Acclimation.....?

When I receive new bowl blocks, I've been "acclimating" them, mainly because it's what's considered standard operating procedure. Even when I didn't do this, I don't recall any negative drawbacks to not acclimating a chunk of wood.

Sooooo, tell us what the drawbacks are supposed to be, and what does actual experience indicate......?

-----odie-----

 

Isn't acclimating what we do when we rough turn a bowl, or turn to final thickness, and let it sit to dry? Reaching equilibrium? If im doing some flatwork then I'll let the wood acclimate to my shop for a couple of days or longer before I start doing any milling just to get movement out of the way. But I do the same thing if I resaw a board, because I want any movement due to the release of tension gone before final milling, because while I love my hand planes, I don't want to keep planing the same peice of wood.
Im not sure there's a benefit to letting a square blank acclimate much before removing most of it, but wiser heads than mine will have a better idea.

 

Russell.......

Yes, technically, you would be correct that after roughing, what takes place could be construed as acclimating. As you suspect, what I'm referring to is letting a square, or round blank acclimate to its current climate, after a sudden change in climate, due to shipping. Theoretically, it could be better for the block to absorb, or expel moisture content while still in block form.

After having "acclimated" bowl blanks to my shop prior to the rough turning, for a considerable time, I'm suspecting there is little need to do this at all. After not acclimating bowl blanks for a number of years, and then switching to acclimating.....I'm just not seeing any measurable differences.

I have so much work in progress at any given time, that when I receive shipments of bowl blanks, they pretty much always set for at least a few days, and more generally up to a week or two......so, acclimation is now an automatic thing anyway......

I brought this subject up, just to get some input from a few other turners.......especially from those who consider acclimation a necessary step in their turning wood........

-----odie-----

 

I assume you're talking about dry bowl blanks 10/4 to 12/4 in thickness. I have no science to quote, but I suspect your correct, Odie. Acclimation is theoretically beneficial, but as a practical matter the benefit may not be very significant.

The question depends very much on what you're doing. If you're making furniture and resawing an 8/4 board down to 3/4, then you need to produce flat, stable boards, which you are going to join together. And at 3/4 thickness there is going to be some moisture exchange that will happen over days or a week. If you receive a 10/4 or 12/4 bowl blank, dry and unwaxed, it may acclimate in a few days, too. But if it's dry and waxed it's going to be on a months time scale. And if the wood is wet it's certainly not going to "acclimate".

And just the same, I'm not sure how much movement you're gonna see over the length of a 10 inch blank as compared to 10 foot board. Particularly since the bowl blank is not going to be joined, but rather continuously "milled" until the final form is achieved.

 

Yep, Mark......that's pretty much what I have concluded. Bowl blanks do not have the need for acclimation that other woods do......especially boards used in flat work.

thx

-----odie-----

 

Any wood that thick probably is not uniformly dry and leaving it set in your shop won't help. By rough turning it is usually the best way to go. I can remember many years ago when we would hold our meetings in Rockler's or Woodcraft they would often give us exotic wood bowl blanks to raffle off and they always had checks from being on the shelf to long.

 

I suspect purchased bowl blanks are sealed with wax? All blanks I have purchased have been. I had some 5x5x3 sealed blanks around For several years. They were not dry, and probably take 10 yrs or more to dry to equilibrium. Something 2” or more thick will crack and check if not sealed. Sealed blanks wont “acclimate” in months, so a week or 2 is irrelevant. Now they might in the desert SW where they may get hot enough to melt the wax.

 

Yes, all the bowl blanks I purchase are either KD, air dried, or sealed with wax.

I'm beginning to suspect the information that formulated my beliefs on this, was flawed, or misinterpreted by myself. It really is a moot point, however, because I've never seen any difference between processing immediately, or waiting a short period of days to a week, or so, for green wood blanks.

I do process green bowl blanks within a short period, always! Any bowl blanks that are pre-seasoned dry, or KD......now, these are the ones that I have the option of shelving them for extended periods of time, prior to initial processing.

-----odie-----