# Help! Table seams coming apart!



## malawlo (Sep 4, 2011)

Okay, first things first -- I'm not really a woodworker, which is probably why I find myself in this predicament in the first place. Admitting that I don't really know what I'm doing is hard but necessary, hopefully some of you skilled guys can set me straight.

Problem: I've made a few tables using reclaimed scaffolding boards mounted to 3/4" plywood. They're simply made and look really cool when they're done, but I've had a few that have started to come apart at the seams (I'll attach a few photos of finished tables). Basically, I cut the planks down to 1 1/4" thick, then glue/screw them to the plywood in a 'patchwork' fashion -- when it's done, the top is 2" thick. I add some steel legs underneath and that's it, they're solid when they leave my workspace but have been pulling apart later.

So like I said -- I really don't have much skill, I have basic tools and a humid, basement shop to call home. While the wood I use seems to be dry, I haven't checked it for moisture content and honestly, wouldn't even know how to. I'm just butting the boards together (no biscuits) and clamping them, then screwing them down underneath.

Also -- I finish the tops with water-based poly (Minwax Polycrilic), would something else be a better option.....?

So let's hear it, and be brutally honest -- I need whatever help you can give me and I need it fast. Replies will be greatly appreciated, thanks for your time.....

http://i1094.photobucket.com/albums/i442/malawlo/IMG_1629.jpg
http://i1094.photobucket.com/albums/i442/malawlo/IMG_1347.jpg
http://i1094.photobucket.com/albums/i442/malawlo/IMG_1344.jpg
http://i1094.photobucket.com/albums/i442/malawlo/IMG_0187.jpg


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## Big Dave (Sep 16, 2006)

Sounds to me like the boards are drying and shrinking. If they were glued to each other, which it sounds like you don't do, then when they shrunk they would all shrink as a unit and still be tight to each other but a little smaller table top overall.


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## malawlo (Sep 4, 2011)

Big Dave said:


> Sounds to me like the boards are drying and shrinking. If they were glued to each other, which it sounds like you don't do, then when they shrunk they would all shrink as a unit and still be tight to each other but a little smaller table top overall.


No, they're glued together -- I do a row at a time, let them dry for a day or so, then screw them down. Then I add another row of boards, keep going until the whole thing is done.

Could the wood be wet....? Not enough glue....? Too much glue....? Humidity.....?

Most of the seams are good, it's only in a few spots.....

Oh, and thanks for the response, keep 'em coming.....


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## Big Dave (Sep 16, 2006)

The wood could be wet. If that's the case then I would use a polyurethane glue like Gorilla glue. It could also be that your not using enough glue but I highly doubt that. It's a good idea to clamp the boards together while the glue is drying.


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## Big Dave (Sep 16, 2006)

Nice looking tables by the way. I like the rustic stuff.


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## Corbin3388 (Jan 22, 2011)

You work in a humid shop. Table gets taken from shop to a place with a/c cranked up b/c people like to be comfortable. A/C's suck all the humidity out of the air including the table. The wood then shrinks causing the gaps. Sounds to me like a good excuse to install a a/c unit in your basement.

Sent from my iPhone using Wood Forum


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## malawlo (Sep 4, 2011)

Big Dave said:


> Nice looking tables by the way. I like the rustic stuff.


Yeah, I glue and then clamp them -- the joints seem to be good once it's all said and done, but then..... trouble. I use Titebond glue, I'll give Gorilla Glue a shot.

And thanks for the kind words, people really seem to dig the tables (except for the ones who've had problems). I guess I'm just wondering whether or not I should even try to keep making them, you know....?

Oh, and cool site, by the way -- your stuff is amazing, I'm embarrassed to even have to ask these questions.....


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## malawlo (Sep 4, 2011)

Corbin3388 said:


> You work in a humid shop. Table gets taken from shop to a place with a/c cranked up b/c people like to be comfortable. A/C's suck all the humidity out of the air including the table. The wood then shrinks causing the gaps. Sounds to me like a good excuse to install a a/c unit in your basement.
> 
> Sent from my iPhone using Wood Forum


I was thinking about adding a de-humidifier -- would that work....? Couldn't hurt I imagine.

At this point, I'd do just about anything, you know....?


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## Big Dave (Sep 16, 2006)

malawlo said:


> Yeah, I glue and then clamp them -- the joints seem to be good once it's all said and done, but then..... trouble. I use Titebond glue, I'll give Gorilla Glue a shot.
> 
> And thanks for the kind words, people really seem to dig the tables (except for the ones who've had problems). I guess I'm just wondering whether or not I should even try to keep making them, you know....?
> 
> Oh, and cool site, by the way -- your stuff is amazing, I'm embarrassed to even have to ask these questions.....


Thanks for the compliments and don't worry about asking questions, that's how we all learn. Keep making them, practice makes perfect.

You might be screwing them too much to the plywood and it's not letting them move and causing the joints to come apart. Try screwing them just enough to hold them in place or even using nails instead of screws.


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## malawlo (Sep 4, 2011)

Big Dave said:


> Thanks for the compliments and don't worry about asking questions, that's how we all learn. Keep making them, practice makes perfect.
> 
> You might be screwing them too much to the plywood and it's not letting them move and causing the joints to come apart. Try screwing them just enough to hold them in place or even using nails instead of screws.


Sounds good, I'll try it.

If you have any additional ideas, lemme know -- I need all the help I can get....


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## cabinetman (Jul 5, 2007)

I like the look too, very unique. I would forget about Gorilla Glue. The wood is likely experiencing a shrinking due to drying out. If the wood wants to come apart...glue won't stop it. 

You might allow the wood to dry longer before doing the glue up. Try one top that isn't screwed to the plywood and see what happens.













 







.


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## Streamwinner (Nov 25, 2008)

malawlo said:


> Basically, I cut the planks down to 1 1/4" thick, then glue/screw them to the plywood in a 'patchwork' fashion -- when it's done, the top is 2" thick.


Just double checking, because you've said you've glued them, but did you glue them to _each other_ along the edges? (Not just glued them to the plywood.) 

Fastening them to the plywood is likely the culprit, as plywood isn't going to move, thus holding the planks in place while they grow and shrink from each other. I made a table top out of nine rows of left-over hardwood floor planks, but no gapping because they grow and shrink _with _each other.

Beautiful table, BTW. Reclaimed wood in project = A+


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## malawlo (Sep 4, 2011)

Streamwinner said:


> Just double checking, because you've said you've glued them, but did you glue them to _each other_ along the edges? (Not just glued them to the plywood.)
> 
> Fastening them to the plywood is likely the culprit, as plywood isn't going to move, thus holding the planks in place while they grow and shrink from each other. I made a table top out of nine rows of left-over hardwood floor planks, but no gapping because they grow and shrink _with _each other.
> 
> Beautiful table, BTW. Reclaimed wood in project = A+


Stream.....

I took a bunch of scrap off the streets and since I didn't know what I was doing, just decided to cut them down and mount them to plywood. I glue them together at the edges AND glue them to the ply at the same time, thought that was gonna be pretty solid. Having no idea what I was doing..... trouble.

Actually, they're nice and solid for the most part, they just seem to be splitting at the seams here and there. Problem is, I've started making them more and more (people really liked them, then more people asked me to make them -- next thing you know, I was making a bunch) and I really need to get it figured out asap. Either that, or I need to just throw in the towel and leave the table-making to the professionals.....

So I dunno..... guess I should give it a shot with no plywood, eh.....? Will that stop the gaps from opening up....? Just trying to wrap my head around the physics of it.....

Thanks for the help, if you've got some more advice..... it'd be much appreciated.


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## Big Dave (Sep 16, 2006)

I thought about it a little more and if you drill your hole through the plywood quite a bit bigger than the screw your using you could then use a washer on your screw and just snug them up. That way if the wood wants to move the screw will slide in the bigger hole but the washer holds it snug to the plywood.


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## Jim Tank (Apr 28, 2009)

Different species of wood expand and contract at different rates, pine will move more than oak, so that will cause the weakest point to split, however; the glue joint should hold and the wood should split at the weak grain. The properly glued up joint is stronger than the wood. If you can glue up like speices in the same row, then that row will move at the same rate, and the adjacent rows will do the same. You might try gluing up a blank without the plywood, letting it sit a few days, measuring it for expansion or contracting each day, then secure it to the plywood for stability using screws through oversized holes, and dobs of silicone that will move with the wood, but still hold. I agree that a poly urethane glue would not be as good as a wood glue like Titebond or any yellow glue, it actually will adhere to wood poresthat are not completly dried. The other thing to try is get an inexpensive moisture meter off Ebay and glue up boards only when they are at similar moisture contents. The other thing I would definitly do is to lower customer expectations by showing a top that has cracked, explaining that part of rustic character is that different woods move at different rates, so some cracking is possible, but your tables come with a filler kit that is easily applied by the customer, or you will do the application on site for a small charge. Good luck, I think you have a full product line potential there.


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## woodnthings (Jan 24, 2009)

*+ 1 as others suggested*

1. lower the humidity in the shop
2. skip the plywood altogether
3. just edge joint the boards, either on a jointer, router or table saw and glue them using Titebond 2 
4. bring them into a AC room in your home and see what happens.
5. maybe store some of the boards that you have cut up, but not glued in the house, before gluing them together in the shop.

Great looking table BTW! :thumbsup: bill

You can always explain the your tables "aren't all they are cracked up to be" .....


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## Streamwinner (Nov 25, 2008)

Yeah, I agree with what everyone has said. I don't think it's necessary to fasten them to plywood at all. If you're really concerned about the strength at the butt joints and don't want to do biscuits, you could use the plywood as a substrate and either 1.) don't fasten the planks down, or 2.) do one row of screws _only down the center_ *lengthwise*. (Sorry, I know how frustrating it is when you get so many different suggestions, and I'm offering another one.) The wood will expand and contract most width-wise. Thus, if you put a row of screws down the center only, the top will expand and contract from the sides. Does that makes sense?

I'd also suggest elongating or oversizing the holes for the bolts at the ends. Your design is really sustainable, so with some tweaking of your technique you should be able to successfully pull this off. Titebond should hold fine. Use a moderate amount of glue and only apply enough clamping pressure to get a bead of glue coming out from the top (too much pressure and you'll get a "starved" joint). If the boards are 1.5" thick, you have plenty of gluing surface (jointing them is recommended).


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## Chaincarver Steve (Jul 30, 2011)

I like the varied colors of the tops. Very pretty.

You do need to make sure you are getting as much edge contact as possible to ensure the best possible gluing surfaces. That means jointing the edges of all of the boards and making sure that each row is of even width where the end grains meet. Not that I see any gaps in your picture but gaps will certainly weaken your joint drastically.

You may want to consider an AC in your work area. Or, like you said, a dehumidifier.

I also think you may want to glue up all the boards and flatten the surfaces BEFORE attaching to any substrate or support piece.


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## Warnock (Apr 4, 2011)

Can't offer a lot of aid, but the tables look great.

Don't give up - this is a fine place to ask questions and get honest answers. I know I have learned a lot here.

Again - don't quit and the tables look great.


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## Midlandbob (Sep 5, 2011)

I'm new to this forum so if this ends up somewhere inappropriate that's life.
Wood movement is a fact of woodworking and a lot of design issues need to account for it. 

It can not be avoided with humidity control, finish or type of glue. Eventually the humidity will change and the wood will change dimension then later change back. In centrally heated buildings the wood will move from season to season over the years.
Different woods have different changes and the wood usually changes twice as much tangentially as radially(hence warping).
Softwoods move generally less than hardwoods. 
The topic is a bit much for a brief reply. One of the best books on the topic is Bruce Hoadley's. Understanding Wood. 
The advice to fix the boards in the center and allow the sides to move in and out by the oval bolt holes is the best of the tips.
The plywood is only useful if the boards are not strong enough for the load. The top should "float" on the support.
A 18 inch wide board whether it's one piece or glued up will move as much as 1/4 inch or more from winter to summer in most places with seasonal variation in weather. If fixed by glue and fasteners something will give.
Good luck and if you do plan to do much woodwork, get the book. It has a lot of useful or necessary technology.
Bob


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## AndrewJayden (Mar 26, 2011)

Hey Cabinetman! I like very much your post. It’s really beautiful and unique. And you say right that if the wood wants to come apart glue won't stop it.


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## top (Mar 24, 2008)

try to elongating the screw holds it may work.by the way are you screwing each board try not to do each board.

SHOP OF TOP 

TOPPER


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