air dried vs. kiln dried b. locust

[centroid]

I’m looking ahead for the double sawn frame lumber that I’ll need for the 24’ lyle hess cutter. I have a source near by that can supply me with black locust. But right now, its just a bunch of logs. Is it better to cut green and air dry for 6 months to a year (4/4 thickness) or is it better to have them kiln dry (steam process, not sure what it is) ? I was told that this steam process seems to produce less checking. Anyone familiar with this ?

thanks

[Venchka]

I can't help with the drying process. All I can say is, "Get it!"

[Bob Smalser]

Dunno very much about locust and how stable it is in drying...but if you are cutting it now, your outdoors drying season really doesn't begin til next April - you won't gain much over the winter....and if you put it in the shop, the temperature might be too high and the humidity too low to prevent checking w/o several months of outdoor drying first.

And the rule of thumb is one drying season per inch of thickness to go from the 30-60pct M/C of fresh-cut to the 18-20pct you are looking for.

[ 09-17-2003, 02:14 PM: Message edited by: Bob Smalser ]

[tealsmith1]

I've always read and heard that air dried is much better than kiln. Less stressful on the wood. I'll second the 1 yr. of drying per inch rule. Also paint the ends of the boards to help with the checking. Good Luck.

[Bob Smalser]

Nothing wrong with kiln or vacuum drying if it's done right. Gets a bad rap from construction lumber where the mills shove a railroad car of unstickered stock in there to do it quick.

As your quantity is relatively low, you might consider building a cheap solar kiln from lath, poly and a small fan to see how much progress you can make over the winter months....and then move it in a heated shop for the last couple months. Paint the endgrain.

William Brown, "The Conversion and Seasoning of Wood", available from Baileys-online.com has the details.

But I also use green wood for some boatbuilding applications where lateral shrinkage isn't an issue...for short-term jobs where you get it painted and into the water quickly, it doesn't sand well but works fine....the problem is in a long-term project where the exposed green framing is left to bake in the summer sun for months at a time...then it dries too fast and unevenly and can check/warp badly.

[ 09-17-2003, 12:03 PM: Message edited by: Bob Smalser ]

[JFH]

I've dried Black Locust and used it after a year on keels and it was very stable. The stuff really works well for knees too. Just save some of the branches for later use. I agree with the solar idea but, didn't use that method. Now the stuff is 2 years old and ready for most work. I even tried to plank with it and found it was just too stiff. Plenty strong and colourful though!

They (whoever "they" are)call it the Mahogany of north america. Going to mill some in a couple of months.

Jim
www.innerbayboats.com (http://www.innerbayboats.com)

[Dave Fleming]

The oldtimers and MOI, swear by air dried lumber for boat building.
Kiln dried seems to have no ***life*** left in it.
Could be that BobS has something there with the lack of care taken in the kiln drying.
Just run one plank of kiln dried Doug Fir and one of air dried Doug Fir through the planer and look at the difference in the chips/shavings.
Kiln Dried seem crumbly whilst Air Dried are a bit springy and tougher.

Lots of speculation about air drying and pond seasoning too.
Seems some believe fresh cut and especially Winter Cut only was best, and then kept a year in a freshwater pond. 'To drive the sap out' is one reason I have heard.
Others go by the air drying, inch per year of thickness rule.
Personaly in the yards were I worked it was all air dried lumber and in several it came in big cants and we resawed it our selves to what ever dimension was needed along with some stock sizes.
But that costs money and nowadays could affect the tax burden re: inventory tax, of the yard.
True lumber yards had two areas one in the open with portable covers for air dried lumber and a big barn type building for kiln dried stock.

It is not boat related but may I mention in passing a book written in the early 20th Century by an Englishman whose family were several generations of wheelwrights in the countryside.
It, in part, relates the close relationship of a old country wheelwright and the wood he used including the cruising, falling, milling and seasoning of his stock mostly Oak, Elm, Ash and Beech.
The Wheelwrights Shop by George Sturt available from The Astrigal Press.
PB for about $17.00USD
I have had my copy for about 25 years now.
Good read, not a how to but, a view of life long gone. Similar to Dana Story's book on ship building in Essex in the time of his grandfather and father.

To conclude this rambling post...for MOI it is air dried.

[Wayne Jeffers]

When I was young, there was a fence around our front yard with 4X4 black locust from a country sawmill for posts. None of them ever moved that you would notice, so the wood must be pretty stable, IMO.

There's a lot of black locust growing around here, but very little that is yet quite big enough to use for lumber. Wait another 20 years. Until recently, black locust was cut by farmers for fence posts as soon as it was big enough, but the steel posts you can drive seem to have gotten cheap enough so that locust fence posts are no longer worth the trouble of cutting and setting.

The black locust in the woods in our area is really obvious from a distance because, for the last month or so, its leave have been brown, in contrast to the other species which are still green. Oddly, I'm told the locust leaf miner infestation responsible for the early browning does little harm to the trees.

Wayne

[ishmael]

I'm not sure what 'kiln drying it right' means. A fast dry is, by almost all oldtimers accounts, a bad thing. It forces a process, bursts cell walls etc, making the wood as Dave put it, less alive. A solar kiln would be a different matter, I suppose.

If I were building a boat such as you describe I wouldn't want any commercial KD stock in its essential armature.The question is how similar is the kiln drying you propose to what you buy at Home Depot?

There may be ways to do it properly with gentler heat. In a hurry? If not, sticker it well and let it dry.

[Bob Smalser]

Depends on the kiln type...and I don't use one...but "right" means stickered and slow, not bulk-stacked and fast. Personally, I'm in no hurry...I air dry to 18pct and restack and sticker indoors when I need lower than that...and wait....but I always seem to work for $.50/hour at best, too.

Have a reclusive neighbor with several sawmills here and Hawaii who's one of the best in the business at specialty woods, everything from big masts to music wood. What somebody wants an 80' 2x4 for, like I saw there recently, I can't imagine, but he's the guy you go to for it if you have the dough.

He recently built a vacuum kiln for music wood like spruce soundboards, where slow and even drying is critical to tone....and I'm told it's working as well as traditional air drying.

Bottom line is that if it's done sufficiently slowly to not collapse the cells and uniformly so as not to "case harden", it doesn't much matter how you do it. Air drying is merely easier, proper kilning is difficult....fan placement/volume, temperature, humidity, stack/sticker methods, differences tween heart and sapwood in the same log...lotsa opportunities to screw it up....and you see those screwups every day in even the best of mills where volume and profit reign....5 casehardened boards out of 50 from the same log where there's no easy way to discover them until use.

Harvesting when the sap is down makes a difference. Ponding logs makes a difference...mostly in insect damage, but ponded logs do season by losing their cellular water. And natural airdrying makes a difference, if only because there are fewer paths to screw it up.

[ 09-17-2003, 02:24 PM: Message edited by: Bob Smalser ]

[centroid]

thanks everyone. i'll find out more about the exact kiln dried he is talking about. but it sounds like the aired dried might be easier and perhaps cheaper route to go. but i was thinking about stacking in the shop over the winter right away, maybe not a good idea? sounds like stacking outside for a couple of months and then bring inside the shop for the winter ?

[Bob Smalser]

With no moisture meter you can take samples of both green heart and sapwood, weigh them, dry them slowly in the oven, then compare the weight difference to get your starting M/C. I suspect if your logs were felled during the growing season, your sap will be in the 60pct or higher range and needs to be stacked and stickered outside under cover in a place w/good airflow.

As I am unfamiliar with locust, I have no guess at how much drier the heartwood is, but you could stack it seperately and move a test piece inside for a month to see how it reacts. Even with stable wood, I'd want it in the 30pct range before I moved it to full-time heat.

In a shop or storage area that's spaceheated for only a few hours a day, I'd probably paint the ends and move all the heartwood inside..then monitor how it reacts.

But given your timeline, I'd lean toward all of it stacked/stickered on the sunny side of your shop and erecting that makeshift poly tent with a blower fan facing out set up to run during the warmest hours of the afternoon....'cept for snow removal, you only have to mess with it once that way. And if you think it's going too fast, stop using the fan.

[ 09-17-2003, 11:40 PM: Message edited by: Bob Smalser ]