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I recently picked up several koa billets while on a vacation to Kauai. One already had the ends painted, so I sealed the ends of the other two boards with several coats of shellac immediately on getting the boards back to the mainland. After two weeks, the two I sealed with shellac are drying fine with no splitting, but the one that already had the ends painted has developed a couple of deep splits right down the middle of the board about half way through the 4.5" width.

I am hopeful the splits can be closed once the board has been resawn. But I wonder if I would have better luck invisibly closing the joints if I resaw the board now rather than wait another couple of months like I had originally planned. The board was not green and had cured to some degree prior to my picking it up. But I am not exactly sure of the remaining moisture content. My fear in waiting is that the splits may widen and the edges along the split may move in a non-symetrical way, making them even harder to close later. But I fear by resawing too early, I could end up with with other warping issues.

I have had very good success in closing thin panels by spritzing both sides around the split with water and glycerin compressing between paper towels while also clamping the outer edges. Once the wood has stabilized, I remove it from the press and clamps and check the seam. If the seam remains closed when the clamps are removed, I reclamp and wick in CA.

This is a really gorgeous 4.5 x 9.5 x 39 board that I'd hate to not get a number of two piece backs from. So, do I resaw now or later?

Many thanks,

Ken

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http://www.casperguitar.com

You can never tell, I would resaw them myself, it rarely makes maters worse, and I would saw off the ends just enough to remove the sealant, and reseal with something for real, like epoxy, or apparently shellac is working for you. I also have had good luck with super white indoor outdoor Behr latex.

Another thing you can do, after the above is put plastic bags over the ends, sometimes filled with wet shaving. But the bags themselves will retard the loss through the ends, and the end cracks. Plastic over the ends will force the mid section to keep up to speed. Actually saran might be good since you can observe what is happening. While the bags are always good crack wise, they can contain spalted wood when left for a long time unattended.

Back to the sawing for a moment. When you split wood, and then further splits are developing, these are all fractures along the grain line. Sawing along those fractures, particularly into halves, quarters, etc... is pretty risk free. What isn't is cutting through reaction wood, or other bad grain, ad releasing pent up stress, but that will rear it's head regardless of whether the material is dry or not. In almost all cases smaller sections dry faster and more safely. What seems to happen is the air dries the surface, and the water starts moving towards the air. ther further it is to the center of the log, the greater the potential diference in moisture is, so the greater the stresses.

I have never had any wet koa though.

When it comes down to it what you want to avoid for guitar backs is splits right? Warping is not a huge issue on a piece that is going to be thinned to less than .100" is it not? So resawing now seems to be the best gamble. Is there any tangible advantage to drying/seasoning in billet form?

No.

There is always a boutique exception to everything, but bigger pieces mean higher stresses, and longer time drying.

Oh, in other fields where you don't know the final size of the parts, I like to leave as much thicker stock as I can so I have more choice. But where the wood is valuable, the stock straight, and the end in sight, I would get it to as close to final as I could.

There is claimed anthro evidence that a lot more stuff we assume was made of dried lumber, ie not just ladderback chairs, and hayrakes, was actually manufactured in green form. Alexander did some research on mortise and tenon furniture, both chairs and casework. Obviously not the veneered pieces going to the Sun God's palace, but a lot of pretty middle class stuff. Presumably not guitars though.

Up Untill the 1960's here in Australia, the majority of house framing was either imported Douglas fir or unseasoned local hardwoods such as eucalypts.
This timber was just too hard to handsaw or nail when it was dry so it was used green.

Some things are built green to take advantage of the shrinkage factor to help the constructed end product. Such as making pinned joints in timber frameing.As the wood dries and shrinks around the pin it tightens it up. Also for bending to shape as in rakes or tools. But for locking up a box as in a guitar, not so good. I like my billets dry before resawing as thin green lumber tends to move more than thick lumber. It will crack more after reasawing when green than dry because thin lumber dries faster and the faster it dries , the more likely it will crack. Also if that tree was under tension as it grew, that crack will run no matter what you do.

Best to resaw ASAP.

Ends were "painted"? As in latex? Common practice, but it's the least effective thing you can use.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Like Howard states we always cut ASAP. Keeps the blade cool and sets dry much much faster that billets.
You just need to slow down the drying process for the first 10-14 days or so by loosely covering the stack with plastic.
We use clear so that we can see the condensation accumulating on the inside. After 10 days or so you can remove the
plastic. If wood has tension it's going to crack no matter when you re-saw. We use Green wood sealer from Rockler.
Dries clear and waxy. Good product.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Thanks for insight. I have decided to resaw now and should have them all cut up by this evening. I presume it is best to saw and sticker then wait a few weeks to sand until the boards have dried. I don't have a Rockler nearby, but I do have a Woodcraft. I'll see if they have some Anchorseal. I'll see the ends with that and tent as you noted, Bob. Hopefully I can save most of the badly checked board.

I'll keep you posted.

Ken

_________________
http://www.casperguitar.com

Ken we put a fan on low on the stack after removing the plastic. Most woods are in the 8% MC range in a month.
Anchorseal is very good. Just remember not to make the tent air tight. You want moisture to escape.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

I resawed the three boards the other night and was up until about 2 in the morning sealing the ends and stickering. The board that was badly checking and spliting on one side came out better than I hoped. The first four panels sliced from the board may end up being turned into sides or bindings. I was able to get another 8 panels that seem fairly free of splits. The wood was pretty soggy once I cut into it. I had a narrower board from the same tree that will be used for sides, and that board too was pretty wet. It hadn't split yet, so I was able to salvage pretty much the entire board. The moisture content of both of these boards was over 20%. The other billet was much better to work with as the moisture content was much lower to begin with as it had been air dried before I purchased it.

I tented the stickered wood and checked it last night. The humidity inside the tent was 65% without any condensation build up. I had added some weight to the stack to keep it flat, and all the boards seemed well behaved. I didn't have any bucking or curling that I could see, and the panels didn't appear to be developing any new cracks. I think I'll leave the wood tented until the humidity begins to drop a bit. I'll wait to try and fix the split and cracked boards until they have fully aclimatized.

Thanks for the help. I'm glad I sawed these when I did. Once I got into the boards, the wood is quite nice. I would have hated to lose more of the board to checking and spliting.

Ken

_________________
http://www.casperguitar.com

Glad it's working out for you Ken.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

A brief update and follow up question. I was able to salvage almost all of my wood. After resawing the wood, I stickered it, and tented it. I put a humidity gauge in the tent and once the humidity seem to stabilize around 50%, I removed the tent and restickered the wood in the room with my other woods.

I am really glad I resawed when I did. I am certain that if I had waited, my board would have split clear through in numerous places with seams that would have been impossible to close. The one big split I had closed once the board was resawn and the wood dried. I'll wick in some CA prior to building with it those couple of pieces, and the repair should be invisible.

Thanks again for the advice. Now for the question. The wood has been stickered and stored now for about a month and has dried considerably. The humidity is about 40% in the room where it is stored. How long until I can use the wood? Seems that 8 to 12 weeks should be good, but I don't want to build with it only to have the wood shrink further and crack. The wood came from Kauai with me and likely was cut from an already downed tree. The moisture content when I ripped the board the first time was in the mid twenties and was definitely wet to the touch. The panels are rough sawn at 5/32nds to 3/16ths.

Thanks,

Ken

_________________
http://www.casperguitar.com

Take a sample piece and lay it flat, exposing only one side to the air. If the wood is still drying, it will curl up, concave on the exposed side. If it does curl, flip the piece over. Repeat until the curling stops, at which point the wood will be in equilibrium with the air.
Putting a fan on the stickered wood will speed up the process. I use 3-speed box fans, run at the lowest speed.
If you have access to a moisture meter, the equilibrium MC should be about 8% when the RH is 40%.

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John

Plumbers PVC glue works great for end grain sealing...and its cheap.

Cheers

Kim