Want to turn something that has about 12% moisture content.....

[Michael Costa]

I have a 6"x6" timber purchased from Lowe's that I want to use to turn 4" spindle type legs for a coffee table. What are the chances these will split after I'm finished?

I know I probably should have glued up 2x6s but wanted them to be solid. And I have no idea how long it would take this to dry to a 6-7% moisture reading. And would this perfectly straight timber end up twisting if I let it dry.

Anyone know what someone with a kiln might charge me to dry it out. Its 8 foot long and 6x6" as I said.

Thoughts?

[Ted Calver]

Kinda depends on the timber. If it's a boxed heart 6x6 with the pith in the center there's a very good chance cracks will radiate out from the pith. If it's quarter or rift sawn with no pith, chances of cracking are less. Just curious though, I don't ever recall seeing non pressure treated 6x6's in my Lowe's. What kind of wood is it?

[Michael Costa]

Its pressure treated. I did a trial run with a pressure treated 4x4. I then cut it into quarters. Once you get into the middle, it's just regular wood. Or at least it looks like it to me. I figure taking an inch off all sides of the 6x6 will remove all traces of pressure treatment. It's not like anyone is going to chewing on it anyway.

As to how it was cut.... probably plain.

[John K Jordan]

Its pressure treated. I did a trial run with a pressure treated 4x4. I then cut it into quarters. Once you get into the middle, it's just regular wood. Or at least it looks like it to me. I figure taking an inch off all sides of the 6x6 will remove all traces of pressure treatment. It's not like anyone is going to chewing on it anyway.

I once queried a wood company about how the inside of 6x6 posts appeared to be untreated. They assured me that the treatment was all the way to the center even though the process caused the distinctive green color only near the surface. I wasn't entirely convinced, but some chunks I left on the ground out in the weather have not degraded in over 6 years now.

pressure_treated_post.jpg

Almost every post 6x6 and larger that I've bought in the last 10 years have had the pith down the center. I suspect this is either from harvesting younger trees since the old growth is gone, or simple production economics - I've sawn some posts from the center that way after plain-sawing boards from around the outside of a larger log.

Are you sure the moisture is 12% in the center of the post? Unless the post is kiln dried after treatment (KDAT) it may still be wet on the inside but relatively dry on the outside and on the ends.

In general, wood will twist more if the grain is not perfectly straight down the length, i.e., if it runs at even a slight angle, pith or not. If the pith is straight and in the exact position on both ends the warp will be less, although it may still split even if the pith is not included. Some species are worse than others. Eastern red cedar, walnut, and sassafras will probably be fine but you won't find them at Lowes. When I saw I usually cut some 4x4 and larger to dry just for turning.

JKJ

[Michael Costa]

My guess is that it would more moist on the inside being that it's a full 6" thick. My moisture meter only has two 1/4" prongs. I'm going to cut a chunk off right now and check the middle. I'll be back.

[Michael Costa]

I'm back. Okay, so the moisture content in the center 18" from the end is at 22%. I attached a picture. And I also read that pressure treated lumber (even these 6x6 pieces) are treated all the way thru. I'm no expert but is certainly doesnt look like it to me.

I dont have time to let this sit around for 6 months to dry out. I know I can dry wood in my oven but I also know not to dry pressure treated wood in my oven.

This is why I'm wondering if I took an inch off each side would I be okay? I'm willing to open all the windows and give it a go. I'm in Phoenix so won't freeze to death. Hell, I dont think I care if I poison myself.

But I'm now confident that if I turn this as is, it will split.

[Michael Costa]

Forgot the pic.20190225_123442.jpg

[John Keeton]

That is some of the tightest growth rings I have ever seen in pressure treated wood! Doesn’t even look like fast growth pine or spruce, which is typically what is used.

[Joe Meirhaeghe]

The 12% moisture content in my area would probably not be a issue in my climate but I can't say for your climate. However I would never consider using pressure treated exterior wood for a indoor furniture project of any kind. There again that's just my opinion.

[Alex Zeller]

I'm assuming this is for an outdoor table. Can you find 6x6 cedar? My local Lowes occasionally has some in stock for people building decks who don't want to use pressure treated for posts. Never priced it though. A quick search on SMC brought up a thread with a post saying this guy was a good person to deal with: http://www.cedarusa.com/products.htm. Not sure how close they are to you but the do ship small quantities. They say they are a custom sawmill and since you are turning legs and don't need 8' long posts you may get a good deal. Rough cut would be fine and they should be able to send you posts without any pith. While they usually deal with green wood it's possible that you could get lucky and find something that's been sitting for some time. I have no connection to them and you may do better if you can find a local sawmill that deals with cedar.

[Ted Calver]

As John said, that's very tight grain for PT wood. I wonder if it's a west coast species. I personally wouldn't use PT material in the house, but for an outdoor piece, why not? I'd turn it and see what happens. The turning process will remove most of the visible PT coloring and that quarter/rift sawn grain should be much more stable than the boxed heart posts we get here in VA.

[Michael Costa]

After 1 hour in the oven at 220° it split pretty good. I'm guessing due to uneven moisture release since the meter reads 5% on two sides and both ends and 10% on the other two sides.

20190225_224946.jpg

Question, what is the harm in using pressure treated wood for the legs of an indoor coffee table? Everyone is obviously against it for some reason. I get not making toys or baby furniture with the stuff but legs that will be sitting on a base and have a top over them.... what am I missing?

[Michael Costa]

I just found this on a lumber yard website. ProTimber maybe. I already forgot.

"The simple answer is pressure-treated lumber can be used in any interior application except cutting boards and countertops. Some have also asked, after they’ve found pressure-treated lumber installed inside their homes, if there is any danger in having it indoors. The answer is no. There is no danger of either leaching or off-gassing"

[Jason Roehl]

I just found this on a lumber yard website. ProTimber maybe. I already forgot.

"The simple answer is pressure-treated lumber can be used in any interior application except cutting boards and countertops. Some have also asked, after they’ve found pressure-treated lumber installed inside their homes, if there is any danger in having it indoors. The answer is no. There is no danger of either leaching or off-gassing"

Considering it's REQUIRED for framing that contacts concrete...such as all bottom plates in stick-on-slab homes...

[Ted Calver]

After 1 hour in the oven at 220° it split pretty good. I'm guessing due to uneven moisture release since the meter reads 5% on two sides and both ends and 10% on the other two sides....
Question, what is the harm in using pressure treated wood for the legs of an indoor coffee table? Everyone is obviously against it for some reason. I get not making toys or baby furniture with the stuff but legs that will be sitting on a base and have a top over them.... what am I missing?

Maybe you pushed the oven drying a bit fast and a lower temp and longer drying time would be better? Being shy about using PT indoors is probably because some of us still remember the cautions/warnings associated with the old (pre 2003/4) chromated copper arsenate treated lumber. The new copper based materials are supposed to be safe, although I did see a recommendation to seal pieces used inside with an oil finish. I've been using it in the garden for my raised planting beds and am not worried about chemicals leaching into the soil.