In time schedules, dry- and wet . I prefer to empty the water tray manually and record the volume of water collected. 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. Dehumidifier suggestion: http://amzn.to/2iYZqVZThis is the first in a series of videos showing how I built a kiln for drying lumber. Ideally, a lumber kiln would be large enough to dry multiple stacks of lumber. This will allow the DH to drain automatically without you needing to enter the kiln. . Dehumidification Kiln. Instead of using expensive electrically reversible fans designed for commercial kilns, I came up with a simple hardware solution. Website Content Copyright 2023 Nyle Systems |. . After four days, I decrease the RH setting on the DH to 30% and continue to run the fans. 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. Enter the email address you signed up with and we'll email you a reset link. These well-known dehumidification kiln packages have been among our bestselling products for the past 30 years. Changing the position of the doorway in various kiln setups helps provide the best access to the stacks of lumber. Also, since heat rises, ceiling-mounted fans have the added benefit of circulating the warmest air over the lumber. Y}-m+'@DQ4\h8GP]y@ yL. Once the core readings are 6% to 8% on a fresh cut, the lumber is dry and ready for sterilization. Wood-Mizer dehumidification and solar wood kilns range from 300 to 35,000 board feet capacity for drying lumber. In addition, weight on top of the stack can be helpful, but nothing replaces baffles for the best lumber yield. An anemometer confirms that your effort constructing baffles was worthwhile. 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. Can also be used on any mobile device! Keenan Slab Works has a vacuum kiln located at 4917 Elizabethtown Road, Manheim, Lancaster County, Pennsylvania, 17545 and is expanding services for the general public to have their slabs and lumber vacuum dried. The second temperature value is written for the 25 to 30% MC class; the third for the 20 to 25% MC class; and so on. Difficult-to-dry species might not exceed 140 degrees F. Dehumidification kilns are very . In contrast, a dehumidification kiln uses a sealed chamber, with only enough energy input to maintain the desired temperature. If required, look-up and write down the RH (sixth column) and EMC (seventh column) for each schedule step. Lay down the bead of caulking before raising the walls. Another common sticker size is 1 x 2, and these work fine as well. If your lumber stack is built on starter blocks, you will need to limit airflow there as well. The baffles direct airflow over and through the stack and prevent the top layers from drying too quickly. There are two ways to remove water from the DH unit, and they both work well. Warp in dimension lumber is a significant cause for loss in grade and value. The company's small kilns can be configured for drying lumber, firewood, or heat-treating lumber or wood packaging. 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.). Align the stickers over the starter blocks on the first course. Its a nice use of technology and adds a measure of safety as well.) squares, handle stock, gunstock blanks) are given for many species. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. The following tables show some examples of oak schedules for steam dry kilns and dehumidification dryers. Many available kiln designs require a large, heavy door. 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. 4. Diy dehumidifier kiln time table. Nyle. 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? Taking moisture away at the rate the board will "safely" part with it . During the conditioning process, the only equipment operating are the fans, heater and the steam generator no dehumidifier. Go to the first number designation (the temperature designation) and find the corresponding temperatures in the table below. These are rough-saw red oak. The conversion method described in the Dry Kiln Operator's Manual is not really accurate, but it is safe. If it isn't overheating, it is leaking. If severe enough, the lumber can develop honeycomb cracks throughout. If severe enough, the lumber can develop honeycomb cracks throughout. Usually, you need anywhere between five to eight kiln schedules to complete the process. 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. With two-stack and three stack kilns, it is better to have reversible fans to alter the direction of airflow mid-cycle. Contractors work on a tight schedule, and that may not allow much time for curing and drying concrete. WOODWEB is a registered trademark of Woodweb.com. Khmer Kiln: quite similar to the Anagama kiln however, traditional Khmer Kilns had a flat roof. Dehumidification Kilns Main thing is to not rush drying in first stages, as this will cause problems. 0000006297 00000 n Abstract. << A heavy-duty 1,500-watt space heater works fine. Would adding humidity at the start, bringing the initial relative humidity rate to 87% as suggested in the table, result in better product or faster drying? The fact is, most of my stacks of lumber air dry to 15% moisture content before entering the kiln. Dehumidification dry kilns operate at lower drying temperatures (typically below 150F) than do conventional kilns, which results in longer drying schedules. Should I? This shed will be essentially unheated for much of the year and very hot during the kiln-drying cycles. This procedure is discussed in a following section. The problems with solar kilns include limited control over temperature and limited solar exposure, depending on your region and site location. >> From contributor D: Attic fans are a perfect way to provide airflow over the stacks of lumber. (I use the Mini-Ligno MD/C from Lignomat, www.lignomatusa.com.) Job Opportunities and Woodworking Services, Dust Collection, Safety and Plant Operation. After a short period of grumbling, they join me to lay down wood blocks for the first layer of lumber. /BitsPerComponent 1 Share. November 1, 2020. Loading the kiln begins by rousing my sons and letting them know Ive planned a day of work. 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. . Basically, you don't want all of the air rushing out under the stack, so find a way to redirect it. If MC readings still arent at the desired range, the heat may need to be increased for the remainder of the drying cycle. This gives me a secondary method of tracking the drying process, using both water volume and moisture content (MC) readings. A discussion of how to apply "safe drying rate" calibrations with a home-built dehumidifying kiln. 0000000710 00000 n Exterior sheathing and siding type also factors into the heat-holding ability of the structure. My four main baffles consist of sheets of 1" Styrofoam insulation. 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. My shed kiln was stick-built from standard building material, and sized to take advantage of typical 4 x 8 sheet goods. Our capacities are 4,000 board feet in a kiln . Schedules for several thicknesses and specialty products (e.g. With advances in spray foam insulation, it may be possible to seal older, drafty structures as well. This allows for a more gentle kiln schedule to fully dry the timber. Electrical requirements for a DIY kiln are pretty straightforward, but hiring an electrician is still a good idea. Another common sticker size is 1" x 2", and these work fine as well. I like these starter blocks to raise the lumber a few inches off the floor. MC values in the kiln schedules are based on the wettest half of the kiln samples. For a kiln temperature of 140 F, sterilization takes three to five hours. Consider the weight of the lumber that will be placed in the structure and fortify the building accordingly. Always avoid conditions that add moisture back to the lumber, especially during start-up. They are normally mounted in the gable of household attics, and they are designed to be used in high temperature environments. Unlike general shop space, bigger is not always better for kiln design. Select a heater with an adjustable thermostat and a tip-over shutoff. 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 I made a simple frame from plywood strips and attached theinsulation sheets to them with screws and fender washers. This plan allows . 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. 5. 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. I like these "starter blocks" to raise the lumber a few inches off the floor. After seven to 10 days, I reverse the fan direction to make sure all stacks of lumber dry evenly. Measure airflow over the stacks of lumber in various locations. 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. Although I can maintain the 90 degree temperature, I could not start at the recommended humidity level unless I added humidity. Dehumidification Opportunities for Dehumidification Drying Of Hardwood Lumber Dimension Kiln Drying Hardwood Dimension Parts Discoloration Preventing Discolorations in Hardwood and Softwood Logs . Sign In Upload. In smaller kilns, the heat generated by the fans and DH motor is sufficient to maintain temperatures in excess of 100 degrees. Leave an air space between the rigid foam and subfloor for additional insulating properties. The stickers are uniform in size and usually 3/4" or 1" square. hTn8>_l7h.&E:Bem=C9n\8]lMPc. The schedules can also be formulated manually as follows. A variety of wood drying kiln technologies exist today: conventional, dehumidification, solar, vacuum and radio frequency. USDA, 1991) . Only the fans need electricity. Our approach was to build and operate a small dehumidification dry kiln. Download Table of Contents. This helps keep the lumber straight during the drying cycle; in fact, improper placement of stickers can permanently deform lumber. You may also return purchases to a Rockler store near you for store credit. In this research, a drying restraint system was evaluated as a means of warp reduction in 8- and 16-foot-long SYP lumber. I am removing water about 50% below the SDR. The velocity through the load is assumed to be between 275 and . 158 p. Dry kiln schedules for commercial woods : temperate and tropical. 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. If you use a lot of lumber, and youre a decent hand at carpentry, a shed kiln will quickly pay for itself. I've been drying hardwood lumber in this Sauno dehumidification kiln for 4 years with excellent results. For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. Determine the correct designation, such as T3-D2 for 4/4 red oak. Select a heater with an adjustable thermostat and a tip-over shutoff. I dont think the same could be said for an old reefer truck converted into a kiln (no matter how well it dries lumber). Kiln Structure . Size and placement of the access door are critical as well. BE CAREFUL--The first temperature value must be repeated for every MC class (column #2) that is above 30% MC. Particularly, important investment has taken place in lumber drying capacity. I usually see a large volume of water in the DH each night when I check the kiln. We are proud of the quality of our products, and we stand behind them 100%. I can show you the kiln schedules and data. . This will allow the heater to cycle on and off automatically, according to the kiln operators setting. Add to my manuals. Select 3/4 conduit brackets for hanging baffles on 1/2 galvanized pipe. Wood Shrink/Swell estimator - A web-based program to estimate shrink/ swell in wood. A 1.5-kW dehumidifier was installed in the solar dryer to determine the performance of a combined solar-dehumidification dryer. Basically the idea seems to be to maintain a constant temperature, and . Different species should not be loaded simultaneously into the kiln due to often differing kiln schedules. 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. 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 . Temps are in Celsius (20C = 70F, 40C = 105F). Heat comes primarily from an integral dehumidification unit that also removes . 0000001417 00000 n I chose double wall construction with 1/2 sheathing, and 1/2 T1-11 siding. The second most common type of drying is called dehumidification drying. A lazy Susan with 180 detents mounts the fan box to the ceiling. 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. Kiln drying is almost always essential for wood intended for interior uses. Use the gridded drawings provided on the PDF, Woodworking | Blog | Videos | Plans | How To. Basically, you dont want all of the air rushing out under the stack, so find a way to redirect it. I'm trying to find a timetable or drying schedule for the basic dehumidification kilns you see on youtube. The cost associated with shed construction was similar to buying a prefabricated kit. /Length 7 0 R A household dehumidifier (DH) removes moisture from the kiln chamber. H6`2}s=n:l)CR>/"\ 9. Do not know just how the end point of moisture would compare. It should be double-pane, well-insulated with low emissivity (low-E). For the best experience on our site, be sure to turn on Javascript in your browser. A bead of silicone caulking between the subfloor and sill plate will prevent air infiltration. This makes lightweight baffles that can be easily moved and repositioned. Then, write down the appropriate MC ranges (determined in #2 above) in the second column. Both restrained and control boards were dried to approximately 9 percent moisture content, representative of final in-service condi- tions. A better choice might be a solar kiln, as you can dry wood from "wet" to 6-8 percent MC in 6-8 weeks. I also wrapped the shed with Tyvek HomeWrap. This is because it needs to be dried to a lower moisture content than wood will air dry to outdoors. Determine the equalization settings and conditioning settings, as required. Although dehumidification kilns are slower than conventional kilns for drying, the lower drying temperature has the reported advantage of less degrade and less shrinkage. The sheetrock also helps to protect the fiberglass insulation. . 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). 4.4 drying schedule moisture content drying schedule . My aim was to develop a small dehumidification kiln for better control of the three key components of lumber drying: temperature, airflow and humidity. /ColorSpace /DeviceGray Kiln drying normally involves temperatures in the range of 40-75 C (about 100-170 F). The air flow rate through your stacks should be about 350FPM. Our next kiln charge is scheduled to begin around February 6, 2023. These kilns will typically hold several thousand board foot of lumber. A pre-hung steel exterior door is ideal in this situation, because it offers weatherstripping and is fully insulated. The last step requires a short period of high humidity to relieve the drying stresses in the boards. The kiln humidity can be expressed as an EMC, relative humidity, or wet-bulb temperature. (See the following sections for a discussion of how to develop a schedule from these designations.) The KD150 Dehumidification Kiln Kit is a compact, entry-level dehumidification kiln for drying lumber between 300 and 1000 board feet. Sears Canada 70 Pint Dehumidifier. That purchase was an average deal, and one I dont consider a particular bargain. temperature. Share sensitive information only on official, secure websites. the Dry Kiln Operator's Manual (Simpson, 1991). Drying small amounts of lumber using a dehumidification kiln is a suitable option for woodworkers even with limited knowledge of kilns. Staff. A household dehumidifier (DH) removes moisture from the kiln chamber. The lumber was then measured for crook, bow, and twist. Add up the amp draw on all the equipment you plan to use in the kiln, including a heater, dehumidifier, fans and steam generator. Also, today, we are often kiln drying No.2 Common lumber which requires a milder schedule than upper grades; in the 1950s, seldom was this lower grade lumber kiln dried.) A heavy-duty 1,500-watt space heater works fine. Case hardening is a defect caused by the outer portion of a board drying quickly, while the inner portion dries more slowly. However, the natural light and ventilation offered by a small window outweighs any disadvantages. Schedules Dry Kiln Schedules for Commercial Woods 6 0 obj 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. Total costs for the materials were $2,704 based on 2006 prices. Official websites use .gov There may be more depression values than required; ignore the extra depression values in this table. %PDF-1.5 %PDF-1.4 % Insulate the floor with 2 rigid foam for convenience and durability. T8-C3 or similar for hard maple), the article instead provided a table showing the "safe drying rates" (SDR) for a number of species. Dr. Gene Wengert provides schedules for kiln drying hardwood lumber. The DH is not needed at this time, as the lumber is already bone-dry. Remote operation and networking is optional. 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. Kiln drying lumber is a simple, cost effective method recommended for anyone who wants to increase profits by selling dried lumber. Understand how kiln performance must be modified to permit the use of custom schedules for specific product applications; Be able to modify existing conventional kiln schedules to dry products in dehumidifier kilns; Recognize degrades common to various species, including hardwoods, and modify handling practices to minimize these Using a piece of paper with 6 columns, write down the Schedule Step numbers in the first column on the left. This prevents "dead spots" inside the chamber that experience limited airflow. In-service replacement of warped 2 by 4's as wall studs or truss members is costly. 1998. Loading the kiln begins by rousing my sons and letting them know Ive planned a day of work. Then align each subsequent layer of stickers over the last. This air space is absolutely critical for even airflow, so count on the extra floor space right from the design phase. I found that brackets for mounting rigid metal electrical conduit work best. Frequently, the lumber has already air-dried for several years in a barn or outbuilding. You can achieve top-quality results with incredible efficiency. My baffles hang from T-bar assemblies mounted to the ceiling. In addition, weight on top of the stack can be helpful, but nothing replaces baffles for the best lumber yield. Once the lumber is sterilized, it is ready for the conditioning phase. Place the sample board in the lumber stack in a location where it will dry at the same rate as the rest of the lumber in the dryer (see Figure C). 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. hbbd``b` $ &UD\q@u /Height 2587 These figures hold true for lumber up to 2 thick. Perhaps the best part: you wont need to calculate your lumber needs down to the board foot. For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. 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. On the last load of lumber I purchased, I saved $2.50 per board foot compared to retail prices for kiln-dried lumber. Excel Program for Modeling Lumber Dry Kiln Operations - a model for lumber dry kiln operation. 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. JavaScript seems to be disabled in your browser. This Blue&White Ginger Jar is a stunning piece of porcelain and pottery, expertly handcrafted with natural variations in each piece. Gen. Tech. 0000002827 00000 n 0 \ This listing incorporates current market requirements for the various species, as well as the current quality of the lumber resource itself. I usually see a large volume of water in the DH each night when I check the kiln. Dehumidification kiln schedules 145 Sterilizing, equalizing, and conditioning treatments 145 Sterilizing treatments 145 Mold 145 Fungal stain and decay 146 . , , o* j=d Drying lumber too quickly can lead to deep end checking, warping and case hardening. For example, if you dry 7,500BF of fast drying Pine, youd select the 8MBF chamber with the HT18 Dehumidifier. I decided on a dehumidification kiln after reading an article in Fine Woodworking (1991). I recently picked up a back issue of American Woodworker, #94 June 2002, that has a good article on constructing a simple DH kiln. The schedule designations use the popular U.S. Forest Products Laboratory designations. I then manually rotate the fan boxes halfway through the drying cycle. Its a nice use of technology and adds a measure of safety as well.) This kicker board will help distribute the airflow more evenly through all layers of lumber. /Filter /JBIG2Decode Soon the DH wont show much water collected in the tray. A small electric heater supplies auxiliary heat to maintain adequate kiln temperature. End baffles are also a good idea to prevent airflow from bypassing the stack entirely. 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 Sticker spacing can be increased to 24" apart for 5/4 or thicker hardwood. 282 0 obj <> endobj 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%. Sticker spacing can be increased to 24 apart for 5/4 or thicker hardwood. 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. Each layer of lumber is separated from the next by a series of "stickers" or spacer sticks. This would allow a stack of lumber four feet wide and 10 feet long. . Corrosion resistant epoxy coated aluminum cabinets and specially coated dehumidification coils for an extra long life. By setting the relative humidity (RH) on the dehumidifier, you can control how often it runs. Place some sample boards in the stack that will be easy to pull out for moisture testing later. The order was 540 board feet (BF) of 5/4 white oak. These well-known dehumidification kiln packages have been among our bestselling products for the past 30 years. A typical home center sheds floors are underbuilt for the weight of a load of lumber. 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 I am using a household . Also check that air isnt escaping around the side baffles or under the stack of lumber. I use a Rockler steam generator. Formulating a Kiln Schedule Wood poles subjected to a 22- to 34-day dehumidification kiln schedule with a heat treatment to 60C to the poles' core. For a single-stack kiln I recommend a minimum shed size of 8 x 12. 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. /Subtype /Image 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. My question focuses on the initial relative humidity featured in the Safe Drying Rate table. This problem is magnified if the lumber is thin or flatsawn. Kiln schedules are completely assembled and written out for easy use. Temperatures inside the kiln range from 120 to 190 degrees F, depending on the stage of . An outswing door can always be opened, regardless of shed contents. The moisture loss, drying time and drying defects were determined. Kiln drying is the process of drying wood in a controlled environment, where temperature, air circulation and humidity are monitored and stabilized. 3, a simplified transverse section of a kiln chamber with an energy recovery and dehumidification system is shown. As a result, the kiln schedules were too severe. I hope that the sawyer coated the ends of the lumber with Anchor-Seal or oil-based paint when it was green. 2. An anemometer confirms that your effort constructing baffles was worthwhile. Each layer adds approximately .81 R value. On this order alone, I saved over $1,300 by drying the lumber myself. I find that unplugging the DH is helpful during the sterilization phase so I can add a second heater, without overwhelming my electrical circuit. 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. Check your local building codes for regionally specific requirements and electrical permits. When properly loaded, this kiln can dry approximately 600 board feet of 4/4" lumber. Bring your moisture meter to confirm. 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. I cannot stress the importance of baffles enough. For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. 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 . Kiln Drying . In the third column, write down the appropriate dry-bulb temperatures. Kiln drying is usually preceded by air drying to bring the moisture content of the wood down below 30%. With a 130 F kiln temperature, sterilization will take 10 to 12 hours (Dry Kiln Operators Manual, 1991). Dehumidification Kiln Drying. WOODWEB is a registered trademark of Woodweb.com.