LumberJocks

Reducing the twist on my walnut lumber

  • Advertise with us

« back to Wood & Lumber forum

Forum topic by Mcpowell posted 01-14-2017 10:05 PM 696 views 0 times favorited 11 replies Add to Favorites Watch
View Mcpowell's profile

Mcpowell

23 posts in 728 days


01-14-2017 10:05 PM

I have 3 live edge walnut boards which have been drying for about a year in my basement. The boards are 10 feet by 25 inches wide by 3 inches thick. When freshly cut, the grain was gorgeous and I had them earmarked to use for my live edge table. However, they have developed a significant twist (3-4 inches over the length of the boards). I had them ratchet strapped together and they all have the same twist. The moisture content is 11-12%.

If I were to soak them with water (say, run the sprinkler on them for a few hours, several days in a row, and or leave them in the rain), and then flatten them with weight for 4-6 months, do you think they would stay flat after I take the weight off? (I have access to thousands of pounds of steel coils, which I could lay on top of the boards and flatten them).

The table top will have steel u-channels running perpendicular to the grain on the underside, so if I could get them to stay flat through my edge gluing, I think the u-channels will hold them flat.

They don’t have to stay perfectly flat prior to planing, as my design is for the table top to be about 2 inches thick. I plan to plane close to an inch off anyways.

-- I want to be good


11 replies so far

View pintodeluxe's profile

pintodeluxe

5466 posts in 2652 days


#1 posted 01-14-2017 10:18 PM

I would cut them to length first, and try to lose the worst warp. I’m assuming the table isn’t 10’ long, but I guess you didn’t list final dimensions in your post.

From there, assess how much warp remains. Take it to a cabinet shop that has a wide jointer. I don’t know if you’ll find a 25” version, but 20-24” models are common in big shops.

Otherwise you’ll need a router milling setup to surface one side prior to planing.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Mcpowell's profile

Mcpowell

23 posts in 728 days


#2 posted 01-14-2017 10:39 PM



I would cut them to length first, and try to lose the worst warp. I m assuming the table isn t 10 long, but I guess you didn t list final dimensions in your post.

From there, assess how much warp remains. Take it to a cabinet shop that has a wide jointer. I don t know if you ll find a 25” version, but 20-24” models are common in big shops.

Otherwise you ll need a router milling setup to surface one side prior to planing.

- pintodeluxe

Final length to be about 90” long and about 40” wide.

I think there’s too much twist to mill & plane flat, at the moment, and still have 2” thickness left over.

There is a shop in town with a 25” mill and a 25” planer.

-- I want to be good

View Lazyman's profile

Lazyman

1506 posts in 1226 days


#3 posted 01-14-2017 11:15 PM

After you determine the section of wood that has the least twist, warp and cupping, the milling should be done in stages and 1 year of drying time on such thick and long boards is probably not enough unless it was actually drying for 2-3 years before you got it. First, cut it longer than needed because you may get some splitting near the newly cut ends. It may be a good idea to treat the freashly cut ends to slow down the final drying and reduce splits. You will also want to cut the width wider than the final width of each board you will use. Note that when you flatten and plane the surfaces you’ll probably cause additional wood movement so you will need to let it sit for a while before final surface planning. I’ve never worked with such large pieces but even with smaller pieces I usually joint and plane in 2 stages with about a week between them. It might need a much longer resting period between milling steps and more of them for something this large,especially if it is really only a year old. Check the moisture content immediately after milling to see how it looks to determine how much time you need between stages.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View WDHLT15's profile

WDHLT15

1695 posts in 2315 days


#4 posted 01-16-2017 12:56 PM

You cannot un-twist the boards. You can only flatten them by jointing and planing. Cutting them into several pieces each, then jointing one face flat, then planing the opposite parallel, then gluing them back up will reduce the thickness loss to flatten them. However, if they are not dry below 10% and you do this, it is highly likely that they will re-twist. They need to be stable and dry and in equilibrium with the in-use environment.

-- Danny Located in Perry, GA. Forester. Wood-Mizer LT40HD35 Sawmill. Nyle L53 Dehumidification Kiln. hamsleyhardwood.com

View rwe2156's profile

rwe2156

2716 posts in 1319 days


#5 posted 01-16-2017 04:58 PM

What Danny ^ said.

General rule of thumb is 1 year per inch of thickness you’re looking at 3-4 years of air drying.

If they are already twisting that is likely the result of internal stresses that are revealing themselves as the planks dry (which you can’t do anything about). The fact the strapping did not prevent it, and the twist is the same in every board proves this out. It really reflects all the way back to the tree itself. In some cases you just have to give up and find some other material.

Without knowing the moisture content its hard to know whether you should try to mill the lumber yet.
You could try rough jointing one face and then skip plane the other, restack, and forget about them for at least a year. You can use that shop or make a flattening sled and do it yourself. Bottom line if the wood is not dry enough the twist will recur.

Also keep in mind the enviroment you’re expecting the to dry in. I don’t know what your basement is likebut its possible that is not going to be a dry enough environment. I would check the ambient air with a humidity meter.

Also, how/where you stack lumber matters for example out of the direct sunlight, away from fans, and 6” or so off a concrete floor.

-- Everything is a prototype thats why its one of a kind!!

View Mcpowell's profile

Mcpowell

23 posts in 728 days


#6 posted 01-16-2017 06:42 PM



What Danny ^ said.

General rule of thumb is 1 year per inch of thickness you re looking at 3-4 years of air drying.

If they are already twisting that is likely the result of internal stresses that are revealing themselves as the planks dry (which you can t do anything about). The fact the strapping did not prevent it, and the twist is the same in every board proves this out. It really reflects all the way back to the tree itself. In some cases you just have to give up and find some other material.

Without knowing the moisture content its hard to know whether you should try to mill the lumber yet.
You could try rough jointing one face and then skip plane the other, restack, and forget about them for at least a year. You can use that shop or make a flattening sled and do it yourself. Bottom line if the wood is not dry enough the twist will recur.

Also keep in mind the enviroment you re expecting the to dry in. I don t know what your basement is likebut its possible that is not going to be a dry enough environment. I would check the ambient air with a humidity meter.

Also, how/where you stack lumber matters for example out of the direct sunlight, away from fans, and 6” or so off a concrete floor.

- rwe2156

Thanks for the info.

Current moisture content is 10-12%.

My basement has heat & air, and is usually in the 30-50% humidity range.

If I were to lay about 6000 lbs of steel on the boards, forcing them flat, until they are down to 8% moisture content, do you think they will spring right back to their twisted state?

-- I want to be good

View William Shelley's profile

William Shelley

479 posts in 1308 days


#7 posted 01-16-2017 07:00 PM


Thanks for the info.

Current moisture content is 10-12%.

My basement has heat & air, and is usually in the 30-50% humidity range.

If I were to lay about 6000 lbs of steel on the boards, forcing them flat, until they are down to 8% moisture content, do you think they will spring right back to their twisted state?

- Mcpowell

You would likely need to apply steam and more than 6000lbs of force for this to work. Steam bending is possible but usually only done with thin strips although I’ve heard of people steam bending as large as 3/4 oak.

-- Woodworking from an engineer's perspective

View rwe2156's profile

rwe2156

2716 posts in 1319 days


#8 posted 01-16-2017 07:00 PM



If I were to lay about 6000 lbs of steel on the boards, forcing them flat, until they are down to 8% moisture content, do you think they will spring right back to their twisted state?

- Mcpowell

Internal stress will not go away with drying so if thats the cause (and it is) you may get some improvement, but you will have wood that will fight you all the way.

Think of it this way: The grain fibers in wood is like a fist full of straws. If the bundle is twisted then you make cuts lengwise, the twist is still in there.

This is the reason why chairmakers rive all their wood to keep the long grain fibers parallel so the wood will bend well.

-- Everything is a prototype thats why its one of a kind!!

View Aj2's profile

Aj2

1178 posts in 1636 days


#9 posted 01-16-2017 07:59 PM

William save yourself some grief and stop fighting Mother Nature she will win.
You cannot force the wood into a shape that you want.
Somewhere in those planks are a fastasic looking table.
You just have to discover it.
https://m.youtube.com/watch?v=Az014_YkDQ0
Aj

-- Aj

View Mcpowell's profile

Mcpowell

23 posts in 728 days


#10 posted 01-18-2017 11:47 PM

Tomorrow I’m taking the boards to a warehouse to dry with the steel coils on them. If they’re still twisted when they’re dry, I’ll work with them as they are. Hopefully they’ll stay straight long enough for me to make something of them.

I’ll try to report back to this thread in a year or so.

-- I want to be good

View Mcpowell's profile

Mcpowell

23 posts in 728 days


#11 posted 01-21-2017 01:39 AM

Post error

-- I want to be good

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com