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Drying Black Spruce dead straight7/11
I am getting into arrowshaft production for the archery industry. I plan to saw, air-dry, then kiln-dry it down to about 7%. Could someone with experience with spruce or similar woods give my any guidelines ? I am in Manitoba, Canada. We have alot of the nice slow growth straight and limb-free trees out here. I plan to try other woods as well, like birch, tamarack, and possibly black poplar. Thanks ahead.
The first step and the key for any species is to split the wood in both directions-radial and tangential. A split follows the grain, so then saw the blanks without any slope of grain or grain angle, By sawing parallel to the split surfaces. Unless there are nearby knots, these straight grain pieces will be straight, using normal drying practices.
In following what others in the arrowshaft business do, I am cutting into 3' sections, then splitting in half. At that point, I find it difficult to try and bandsaw following those split lines. Plus some of them are spiral grain, causing yet more hardship. I find that if I saw everything once split, the grain is perfectly parallel. Does this leave me open to some cross grain still ? Thanks
There is always cross grain around a knotty area...it is in the tree.
So I understand that I am to orient the bolt (log section) so that the saw blade is right parallel with the split edge, then all my wood is as straight as an arrow? Growth rings then are quarter and rift sawn, right? Thanks ahead Gene.
There are two grain directions, so you need to align with both, so that the face and the edges are both parallel to the split faces. So you need to split the log twice, with the splits at 90 degrees about.
Gene, if you would, could you post a drawing or similar way of seeing just what you mean ? Sorry, I must have relatives from Missouri. Could you show me? Thanks
Consider a pie that you cut into four equal pieces. That is what you do with the end of a log.
Honestly, I got that quickly but I really don't know what you mean by another grain direction to consider when sawing into smaller boards after quartering. Please elaborate your meaning. Thanks again.
With a pie wedge that is 1/4 of a pie, the two cut faces are 90 degrees to each other and represent two different grain angles. You need to follow both grain angles...one follows the one split grain face with one face of the blank and the other grain angle with the other 90 degree face of the blank
Stated another way, you can saw one piece of lumber so it's face is aligned with the split face. Then before you rip this lumber into small blanks, you must split the lumber so you know what direction to rip the lumber. Oftentimes this rip direction will be parallel to the bark and not the pith.
I believe that this time, I've got it! Your latest post was what really made it clear to me. I will do that, thankyou.
Well at last I am loading the spruce into the dry kiln (Nyle L200). Is there concern for problems relating to drying such small wood dimensions? They are 36" long, with 3-8" wide, and 5/8" thick. This is all air dried down to 12% in the summer. My target is 7% on the wettest of wood. Thanks in advance.
Thin wood warps much more than 1" or thicker. Stickering must be perfect and top weights are suggested.
Narrow pieces also like to warp much easier than wider strips, but there is little you can do about his except to use perfect stacking.
On the other hand, defects are initiated at high MCs, so there is little, if any, risk at this low MC, except that drying under 10% MC will make the wood brittle.
Gene are you saying that the wood may be brittle at 6 or 7%, but less so at maybe 9%? I always thought that drier wood means stronger wood. For certain what I long for is my product to be stable. And would your advice be different had we be speaking of hardwoods, say like birch? Thanks again.
Something can be strong, but brittle, meaning it will develop large cracks, etc.
So, yes indeed about 9% compared to 7%. Also, hardwoods do not get as brittle as softwoods until they go under about 6% MC.
Hi once again. Just finally started up the Nyle L200 kiln in the chamber. Air dried wood is around 14%. This kiln has been dormant for a few years but seems to be working alright, but with a funny thing happening thus far; I am finding the compressor seems to stop removing moisture after about 6 hours of operation. I did have it checked out with a moderately competent Hvac serviceman. He may have to come back it seems. Curious if water generally should be flowing steadily once it starts coming ?(I understand that it may or may not slow during the off-cycle of compressor (its at 80% run time so far.) I am running a temp of 90-105 deg. Any help is appreciated. Thanks, RR
Update on this. The issue with the kiln was a refrigerant problem, now rectified! Kiln is working well. Can someone tell me if conditioning of softwood is needed the same as hardwoods? This is Black Spruce, and is thinly cut (5/8"). Moisture seems to be exiting well. I will test with tuning fork samples when it is nearer to its target MC. So, I ask, is it common to condition softer woods the same as hardwoods? I want stress-free wood for sure. Thanks.
The conditioning EMC for softwoods is = target MC + 3. This is a fairly high EMC as the target is often 11% MC. This high EMC is hard to obtain in most kilns. As you know, a lower target means brittle machining.
Remember that the prong or fork test for stress requires no moisture gradient, so instant tests during a run are no good unless you use the microwave on high (after cutting) for 15 seconds on each prong test separately and then wait several minutes.
Ok, thankyou again Gene. So with a final target MC of 9 or 10%, at what point do I stop the compressor and add steam? My kiln is a '95 model with all manual controls, so no wet bulb temp. Thanks.
It is a long answer. Do you have Nyle’s book on drying?
I have only the binder that came with the L200 back in '95.