drying syp

[slider]

Here in south georgia at this hot and humid time of the year pine will mold in no time without circulation .at what moisture content can I pull the fans and let it air dry safely.I am under an open shed .

[WDH]

I am thinking 2 to 3 weeks, but I have no hard data to support that. It should dry pretty fast in this heat and with good air circulation.

[Magicman]

I have had stickered SYP to dry so much in two weeks (lost weight) that I thought someone had traded lumber with me.   ;D

[wwsjr]

I have used a 50% mix of bleach and water to prevent mold. While stacking with stickers, I spray the top of each layer with a garden sprayer. Works for me.

[slider]

Thanks for the timely response.On nice 1x's i have used bleach for years with good results but this time i'm using a big high flow fan only to see if i can get around the bleach.Some of this wood was very wet when i sawed it a week ago.I checked it this morning and it ranges from .15 to 22%.I am going to blow it for one more week and see what happens.Temps and humidity here are very high here now.

[GeneWengert-WoodDoc]

Mold is a fungus that does not eat anything in the wood but rather dirt, microorganism, etc. on the lumber's surface.  As a result, mold does not go into the wood.  As most pine is planed before use, mold would not be a defect as it will be planed off.  However, blue stain (also called sap stain) fungus does go deeply into the wood.  This fungus must be prevented from entering the wood, as a surface treatment will not control the fungus once it is inside the wood.  So, we usually poison the outside or else apply a killer, like bleach, before the fungus can get established.  I hope this technical info helps with control.

The mold or blue stain fungi need higher than 22% MC to be active, and probably higher than 35% MC most of the time.  Without water, the fungus cannot grow.  So, the mold needs higher than 22% MC at the surface.  Of course, freshly sawn syp is around 100% MC when first sawn, so there is a substantial risk initially.

I just checked (5PM) the temperature here in Athens, GA and it is 93 F and feels very humid, but it is actually 39% RH, or 8% EMC, so the surface will dry very fast...a couple of days...before the surface is too dry to support much new mold or blue stain growth.  Macon, GA is 94 F and 40% RH.  So, bleach initially will stop growth at the time it is applied (it does not carry over for many hours).  So use bleach the first couple of days (unless the lumber surface gets rewetted from rain) and then the surface should be dry enough so mold will not happen.

Hint:  if you have an I-phone, you probably know how to check the temperature using the built-in app, or the Weather Channel app.  But did you know that if you tap the temperature, you will then get humidity and other data?

[WDH]

Here, South of Perry, it was 97 degrees at 7:00 p.m.  Awful.  I have had issues with sticker stain in this type weather. 

[red oaks lumber]

that kinda weather you should be worried about sweat stain :D  i would think ya'll would do most of the sawin in the "cool" months thus avoiding heat/humity issues.

[GeneWengert-WoodDoc]

Actually, the average relative humidity in Madison, WI in the summer months is higher than in most of GA.

The sticker stain reaction, as well as non-fungal greying, is caused by slow drying (high RH and low air flow).  At warmer temperatures, the chemical reaction goes almost twice as fast as when the temperature is in the 70s.

[red oaks lumber]

thats basically what i said ,avoid the heat of summer ;)

[WDH]

But that is half the year  . 

[elk42]

And some years could be 8 months.

[red oaks lumber]

you just saw harder in the better months,no differant than in the frozen tundra just differant temps. ;D

[WDH]

Not sawing for six months would be like prison. 

[Magicman]

Surely it is.    ;D

[willmyers0169]

I just checked (5PM) the temperature here in Athens, GA and it is 93 F and feels very humid, but it is actually 39% RH, or 8% EMC, so the surface will dry very fast...a couple of days...before the surface is too dry to support much new mold or blue stain growth.  Macon, GA is 94 F and 40% RH.  So, bleach initially will stop growth at the time it is applied (it does not carry over for many hours).  So use bleach the first couple of days (unless the lumber surface gets rewetted from rain) and then the surface should be dry enough so mold will not happen.


Mr. Gene, now that you live in GA will you be doing any drying classes with UGA or maybe just for fun.  I live about 30 miles south of you and would love to pick your brain!

[GeneWengert-WoodDoc]

Sweet tea, biscuits and gravy, and grits is all I Need to have for me to visit you some morning early.  Having been born and raised (partly) in eastern TN, I do know what makes a good breakfast.

At this time, no classes are planned...except the Advanced class in TN in November.