Resawing for beginners

Sometimes that just happens. They may equalize after a while.

You could try spraying some water on the cupped side and if a flattens out clamp it while it dries.

Good luck.

-- Gary, East TX -- The longest journey begins with a single step.

I had that happen to me with some cherry. I have it clamped down to see if it will flatten.

-- Maplewood, MN

Resaw the material and then leave it alone for a day or two. Then surface it (oversized) and leave it alone again overnight. You didn’t mention where your shop was, what the temp was, Hg pressure etc. All of those have something to do with your lumber as does drying rate and how it was dried, air dried or in a kiln. Did you check the moisture content? There is a reason why flitch sawn veneers cost what they do.

I’m sure that with practice you can get spectacular material from your shop but just buying a bandsaw does not guarantee you results from the mere purchase of it.

I have found that I have better results following the method Grumpycarp proposed. If I go to final thickness quickly mine will nearly always cup or warp. I’ve even had a piece of Purple Heart split up the middle!

-- Chris

It’s true, that almost always happens. Follow grumpy’s advice. The cupping will almost centainly get much better after a few days. If the pieces are too wide to surface on the jointer, rip them down the middle with the band saw, surface them on the jointer, plane them, joint the edges, then glue them back together. You can get creative with the panels by bookmatching wide panels inside the frame without a rail in between. Look at this bathroom vanity I made from maple. The left and right doors have bookmatched figure using that technique.

Don’t give up! Wood is not plastic or metal. It moves.

-- Scott - Chico California http://chicowoodnut.home.comcast.net

grumpycarp’s suggestions are on the money. It’s notj ust moisture gradients that can cause this. Stress in the tree (leaners, etc.) it came from can also cause wood to move when sawn.

-- Wonderful new things are coming! - God

I do a lot of resawing and in my opinion here is what happens EVERYTIME you resaw a thicker piece down to multiple thinner pieces. You have just exposed interior wood that has not been exposed to the local environment and now it will try to acclimate.

Wood gains and loses moisture content from the outside in, and it does so rather slowly. So, even if you buy lumber and let it acclimate in your shop for weeks, the internal wood is probably going to have a different moisture content than the outside surface that has been exposed and has already acclimated.

Then when you slice it, the internal wood immediately begins to adjust to the relative humidity of its surroundings, but the external wood isn’t changing because it has already adjusted…....Bingo, this causes cupping!

The three rules I use whenever resawing are to;

1) flat stack the slices under heavy weight immediately as they come off the saw, (I use wrapped bricks) and then when I’m done resawing,

2) I sticker and clamp the slices to keep everything flat and allow good air circulation around all sides of the freshly sawn material until either acclimated, or used in the project.

3) always complete the resawing of each board without stopping. If you are making multiple slices from some thick stock, and you take a lunch break half way through, you may find upon your return that the “mother board” has also cupped and you can’t continue without re-jointing.

Here is a picture of how I store freshly resawn boards. These are stickered and clamped exotics right after completing the resaw session.

Most people will say to “sticker and weight” and that is fine, but for me, I sticker and “clamp” so I can use the clamps as handles and move the stacks around the shop without them being in my way. The clamps are only tightened enough to maintain flatness, but not so tight that they don’t allow the wood to expand and contract.

Here is a stack of 1/16” shop sawn veneers stored the same way right off the saw.

It is true that there can be other factors, like tension, or crooked growing trees (?), but it is my experience that says 98% of the time it is nothing more than a freshly cut board that has two faces of different MC trying to adjust to the external RH.

-- John, Chisel and Bit Custom Crafted Furniture, www.chiselandbit.com

That’s a nice bit of information John. I sure like the idea of being able to pick up the stack and move it all at once.

Thanks

-- Scott - Chico California http://chicowoodnut.home.comcast.net

Thanks, John – you seem to be the re-saw master!

-- -Be Blessed!, Patrick

Great explanation and pic’s John. I also re-saw a lot of exotics for acoustic guitar backs, sides and spruce soundboards. I do it just about the same way except that I needed way too many clamps. I use a bottom and top piece of 3/4” plywood or melamine covered MDF. Then I use a couple of wraps of narrow shrink wrap on each end and the middle and remove the clamps. Another problem that causes this is case hardening during the kiln drying process. I cut most of my wood green and air dry with the aid of fans in my humidity controlled shop.

-- Bob C www.rctonewoods.com

John, How long do you need to keep the boards stickered?

-- Bob from Northwest Florida

I have been told by my lumber guy and a few others, that you should let it set for a week or so. This is the same for brining home lumber.

Thanks for the hot tips, John. I would have never thought about it untio it was too late!

-- Topamax Survivor