Help! Warped Body Blank =(

[thame2010]

Hi everybody,
A few weeks ago I cut myself a nice piece of pine for my first build, it's a flatsawn piece from the center of the log.

The log was cut down a year ago, and it's 2 inches thick, I know, still humid. So I left it in my room to dry but it started to warp! Now it's too late, it has a "bow" curvature and I don't think I can fix it with my power tools.

Here's a solution I found on the net:

#
Water a section of lawn at least as big as the board or panel. Do this in mid-morning of a hot and sunny day.
#
Lay the wood down on the watered lawn with the concave side facing down. The concave side is the side that is "caved" in. Severely warped boards may only touch the grass on the very ends when laid down this way.
#
Leave the wood out on the lawn all day. When the sun starts to set and the heat of the day has passed, bring the board into a garage or basement.


Anyone knows if this will work?


Please give me some advise

P.S.: Here's a picture of the warped piece, arrows indicate the direction of the "bow". I know you can barely see it but there's like 3mm of difference between the center and the borders.

[mijstrat72]

That is the unfortunate part of having freshly cut wood. About the only thing you can do besides sanding it down is having it planed down. I have never heard of the lawn idea before, but I would imagine if you introduce moisture into the scenario, the wood will just cup again once it dehydrates.

I would perhaps take to a wood products shop and have them kiln cure the wood, then have them plane it down.

[Joefaity]

If it's 2 inches thick and a body blank is usually about 1 3/4 I would have it planed down if possible.

[spannerman]

if it's a 3mm difference u can plane that off the top and bottom and u'll hav a 1.75" thick piece of wood. Is that not thick enough for what you had in mind? Definitely a good shout of mijstrat72 to have somewhere kiln dry it to stop it happening again.

[originalmatthew]

+1 on having it kilned and planed. Also use good grain sealer when you finish it.

[pmjennin]

You could try placing a weight on the convex side and letting it sit for a few weeks/months to see if it will flatten out. But not too heavy, as it may split the board!

In the future, I'd advise not to use wood cut from the center of the log such as the blank you have there, especially with pine. It's hard to keep those boards from NOT cupping or warping. It just naturally wants to.

[68thinline]

A planer won't do you much good until the wood is dry. Use a moisture meter to verify. It should be between 8-12% before using.

Or you could let it sit for another year. You'll need a joiner to flatten the face before you plane it to thickness. Not many joiners can handle the width of a guitar blank. You could always rip it in half again and reglue it when it's dry. Or you could use a wide, flat sanding board.

It's a nice looking board. I'd wait until it's properly dried before making an instrument.

[jrfrond]

It's called "seasoning", and most seasoned wood needs to be planed flat and square prior to use to remove warps and checks. You do NOT reintroduce moisture back into it.

[Rooney]

The only solution I would think of would be to take it to a jointer and surface the face and then plane it to thickness. I don't think 3mm should make much of a difference. You may have to have someone joint and plane it for you unless you have the machines necessary to do it yourself.

[tonewoods]

OK, first do this:


"An excellent way to quickly and safely dry wood is to use a black garbage bag as a mini-solar kiln.

This is especially useful for larger pieces of wood...say, a cello neck or Tele body...

Put the wood inside of the bag and stick it in the sun. Important! Seal the bag...

Let it sit in the sun for a few hours, then turn it inside out to evacuate the moisture. The small volume of the bag will insure that the wood will not dry too quickly and crack, or case harden your wood...

This method is great for a "final cure" on pieces of wood that you're not sure of how much moisture is still in them...
But it will also work of wood that is hovering at the 20% MC point...

Luck!"



Then, after you've "seasoned" the wood using the ol' garbage bag method, do what was recommended, namely:



"#
Water a section of lawn at least as big as the board or panel. Do this in mid-morning of a hot and sunny day.
#
Lay the wood down on the watered lawn with the concave side facing down. The concave side is the side that is "caved" in. Severely warped boards may only touch the grass on the very ends when laid down this way.
#
Leave the wood out on the lawn all day. When the sun starts to set and the heat of the day has passed, bring the board into a garage or basement."

But this is important....
Monitor the wood until it's flat...

I might take all afternoon, but it might only take an hour...
Monitor it...

Then, when it's flat, hang it in the air so that all sides of the wood receive equal air circulation...

Then you should be good to go....

[iansmitchell]

All those saying not to introduce moisture...
Acoustic guitar sides are ALWAYS bent by steaming.

[otterhound]

Originally Posted by iansmitchell

All those saying not to introduce moisture...
Acoustic guitar sides are ALWAYS bent by steaming.

Correct me if wrong , please . Side bending is done with heat , not necessarily with steam . I am sure that steam was once the way , though .

[ievans]

Need I point out that steaming, ie increasing moisture, to thin sheets of wood for forming acoustic guitar sides is exactly the opposite of what you want when you're drying green wood to make it stable? And they have zero to do with one another?

If you don't know what you're talking about, it's best to not say anything.

[iansmitchell]

Originally Posted by otterhound

Correct me if wrong , please . Side bending is done with heat , not necessarily with steam . I am sure that steam was once the way , though .

Wood must be soaked or at the least spritzed to respond to heat by bending, rather than burning and/or splitting.
Stewart macdonald's bending iron instructions can give you an idea.
The reason water(i.e. steam) is integral is that the wood fibers are only really flexible when wetted, compare a wet piece of newspaper to dry, and drying status causes wood to warp. Side bending is the extreme and controlled use of such properties.

[edgemarc]

Thanks tonewoods! good to learn some tricks from someone who knows wood.

[Groovey Records]

You guy have totally warped ideas

[ehawley]

Originally Posted by iansmitchell

Wood must be soaked or at the least spritzed to respond to heat by bending, rather than burning and/or splitting.
Stewart macdonald's bending iron instructions can give you an idea.
The reason water(i.e. steam) is integral is that the wood fibers are only really flexible when wetted, compare a wet piece of newspaper to dry, and drying status causes wood to warp. Side bending is the extreme and controlled use of such properties.

Actually...it is the resin in the wood that you are heating up and softening that allows the wood to move. All sides today are bent after they are dry and with an electric heat pad and pressure bending fixture. PRS has some neat videos on youtube of the process.

[iansmitchell]

Originally Posted by ehawley

Actually...it is the resin in the wood that you are heating up and softening that allows the wood to move. All sides today are bent after they are dry and with an electric heat pad and pressure bending fixture. PRS has some neat videos on youtube of the process.

That's not true, at all. It is the moisture, allowing the fibers to bend.
Saying that the process is only done dry, is about like saying "all necks today are bolt-on".
Now, taylor uses some process that make the added moisture unecessary, but these are very new.
It's still only about as popular as bolt-on necks or full-length fingerboards.

[guitarbuilder]

Aren't barrel staves bent dry? I seem to remember watching some show where they have a fire and it helps make the wood pliable for the metal bands to pull it together.

[jkingma]

Originally Posted by guitarbuilder

Aren't barrel staves bent dry? I seem to remember watching some show where they have a fire and it helps make the wood pliable for the metal bands to pull it together.

You might have to ask Mr. Cooper that question.

[guitarbuilder]

According to a youtube video.... the answer is no... they must just char it for flavor.

[mcgeorgerl]

From Hoadley"s "Understanding Wood"...

For centuries woodworkers have been discussing what might be the best moisture content for bending stock and how long the pieces should be steamed. Such considerations are interrelated, since the drier the wood, the stronger it is to begin with and the longer it must be steamed to become sufficiently plastisized. Wood bends best at a moisture content near its fiber saturation point......a fair compromise is air-dry levels of 12% tp 20% MC.

Even at a relatively dry moisture content of 6%, there's still a significant amount of water in wood that when a heat source is applied the water turns to steam. Is it the heat or steam that allows the wood to bend? The argument is moot because they're interrelated. You can't have a 300 degree heat source and water without creating steam.

Because I'm not a skilled bender, I tend to over-soak the wood when using a hot pipe because if the wood gets dry during the bending process, it will scortch. I even have to be carefull on my Fox Side Bender and its heat source is 150, 200 and 300 Watt light bulbs.

The moist lawn trick was written up in a wood magazine recently (within the last few years). The idea is that if the wood got too dry you could introduce some moisure, stabilize the table top and then introduce the table into a contolled moisure enviroment. Think of it like taking a table out of grandma's attic where it's be stored for 25 years and now you want to use it as a table in your temperature controlled house. It won't work on this board IMO.

[thame2010]

Wow, thanks for all the replies! I'm kinda confused right now

Originally Posted by pmjennin

You could try placing a weight on the convex side and letting it sit for a few weeks/months to see if it will flatten out. But not too heavy, as it may split the board!

In the future, I'd advise not to use wood cut from the center of the log such as the blank you have there, especially with pine. It's hard to keep those boards from NOT cupping or warping. It just naturally wants to.

Jennin, do you know why I chose the center of the log? Because I thought that would be the part of the log that's more stable and won't tend to warp as easily! I remember reading that somewhere.

I believe this wood warped because I let it dry too quickly, and it only recieved direct sunlight from one side (I only go to my house on weekends right now and that's where the wood is).

Originally Posted by tonewoods

OK, first do this:


"An excellent way to quickly and safely dry wood is to use a black garbage bag as a mini-solar kiln.

This is especially useful for larger pieces of wood...say, a cello neck or Tele body...

Put the wood inside of the bag and stick it in the sun. Important! Seal the bag...

Let it sit in the sun for a few hours, then turn it inside out to evacuate the moisture. The small volume of the bag will insure that the wood will not dry too quickly and crack, or case harden your wood...

This method is great for a "final cure" on pieces of wood that you're not sure of how much moisture is still in them...
But it will also work of wood that is hovering at the 20% MC point...

Luck!"



Then, after you've "seasoned" the wood using the ol' garbage bag method, do what was recommended, namely:



"#
Water a section of lawn at least as big as the board or panel. Do this in mid-morning of a hot and sunny day.
#
Lay the wood down on the watered lawn with the concave side facing down. The concave side is the side that is "caved" in. Severely warped boards may only touch the grass on the very ends when laid down this way.
#
Leave the wood out on the lawn all day. When the sun starts to set and the heat of the day has passed, bring the board into a garage or basement."

But this is important....
Monitor the wood until it's flat...

I might take all afternoon, but it might only take an hour...
Monitor it...

Then, when it's flat, hang it in the air so that all sides of the wood receive equal air circulation...

Then you should be good to go....

Thanks for the tip tonewoods. Do I have to repeat the process of the garbage bag a few times? Or should I get a moisture meter and repeat until it is below the 12% mark?

Thanks everybody!

[tonewoods]

Originally Posted by thame2010

Do I have to repeat the process of the garbage bag a few times? Or should I get a moisture meter and repeat until it is below the 12% mark?

Do it until the inside of the bag no longer yields moisture...

BTW, this is a common problem, even with wood that is 50 years old and seasoned...

If you subject one face of a Tele blank to different conditions than the other face--like bringing a piece of wood in from the garage into a heated room and laying it on a table--it will cup...
Happens all the time...

Oh, and forget the lawn deal...

Just use a wet towel, and the forces that originally cupped the wood will bring it back to flat where it really wants to be....

Luck!

[68thinline]

Originally Posted by tonewoods

Just use a wet towel, and the forces that originally cupped the wood will bring it back to flat where it really wants to be....

Luck!

Why does the wood want to be flat? The wood is just looking for equilibrium with its environment. If you add moisture now you're likely to get checking in the end grain, or worse yet a crack! IMO you can't control how the wood is going to dry.

thame2010, you say the log has dried for a year, but when was it sawn into lumber? A cut from the center of the log may not be fully dry. If you're not sure, let it sit. If you are sure, use a jointer or a large sanding board to flatten it.

[tonewoods]

Originally Posted by 68thinline

Why does the wood want to be flat?

Well, if you just run it through a planer, you are "capturing" a piece of wood in the middle of a warp--and it will likely warp back to where it originally was...
Or at least that's what my instincts tell me...

It's easy to flatten a board using the same forces that warped it, and making sure that it's as dry as it can be when it's flat...

[68thinline]

Originally Posted by tonewoods

Well, if you just run it through a planer, you are "capturing" a piece of wood in the middle of a warp--and it will likely warp back to where it originally was...
Or at least that's what my instincts tell me...

If the wood was not properly seasoned before the surface was flattened, I would agree, if by "warp back" you mean it would continue to warp in the same direction.

It's easy to flatten a board using the same forces that warped it, and making sure that it's as dry as it can be when it's flat...

Not sure what "forces" you're talking about. My understanding of wood is that it warps because it either dries or absorbs moisture unevenly across the grain (this is why end grain absorbs more stain that the rest of the board, for instance). Or, it bends after it's been ripped (or significantly reduced in thickness) because it's no longer acting against the wood that's been removed. I'm not an expert, but I would think that the forces that cause wood to move in this way are not the "same forces" that are used when holding a board flat while it dries. (I'm sorry if I'm splitting hairs)

I've never used your method to flatten wood so I can't say for sure it won't work (though I have my doubts). Maybe you've had success that way, but I was always taught to flatten wood on a joiner.

[old_picker]

rule of thumb in these parts is:
cut wet timber
seal the board ends with wax
sticker stack the boards
let dry for 1 year per inch of thickness plus 1 year
turn once a month if practicable

if your timber was cut 1 year ago it needs to sit 2 more years
dont build a guitar out of this board or you will have warping and even worse cracking after the build is finished - you can flatten this board till the cows come home but until it is at 8 to 10% MC at the dead centre of the board it will continue to move

there is no quck way to evenly dry timber unless you have access to a timber kiln and moisture measuring equipment to check the MC in the centre of the board -

i serously doubt the methods outlined above will pull moisture from the dead centre of this board -

btw pine is notorious fo being unstable so do yourself a favor and let it dry properly before using it

[tonewoods]

Originally Posted by old_picker

rule of thumb in these parts is:
cut wet timber
seal the board ends with wax
sticker stack the boards
let dry for 1 year per inch of thickness plus 1 year
turn once a month if practicable

Great, but you're forgetting one thing...
And that's what we are discussing here...

Your top board will be stickered on one face, and exposed to the great wide outdoors on the other...
And it will cup...

So-ooo, you need to cover the pile with a dry board--or a board you don't care about--if you want it to turn out flat...

And, you don't need to "turn once a month if practicable"...

Originally Posted by old_picker

i serously doubt the methods outlined above will pull moisture from the dead centre of this board

The 'ol garbage bag kiln sure will, and it will treat your thick wood much more gently than other other kilning method I know of....

[thame2010]

I ordered a moisture meter from eBay to be sure how dry the wood is.

When it arrives I'm going to try the garbage bag method with some other blanks I have (which are basically the same as the one pictured, not so warped though) and I'll let you know the results ;)

Also, I have another flatsawn blank from the center of the log, which I planned, sanded and removed the center part of the log which seems to be causing trouble. Now it's like having 2 quartersawn pieces and it doesn't seem to be warping

Check it out..