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Walnut table tops twisting

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Forum topic by dougdeg posted 1181 days ago 1722 views 0 times favorited 7 replies Add to Favorites Watch
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dougdeg

107 posts in 2405 days


1181 days ago

Topic tags/keywords: question walnut milling joining sanding arts and crafts

I have built a few wide slab walnut tables with natural edges and stump bases, I have had a few twist up on me not sure why,
Moisture content down to 8%
Glued up mya three pcs, 2” thisk sometimes just two 24” slabs glued together.
We seal all sides with minwax wipe on poly.
Sometimes they will twist before getting thm finished some will cup, but i even think 3/8” cup is to much for a dining table, some tell my not to worry they are ructis, but i dont think they should what am i doing wrong.
Im in michigan so weather could be a factor.

-- Doug Cedar Log Furniture, www.cedar-stuff.com


7 replies so far

View BobTheFish's profile

BobTheFish

361 posts in 1186 days


#1 posted 1180 days ago

my first question is where did you get the wood, and did you let it acclimate? That seems a little on the low end for moisture, and especially if you’re in michigan, and possibly near the lakes…

View Nomad62's profile

Nomad62

706 posts in 1593 days


#2 posted 1180 days ago

Wood movement is almost always attributed to moisture content. I have been seeing/reading alot lately about how a person gets wood from the kiln and it was x%, only to find out it was very wet inside. Some kiln operators use them like ovens instead of kilns; the time just has to be taken for the job to be done right. Wood can read 8% and still be 16-18% inside. When getting wood from the kiln, find out how long it had been in it; if it was a couple weeks, the wood will very likely be wet inside. It needs, at the very least, a month of careful kiln time to do the job right, 6-8 weeks is better. 2-3” thick wood requires quite a bit of time to leach all the water out. Of course this is unwelcome info to the kiln operator, as time is money. But the real thing here is the fact that you are trying to get a valuable product, and shortcuts along the way in generating said product only minimizes its quality. Your success in such a table top will depend on the quality of your woods’ handling before you get it. All that said, if you are unsure about what you are buying then either keep looking, find a reputable kiln operator, or let the wood dry out in your home or similar environment for a few months (using a moisture meter every now and then) before you use it.

-- Power tools put us ahead of the monkeys

View buckles's profile

buckles

24 posts in 1176 days


#3 posted 1176 days ago

Doug
If you let rough sawn lumber stand in your shop for a month or more before using it you will have better results. You can not make fine furniture unless your wood is straight and square. You have to run rough lumber through a joiner first of all. NOT a planer. Get one side flat and turn it up on edge to get a straight square edge. Now run it through a TS to get the other edge straight and square. Now run it through a planer.
Now you have a piece of lumber that is ready to build something with. DO NOT store it flat.
Remember that you MUST do the opposite side what you do to any other side.
Regards
the other Joe

-- Politicians are like diapers. They need to be changed for the same reasons.

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dougdeg

107 posts in 2405 days


#4 posted 988 days ago

Sorry got lost a ways back
The walnut slabs were 2 1/2” thick and kiln dried to 8-12%, once i started working with it it was very flat and straight the slabs were about 22” wide each, I have a flat sled that i shim boards up on and then run them through a planner this will flatten them up nice,
The table top was finished on the top side only with minwax wipe on poly. could this be a problem,

Also the kiln i use air dries the wood down to about 20$ and then kiln dries them but still he dries them in a week or two at theat point.

-- Doug Cedar Log Furniture, www.cedar-stuff.com

View HerbC's profile

HerbC

1162 posts in 1494 days


#5 posted 987 days ago

Doug,

You’re closing in on the cause(s) for the problems.

I think your kiln operation is not doing a very good job drying these slabs. They are probably much wetter inside than on the surface.

Also, you need to apply finish to the bottom side of the tabletop. If you don’t do that, the bottom will dry quicker than the top and you’ll wind up with a cupped top.

Good Luck and

Be Careful!

Herb

-- Herb, Florida - Here's why I close most messages with "Be Careful!" http://lumberjocks.com/HerbC/blog/17090

View TCCcabinetmaker's profile

TCCcabinetmaker

925 posts in 989 days


#6 posted 987 days ago

Well I could rattle off an A.W.I standard, but there’s some more questions we could ask here to. (anything over 10 inches needs to be glued up, but I forget last I heard those silly rules was 3 years ago)

2” thick walnut slabs can have some significant weight to them, and while it is uncommon, it is possible for gravity to warp the wood. How/Are you braccing the undersides of these slabs?

How quickly did you work the wood after you got it? In some cases in the past, wood would be allowed to acclimated 3-even 6 months in the shop before it got used. But I buy from a wholesaler who brings me quality wood, because he knows I won’t accept it if it isn’t good, or I’ll let him hear about it if I have problems.

-- The mark of a good carpenter is not how few mistakes he makes, but rather how well he fixes them.

View Nomad62's profile

Nomad62

706 posts in 1593 days


#7 posted 985 days ago

No way to accurately dry the wood from that moisture level in 1-2 weeks. There is your answer, you need to have the wood correctly dried, not just stuck in a kiln and labeled as dry. The work you put into such a project deserves a better product to begin with; even letting it acclimate after such a short kiln time will do little to help you. Pay the kiln operator to leave it in for a month, on a slower dry rate. The wood should get to 6% thru and thru, then allowed to acclimate in a home type environment for at least 2 weeks before final milling. This will all but eliminate your troubles. If the kiln operator will not do this (it’s his business, he can do what he wants) then I would find someone who will be interested in getting you a valuable service. Paying for a less-than-adequate job is tossing money into the wind.

-- Power tools put us ahead of the monkeys

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