Drying stock blanks

[webradbury]

I have some slabs of Cherry I cut back in November, they are air drying in my shop right now. Would it be better to cut the blanks out now or wait until they are dry.  a couple of them are checking pretty bad which concerns me. I thought about having them kiln dried but I don't know if this would make the cracking worse.

[bob in the woods]

Did you seal the end grain ?   I sticker my boards, and seal the end grain with wax.  After a year , I move them to the loft of my shop for another year or so, or until I need some.  Always keep an eye on them for insects, mould etc.  Even after they are "dry" I still rough cut to shape, and then leave them to stabilize for as long as I can.  I've got some ebony fingerboards, and mahogany neck blanks that were rough cut to shape some 20 years ago. Trying to speed up drying slabs is not something I'd recommend.  For 2 1/2 to 3 inch thick cherry, I 'd want a year or 2 at least . [ I don't do anything quick anymore  ]

[mtlonghunter]

It's best to figure at least one year per inch of wood thickness on boards up to 2 inches. Thicker than that requires more than a year per inch. As the last comment ask, end seal is a must if you don't want a lot of defects. Good air circulation and never kiln dry. It ruins color and sometimes can cause defects due to too rapid moisture removall  .   Cutting out profile is not a good idea as relieving certain areas of stress can also cause defects occurring during drying. Keep it in a plank until it is dry or relatively so. Cutting it out will not help it dry sooner. If you have a moisture meter or access to one it is helpful to determine when "dry" is. A moisture content of around 6 to 8 percent is nice for building a rifle . Depending on where you live, this may be unobtainable without some help from an indoors condition . However this does not mean power dry behind a stove or some other forms of intense heat.

[mtlonghunter]

Any latex or oil paint will work for end seal. There are also commercial products available with a certain wax content. However these products are more costly and do no better job. The sooner the better, as cracks that start to form are hard to stop with out ruining more of the plank.

[mtlonghunter]

The reason to end seal is as the moisture leaves the wood it starts too shrink .Moisture can get out of the the end grain easier than the side grain , whether vertice or flat grain. the drier end of the plank want to move but the wood a little ways into the board won't let it so the only  thing it can do is crack.  So end seal just slows the drying rate of the end to try to match the rest of the board.

[webradbury]

Yes I sealed the ends with paint. I know it will be a good three years before I can use them and I don't mind the wait. I didn't know if kiln drying might prevent the checking. I have no experience with forced drying but have a small company in my area that will do it, so thought I would look into it. Seems like I need to scrap that idea and hope for the best. If I end up with one or two good blanks out of the bunch, I will still come out ahead. I only have $35 in the wood which was the sawyer's fee for sawing into slabs.

[Long John]

we,

I have worked for many producers in the forest products industry over the past 30 years.  Here is what I have learned in the process.

Checking occurs because the wood in one part of the plank is drying, and shrinking, faster than the rest of the board.  This difference in shrink rate produces a force which causes the plank to split along the boundary between layers of wood cells.  In modern dry kilns the green planks are stacked in "hacks" with wood stickers between the adjacent planks.  The stickers are usually about 3/8 to 1/2 inch thick, usually pine, and are placed across the grain between each layer of planks.  When the kiln is loaded and closed up the temperature is increased to about 120 degrees and steam is injected into the kiln to bring the absolute humidity, not relative humidity, level up to approximately 30 %.  At this absolute humidity the moisture content of the atmosphere is close to the moisture content in the planks.  While keeping the temperature at approximately 120 F,  different kiln operators have different time/temperature schedules so this is approximate, the humidity is slowly allowed to decrease over an extended period of time.  Some kiln schedules run 3 months or more for thick planks of hardwood.  (Working in an operating dry kiln is tough duty because it is so hot and the humidity is so high sweat does NOT evaporate.)  The elevated temperature hastens the drying by increasing the mobility of moisture within the wood.  The objective is to ensure that the moisture content of the surface of the plank is only slightly lower than the core, usually by about 2%, dry basis.  For 10 fourths planks of oak it will take almost 4 months to get the planks down to a nominal 7% MC-dry basis, which is a commonly sited target moisture content.  As soon as the lumber is removed from the kiln the surface moisture content will increase due to moisture absorption from the air.  Generally, unless you live in the Rocky Mountains, air drying at ambient temperature usually results in a MC of about 8 to 10 %. 

So what we can do with our home-made planks is first heavily coat the ends of each plank with a wax or oil-based paint to retard moisture loss.  We should also coat the flat faces of the planks with something like lard, bear grease or ordinary store-bought linseed to slow down the moisture loss from the plank faces.  Then stack the planks with sticker between them and allow at least 1 year for each 1/2 inch of plank thickness.  This strategy has worked for me for many years.

Best Regards,

John Cholin

[webradbury]

Went out and inspected each slab closely today and looks like I'll have some mighty fine firewood when it turns cold. Oh well

[ron w]

the problem with drying blank cut out to a profile is that you took all the extra material away the would be there to have the checks and cracks in.