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Minor cupping in boards

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Forum topic by lateralus819 posted 03-25-2013 08:39 AM 953 views 0 times favorited 13 replies Add to Favorites Watch
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lateralus819

1395 posts in 545 days


03-25-2013 08:39 AM

Hello all, new here, i am currently a member at woodworkingtalk and figured I’d check this place out and get some tips here.

Previously (a week ago) I purchased 26 bdft of sapele to build a table for my kitchen.

I had them cut into 4’ sections, brought them home and stickered them all. I’ve been periodically checking them for flatness and to make sure nothing is going wonky on me. I’m going to wait another week until i bring them to final dimensions.

They’re of varying widths, but all 4’. I plan on bringing them to the maximum width i can.

I’ve noticed in some spots, some pieces are cupped at most 1/16th. Is this a problem? Would they flatting when i attach my aprons on the bottom, pulling them flat?

They’re just over 3/4” thick, which is what i want, and they’re S2S with 1 jointed side. Should i run them through the planer?.

Any help is greatly appreciated!

-- Never confuse mistakes with failure. Kevin


13 replies so far

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Monte Pittman

14197 posts in 993 days


#1 posted 03-25-2013 10:21 AM

My guess is that they weren’t properly dried when you got them. If you have a moisture meter check them. You don’t want to use them till they are done moving. Never trust a lumber store.

Welcome to LumberJocks

-- Mother Nature created it, I just assemble it.

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bannerpond1

233 posts in 554 days


#2 posted 03-25-2013 10:30 AM

I doubt they can be flattened with the aprons. I believe you are going to waste time and probably money if you try to build this project without flattening the boards.

You need to joint the boards flat. Put the board on the jointer table with cup pointing down, not so that the board will rock. If it’s only 1/16th, a couple of passes should suffice. Then plane the other face to thickness.

I would flatten them before gluing up any panels with them. You’d probably end up having to take off more material and you might get something so disformed that you can’t fix it.

Flat (plain) sawn boards are going to move around. It’s not “if,” it’s “how much.” Whether it’s a jointer and surface planer, or hand planes, you’re going to have this chore for everything. Don’t start a project with boards that aren’t flat. Just my opinion.

-- --Dale Page

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sprucegum

323 posts in 653 days


#3 posted 03-25-2013 11:06 AM

ditto on jointing them I am not familiar with the qualities your wood but if it is a fairly stiff strong wood you may be able to remove the cup just by running them through a planer and taking light passes. With soft weak woods like Eastern White Pine the feed rolls will flatten the board against the planer bed and when the pop out the other end of the planer you will still have a cupped board. Jointing them is the best way to go of course. If you lack a jointer and planer you can of course use a hand plane.

-- A tube of calk and a gallon of paint will make a carpenter what he ain't

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unbob

404 posts in 559 days


#4 posted 03-25-2013 02:23 PM

I will suggest the opposite of conventional approaches and explain why.
When running a cupped board through a jointer with the concave side down, the stresses are still in the wood. The wood will cup rather rapidly again. Its better to break the back of the source of the stress, by flattening the convex side first. This can be made alittle easier by running a hand plane down the center of the convex side first, giving a flat to guide through the jointer. Then, run the board through the the planer to take care of the concave side. Of course, this would be the normal approach if done completely by hand planing.

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404 - Not Found

2544 posts in 1624 days


#5 posted 03-25-2013 05:23 PM

Sapele has a mind of its own. It is full of stresses that will change the shape of the board and ruin your day depending on how you cut it or even even plane it.

Are they cupped or bowed?

If they are bowed: unbob gives good advice, but, as you are already at the thickness you want, I would biscuit joint it together alternating covex and concave pieces, and use cauls across the glue up to keep the surface flat. If you try planing your 3/4” stock to get it flat you’ll be lucky to get 1/2” out of it. Then just level it with planes/sanding.

If they are cupped, split the boards first and rejoint them alternating crown up/crown down on the glue up.

Try to get the grain orientation all the same direction so you don’t get a big tear out cleaning up with a plane.

At 3/4, there should be sufficient spring in the wood to allow you to get it all flat using curved clamping cauls. Maybe before you do anything, you should try a dry fit and see how well it will go together.

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lateralus819

1395 posts in 545 days


#6 posted 03-25-2013 08:30 PM

I dont have a jointer unfortunately, so in that regard im screwed, but i did check them and the cup is only on the ends, not through the whole piece. And not on every board, and it isn’t THAT cupped.

-- Never confuse mistakes with failure. Kevin

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pintodeluxe

3363 posts in 1468 days


#7 posted 03-25-2013 08:42 PM

Flat sawn lumber will do that from time to time (every single time).
I am fortunate to work almost exclusively with quartersawn lumber. It tends to stay straighter and flatter than flat sawn lumber. It won’t replace a good jointer though.
Do the best you can with your planer, and look to add a jointer to your arsenal at a later date.

Best of luck!

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

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lateralus819

1395 posts in 545 days


#8 posted 03-25-2013 08:53 PM

I think i bit off more than i could chew with this table! I’m fairly new and i think it was a big challenge, which is fine. Just has cost a lot of money and will cost more with tools i need. I would definitely like to add a jointer sooner or later.

-- Never confuse mistakes with failure. Kevin

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lateralus819

1395 posts in 545 days


#9 posted 03-25-2013 08:57 PM

Being that they’re only cupped a tiny bit, couldn’t i just glue them up and flatten with a hand plane?

-- Never confuse mistakes with failure. Kevin

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sprucegum

323 posts in 653 days


#10 posted 03-26-2013 11:00 AM

I would glue them up into the widest width that would fit through my planer, then plane them to a uniform thickness. Do this until you have enough pieces to do your table then glue up the pieces using some dowel pins to help with allinement, from this point on you will have to hand plane or sand. Search this site for poor mans jointer and you will find a skill share I posted a while back it will show you how to make perfect glue joints using your table saw.

-- A tube of calk and a gallon of paint will make a carpenter what he ain't

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bannerpond1

233 posts in 554 days


#11 posted 03-26-2013 01:11 PM

Lateralus819, if you glue the cupped boards, consider this: The edges should be 90 degrees to the faces. To what will your edges be 90 degrees in a cupped board? If you don’t have a jointer, you are going to be really frustrated in this. You will end up with a panel with waves in it. Pintodeluxe has the answer, but it’s not going to be convenient for you. Buy quarter sawn boards so you don’t have this problem.

Without the proper tools, you’re either going to get really proficient in hand planing, or you’re going to get really frustrated. You’ll have to decide which it’s going to be.

-- --Dale Page

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lateralus819

1395 posts in 545 days


#12 posted 03-26-2013 11:48 PM

Yeah, probably so banner. I talked to a guy at work who owns a mill. He has a jointer as well and said he wouldn’t mind jointing them for me. So what i may do is rip them in half since they’re almost 9 inches each and have him joint them.

-- Never confuse mistakes with failure. Kevin

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lateralus819

1395 posts in 545 days


#13 posted 03-27-2013 01:04 AM

Been thinking, if i do have him joint them, I’ll probably be left with, if im lucky, 5/8”. Is that suitable for a table top? Its only 4’x just over 4’

-- Never confuse mistakes with failure. Kevin

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