Our planer supervisor tells us 8-10 hours minimum. It kinda depends on the weather also. I know if we try to run hot wood through our planer, the moisture sytem we have will call alot of it wet. I have also noticed that when you try to plane hot wood it will tend to come out fuzzy. White fir is the worst for this.

So is there any set standard for how cool (temperature wise) lumber should be exiting the planer before there is a problem?
Our mill only has dry storage for about 1.5 million bf of lumber, so we have pretty quick turnaround times.  Resulting in animated discussions from time to time. . . .

 

Would love to break the argument circle by coming up with an established standard.  We have discussed taking a temperature gun up to the planer feed table and check the wood any time it is deemed questionable and then stop and run something else if it is above a certain temperature, but we don't know what temperature that should be.

Suggestions?

We are a studmill, and our sawmill stackers actually stack on carts.  These carts run on tracks out of the mill, to a transfer system, through the kilns, to dry storage, and then the planer unstacker actually unstacks off of carts.  The first time a forklift touches our lumber is after the planer.  So our storage is absolutely limited, and stacking down outside of our covered dry storage is not an option at all. 

Handy design for eliminating forklift damage, and dirt, grit etc introduction - but not good for allowing long cooling times, and without tearing down the mill and starting over, we are kind of stuck with what we have. . . .

We have even considered large fans in our storage areas to circulate air through the lumber as it cools. . .

My understanding is that the main reason it is a problem to run warm wood is about the fact that as wood is cooling it continues to shrink, so finished dimensions can be off spec if the wood is too warm.  Also moisture is still being released quickly as the wood cools, which gets caught in the solid stacked finished product, resulting in mold, stains, etc.

This is why I was looking for an actual cooling temperature where these problems can be minimized.  Does anyone have any data from tracking this, or see any holes in what I am thinking?

From a hardwoods standpoint...our mill's biggest concern seems to be the planer itself and what high temps may do to our planer knives etc.  I rarely run 'out of a kiln'.  Try to give it a few hours minimum.