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%. The approach described in the article where you try to keep the water leaving at a steady rate is fine. This returns some moisture to the very dry exterior of the lumber, while not affecting the core moisture level. This makes lightweight baffles that can be easily moved and repositioned. Select a heater with an adjustable thermostat and a tip-over shutoff. HDE small kilns feature all-aluminum construction for a long, maintenance-free life span . 5. WOODWEB is a registered trademark of Woodweb.com. I recently picked up a back issue of American Woodworker, #94 June 2002, that has a good article on constructing a simple DH kiln. Diy dehumidifier kiln time table. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. /ColorSpace /DeviceGray 301 0 obj <>stream As you can recycle . If it isn't overheating, it is leaking. Operates at a temperature range from 80F - 160F (26 - 71C). End baffles are also a good idea to prevent airflow from bypassing the stack entirely. A locked padlock Case hardening is a defect caused by the outer portion of a board drying quickly, while the inner portion dries more slowly. I chose double wall construction with 1/2 sheathing, and 1/2 T1-11 siding. Use the gridded drawings provided on the PDF, Woodworking | Blog | Videos | Plans | How To. Installing sheetrock and fire taping is a good idea for a heated room. (Dry Kiln Operator's Manual. The sheetrock also helps to protect the fiberglass insulation. Always avoid conditions that add moisture back to the lumber, especially during start-up. Warp in dimension lumber is a significant cause for loss in grade and value. I hope that the sawyer coated the ends of the lumber with Anchor-Seal or oil-based paint when it was green. Also check that air isnt escaping around the side baffles or under the stack of lumber. These well-known dehumidification kiln packages have been among our bestselling products for the past 30 years. Conventional kiln drying. For a kiln temperature of 140 F, sterilization takes three to five hours. The KD150 Dehumidification Kiln Kit is a compact, entry-level dehumidification kiln for drying lumber between 300 and 1000 board feet. Once the core readings are 6% to 8% on a fresh cut, the lumber is dry and ready for sterilization. _0e`bd\ p@ Low Temperature Kiln Drying Systems (120F) 300BF - 4000BF Capacity . Reweigh and obtain the oven dry weight. The schedules can also be formulated manually as follows. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. If your lumber stack is built on starter blocks, you will need to limit airflow there as well. Recently, either Wood, or American Woodworker showed how to build a small version of a solar kiln. Should a Moulding Mill Bring Sawmill Operations In-House? This plan allows . These figures hold true for lumber up to 2 thick. Small, complete dehumidification dry kilns under 5,000 board-foot capacity are not available for sale. To hang the baffles, simply attach hooks to the plywood frame. A maximum 45 F depression often produces better lumber. There are two ways to remove water from the DH unit, and they both work well. This makes lightweight baffles that can be easily moved and repositioned. By setting the relative humidity (RH) on the dehumidifier, you can control how often it runs. Windows and doors are also sealed, as well as any holes cut for electrical service. . However, the natural light and ventilation offered by a small window outweighs any disadvantages. temperature. )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. A kiln schedule is a set of temperatures and humidities that are used during kiln operation. 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.) USDA, 1991) . 0000000710 00000 n 0000006297 00000 n Perhaps the best part: you wont need to calculate your lumber needs down to the board foot. Choosing a Kiln Schedule Typical dehumidification kiln (FPL 1999 p. 12-10). This kicker board will help distribute the airflow more evenly through all layers of lumber. I'm trying to find a timetable or drying schedule for the basic dehumidification kilns you see on youtube. I modified one of the Radio Shack combo units so it could measure the RH remotely as well as the temp. 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. 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. Drying small amounts of lumber using a dehumidification kiln is a suitable option for woodworkers even with limited knowledge of kilns. End baffles are also a good idea to prevent airflow from bypassing the stack entirely. I made a simple frame from plywood strips and attached theinsulation sheets to them with screws and fender washers. KD150 Series dehumidifier pdf manual download. JavaScript seems to be disabled in your browser. They are easy to use and give you precision control over your drying. However, if you kiln dry hardwood lumber that has already been air dried, the process is much more forgiving. 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. 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. Frequently, the lumber has already air-dried for several years in a barn or outbuilding. This prevents dead spots inside the chamber that experience limited airflow. You can achieve top-quality results with incredible efficiency. Also, since heat rises, ceiling-mounted fans have the added benefit of circulating the warmest air over the lumber. 3.24 solar-dehumidification drying kiln A small electric heater supplies auxiliary heat to maintain adequate kiln temperature. Wood-Mizer dehumidification and solar wood kilns range from 300 to 35,000 board feet capacity for drying lumber. I have sensors in the kiln for moisture levels & probes in the center of the wood attached to a lignomat moisture meter. The conversion method described in the Dry Kiln Operator's Manual is not really accurate, but it is safe. 0000006274 00000 n 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 WOODWEB is a registered trademark of Woodweb.com. Place some sample boards in the stack that will be easy to pull out for moisture testing later. They are easy to use and give you precision control over your drying. A higher humidity setting will run the unit sporadically to maintain that RH. The kiln schedule information in the tables below has been assembled from many different sources, including drying texts and industrial contacts. Kiln drying is almost always essential for wood intended for interior uses. Difficult-to-dry species might not exceed 140 degrees F. Dehumidification kilns are very . You can download the paper by clicking the button above. These figures hold true for lumber up to 2" thick. noun: kiln; plural noun: kilns. 158 p. Dry kiln schedules for commercial woods : temperate and tropical. Measure airflow over the stacks of lumber in various locations. A.gov website belongs to an official government Using a piece of paper with 6 columns, write down the Schedule Step numbers in the first column on the left. Basically, you dont want all of the air rushing out under the stack, so find a way to redirect it. Place a sticker at each end, and every 16" along the stack for 4/4 stock. The velocity through the load is assumed to be between 275 and . 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. 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. 0000001186 00000 n 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. 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. Thicker lumber like 5/4 or quartersawn lumber is naturally more stable. Unlike general shop space, bigger is not always better for kiln design. 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. Using a Kiln Schedule A household dehumidifier (DH) removes moisture from the kiln chamber. Schedules. The starter blocks should be as long as the stack is wide. Adjust the baffles or fan direction to achieve good airflow. I find that unplugging the DH is helpful during the sterilization phase so I can add a second heater, without overwhelming my electrical circuit. Changing the position of the doorway in various kiln setups helps provide the best access to the stacks of lumber. If severe enough, the lumber can develop honeycomb cracks throughout. the Dry Kiln Operator's Manual (Simpson, 1991). Instead of using expensive electrically reversible fans designed for commercial kilns, I came up with a simple hardware solution. When the operating conditions of this option are followed the material will meet the requirements of being kiln dried (KD) and heat treated . Built properly, a shed kiln may even increase the value of a property. When that is the case, I know Ill have usable lumber in just a few weeks. The baffles do not need insulating properties, and plywood would work just as well. This fact sheet summarizes the basics of kiln drying wood, the most commonly used methods, drying schedules and some drying defects. Lock Kiln Drying . 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. 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. By setting the relative humidity (RH) on the dehumidifier, you can control how often it runs. Insulation for walls and ceilings should be a minimum of R13. For example, if you dry 7,500BF of fast drying Pine, you'd select the 8MBF chamber with the HT18 . << By. It should be double-pane, well-insulated with low emissivity (low-E). Created and Presented by: Henco Viljoen and Elijah McCarty with Nyle Dry Kilns. Corners where walls meet should be sealed with expanding foam sealant. This listing incorporates current market requirements for the various species, as well as the current quality of the lumber resource itself. Once the core readings are 6% to 8% on a fresh cut, the lumber is dry and ready for sterilization. (116 C) temperature. I selected a 36 outswing exterior door. 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. . Staff. Solar kiln drying was most effective in the summer and early fall, when kiln efficiencies were 90% to 67%, respectively, and drying times were 2 to 3/one-half/ times faster than air drying. Dehumidification: This kiln-drying process requires the use of a heat pump system to remove water from the wood. Construction of a kiln chamber is very similar to building a small house. Wood-Mizer dehumidification and solar wood kilns range from 300 to 35,000 board feet capacity for drying lumber. A pre-hung steel exterior door is ideal in this situation, because it offers weatherstripping and is fully insulated. This report contains suggested dry kiln schedules for over 500 commercial woods, both temperate and tropical. Not bragging or anything! For the sterilization phase, air temperature needs to be around 140 F, for three to five hours. 6 0 obj With two-stack and three stack kilns, it is better to have reversible fans to alter the direction of airflow mid-cycle. A 1.5-kW dehumidifier was installed in the solar dryer to determine the performance of a combined solar-dehumidification dryer. 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? Schedules for several thicknesses and specialty products (e.g. Vote. My aim was to develop a small dehumidification kiln for better control of the three key components of lumber drying: temperature, airflow and humidity. The thinner the stock, the more critical sticker placement becomes. Take a moisture reading in the end grain with a pin-type moisture meter or remote probe. Insulate the floor with 2 rigid foam for convenience and durability. An anemometer confirms that your effort constructing baffles was worthwhile. I then manually rotate the fan boxes halfway through the drying cycle. But kiln drying may also introduce internal stresses into the woodparticularly if an improper kiln schedule is used, . Can also be used on any mobile device! I was hoping someone could point me in the right direction or share experience. Website Content Copyright 2023 Nyle Systems |. The starter blocks should be as long as the stack is wide. I hope that the sawyer coated the ends of the lumber with Anchor-Seal or oil-based paint when it was green. Over 40 years experience building kilns. Please refer to Appendix A which shows the Lumber Dry Kiln Bill of Materials. To hang the baffles, simply attach hooks to the plywood frame. Kiln drying lumber is a simple, cost effective method recommended for anyone who wants to increase profits by selling dried lumber. Exterior sheathing and siding type also factors into the heat-holding ability of the structure. Nyle. After four days, I decrease the RH setting on the DH to 30% and continue to run the fans. 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 . This helps keep the lumber straight during the drying cycle; in fact, improper placement of stickers can permanently deform lumber. Particularly, important investment has taken place in lumber drying capacity. This kicker board will help distribute the airflow more evenly through all layers of lumber. These are rough-saw red oak. Also, for that approach to work, the chamber needs to be air tight. 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.. The kiln climate is controlled by venting the hot air and replacing it with ambient air. With a well-designed dehumidification kiln, hardwood lumber can be dried for mere pennies per board foot. The baffles do not need insulating properties, and plywood would work just as well. 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. Omitting the sterilization phase can lead to costly losses from insect damage, so dont skip it. I know mixed loads are taboo, but this one worked well, other than the horse chestnut. My kiln uses four ceiling-mounted fans, each rated for 1,600 CFM. This problem is magnified if the lumber is thin or flatsawn. You won't ever have the fastest kiln in town, but it can still work. %PDF-1.5 The thinner the stock, the more critical sticker placement becomes. The kiln operator sets the kiln controls based on the initial moisture of the lumber as it is loaded into the kiln. A dehumidification kiln makes sense particularly when the lumber is air-dried first. Another common sticker size is 1" x 2", and these work fine as well. For single-stack kilns, stationary fans are adequate. Share sensitive information only on official, secure websites. 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. The schedules are all moisture content based, using the moisture content of the wettest half of the kiln samples. I am using a household . 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. 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 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). Heat comes primarily from an integral dehumidification unit that also removes . If the temperature is below this range, I start the heater and adjust the thermostat accordingly. For a single-stack kiln I recommend a minimum shed size of 8 x 12. 0 \ Our approach was to build and operate a small dehumidification dry kiln. This will allow the heater to cycle on and off automatically, according to the kiln operator's setting. Wood Drying/ Seasoning. What can you do to speed up drying time? For sterilizing thicker lumber, additional time is required. John Baines Reply to Dann Barry 1 year ago In addition, weight on top of the stack can be helpful, but nothing replaces baffles for the best lumber yield. 1998. by Dr. Eugene Wengert. January 27, 2007. A lock ( A better choice might be a solar kiln, as you can dry wood from "wet" to 6-8 percent MC in 6-8 weeks. This prevents "dead spots" inside the chamber that experience limited airflow. Main thing is to not rush drying in first stages, as this will cause problems. ) or https:// means youve safely connected to the .gov website. The dry kiln operator is fully in control, with the ability to make changes as the dry kiln schedule is executing. The membrane was taped and lapped to the weather so if the tape ever fails, any rain that gets behind the siding would still be shed down and away by the HomeWrap.