http://owic.oregonstate.edu/bboard/ Mon, 23 Nov 2009 01:40:06 -0800 MyBB http://owic.oregonstate.edu/bboard/showthread.php?tid=46 Sun, 04 Oct 2009 12:49:39 -0700 http://owic.oregonstate.edu/bboard/showthread.php?tid=46 Ask the Expert forum posted the question, "What suggestions do you have for drying eucalyptus wood in a solar kiln?"

There really isn't much detailed information on drying any wood species in a solar kiln since you have such limited ability to control temperature and humidity. The most important thing is to closely monitor drying and take the appropriate steps when there is evidence that the wood is drying either too slowly or too rapidly.

If the species of eucalyptus is very dense and prone to warp and checking, high temperatures and rapid airflows (which are possible in a solar kiln) can dry the wood too quickly and result in significant degrade of the lumber. The common approach for 'difficult to dry wood species' is to air dry the lumber for 6 to 9 months. Even with air drying, when it is hot and windy, the wood may begin to warp and check. If so, you could place the wood in a covered location and/or cover it with a shade cloth to slow the drying rate. On the other hand, if the wood begins to mold due to drying too slowly, you need to take steps to speed the drying process (which can be difficult in cool, humid climates).

Once the wood is below about 20% moisture content, you can move it into the solar kiln. As with air drying, you will have to closely monitor the wood - if the wood is warping and checking you need to the slow drying rate. Often the way to do that in a solar kiln is to either open the doors and turn off the fans and/or cover the glass panels with a tarp to lower the temperatures.]]> Ask the Expert forum posted the question, "What suggestions do you have for drying eucalyptus wood in a solar kiln?"

There really isn't much detailed information on drying any wood species in a solar kiln since you have such limited ability to control temperature and humidity. The most important thing is to closely monitor drying and take the appropriate steps when there is evidence that the wood is drying either too slowly or too rapidly.

If the species of eucalyptus is very dense and prone to warp and checking, high temperatures and rapid airflows (which are possible in a solar kiln) can dry the wood too quickly and result in significant degrade of the lumber. The common approach for 'difficult to dry wood species' is to air dry the lumber for 6 to 9 months. Even with air drying, when it is hot and windy, the wood may begin to warp and check. If so, you could place the wood in a covered location and/or cover it with a shade cloth to slow the drying rate. On the other hand, if the wood begins to mold due to drying too slowly, you need to take steps to speed the drying process (which can be difficult in cool, humid climates).

Once the wood is below about 20% moisture content, you can move it into the solar kiln. As with air drying, you will have to closely monitor the wood - if the wood is warping and checking you need to the slow drying rate. Often the way to do that in a solar kiln is to either open the doors and turn off the fans and/or cover the glass panels with a tarp to lower the temperatures.]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=45 Fri, 11 Sep 2009 08:23:52 -0700 http://owic.oregonstate.edu/bboard/showthread.php?tid=45 http://owic.oregonstate.edu/bboard/showthread.php?tid=44 Fri, 06 Feb 2009 15:35:06 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=44
A. Develop a succinct mission statement for the organization.  Tony agreed to do this within the next 3 weeks.

B. Develop a questionnaire asking QC professionals what they want from an association; questionnaire to be completed via phone interviews.  Scott and John agreed to do this within the next 3 weeks. 

C. Host a meeting at a mill (potentially RFP in Dillard) to present the concept for a Wood Products QC Association and tour the mill.  Format of meeting would also include each participant introducing themself and asking a question they are currently facing related to QC.  Meeting agenda would then include participants answering each other's questions.  We agreed to leave the planning of this until tasks A and B are completed.

We also agreed to use the on-line discussion forum for communication.  If you're reading this - that means you signed up and found it!  

We also agreed that, at least initially, the organization would focus on lumber and plywood personnel in Oregon, Washington, and California.

Other Information:

We talked about some of the challenges facing wood products QC personnel:
* Limited opportunities for training
* Trade-offs with real-time/automated systems and hands-on.  Users of automated systems still need to know what the system is telling them
* Challenges with varied backgrounds of participants in workshops - some lack basic math skills, others are ready for advanced topics
* Trade-offs between quality and production mindsets
* QC as a career vs. a stepping stone to other positions.  We talked about this quite a bit.  How do we elevate the status of the QC professional?  A certification program was mentioned as one option.

I mentioned curriculum design/body of knowledge several times.  What do we think a wood products QC professional needs to know to be successful - both now and in 5-10 years?  

We also discussed the challenges of selling the importance of quality to upper managers and the need to speak in $$$$.  What is the value of 0.010", for example?  

Dean mentioned the importance of considering linkages not only to upper management but also to preventive maintenance and sales & marketing.  

The idea of creating a sawmill checklist similar to the dry kiln checklist was discussed.  I mentioned that developing a companion publication for sawmills/planermills might serve as a first step for defining the training needs of QC professionals in the industry.

Last but not least, I offered to send the link to the curriculum for our Wood Industry Production Planning & Quality Control option for B.S. students.

Of course, we talked about much more than this - existing resources such as ASQ, FPS, the Wood Products Quality Council of Canada, etc.  These are simply the notes I captured.  Feel free to add detail by replying to this post.

Scott]]>
A. Develop a succinct mission statement for the organization.  Tony agreed to do this within the next 3 weeks.

B. Develop a questionnaire asking QC professionals what they want from an association; questionnaire to be completed via phone interviews.  Scott and John agreed to do this within the next 3 weeks. 

C. Host a meeting at a mill (potentially RFP in Dillard) to present the concept for a Wood Products QC Association and tour the mill.  Format of meeting would also include each participant introducing themself and asking a question they are currently facing related to QC.  Meeting agenda would then include participants answering each other's questions.  We agreed to leave the planning of this until tasks A and B are completed.

We also agreed to use the on-line discussion forum for communication.  If you're reading this - that means you signed up and found it!  

We also agreed that, at least initially, the organization would focus on lumber and plywood personnel in Oregon, Washington, and California.

Other Information:

We talked about some of the challenges facing wood products QC personnel:
* Limited opportunities for training
* Trade-offs with real-time/automated systems and hands-on.  Users of automated systems still need to know what the system is telling them
* Challenges with varied backgrounds of participants in workshops - some lack basic math skills, others are ready for advanced topics
* Trade-offs between quality and production mindsets
* QC as a career vs. a stepping stone to other positions.  We talked about this quite a bit.  How do we elevate the status of the QC professional?  A certification program was mentioned as one option.

I mentioned curriculum design/body of knowledge several times.  What do we think a wood products QC professional needs to know to be successful - both now and in 5-10 years?  

We also discussed the challenges of selling the importance of quality to upper managers and the need to speak in $$$$.  What is the value of 0.010", for example?  

Dean mentioned the importance of considering linkages not only to upper management but also to preventive maintenance and sales & marketing.  

The idea of creating a sawmill checklist similar to the dry kiln checklist was discussed.  I mentioned that developing a companion publication for sawmills/planermills might serve as a first step for defining the training needs of QC professionals in the industry.

Last but not least, I offered to send the link to the curriculum for our Wood Industry Production Planning & Quality Control option for B.S. students.

Of course, we talked about much more than this - existing resources such as ASQ, FPS, the Wood Products Quality Council of Canada, etc.  These are simply the notes I captured.  Feel free to add detail by replying to this post.

Scott]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=43 Tue, 26 Aug 2008 14:25:36 -0700 http://owic.oregonstate.edu/bboard/showthread.php?tid=43 http://owic.oregonstate.edu/bboard/showthread.php?tid=42 Tue, 22 Jan 2008 12:09:27 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=42 http://owic.oregonstate.edu/bboard/showthread.php?tid=41 Tue, 04 Dec 2007 16:30:32 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=41

1. Would there be an advantage to move away from "green" or "sustainable" and instead jointly promote high performance (e.g., lower utility bills) and healthy homes built with sustainable (e.g., wood) products harvested as a renewable resource?
2. I don't hear/ read about economic & social sustainability of our rural communities.  Why?
3. For the State Board of Forestry representatives:  Washington is moving forward on FSC certification on a forest in the Olympic peninsula area.  When will Oregon look at certifying its state forests to either FSC or SFI?
4. What would it take to have compliance of the Oregon Forest Practices Act serve as the certification system?
5. National climate change policy is coming; if Oregon steps up as an early adopter in the Western Climate Initiative, we can put some stakes in the ground to shape national policy.  So - what are some of those carbon policy elements that green builders and forest industry folks can agree on that will advance Oregon's sustainability competitive advantage?
6. Has the panel discussed specific tax reduction incentives to support sustainable practices, and commensurate replacement revenue mechanisms?
7. Why is LEEDs pro-steel and anti-wood?  Why is LEEDs anti-SFI?
8. What is potential for green building value-added wood products as a competitive strategy for sustainability?
9. Why just wood?  Forestland provides a lot of services (water, carbon, etc.).  The kind of wood demanded by green building creates these products that can be sold.
   

]]>

1. Would there be an advantage to move away from "green" or "sustainable" and instead jointly promote high performance (e.g., lower utility bills) and healthy homes built with sustainable (e.g., wood) products harvested as a renewable resource?
2. I don't hear/ read about economic & social sustainability of our rural communities.  Why?
3. For the State Board of Forestry representatives:  Washington is moving forward on FSC certification on a forest in the Olympic peninsula area.  When will Oregon look at certifying its state forests to either FSC or SFI?
4. What would it take to have compliance of the Oregon Forest Practices Act serve as the certification system?
5. National climate change policy is coming; if Oregon steps up as an early adopter in the Western Climate Initiative, we can put some stakes in the ground to shape national policy.  So - what are some of those carbon policy elements that green builders and forest industry folks can agree on that will advance Oregon's sustainability competitive advantage?
6. Has the panel discussed specific tax reduction incentives to support sustainable practices, and commensurate replacement revenue mechanisms?
7. Why is LEEDs pro-steel and anti-wood?  Why is LEEDs anti-SFI?
8. What is potential for green building value-added wood products as a competitive strategy for sustainability?
9. Why just wood?  Forestland provides a lot of services (water, carbon, etc.).  The kind of wood demanded by green building creates these products that can be sold.
   

]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=37 Tue, 09 Oct 2007 08:41:00 -0700 http://owic.oregonstate.edu/bboard/showthread.php?tid=37 http://www.fpl.fs.fed.us/tmu/grant-2008/...http://www.fpl.fs.fed.us/tmu/grant-2008/biomass-2008/.

Best of luck.

Chris]]> http://www.fpl.fs.fed.us/tmu/grant-2008/...http://www.fpl.fs.fed.us/tmu/grant-2008/biomass-2008/.

Best of luck.

Chris]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=36 Thu, 26 Jul 2007 14:59:41 -0700 http://owic.oregonstate.edu/bboard/showthread.php?tid=36 http://www.arb.ca.gov/toxics/compwood/compwood.htm.

]]> http://www.arb.ca.gov/toxics/compwood/compwood.htm.

]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=35 Wed, 18 Jul 2007 16:43:47 -0700 http://owic.oregonstate.edu/bboard/showthread.php?tid=35
If I understood correctly, all these panels that contain formaldehyde-added resin (even PF and MF) will require testing. Apparently, grade marked structural panels containing PF are exempt. Who will do all of this testing? By CARB rule it must be a certified laboratory.

The options for no-added formaldehyde resin are slim. MDI and soy protein resins are possibilities, but there are some convincing reasons to argue that this will not be the solution for everyone.

Thanks to FPS and OWIC for a great workshop.]]>
If I understood correctly, all these panels that contain formaldehyde-added resin (even PF and MF) will require testing. Apparently, grade marked structural panels containing PF are exempt. Who will do all of this testing? By CARB rule it must be a certified laboratory.

The options for no-added formaldehyde resin are slim. MDI and soy protein resins are possibilities, but there are some convincing reasons to argue that this will not be the solution for everyone.

Thanks to FPS and OWIC for a great workshop.]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=34 Mon, 16 Jul 2007 12:02:41 -0700 http://owic.oregonstate.edu/bboard/showthread.php?tid=34 Air Toxic Control Measure to regulate emissions of formaldehyde from composite wood products.  This discussion forum is a follow-up to a 2-day conference held July 10th and 11th in Eugene, Oregon.  See http://owic.oregonstate.edu/formaldehyde for an overview of the program and links to presentations.

The conference, and this forum, are intended to provide information on that regulation and a venue for further discussion.  

 ]]> Air Toxic Control Measure to regulate emissions of formaldehyde from composite wood products.  This discussion forum is a follow-up to a 2-day conference held July 10th and 11th in Eugene, Oregon.  See http://owic.oregonstate.edu/formaldehyde for an overview of the program and links to presentations.

The conference, and this forum, are intended to provide information on that regulation and a venue for further discussion.  

 ]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=30 Thu, 07 Jun 2007 06:24:29 -0700 http://owic.oregonstate.edu/bboard/showthread.php?tid=30 http://owic.oregonstate.edu/bboard/showthread.php?tid=26 Fri, 30 Mar 2007 07:42:25 -0700 http://owic.oregonstate.edu/bboard/showthread.php?tid=26 http://owic.oregonstate.edu/bboard/showthread.php?tid=25 Fri, 09 Mar 2007 11:35:02 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=25 Information on Oregon Woods page recently asked:

I have recently come across some holly (Oregon Grape???) and was wondering how best to dry it for use in projects.
>>>>>>>>>>>>>>>>>>

The leaves for holly look similar to Oregon grape, but they are different species.  I know Oregon grape can get fairly large, but my hunch would be if you have lumber of any width greater than 2 or 3 inches, it's probably holly.  The book "Dry Kiln Schedules for Commercial Woods - Temperate and Tropical lists a schedule for American holly.  See Table 56 on page 59 of the PDF.]]> Information on Oregon Woods page recently asked:

I have recently come across some holly (Oregon Grape???) and was wondering how best to dry it for use in projects.
>>>>>>>>>>>>>>>>>>

The leaves for holly look similar to Oregon grape, but they are different species.  I know Oregon grape can get fairly large, but my hunch would be if you have lumber of any width greater than 2 or 3 inches, it's probably holly.  The book "Dry Kiln Schedules for Commercial Woods - Temperate and Tropical lists a schedule for American holly.  See Table 56 on page 59 of the PDF.]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=22 Tue, 06 Mar 2007 14:27:32 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=22
Our answer was, a vertical grain board will shrink more in thickness as a percentage of the original dimension (but not in actual amount), than it will in width. Conversely, a flatsawn board will shrink more in width than in thickness.

Wood shrinks (or swells) as a percentage of its overall size. While the amount varies by species, a very rough estimate is that it shrinks about 8% from green to ovendry in the tangential direction (around or parallel to the growth rings) and 4% from green to ovendry in the radial direction (across or perpendicular to the growth rings). For vertical grain, the thickness is in the tangential direction and width is in the radial direction. For flatsawn lumber the thickness is in the radial direction and width is in the tangential direction.

Here's an example:
Coastal Douglas-fir 2x6 (actual size 1.5 x 5.5) starting at 19% moisture content and going to 8% moisture content:

* Vertical grain would shrink about 0.04 inches in thickness and about 0.10 inches in width

* Flatsawn would shrink about 0.02 inches in thickness and about 0.14 inches in width

You can use our wood shrink/swell program to estimate the amount of shrink or swell in 100+ different species, under different conditions (moisture content or temperature and humidity), different sizes, and for vertical grain/ flat sawn/ or mixed grain. The program is available for free (though we do ask you to fill out a registration form) at http://owic.oregonstate.edu/woodxlsform.php ]]>
Our answer was, a vertical grain board will shrink more in thickness as a percentage of the original dimension (but not in actual amount), than it will in width. Conversely, a flatsawn board will shrink more in width than in thickness.

Wood shrinks (or swells) as a percentage of its overall size. While the amount varies by species, a very rough estimate is that it shrinks about 8% from green to ovendry in the tangential direction (around or parallel to the growth rings) and 4% from green to ovendry in the radial direction (across or perpendicular to the growth rings). For vertical grain, the thickness is in the tangential direction and width is in the radial direction. For flatsawn lumber the thickness is in the radial direction and width is in the tangential direction.

Here's an example:
Coastal Douglas-fir 2x6 (actual size 1.5 x 5.5) starting at 19% moisture content and going to 8% moisture content:

* Vertical grain would shrink about 0.04 inches in thickness and about 0.10 inches in width

* Flatsawn would shrink about 0.02 inches in thickness and about 0.14 inches in width

You can use our wood shrink/swell program to estimate the amount of shrink or swell in 100+ different species, under different conditions (moisture content or temperature and humidity), different sizes, and for vertical grain/ flat sawn/ or mixed grain. The program is available for free (though we do ask you to fill out a registration form) at http://owic.oregonstate.edu/woodxlsform.php ]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=21 Tue, 06 Mar 2007 14:23:56 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=21 __________________________________________________

The usual target moisture content for wood used indoors is 6-8%. That pretty well covers the range of moisture content wood will experience in a temperature-controlled interior environment.

The book - Dry Kiln Schedules for Commercial Woods: Temperate and Tropical - lists kiln schedules for dozens of wood species. On page 11, the schedules are listed for black walnut. For 4/4, 5/4, and 6/4 thick stock, the schedule is T6-D4 (Table 56). Table 56 is on page 55.

You'll note that the schedule is not time-based, but moisture content based. That is, you make adjustments to the temperature and humidity based on the wood reaching specific steps in moisture content. Thus, given that you've been air drying the wood, you'll likely be able to skip several of the first steps.

Note: If temperature is not controlled in the summer, for example in a home without air conditioning, the humidity will often get quite high and the wood can get as high as 20% moisture content. Granted this is assuming pretty extreme conditions (90 degrees and 90% humidity) for a prolonged period, however it's a worst-case scenario. In such a situation, a 3.5 inch wide black walnut board might swell up to 1/8 inch in width. You can download our wood shrink/swell program to estimate shrink or swell depending on initial and final conditions (moisture content and/or temperature and humidity).]]> __________________________________________________

The usual target moisture content for wood used indoors is 6-8%. That pretty well covers the range of moisture content wood will experience in a temperature-controlled interior environment.

The book - Dry Kiln Schedules for Commercial Woods: Temperate and Tropical - lists kiln schedules for dozens of wood species. On page 11, the schedules are listed for black walnut. For 4/4, 5/4, and 6/4 thick stock, the schedule is T6-D4 (Table 56). Table 56 is on page 55.

You'll note that the schedule is not time-based, but moisture content based. That is, you make adjustments to the temperature and humidity based on the wood reaching specific steps in moisture content. Thus, given that you've been air drying the wood, you'll likely be able to skip several of the first steps.

Note: If temperature is not controlled in the summer, for example in a home without air conditioning, the humidity will often get quite high and the wood can get as high as 20% moisture content. Granted this is assuming pretty extreme conditions (90 degrees and 90% humidity) for a prolonged period, however it's a worst-case scenario. In such a situation, a 3.5 inch wide black walnut board might swell up to 1/8 inch in width. You can download our wood shrink/swell program to estimate shrink or swell depending on initial and final conditions (moisture content and/or temperature and humidity).]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=20 Tue, 06 Mar 2007 14:20:53 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=20 Ask the Expert page on our website asked the question:

"I have a project scheduled to start and the engineer has specified Douglas Fir-Larch Select Structural Lumber, sizes 4 x 10 and 4 x 12 be KDAT to less than 19%. This lumber is to be used in an outdoor, western Alaska coastal environment, 12" above the ground. It will be transported via ocean barge to the site. I am concerned about checking, warping, and other defects possible as a result of drying this lumber to <19%. The potential vendors have each raised these concerns and are recommending 23-25%. Can you give me some guidance please?"

Two types of checking may occur. Small checks are likely to occur, especially in denser areas (the latewood, also called summerwood). These should go in only a growth ring or two and are minimized with the kiln schedule. Of greater concern to you is probably large checks that are clearly visible and run for several feet down the face or edge of the board. These are very difficult to avoid if the member comes from near the pith (center of the tree) of the tree or contains the pith. Careful drying might help, but expect significant spiltting unless the pith is excluded. Further, if the beams are sawn free-of-heart-center and properly restrained during drying, warp should be minimized as well. Of course, this will be a more expensive member.

One important point is to have a clear understanding between the buyer and seller on how the moisture content is measured. 19% average is much different than 19% at the center, which is much different than 19% measured an inch from the surface. With beams this size, I'm not sure you're going to see much difference between 19% (assuming that's the target) and 23-25%. In looking at the equilibrium moisture content of wood in coastal Alaska (see http://owic.oregonstate.edu/pubs/emc.pdf) it seems the range is around 12-20% annually. Thus, wood dried to 23-25% would lose moisture once placed in-service, and would cycle annually between these extremes. Such annual cycling may also lead to checking.

In short, I don't know if it's going to make much that much difference in appearance if they are dried to 19% or 25%. Realize however that as they dry out in-service, further checking may also occur. Before changing the moisture specification, be sure to go back to the structural engineer and have the change approved. In some cases, such as bolted connections, the design values are very different for green versus dry lumber. At <19% the members are S-DRY, if they are above 19% they are stamped S-GRN.]]> Ask the Expert page on our website asked the question:

"I have a project scheduled to start and the engineer has specified Douglas Fir-Larch Select Structural Lumber, sizes 4 x 10 and 4 x 12 be KDAT to less than 19%. This lumber is to be used in an outdoor, western Alaska coastal environment, 12" above the ground. It will be transported via ocean barge to the site. I am concerned about checking, warping, and other defects possible as a result of drying this lumber to <19%. The potential vendors have each raised these concerns and are recommending 23-25%. Can you give me some guidance please?"

Two types of checking may occur. Small checks are likely to occur, especially in denser areas (the latewood, also called summerwood). These should go in only a growth ring or two and are minimized with the kiln schedule. Of greater concern to you is probably large checks that are clearly visible and run for several feet down the face or edge of the board. These are very difficult to avoid if the member comes from near the pith (center of the tree) of the tree or contains the pith. Careful drying might help, but expect significant spiltting unless the pith is excluded. Further, if the beams are sawn free-of-heart-center and properly restrained during drying, warp should be minimized as well. Of course, this will be a more expensive member.

One important point is to have a clear understanding between the buyer and seller on how the moisture content is measured. 19% average is much different than 19% at the center, which is much different than 19% measured an inch from the surface. With beams this size, I'm not sure you're going to see much difference between 19% (assuming that's the target) and 23-25%. In looking at the equilibrium moisture content of wood in coastal Alaska (see http://owic.oregonstate.edu/pubs/emc.pdf) it seems the range is around 12-20% annually. Thus, wood dried to 23-25% would lose moisture once placed in-service, and would cycle annually between these extremes. Such annual cycling may also lead to checking.

In short, I don't know if it's going to make much that much difference in appearance if they are dried to 19% or 25%. Realize however that as they dry out in-service, further checking may also occur. Before changing the moisture specification, be sure to go back to the structural engineer and have the change approved. In some cases, such as bolted connections, the design values are very different for green versus dry lumber. At <19% the members are S-DRY, if they are above 19% they are stamped S-GRN.]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=19 Tue, 06 Mar 2007 14:18:23 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=19
There is an article on this topic by Klimesh from Fine Woodworking (p. 40, issue #45, 1984). The article talks about the author's experience building and using a chest-freezer sized kiln that will dry about 300 board feet of lumber. It uses a department store dehumidifier and coffee cans over 150W light bulbs. 

[2007 Update] - There is also now a publication by Scott Bowe (University of Wisconsin Extension Service) and others titled Dehumidification Drying for Small Woodworking Firms and Hobbyists: Building your Own Lumber Dry Kiln with Local Building Materials. ]]>
There is an article on this topic by Klimesh from Fine Woodworking (p. 40, issue #45, 1984). The article talks about the author's experience building and using a chest-freezer sized kiln that will dry about 300 board feet of lumber. It uses a department store dehumidifier and coffee cans over 150W light bulbs. 

[2007 Update] - There is also now a publication by Scott Bowe (University of Wisconsin Extension Service) and others titled Dehumidification Drying for Small Woodworking Firms and Hobbyists: Building your Own Lumber Dry Kiln with Local Building Materials. ]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=18 Tue, 06 Mar 2007 14:16:13 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=18
The Dry Kiln Operator's Manual states that Doug-fir lam stock is to be treated as upper grades and the schedule for drying is in Table 7-19 in Chapter 7 beginning on page 166. Douglas-fir is addressed on pg. 166 and Ponderosa pine is addressed on pg. 167.]]>
The Dry Kiln Operator's Manual states that Doug-fir lam stock is to be treated as upper grades and the schedule for drying is in Table 7-19 in Chapter 7 beginning on page 166. Douglas-fir is addressed on pg. 166 and Ponderosa pine is addressed on pg. 167.]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=17 Mon, 05 Feb 2007 21:18:29 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=17 >>>>>>>>>>>>>>>>>>>>>>>>>>>
I have been meeting with representatives from various companies who have real time size monitoring systems for sawmill applications. I have only looked at one system that is in operation here in southern Oregon.

I am looking for input from people who have used these effectively and could give me input on what works and what doesn't. My company is going to go forward with one of these systems, however, some input from those currently using them would be helpful in making some decisions. Info. on user friendliness, software packages, training and support, etc.
>>>>>>>>>>>>>>>>>>>>>>>>>>>
Note: You can either reply to this post or simply send an email to me at Scott.Leavengood@oregonstate.edu and I'll pass the info along.

Scott]]> >>>>>>>>>>>>>>>>>>>>>>>>>>>
I have been meeting with representatives from various companies who have real time size monitoring systems for sawmill applications. I have only looked at one system that is in operation here in southern Oregon.

I am looking for input from people who have used these effectively and could give me input on what works and what doesn't. My company is going to go forward with one of these systems, however, some input from those currently using them would be helpful in making some decisions. Info. on user friendliness, software packages, training and support, etc.
>>>>>>>>>>>>>>>>>>>>>>>>>>>
Note: You can either reply to this post or simply send an email to me at Scott.Leavengood@oregonstate.edu and I'll pass the info along.

Scott]]> http://owic.oregonstate.edu/bboard/showthread.php?tid=16 Fri, 05 Jan 2007 13:16:07 -0800 http://owic.oregonstate.edu/bboard/showthread.php?tid=16
This seems to fall into the category of tolerance stacking, i.e., when you combine two or more parts together in an assembly, the variability of the assembly is a combination of the means and variations of the individual components.  

A spreadsheet is at http://owic.oregonstate.edu/spc/tolerance.xls that calculates the nonconforming parts per million (ppm) using various combinations of average part size and standard deviation.  

The 'clearance' and the gap are really the same thing - the amount of slop in the fit.  You can play around with the mean dimensions of each part to see which gives you the best situation.  As I have it set now, the tenon is at 0.721 inches, mortise at 0.763 and both have standard deviation of 0.007 inches.  This will result in about 11 parts that don't fit together and about 62 ppm with excessive slop.  

Thus, if your control chart showed an in-control average of 0.721 and 0.763 for the parts, AND an estimate of sigma of 0.007, then you'd be able to meet the specifications.  

As is always the case with quality control, controlling (and hopefully reducing) the standard deviation is crucial. See what happens if you adjust the standard deviation to be, for example, 0.010.  Nonconforming ppm jumps to nearly 5,100!

Scott]]>
This seems to fall into the category of tolerance stacking, i.e., when you combine two or more parts together in an assembly, the variability of the assembly is a combination of the means and variations of the individual components.  

A spreadsheet is at http://owic.oregonstate.edu/spc/tolerance.xls that calculates the nonconforming parts per million (ppm) using various combinations of average part size and standard deviation.  

The 'clearance' and the gap are really the same thing - the amount of slop in the fit.  You can play around with the mean dimensions of each part to see which gives you the best situation.  As I have it set now, the tenon is at 0.721 inches, mortise at 0.763 and both have standard deviation of 0.007 inches.  This will result in about 11 parts that don't fit together and about 62 ppm with excessive slop.  

Thus, if your control chart showed an in-control average of 0.721 and 0.763 for the parts, AND an estimate of sigma of 0.007, then you'd be able to meet the specifications.  

As is always the case with quality control, controlling (and hopefully reducing) the standard deviation is crucial. See what happens if you adjust the standard deviation to be, for example, 0.010.  Nonconforming ppm jumps to nearly 5,100!

Scott]]>