Wood Movement

[Gofor]

Sorry for the picture quality. This breadboard end was installed in my non-climatically controlled shop when the humidity was up around 100%. The end of the breadboard and the edge of the table were flush (I know I should have left it a little proud, but figured with max humidity I was okay).

After a couple weeks inside the house while I made the base, the 40" wide table contracted this much on both sides of each end. (about 3/64ths" as pictured). I would guess the humidity in the house is about 50%. Just a pic to convince any doubters concerning wood movement.



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[DaveO]

Ain't that cool. I love to use breadboard ends for just that reason. It's fun to explain to folks why you built something that way, and have some concrete proof.

Dave

 

[skysharks]

Mark , You and I have built the same table design, trestle and used the same wood, Black Walnut:icon_thum.
Wow, and we didn't even discuss it, lol.
I too did the breadboard on my ends, in thinking that I may get wood movement. I have had it happen before. However this time, not so much yet.:eusa_pray
Pictures are in my photo gallery.
Great looking table by the way. I really like the angles cut off of the corners.
makes passing around the the ends of the table more enjoyable, if you get my drift, lol
Very nice table, finish, that is that Rocky Hard stuff that DaveO, recommended? I just might have to try that stuff out.

 

[woodnick]

It's not IF, but how FAR wood will move :icon_scra

 

[jeff...]

A old wise finisher once told me - on big flat solid wood pieces like table tops do the same to the bottom as you do top and sides, but no need to buff out the bottom. What I learned from him is if you apply 4 coats to the top also apply 4 to the bottom. It kinda makes sense... it seals up all the surfaces and makes it some less prone to move. It's not nearly as exposed to environmental factors as unsealed wood would be.

Yep wood WILL move that's for sure... it's a natural product, not some man made piece of plastic or resin material.

 

[skysharks]

Jeff that is a very good point. About sealing up all edges. I have found that when I tried to explain that point to some the 6th edge never got done.
ie. there is always 6 sides in flat work.
Example: I inlaid black walnut into the tile work that I did my masterbath floor.
During my research and designing phase of that project. I was always hit up with, that the wood is going to move with the seasonal changes, bathroom humidity etc.
I did not want the wood to separate from the tile, thus causing cracks in the grout line, etc.
So I cut all the pieces and then sealed all 6 sides up with 3-4 coats of gloss poly prior to installing the pieces in the floor.
To this day almost 4 years later, I have never had the wood shift or move at all. Not even hair line cracks.
Did I get lucky?? other forces at work?? not sure!.
But I am happy about it.
So since then if I have a piece that I do not want to contract/expand I seal up all edges.
Now I guess that if there is allot of moisture in the wood and you sealed it up completely. Then during temperature changes, maybe something could happen to the inside. I am guess here, but maybe bulging.
But one would think that would have to be extremes.
All that said I STILL installed breadboard ends fastened with dowels across the ends of my dining room table to accommodate wood movement.

I Love wood working.

 

[jeff...]

All that said I STILL installed breadboard ends fastened with dowels across the ends of my dining room table to accommodate wood movement.

I Love wood working.

Mac as you should have, sealing all the surface of wood helps a lot with movement but won't I don't think it would eliminate it

 

[Gofor]

Just to clarify, the picture and the wood movement took place before any finishing. In this thread http://www.ncwoodworker.net/forums/f29/dining-table-finish-17683/ I have posted a picture of the table without finish, and then the top with just the first seal coat of Behlen's Rockhard Tabletop Finish. I, too, apply finish to bottoms of tops, etc, to equalize moisture absorbtion. It also gives me a place to see exactly how the finish will look on the display surface before I commit to a particular finish blend, etc.

Mac, I can tell you now that your book-matched slab and perfectly flat smooth top of yours is much better than mine, and my base design is pretty plain and simple compared to yours. (Mine came out of my head, so it had to be simple!!:wconfused Mine is kitchen quality, yours is Salon quality.:icon_thum:icon_thum

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[Travis Porter]

Go, you going to trim it or leave it?

Not to argue the finishing all sides point (I do it myself), but I read not too long ago I believe an article by Bob Flexner that says it isn't necessary. Personally, I think it is, and it makes good sense to me.

 

[Gofor]

I'm going to leave it. The location and orientation of our house lets us enjoy one to two months in the spring and fall when we can leave the windows open for the majority of the time, so humidity changes are going to occur. With the coatings, the changes will be slower occuring and will last longer, but I would rather have the end a little proud than short which would expose end grain on the side that may get snagged and split off.

I also read Bob Flexner's opinion in his finishing book, but, like you, think its a good idea.

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