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 For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. I then manually rotate the fan boxes halfway through the drying cycle. Then align each subsequent layer of stickers over the last. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. A lazy Susan with 180 detents mounts the fan box to the ceiling. The schedules can also be formulated manually as follows. For example, if you dry 7,500BF of fast drying Pine, you'd select the 8MBF chamber with the HT18 . Maderas. organization in the United States. Difficult-to-dry species might not exceed 60 C (140 F). My question focuses on the initial relative humidity featured in the Safe Drying Rate table. Recently, either Wood, or American Woodworker showed how to build a small version of a solar kiln. 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. Featuring lower cost drying at speeds equal to gas & steam, these kilns are continuously exceeding industry standards and changing the game. (Sawing and Drying Forum) Share. This slows the end-grain drying and limits the severity of end checking. Leave an air space between the rigid foam and subfloor for additional insulating properties. The T-bars are made from 1/2 galvanized pipe and are attached to the rafters with threaded pipe flanges. Many regions have increased the shed and outbuilding maximum allowable size without need for a permit. On this order alone, I saved over $1,300 by drying the lumber myself. Total costs for the materials were $2,704 based on 2006 prices. 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 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. 5. Additionally, a 12 air plenum is required between the walls and stacks of lumber. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. 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. Once the core readings are 6% to 8% on a fresh cut, the lumber is dry and ready for sterilization. Ideally, a lumber kiln would be large enough to dry multiple stacks of lumber. Kiln drying is usually preceded by air drying to bring the moisture content of the wood down below 30%. Without baffles, the top layers of lumber experience potato chipping with cupping, twisting or warping. The velocity through the load is assumed to be between 275 and . The last thing to do before starting the kiln is to close the gable vent with an insulated cover. Windows and doors are also sealed, as well as any holes cut for electrical service. Remove samples from the stack, and cut an inch or two off one end. At the planer mill, warped 2 by 4's represent a significant loss in value. Omitting the sterilization phase can lead to costly losses from insect damage, so don't skip it. Do not know just how the end point of moisture would compare. Abstract. Changing the position of the doorway in various kiln setups helps provide the best access to the stacks of lumber. The dry kiln operator is fully in control, with the ability to make changes as the dry kiln schedule is executing. Case hardening is a defect caused by the outer portion of a board drying quickly, while the inner portion dries more slowly. Unlike general shop space, bigger is not always better for kiln design. With a 130 F kiln temperature, sterilization will take 10 to 12 hours (Dry Kiln Operators Manual, 1991). HDE small kilns feature all-aluminum construction for a long, maintenance-free life span . The delicate blue and white color scheme c We proudly stand behind all of our products. Place a sticker at each end, and every 16 along the stack for 4/4 stock. Also check that air isnt escaping around the side baffles or under the stack of lumber. With a 130 F kiln temperature, sterilization will take 10 to 12 hours ( Dry Kiln Operators Manual, 1991 ). For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. After two days operating only the fans and DH, I take note of the temperature. Oregon-based HDE Dry Kilns has launched a new line of small kilns ranging from 2,000 to 12,000 board feet. 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.) 0000004213 00000 n To browse Academia.edu and the wider internet faster and more securely, please take a few seconds toupgrade your browser. Formulating a Kiln Schedule 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. The KD150 Dehumidification Kiln Kit is a compact, entry-level dehumidification kiln for drying lumber between 300 and 1000 board feet. Dehumidification drying equipment is available, but an enclosure must be built to house the equipment and dry the lumber. Regardless of size, allow for a 36 door that opens to a hallway of open space. 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). Insulate the floor with 2 rigid foam for convenience and durability. Check out More On the Web for my complete calculations to figure savings. Consider not only the space for the lumber stacks, but extra floor space to easily load and monitor the charge of lumber. Saving money by drying your lumber may not be the answer for every woodworker, but the basics shown here demonstrate that it is within the reach and skills of the average person. An outswing door can always be opened, regardless of shed contents. Select a heater with an adjustable thermostat and a tip-over shutoff. I selected a 36 outswing exterior door. The second most common type of drying is called dehumidification drying. Sign In Upload. End baffles are also a good idea to prevent airflow from bypassing the stack entirely. Place some sample boards in the stack that will be easy to pull out for moisture testing later. Drying lumber too quickly can lead to deep end checking, warping and case hardening. 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.. Among dimension lumber, the 2- by 4-inch size is typically the most susceptible to warp for a variety of reasons. 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 Enter the email address you signed up with and we'll email you a reset link. My number one priority was to build a kiln that was easy to load and easy to monitor. In vacuum kiln trials, logs were heated to 56C at 70 percent log radius depth and the temperature maintained for . Once the flooring deck is constructed, think about sealing the shed framing at every opportunity. You can achieve top-quality results with incredible efficiency. The conversion method described in the Dry Kiln Operator's Manual is not really accurate, but it is safe. In time schedules, dry- and wet . Corners where walls meet should be sealed with expanding foam sealant. Soon the DH won't show much water collected in the tray. stream They are normally mounted in the gable of household attics, and they are designed to be used in high temperature environments. Our approach was to build and operate a small dehumidification dry kiln. These well-known dehumidification kiln packages have been among our bestselling products for the past 30 years. 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. The remaining width allows for a 36-wide door and space for your drying equipment. In contrast, a dehumidification kiln uses a sealed chamber, with only enough energy input to maintain the desired temperature. Schedules. The common lumber name is used throughout. For end baffles, I use 2"-thick rigid foam insulation screwed to the main baffles. On the last load of lumber I purchased, I saved $2.50 per board foot compared to retail prices for kiln-dried lumber. HT systems use 40-60% less energy than gas-fired or steam dry kilns. Inexpensive Dehumidification KilnIn this video we'll build and load a 14' long 4' by 4' wood kiln that dries wood by heat and dehumidification.We had quite a. Low Temperature Kiln Drying Systems (120F) 300BF - 4000BF Capacity . Place a 1x6 board on the floor behind the stack, tilted to a 45 angle. An anemometer confirms that your effort constructing baffles was worthwhile. Perhaps the best part: you wont need to calculate your lumber needs down to the board foot. Academia.edu no longer supports Internet Explorer. Main thing is to not rush drying in first stages, as this will cause problems. Should a Moulding Mill Bring Sawmill Operations In-House? Forum Responses Check your local building codes for regionally specific requirements and electrical permits. There are two ways to remove water from the DH unit, and they both work well. Kiln drying is almost always essential for wood intended for interior uses. My kiln schedule starts with running all fans and the dehumidifier for two days, measuring and removing water as it accumulates. An official website of the United States government. The order was 540 board feet (BF) of 5/4 white oak. Equalizing and Conditioning 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? Most species of hardwood lumber can be safely dried this way, once the moisture content is 20% to 25% or less. In a professional DH kiln, the final climate for oak is 120F and <40>t over-dry it at that rate. You can achieve top-quality results with incredible efficiency. . 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. I made a simple frame from plywood strips and attached the insulation sheets to them with screws and fender washers. This gives me a secondary method of tracking the drying process, using both water volume and moisture content (MC) readings. Kiln Drying . 3.24 solar-dehumidification drying kiln 0000002827 00000 n The baffles do not need insulating properties, and plywood would work just as well. This lets the operator sort stacks by lumber species, so they will be easy to retrieve when the drying cycle is complete. 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). A household dehumidifier (DH) removes moisture from the kiln chamber. In the majority of cases, the drying schedules are from the world literature, with emphasis on U.S., Canadian, and British publications. If required, look-up and write down the RH (sixth column) and EMC (seventh column) for each schedule step. There may be more depression values than required; ignore the extra depression values in this table. _0e`bd\ p@ Be sure that all of the kiln equipment is working prop-erly before lumber is loaded into the kiln. /BitsPerComponent 1 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. kiln/. Choosing a Kiln Schedule Lock If your lumber stack is built on starter blocks, you will need to limit airflow there as well. . 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 If your lumber stack is built on starter blocks, you will need to limit airflow there as well. We are proud of the quality of our products, and we stand behind them 100%. Excel Program for Modeling Lumber Dry Kiln Operations - a model for lumber dry kiln operation. Take the electronics out of the kiln, and continue operating the heater and fans during this phase. Air speed of 350 feet per minute is appropriate for common hardwoods such as oak and maple. 1998. With two-stack and three stack kilns, it is better to have reversible fans to alter the direction of airflow mid-cycle. During the conditioning process, the only equipment operating are the fans, heater and the steam generator no dehumidifier. 0000001417 00000 n This gives me a secondary method of tracking the drying process, using both water volume and moisture content (MC) readings. Temps are in Celsius (20C = 70F, 40C = 105F). Using a Kiln Schedule Each layer of lumber is separated from the next by a series of stickers or spacer sticks. In addition, wood can be dried by special methods that include solar drying (use of greenhouse-type dryers or those equipped with solar collectors . Sears Canada 70 Pint Dehumidifier. Sticker spacing can be increased to 24" apart for 5/4 or thicker hardwood. The fact is, most of my stacks of lumber air dry to 15% moisture content before entering the kiln. Should I? When the operating conditions of this option are followed the material will meet the requirements of being kiln dried (KD) and heat treated . There are two ways to remove water from the DH unit, and they both work well. Looking at the cost-benefit analysis of a shed kiln can be enlightening. But kiln drying may also introduce internal stresses into the woodparticularly if an improper kiln schedule is used, . Taking moisture away at the rate the board will "safely" part with it . Basically, you don't want all of the air rushing out under the stack, so find a way to redirect it. Also, since heat rises, ceiling-mounted fans have the added benefit of circulating the warmest air over the lumber. Once all the lumber is stacked and stickered, place baffles over the lumber. Using a piece of paper with 6 columns, write down the Schedule Step numbers in the first column on the left. (See the following sections for a discussion of how to develop a schedule from these designations.) 0000000591 00000 n The starter blocks should be as long as the stack is wide. Then, write down the appropriate MC ranges (determined in #2 above) in the second column. Although dehumidification kilns are slower than conventional kilns for drying, the lower drying temperature has the reported advantage of less degrade and less shrinkage. That purchase was an average deal, and one I dont consider a particular bargain. )f7haRoMRhib5Sd|-=RBkBBN r-hzf+1\IFgk;v]3_, KxL$9oL "Qw#"BFGfk}>cT2g yP K|7@N*v9!Wy9jB. op(y"X)Fz"q]fQC/ha>7=k_p}}^VXQmj e'2fyXQ{~23X^H1,d>Hq|^KQ*cN=yF%z. 0000000710 00000 n Construction of a kiln chamber is very similar to building a small house. They are easy to use and give you precision control over your drying. After a short period of grumbling, they join me to lay down wood blocks for the first layer of lumber. In addition, weight on top of the stack can be helpful, but nothing replaces baffles for the best lumber yield. Instead of using expensive electrically reversible fans designed for commercial kilns, I came up with a simple hardware solution. The T-bars are made from 1/2" galvanized pipe and are attached to the rafters with threaded pipe flanges. If MC readings still arent at the desired range, the heat may need to be increased for the remainder of the drying cycle. During the conditioning process, the only equipment operating are the fans, heater and the steam generator no dehumidifier. My shed kiln was stick-built from standard building material, and sized to take advantage of typical 4 x 8 sheet goods. Once the lumber is sterilized, it is ready for the conditioning phase. 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. Anyway, I included my log of a load I did in Nov '06 for everyone's amusement. Seems like a pretty simple way to run the kiln - once or twice a day just measure the amount of water extracted, and turn down the humidity a bit as needed. Dehumidification Kilns %PDF-1.5 Dehumidification kiln schedules 145 Sterilizing, equalizing, and conditioning treatments 145 Sterilizing treatments 145 Mold 145 Fungal stain and decay 146 . Diy dehumidifier kiln time table. Only the fans need electricity. The DH is not needed at this time, as the lumber is already bone-dry. I am using a household . Q,kjifT33P[! Select a heater with an adjustable thermostat and a tip-over shutoff. They are normally mounted in the gable of household attics, and they are designed to be used in high temperature environments. In Fig. Remove samples from the stack, and cut an inch or two off one end. In this paper, the effective schedules were further investigated for longer culm parts treated with boron. 4. hbbd``b` $ &UD\q@u Soon the DH wont show much water collected in the tray. MC values in the kiln schedules are based on the wettest half of the kiln samples. . For the sterilization phase, air temperature needs to be around 140 F, for three to five hours. Most species of hardwood lumber can be safely dried this way, once the moisture content is 20% to 25% or less. Always use adequate samples representing both the wettest and driest lumber in the dryer. Dr. Gene Wengert provides schedules for kiln drying hardwood lumber. They are easy to use and give you precision control over your drying. The column on the right I added part way through is the kiln's internal RH. KD150 Series dehumidifier pdf manual download. I know your kiln is absolutely tight and perfectly sealed, but it has to vent some or it would overheat. This kicker board will help distribute the airflow more evenly through all layers of lumber. 3. %PDF-1.4 % A household dehumidifier (DH) removes moisture from the kiln chamber. 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. 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. For a kiln temperature of 140 F, sterilization takes three to five hours. When that is the case, I know Ill have usable lumber in just a few weeks. Its a nice use of technology and adds a measure of safety as well.) Each layer of lumber is separated from the next by a series of "stickers" or spacer sticks. 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. Dehumidification kilns are similar to other kilns in basic construction and drying times are usually comparable. A.gov website belongs to an official government 0000001186 00000 n A locked padlock 0000006297 00000 n 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. However, the natural light and ventilation offered by a small window outweighs any disadvantages. Question For sterilizing thicker lumber, additional time is required. Measure airflow over the stacks of lumber in various locations. 6. It can be constructed in any style, with architectural features that match or complement an existing home. Staff. This kicker board will help distribute the airflow more evenly through all layers of lumber. Dehumidification Kiln Drying. A shed kiln is an attractive alternative for a couple of reasons. temperature. Ciencia y Tecnologia, Duygu Kocaefe, Ayhan Aytin, The Bolivian secondary forest products industry has experienced substantial growth during the last 10 years. I found that brackets for mounting rigid metal electrical conduit work best. Basically the idea seems to be to maintain a constant temperature, and to keep lowering the humidistat to maintain the SDR until the moisture content gets to the desired level. 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. Such temperatures are high enough to kill insectsanother advantage of kiln drying over air drying. Know how to choose and apply the correct schedule for the lumber. the Dry Kiln Operator's Manual (Simpson, 1991). (I use the Mini-Ligno MD/C from Lignomat, www.lignomatusa.com.) Over 40 years experience building kilns. A higher humidity setting will run the unit sporadically to maintain that RH. Place a 16 board on the floor behind the stack, tilted to a 45 angle. The four charges of lumber ranged from 600 to 700 board feet (bf), and a woodworker with no dry-kiln experience operated the kiln. the hardwood kiln schedule is the equalization of the moisture content of all boards at 6-8%. This publication outlines the basic construction of a small scale dehumidification dry kiln. The baffles direct airflow over and through the stack and prevent the top layers from drying too quickly.