Series and HT Dehumidifiers they can handle whichever species you are drying, fast drying softwoods to slow drying hardwoods. Consider not only the space for the lumber stacks, but extra floor space to easily load and monitor the charge of lumber. Dehumidification Kiln. Kiln drying lumber is a simple, cost effective method recommended for anyone who wants to increase profits by selling dried lumber. 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. I use a Rockler steam generator, item #42826 (www.rockler.com). For a single-stack kiln I recommend a minimum shed size of 8 x 12. 5. 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? The first load was started with 60% and this load was started with 78%. . Take a moisture reading in the end grain with a pin-type moisture meter or remote probe. Thicker lumber like 5/4 or quartersawn lumber is naturally more stable. txN.a!HQ)FmCw~{B1Aq_!+zN#+j A lazy Susan with 180 detents mounts the fan box to the ceiling. 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. I hope that the sawyer coated the ends of the lumber with Anchor-Seal or oil-based paint when it was green. I am using a household . To accommodate the floor insulation, blocking between joists is oriented horizontally instead of the normal vertical position. This lets the operator sort stacks by lumber species, so they will be easy to retrieve when the drying cycle is complete. I use a Rockler steam generator. . That purchase was an average deal, and one I dont consider a particular bargain. A dehumidification kiln makes sense particularly when the lumber is air-dried first. noun. Total costs for the materials were $2,704 based on 2006 prices. There are two ways to remove water from the DH unit, and they both work well. Among dimension lumber, the 2- by 4-inch size is typically the most susceptible to warp for a variety of reasons. - Model L300, L500, L1200-S Series - Medium Dehumidification Dry. The order was 540 board feet (BF) of 5/4 white oak. Delete from my manuals. (In the original Dry Kiln Operators Manual written in the early 1950s, some species were not used in high quality products. An official website of the United States government. In smaller kilns, the heat generated by the fans and DH motor is sufficient to maintain temperatures in excess of 100 degrees. Willie Sandry is a furniture maker and a lumber kiln operator in Camas, Washington. 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. This will allow the DH to drain automatically without you needing to enter 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 . 0000002536 00000 n Another common sticker size is 1 x 2, and these work fine as well. 6. By. This Blue&White Ginger Jar is a stunning piece of porcelain and pottery, expertly handcrafted with natural variations in each piece. . 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 . Initially, I set the DH to 40% RH, because I dont want to remove moisture too quickly. 0 \ The schedules can also be formulated manually as follows. Main thing is to not rush drying in first stages, as this will cause problems. Place a sticker at each end, and every 16" along the stack for 4/4 stock. This will allow the heater to cycle on and off automatically, according to the kiln operators setting. Khmer Kiln: quite similar to the Anagama kiln however, traditional Khmer Kilns had a flat roof. For the best experience on our site, be sure to turn on Javascript in your browser. If MC readings still arent at the desired range, the heat may need to be increased for the remainder of the drying cycle. Add to my manuals. A typical home center sheds floors are underbuilt for the weight of a load of lumber. Forum Responses Our approach was to build and operate a small dehumidification dry kiln. Formulating a Kiln Schedule Low Temperature Kiln Drying Systems (120F) 300BF - 4000BF Capacity . The Bolivian wood products industry was surveyed to determine lumber drying capacity, technology and. This gives me a secondary method of tracking the drying process, using both water volume and moisture content (MC) readings. The remaining width allows for a 36-wide door and space for your drying equipment. . I have constructed a kiln using these plans. This gives me a secondary method of tracking the drying process, using both water volume and moisture content (MC) readings. I made a simple frame from plywood strips and attached the insulation sheets to them with screws and fender washers. Dehumidification dry kilns operate at lower drying temperatures (typically below 150F) than do conventional kilns, which results in longer drying schedules. 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. Initially, I set the DH to 40% RH, because I dont want to remove moisture too quickly. For end baffles, I use 2"-thick rigid foam insulation screwed to the main baffles. Choosing a Kiln Schedule Its a nice use of technology and adds a measure of safety as well.) 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. I've been drying hardwood lumber in this Sauno dehumidification kiln for 4 years with excellent results. Question With advances in spray foam insulation, it may be possible to seal older, drafty structures as well. Phytosanitary heat treatments of Ceratocystis lukuohia and Ceratocystis huliohia-colonized Metrosideros polymorpha wood were evaluated using kilns. A higher humidity setting will run the unit sporadically to maintain that RH. %PDF-1.4 % You could use the dehumidifier to dry wood but it would not be part of a "kiln." Just be a different process. Operates at a temperature range from 80F - 160F (26 - 71C). (116 C) temperature. (See the following sections for a discussion of how to develop a schedule from these designations.) However, you may need more cycles depending on the species, moisture content, and size of the timber. Dehumidification Kilns Moisture content step schedules can be converted to schedules based on time once a kiln operator develops a data record from at least 6 different kiln runs with lumber of the same thickness and species. Place a 16 board on the floor behind the stack, tilted to a 45 angle. Using a piece of paper with 6 columns, write down the Schedule Step numbers in the first column on the left. Also, for that approach to work, the chamber needs to be air tight. Use the gridded drawings provided on the PDF, Woodworking | Blog | Videos | Plans | How To. 44. 0000001417 00000 n We proudly stand behind all of our products. I know mixed loads are taboo, but this one worked well, other than the horse chestnut. Difficult-to-dry species might not exceed 140 degrees F. Dehumidification kilns are very . By setting the relative humidity (RH) on the dehumidifier, you can control how often it runs. Any small building could work, as long as it has a minimum of 2 x 4 framing, and will seal out unwanted air. endstream endobj startxref Sign In Upload. Recently, either Wood, or American Woodworker showed how to build a small version of a solar kiln. There are two ways to remove water from the DH unit, and they both work well. 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 In time schedules, dry- and wet . For a kiln temperature of 140 F, sterilization takes three to five hours. I recently picked up a back issue of American Woodworker, #94 June 2002, that has a good article on constructing a simple DH kiln. Check your local building codes for regionally specific requirements and electrical permits. For a kiln temperature of 140 F, sterilization takes three to five hours. There might be a problem with that if the chamber overheats and has to be vented because some water will leave that way. Omitting the sterilization phase can lead to costly losses from insect damage, so don't skip it. 1998. by Dr. Eugene Wengert. 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. After two days operating only the fans and DH, I take note of the temperature. 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. Kiln drying is the process of drying wood in a controlled environment, where temperature, air circulation and humidity are monitored and stabilized. Place a sticker at each end, and every 16 along the stack for 4/4 stock. It should be double-pane, well-insulated with low emissivity (low-E). This, of course, is gross savings; we must calculate electrical costs to determine the net savings: in this case, about $62. I recommend a 2 x 3 sliding window with bug screen. 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. 2. These are rough-saw red oak. But kiln drying may also introduce internal stresses into the woodparticularly if an improper kiln schedule is used, . Loading the kiln begins by rousing my sons and letting them know Ive planned a day of work. Only the fans need electricity. Insulation for walls and ceilings should be a minimum of R13. (I have found that remotely monitoring the temperature and humidity with a WiFi sensor can be very helpful. Basically, you don't want all of the air rushing out under the stack, so find a way to redirect it. Then, write down the appropriate MC ranges (determined in #2 above) in the second column. 10. Adjust the baffles or fan direction to achieve good airflow. Table 1 shows a typical drying schedule for sugar maple. During the conditioning process, the only equipment operating are the fans, heater and the steam generator no dehumidifier. An Overview. Wood Shrink/Swell estimator - A web-based program to estimate shrink/ swell in wood. kiln/. The first thing to consider when designing a shed kiln is size. Items shipped directly from the manufacturer cannot be returned in store. I found that brackets for mounting rigid metal electrical conduit work best. Instead of using expensive electrically reversible fans designed for commercial kilns, I came up with a simple hardware solution. Always avoid conditions that add moisture back to the lumber, especially during start-up. For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. Academia.edu no longer supports Internet Explorer. %PDF-1.6 % Vacuum Kiln Drying. Additionally, a 12 air plenum is required between the walls and stacks of lumber. For single-stack kilns, stationary fans are adequate. Also, you can't really control well by measuring the collected water because some of the water leaks out with vented or leaking air. 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 . Then align each subsequent layer of stickers over the last. Another great option is to convert an existing shed or outbuilding to a lumber kiln. This returns some moisture to the very dry exterior of the lumber, while not affecting the core moisture level. Instead of using expensive electrically reversible fans designed for commercial kilns, I came up with a simple hardware solution. If the fans and dehumidifer generate enough heat to maintain a temperature of 100 to 120 F, then I wont use the auxiliary heater. 1. This slows the end-grain drying and limits the severity of end checking. 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 also wrapped the shed with Tyvek HomeWrap. In exchange for building the shed myself, I wound up with a shed of higher quality, with more features. 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. 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. Additionally, I have been underwhelmed by the performance of solar-operated fans. 0000000710 00000 n Dehumidification kiln schedules 145 Sterilizing, equalizing, and conditioning treatments 145 Sterilizing treatments 145 Mold 145 Fungal stain and decay 146 . It is a good idea to sterilize the lumber at the end of the kiln run. 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. Once the lumber is sterilized, it is ready for the conditioning phase. The schedules are all moisture content based, using the moisture content of the wettest half of the kiln samples. In this paper, the effective schedules were further investigated for longer culm parts treated with boron. The T-bars are made from 1/2 galvanized pipe and are attached to the rafters with threaded pipe flanges. I cannot stress the importance of baffles enough. 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 . Case hardening is a defect caused by the outer portion of a board drying quickly, while the inner portion dries more slowly. In-service replacement of warped 2 by 4's as wall studs or truss members is costly. In larger kilns, the heater may be needed in the latter part of the drying cycle. (I use the Mini-Ligno MD/C from Lignomat, www.lignomatusa.com.) 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.. Using a Kiln Schedule Frequently, the lumber has already air-dried for several years in a barn or outbuilding. Dehumidification drying system. Please refer to Appendix A which shows the Lumber Dry Kiln Bill of Materials. 0000006297 00000 n Rep. FPL-GTR-57. The lumber was then measured for crook, bow, and twist. Manufacturer guarantees/warranties for power tools, CNC and laser products will supersede the Rockler Guarantee if these items are damaged or defective. BE CAREFUL--The first temperature value must be repeated for every MC class (column #2) that is above 30% MC. The kiln climate is controlled by venting the hot air and replacing it with ambient air. The problems with solar kilns include limited control over temperature and limited solar exposure, depending on your region and site location.