dehumidification kiln drying schedules

The four charges of lumber ranged from 600 to 700 board feet (bf), and a woodworker with no dry-kiln experience operated the kiln. Main thing is to not rush drying in first stages, as this will cause problems. Drying Wood With A Home Dehumidifier - LumberJocks By setting the relative humidity (RH) on the dehumidifier, you can control how often it runs. To hang the baffles, simply attach hooks to the plywood frame. BE CAREFUL--The first temperature value must be repeated for every MC class (column #2) that is above 30% MC. Heres a classic project that both steps up and provides overflow seating. Place a sticker at each end, and every 16 along the stack for 4/4 stock. This slows the end-grain drying and limits the severity of end checking. Take a moisture reading in the end grain with a pin-type moisture meter or remote probe.) 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 . HT systems use 40-60% less energy than gas-fired or steam dry kilns. Construction of a kiln chamber is very similar to building a small house. In smaller kilns, the heat generated by the fans and DH motor is sufficient to maintain temperatures in excess of 100 degrees. A household dehumidifier (DH) removes moisture from the kiln chamber. . endstream endobj startxref This is because it needs to be dried to a lower moisture content than wood will air dry to outdoors. Our approach was to build and operate a small dehumidification dry kiln. Check out More On the Web for my complete calculations to figure savings. Many available kiln designs require a large, heavy door. 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 hardwood kiln schedule is the equalization of the moisture content of all boards at 6-8%. The schedules are all moisture content based, using the moisture content of the wettest half of the kiln samples. (In the original Dry Kiln Operators Manual written in the early 1950s, some species were not used in high quality products. 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. /Name /ImagePart_0 Staggering the seams between the sheathing and siding layers helps avoid air infiltration. There are two main reasons for drying wood: Woodworking When wood is used as a construction material, whether as a structural support in a building . 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. 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 some sample boards in the stack that will be easy to pull out for moisture testing later. Measure airflow over the stacks of lumber in various locations. 2. Kiln drying lumber is a simple, cost effective method recommended for anyone who wants to increase profits by selling dried lumber. For single-stack kilns, stationary fans are adequate. A higher humidity setting will run the unit sporadically to maintain that RH. An anemometer confirms that your effort constructing baffles was worthwhile. Should I? 301 0 obj <>stream For single-stack kilns, stationary fans are adequate. Another common sticker size is 1 x 2, and these work fine as well. Reweigh and obtain the oven dry weight. (Note: This letter designation is related to the green MC of the species. Windows and doors are also sealed, as well as any holes cut for electrical service. So, with that lengthy introduction, here is my question. 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. 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 we revisit the example of a $1,300 gross savings from a load of 540 BF of white oak lumber, and we subtract the estimated cost of $62 to kiln dry the lumber, we arrive at a net savings of $1,238 less than retail. INDUSTRIAL DEHUMIDIFICATION DRYING OF SOFTWOODS - Oregon State University The problems with solar kilns include limited control over temperature and limited solar exposure, depending on your region and site location. 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). 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. After four days, I decrease the RH setting on the DH to 30% and continue to run the fans. 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. These figures hold true for lumber up to 2" thick. Using a Kiln Schedule 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. . Add up the amp draw on all the equipment you plan to use in the kiln, including a heater, dehumidifier, fans and steam generator. They are easy to use and give you precision control over your drying. 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. Our approach was to build and operate a small dehumidification dry kiln. However, the natural light and ventilation offered by a small window outweighs any disadvantages. This lets the operator sort stacks by lumber species, so they will be easy to retrieve when the drying cycle is complete. Wood boiler for Lumber Kiln | Hearth.com Forums Home Also, you can't really control well by measuring the collected water because some of the water leaks out with vented or leaking air. Dry kiln schedules for commercial woods : temperate and tropical | US A locked padlock 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.). They are easy to use and give you precision control over your drying. The dry kiln operator is fully in control, with the ability to make changes as the dry kiln schedule is executing. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. With each load I did not have the initial relative humidity rate. (A major source was Dry Kiln Schedules for Commercial Woods which is available from the Forest Products Society in Madison, WI.) Basically, you dont want all of the air rushing out under the stack, so find a way to redirect it. Dehumidifier suggestion: http://amzn.to/2iYZqVZThis is the first in a series of videos showing how I built a kiln for drying lumber. Forum Responses 6 0 obj Remote operation and networking is optional. Then align each subsequent layer of stickers over the last. Sticker spacing can be increased to 24" apart for 5/4 or thicker hardwood. In the majority of cases, the drying schedules are from the world literature, with emphasis on U.S., Canadian, and British publications. For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. My kiln uses four ceiling-mounted fans, each rated for 1,600 CFM. Dehumidification Opportunities for Dehumidification Drying Of Hardwood Lumber Dimension Kiln Drying Hardwood Dimension Parts Discoloration Preventing Discolorations in Hardwood and Softwood Logs . The KD150 Dehumidification Kiln Kit is a compact, entry-level dehumidification kiln for drying lumber between 300 and 1000 board feet. hbbd``b` $ &UD\q@u By setting the relative humidity (RH) on the dehumidifier, you can control how often it runs. Case hardening is a defect caused by the outer portion of a board drying quickly, while the inner portion dries more slowly. 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. 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. Be sure that all of the kiln equipment is working prop-erly before lumber is loaded into the kiln. Installing sheetrock and fire taping is a good idea for a heated room. Then align each subsequent layer of stickers over the last. If you use a lot of lumber, and youre a decent hand at carpentry, a shed kiln will quickly pay for itself. Kiln Systems. Delete from my manuals. For all kiln drying schedules, a heater should be used to sterilize the lumber and kill any insects that may be present. With a well-designed dehumidification kiln, hardwood lumber can be dried for mere pennies per board foot. I cannot stress the importance of baffles enough. 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. (I use the Mini-Ligno MD/C from Lignomat, www.lignomatusa.com.) 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. Contractors work on a tight schedule, and that may not allow much time for curing and drying concrete. Case hardening is a defect caused by the outer portion of a board drying quickly, while the inner portion dries more slowly. Align the stickers over the starter blocks on the first course. 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. Know how to choose and apply the correct schedule for the lumber. PDF Dry Kiln Schedules for Commercial Woods - Temperate and Tropical Detailed design and custom manufacture of dehumidification and chiller systems for food processing, lumber drying and industrial applications. Secure .gov websites use HTTPS I'm trying to find a timetable or drying schedule for the basic dehumidification kilns you see on youtube. 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? Made in China, it exudes the classic style of Asian and Chinese cultures, featuring a unique shape that sets it apart from traditional jars. When that is the case, I know Ill have usable lumber in just a few weeks.