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First charge - now what? need advice

Started by OneWithWood, October 26, 2007, 12:05:36 PM

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OneWithWood

Well I finally got a charge into my kiln  8)  about 2000 bd ft of red maple, mostly spalted flatsawn and some fresh out of the tree quarter sawn.

Pics will be in the wannabe thread in a few days I hope.

Here are the known mistakes I made:

There are at least 5 4/4 8x104 basswood boards in the pile somewhere. 

A small amount of water is leaking out from under the rails.  I guess I did not foam under the rails like I intended to  ::)

I made six sample boards but forgot to weigh the boards before I fired up the kiln two days ago (I just had to fire it up and jumped the gun)

The microwave I was going to use to 'oven dry' the 1" samples crapped out on me.

I started the kiln (WM4000, a Nyle 200 with a Honeywell controller) at 90°F and 80%RH

I measured the sample boards in the pile using a Delmhorst R2000.  Of course the reading was 99.9 indicating the moisture was greater than 30% (Duh, even I knew that)

The temp last night for the sample boards was 40°F and the RH was still off the chart.

The kiln temp last night had climbed to 92°F and the RH was reading 79.9%.  The set points are still 90°F and 80.0%

So now I have a dilemma:
I cannot accurately measure my sample boards until the moisture drops below 39% to tell how much moisture is being lost each day.  My goal is 7% or less. 
I did weigh the 1" samples but they had sat out for a coulple of days and may have lost some moisture.
I can still weigh the sample boards.  I forgot to do that again last night (don't know what is going on with the old mind of late - I think I gots Jeff disease  :D )

Is it normal for the temp to climb above the set point?  No alarms were set.
How can I monitor this pile?
One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

beenthere

OWW
Can you just go in and get the sample boards, and weigh them? But cut another 1" moisture sample for oven drying off first. Then weigh the sample boards, should give you a new starting point.
Then subsequent removal of the sample board and just weighing it will give you it's moisture content the rest of the way in the kiln schedule. Seems like, anyway.  :)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

scsmith42

OWW - I would recommend that you invest in a better moisture meter made specifically for kiln use.  One of mine is the Delmhorst J2000X that they make specially for Nyle.  It measures up to 80% MC.  Get the slide hammer option with it if you don't already have one with your R2000, and get some 1" or 1.5" pins to allow you to take core readings from the outside of the board..

I have the same unit that you do (Nyle 200 with Woodmizer controller), and now have the Kil-mo-trol plus system.  I bought the Kil-mo-trol based upon advice from someone on the FF, and long term if you do a lot of drying I would highly recommend one.  I absolutely love mine (I'd definitely go for the plus over the standard unit - the plus automatically takes readings and stores them in a spreadsheet format) and the information that it provides me regarding the drying process.

My drying system is thus:  When I stacking and stickering the boards on my kiln carts, I will check each layer with an pinless type of meter.  I have a Merlin unit that I bought from Ex-Factory; however Bailey's has the same unit on sale right now.  I bought the one designed for kiln operators; it reads up to 1.5" deep.

Based upon the MC%'s indicated in the layers, I'll pick out six boards per load to use for taking my measurements.  These are not oven sample boards, but rather moisture meter sample boards.  Of these six, two will be the average of the driest boards (but not necessarily the very driest board), two will be middle of the pack and two will be the average of the greenest boards.  I look for relative MC% consistency across the board so that I'm not using a board with unusual drying defects (such as bacterial wetwood in walnut) for my samples.

Check the same board with your pin meter every day.  Take both a core and a shell reading from it, and keep a log of the readings.  Start with the factory recommended DH settings, but adjust them as needed to obtain the DRI for your species, w/o overdrying the driest boards.  Also watch the delta between the core and shell readings; they should be reducing at a similar rate (even if they are not the same reading).  If you run into a situation where the shell is reducing but the core is not, then you  may need to adjust your drying process to treat for case hardening.

It is normal for the temperature to rise somewhat over what you have the kiln controller set for.  The rise will vary depending upon several factors, including how well your kiln is insulated and the ambient temps outside.  The fans within the kiln create heat, as does the compressor and fan on the DH unit, and that is partially where the heat rise comes from.

Thus, sometimes you will want to set your controller a little lower initially in order to keep your heat rise under control.

The biggest challenge that I see during the initial phases of my loads is mold development.  If there are any "dead spots" in the kiln with a lower air flow it will start there first.  I have also found that the MC% readings typically rise during the first 48 - 72 hours of kiln operation, and then stabilize and start dropping.

Precise record keeping from start to finish is a huge help in improving your quality; as it allows you to know what's happening with your load, and provides you with the information necessary to make adjustments to reduce degrade. 

Regards,  Scott
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

beenthere

Scott
Have any more info on the moisture meter that measures 80% moisture content in wood? 
Is it 80% on oven-dry basis?
Is it a resistance meter or capacitance?

Curious.. :)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Den Socling

no no! The J2000 isn't made specially for Nyle and no meter can read up to 80%.

And a deviation alarm, if you have one, should be used to dump excess heat through the vent(s).

OneWithWood

BT, thanks.  It amazes me sometimes how the obvious can be so hard for me to see  :D

I did as Beenthere suggested and now have some baseline data to work with. 
I have noticed the temp going up in the chamber (up to 101.3°F) as of 7pm last night.  The RH was hanging around 79.5%.
The initial settings were 90°F and 80%.
The MC has been decreasing ever so slowly averaging about 3.5% decrease per day if I did my math right.
I reset the target RH to 70% to try and get to a daily loss of about 7%.  We will see what the readings are tonight.
The MC by math for the sample boards appears to be around 23-24%.  My R2000 Delmhorst meter still defaults to 99.9 so I am still weighing the samples and doing the math.

Thanks for the information and assistance folks.
One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

scsmith42

Oops - I made a typo - that should have read "60%" not 80%.

BT - it's a pin type resistance meter.

Den - the "X" model J2000 is made specifically for Nyle.  It will read a higher amount of MC% than the standard J2000
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

beenthere

scsmith
I would be suspect that it is just an advertising gimmick by Nyle, and/or based on wet-weight basis, rather than oven-dry basis.

For kicks, I'd try taking some 1-inch samples of your sample boards, weigh and oven-dry them, and nail down the true moisture content to compare to your J2000 readings (at least once in awhile).  A good thing to do to verify and calibrate all moisture meters used for lumber.

south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

OneWithWood

Here are the promised pics - I thought I took more but there were only two in the camera  ::)

Charge stickered and ready to go

The quareter sawn boards still have bark on them.  The gaps are where my sample boards reside

Charge prior to pulling it into the chamber
One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

Den Socling

I'm sure that the J2000 is just labeled for Nyle and I'm sure it isn't made especially for Nyle. I know that no resistance or capacitance meter can give realistic numbers above FSP - about 28%. And I know that my J2000 doesn't always agree with my Wagner L612 and sometimes both are proven wrong by baking samples.

scsmith42

Den and BT - thx for the tip.  I'll try baking samples and comparing them as a calibration tool. 

I have a J2000X, an R2000, a Kil-mo-trol plus and a Merlin meter; and the J2000X, Merlin and Kil-mo-trol Plus are usually fairly close.  The Merlin that I have is the one that they make for kiln operators (it reads to a 1.5" depth).  I recall that the Kil-mo-trol plus reads to 73%.

According to Vincent at Delmhorst (he's in the technical support department), they make the "X" model just for Nyle and it is calibrated to measure a wider range than their standard meter (at least that's what he told me earlier this year).  They would not sell me an "X" model directly - I had to purchase mine through Nyle.

I have found the output from the Kil-mo-trol Plus system to be pretty interesting.  Based upon y'alls comments I would presume that its not as accurate as baking samples; however even if it is not accurate it does seem to be consistent in the measurements that it records.  I usually set mine up to take readings every 15 minutes, and the readings are consistent (such as on a core reading it will indicate 43.6% for an hour or two, then 43.5% for an hour or two, then 43.4%, etc as the load goes through the drying process).  The actual rate depends upon the species and settings - this is just an example.  I have six probe pairs (shell and core readings per pair), and they are all fairly consistent with their measurements.  I have also noted consistencies between the rate of MC% reduction between the core and the shell probes, and that they are usually (a percentage point or few different as the load dries).

It would be interesting to compare the trending between the Kil-mo-trol plus and sample baking throughout a load, to see how accurate the trending lines really are.

Scott
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

beenthere

Scott
Not to pick at this, but measuring moisture content above fiber saturation point (around 30% mc) is an attempt to also estimate the free water in the cells, not just the moisture in the cell walls. With the free water in the cells above 30%, measuring the resistance between pins or capacitance between two or more points gets a bit flaky and I'm being curious if there has been some breakthrough in the moisture meter technology.

Confounding these measurements of moisture changes is the variation in wood density, between as well as within, a species. And density between two is also affected by grain angle and growth rate, as well as summerwood and latewood bands.

:)   
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Den Socling

BT hit the nail(s) on the head. I don't want to pick at the issue either but, if there was a breakthrough in technology, Delmhorst would be selling it. It sounds like a gimmick where they simply extended the readout of a regular J2000. i can't imagine why either company would do such a thing. A Delmhorst rep will be speaking at a coming kiln dryers meeting that I will be speaking at and I'll ask him why.

A few years ago, Delmhorst made a capacitive meter. I discovered that it wouldn't work at temperatures above ~120'F. When I asked them about the fact that you can't always use it in a kiln, they said it wasn't intended for dry kiln operators. That didn't sit too well with me. They didn't say that in their ad. Delmhorst has been basically good to me over the years but nobody is perfect, I guess.

Homer

to all   Remember with moisture meters your only reading at one small area. Oven dry method gives you more accurate MC. When I'm kiln drying, initial samples are oven dried in microwave, when mc reaches about 20%, I cut samples from about 12 to 16 " from one end, about one inch long. Then I take meter checks both surface and core. Fresh cut end of board sample taken from is end sealed and put back in stack, Repeat every day, make corrections as you go.  Homer

WIwoodworker

OWW...That's a nicely stickered stack of wood you got  there. Hope all turns out well with this load. Thanks for posting the pics.
Peterson 9" WPF

OneWithWood

I found it!

Here is the blurry pic of a quarter sawn red maple board


Beenthere,
Thanks for posting one of the two other alternative ways of quartersawing.  I considered the method but the constant turning on a woodmizer put me off.  And the fact that I can get wider boards with the pictured method sold me on the method I chose.  I want to try both your illustrated method and the third way ( d cuts ) eventually.

Anyone with another way of accomplishing true quartersawing please chime in. 
It would be good to have all the methods encapsulated in a single post.  Each method has its strengths and drawbacks.  I think a sawyer would be wise to try them all and then choose the one that fits the task at hand the best.

One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

scsmith42

As usual, there is a lot of very good insight being shared.  I always feel like I receive much more insight than I share on this forum.

I'm curious if anyone has already compiled a comparison between the daily MC% reductions indicated by the oven samples versus what their moisture meter is telling them?

Den, let us know what the Delmhorst rep responds with.  In particular, ask him about their Kil-mo-trol plus system and how it is able to provide consistent readings above 30% MC during the drying process.  If I speak with them in the interim, I'll pose the same question and post their response.

Scott
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

OneWithWood

Would someone post the formulas they use to determine MC of wet wood, oven dry wood, the sample boards and the % water loss per day?  The formulas in my manual seem to be missing some key parenthesis.  I think I am doing it correctly but I am not sure.
I would post the formulas but the manual is over in the barn and I need to be getting to work.  I will try to remember to grab the manual when I do my readings tonight.
One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

beenthere

south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

OneWithWood

One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

Den Socling

Tom Laurenzi from Delmhorst spoke before me at the NEKDA meeting this morning. After his presentation, I didn't ask about readings above 30%. He said during his presentation that accuracy drops between 20 and 30%. And he said that above 30%, readings are "qualitative" whatever that is supposed to mean.  :P I suppose that it means it is not "quantitative".

scsmith42

About a hundred and sixty years ago Abraham Lincoln stated "better to remain silent and be thought a fool, than to speak out and remove all doubt"

I think that I just proved "Ol Abe's wisdom...  ::)

I spoke with Tom Laurenzi from Delmhorst today (President), and in essence he repeated what Den and BT stated - the impossibility to accurately measure MC% with a moisture meter above 30%.

The algorythm's used in the Kil-mo-trol Plus system do provide very good trending information, and they are able to consolidate varying MC% readings into a usable trend line; however they are not absolutely accurate in measuring the actual MC% above 30%.  Tom supported the concept of using sample boards for determining actual MC%'s, but felt that the Kil-mo-trol Plus system was a valuable tool as it clearly indicated trends and acceleration or deceleration in terms of drying rates.

Tom did confirm that the J2000X model had a higher range of MC% detection than the standard J2000 meter.

Den and BT - thanks for setting me straight.

Scott
Peterson 10" WPF with 65' of track
Smith - Gallagher dedicated slabber
Tom's 3638D Baker band mill
and a mix of log handling heavy equipment.

Ga_Boy

OWW,

If you are anyone else uses Excel (spreadsheets) I built one to track my kiln charges.  There are inputs for Oven dry weights, green sample board weights, kiln sample before the charge starts and daily inputs for the kiln sample.

The sheet will give you the calculated MC each day as you weigh your kiln sample.

If anyone wants a copy send me a pm with you e-mail address.


This thread confirms what I was taught in Kiln Operators course, there is no meter on the market that can measure above 30%.  But, this does not stop the manufactures from using creative marketing.... ::)
10 Acers in the Blue Ridge Mountains

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