Live and learn. A tabletop I made a few years back that has killed itself from seasonal wood movement.
imgur.com/a/YWBPX
imgur.comPosted Mar 3, 2015, 7:14 PM UTC
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imgur.comVeneer is the path to enlightenment. Has been done for over a hundred years for this exact purpose.
I'm actually really impressed with how well you fit everything to begin with. But solid wood for these kinds of patterns is never a good idea.
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Thank you for posting this. Always good to have a real-world example to point to prove the point to the doubters, but especially for the deniers, who claim you can ignore it without consequence in modern homes with central air and heating.
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is there a good way to prevent this from happening?
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Yes, design you're project to allow the wood to move. If you don't allow the wood to move it is going to move anyway.
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can you give me an example of how to design to allow the wood to move without just leaving things loose?
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Sure! So first thing to understand is that expansion usually happens across the grain rather than with the grain. So the width is what fluctuates the most.
The most classic example I can think of is a raised panel door. you construct the rails and style with a groove all around the inside of the frame. When you glue up the door the panel fits inside that groove but you don't glue it.
Also a table top is a pretty common example. In table tops typically we use a figure 8 fastener screwed to the top that fits into grooves in the aprons or frames. This allows the table top to expand and contract seasonally while still holding the top to the frame.
Now don't take my word for it because I am not the authority on these sorts of things. There are plenty of articles here and elsewhere on the internet written by people much more knowledgeable than myself.
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Thanks. I'm just getting started and hoping to learn from the mistakes of others.
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Easiest way I've found to remember it is that wood changes WIDTH but not LENGTH (at least not significantly.) If you don't give it somewhere to go, it will relieve that stress via either splitting, or breaking apart the surrounding material. OP's table design wasn't impossible...if he had arranged the pattern in the middle so that the expansion was all going the same way, and then placed it INSIDE the frame in a dado, instead of just gluing it directly, it very likely would have survived.
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This might help. In general, expect wood to grow and shrink across the grain but not in length. In most kinds of wood, you can attach things cross grain for up to a few inches, but if you start pushing 8 inches or so you really need to accommodate movement. Some traditional techniques for this are frame and panel construction, where wide pieces float in a groove in a frame, Breadboard ends, which are similar but only have end pieces, not a full frame, and tabletop fasteners, which create a moveable connection between a wide slab and a supportive frame. Another option is to make wide pieces out of a group of narrow boards that aren't attached to each other, but have gaps between each, or tongues and grooves, to allow each narrow board to move individually. For a project like OP's, using a single slab for the structure and thin veneers for the design could work. Safer yet is to do veneers on plywood (which is really just a big veneer sandwich)
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All of the wood needs to be well sealed. This means top, bottom, and sides. And, it never hurts to run a humidifier during winter. I thought I saw a comment about veneer being the answer. It is not. If the piece is not completely sealed, the secondary wood will still expand and contract leading to cracking/separation of the veneer.
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From my understanding, even a few coats of poly all over won't keep the wood from moving. It would have to be truly encased in plastic. Also, veneer would work if ply was used underneath.
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Sorry, I didn't think of plywood. You and "jaggederest" are spot on. I come from an antique restoration background and the cure for moving wood or veneer is to stabilize the water content and shellac any raw wood.
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Unless it's engineered wood - plywood, fiberboard, what have you, will all generally be dimensionally stable since the fibers do not run in any particular direction.
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If that it still in great shape you should do this
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I think it's a lost cause. It moves way too much between seasons. I might try to replicate it someday but using proper techniques.
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This winter has been so hard on the furniture in my house too.
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I hear you on that. I made a table a year ago with breadboard ends. The middle has shrunk up so much compared to the ends it is crazy. You can see where the poly has cracked from the wood moving so much apart: http://i.imgur.com/20fbh7h.jpg
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On the plus side, the frame still looks ok, so you could just make another panel and do a tongue-and groove construction to allow it enough float to expand.
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Honestly I don't have the heart to take it apart. This was my first real project and it took me forever. I keep planning to hang it on the wall in my man cave but it hasn't happened yet.
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Ive posted this here before but I think its always a good reminder of how wood movement can destroy your projects. I live in Michigan so the moister difference between summer and winter is about as extreme as it gets. Add the fact that my furnace is 20+ years old so my house is drier than desert during the winter.
During the summer this will expand back out and the cracks in the middle oak and poplar panels will almost close back up. This will push the cherry frame parts out away from each other even further though. Every winter is gets much much worse though.
Reasons why this was a bad design:
This is a valuable post, thank you. It's good because it shows not only what the mistakes were, but how you'd do it differently armed with more knowledge.
It looked good while it lasted though :)
Do you really think that a dado would allow enough movement to occur with all the differences in the directions of the wood that you have in the middle? Also, did you use anything as a backer to the wood in the middle? Something to stabilize it from twisting?
If the design was done like a typical frame and panel construction where the panel isn't glued into the frame, I think it would have had a better chance as long as the dado was deep enough.
Yes, I think that's the answer. If the center tile had floated freely, it probably would have held up fine. Because it was glued on the sides, it got ripped apart. Which is a shame, because it was really nice work.
Nothing you can't fix with a bit of turquoise inlay and a bit of superglue, though :-)
This is what I was trying to refer to. I don't think radio is the pepper term for this... but idk. My terminology isn't always the best.