Wood shrinkage

[Resolutionuk]

Hello forum members, my first post/question, so be gentle. I'm new to woodworking world but learning quickly.

I have made my first dining table from reclaimed timber, HT pallets mainly with a chevron design and I'm very pleased with the results. Very strong, sanded and finish beautifully, although worked to keep the rustic feel on the reclaimed wood. Wood had been stored in my workshop, before and during construction.

The table once finished was moved to its new home, a property which has underfloor heating and has a fairly high average temperature of approx 25 degrees. After 36-48hrs it's very clear the wood has shrunk with the change of moisture within it. The chevron design on the top side has not been glued together, just screwed from underneath so the gaps between each length of wood have opened 2-4mm throughout. I'm aware the moisture change in the wood would result in this regardless, but would gluing prevent or minimise this effect or what else can I do to minimise this on my next furniture project?

What are the ideal conditions for storing wood?

Any advise appreciated

 

[Racers]

It needs to be stored in the location where it is going to end up, or in a similar level of humidity.
I move my wood indoors at least a fortnight before using it and return it indoors over night.
Luckily I have an understanding wife who puts up with a hall full of wood.

You could glue strips of darker timber in the gaps if they are too large.

Pete

 

[ED65]

...would gluing prevent or minimise this effect or what else can I do to minimise this on my next furniture project?

No you can't halt movement with glue, the shrinking wood will just break the glue lines or itself split as needed to relieve stress that has built up.

Doing chevrons stably is tricky, I think ideally you want to use very well seasoned quartersawn wood, or do the effect using veneers over a ply/chipboard/MDF panel.

What are the ideal conditions for storing wood?

There are many suitable conditions under which wood can be stored at different stages, but for making furniture what you want ideally is to have workshop conditions as close as possible to the conditions to be found at the location the finished piece will be placed are the ideal. That way the wood will be at the right equilibrium, rather than having to come to a new equilibrium (often drier) once it's moved into the house.

This won't avoid all problems, since wood naturally expands and contracts through the year unless your house is very very stable which most aren't. What's needed is to build in ways that wood movement is fully accounted for in the design of the piece; most conventional designs take it into account, many cheap or free plans found on the Internet do not.

 

[transatlantic]

Ideally, the wood would be left for a while in an enviroment that is similar to the enviroment it's going to be placed into once complete, but this is often not possible.

You want stable wood, this means a species that is known to be stable to begin with, as well as being suitably dried out and sawn in a particular fashion as to orient the grain in a direction to minimise wood movement, again, not always possible.

The wood is going to move whatever you do, it's just how much, and is it going to be an issue? Ideally, you want to design your furniture in such a way that it is flexable enough to cope with any movement, without bringing it to attention.

In your case, was the pallet wood dry? .. to be honest, this is hard to judge without a meter, as what can fell dry isn't always the case.
Secondly, thats a pretty warm enviroment, and I'd be interested to know what others would do in that situation.

It's a tricky aspect of woodworking and you really have to be thinking about it from the initial design, not an after thought, and something I'm still learning myself, so I'll let other more experienced members give their thoughts.

 

[thetyreman]

it was probably not ready to be worked, wood needs to be seasoned properly before using it. In this case it might have been a good idea to put the wood into the room first with the heating, let it shrink, and then assemble it, 2-4mm isn't that bad, it could always be worse.

It's probably the design of the table as well, you see if you had a solid top, you can create turnbuttons which are designed especially for expansion and contraction that you never see underneath the table. And yes gluing it together, laminating the long pieces is a good idea if you didn't do that.

 

[Resolutionuk]

Outstanding response time on this topic. Thank you for your quick responses folks. Much appreciated.

A fortnight was quoted for the wood to be placed in the environment it will end up. Is this a safe time frame, or can it be less than this? I'm guessing if the temperature of my workshop could be maintained between 18-21 degrees (as well as being aware of the humidity), this would also help. (I don't think my wife would be as understanding if I start bringing my wood stock in :shock: )

I foresee this being a big issue with the different variety of wood joints etc.

 

[ColeyS1]

Must say i really like the table ! Perhaps a glass top might be an option ?

Coley

 

[Resolutionuk]

Must say i really like the table ! Perhaps a glass top might be an option ?

Coley

Really appreciate that, I never expected a compliment on my first major project from experienced woodworkers.

Main visible issue with the shrinkage, is that the varnish has stretched in the gaps making it look untidy. I don't really mind the gaps being there as it adds to the character. Maybe varnishing after the shrinkage has happened may be an option if I don't get a chance to climatise the wood before construction. Suppose all depends on the project and the desired finish.

 

[Phil Pascoe]

If the pallet were salvaged from outdoors, I wouldn't use the wood until it had been indoors for at least a month, and probably longer, and at 25c probably a couple of months to have a realistic chance of stability (and being wood from a pallet I wouldn't put much money on it then). At 25c I think I would shrink by more than that.

 

[paulrockliffe]

You could fill the gaps with resin to tidy it up. But I'd leave it a while to let the wood properly dry first.

 

[Sheffield Tony]

It is a nice looking table. Probably part of its interest is that it is an unusual design. But there's a reason it is unusual !

Ideally, you want to design your furniture in such a way that it is flexable enough to cope with any movement, without bringing it to attention.

IMHO, designing and building stable pieces from a material that will always be on the move is the essence of woodwork. It's what distinguishes working with wood from other materials. The traditional designs are worth studying, because they rely upon the grain directions along which the wood is fairly stable, whilst allowing for movement across the grain which is much larger. The trick is to take on board those ideas but without losing the creativity and making rather boring furniture (as I usually do).

 

[ColeyS1]

Might sound obvious,but did the underside get the same number of coats of varnish as the top ? Are you planning on making alot of these tables or is it a one off for yourself ?

Coley

 

[Resolutionuk]

Might sound obvious,but did the underside get the same number of coats of varnish as the top ? Are you planning on making alot of these tables or is it a one off for yourself ?

Coley

Now this is a debate I had with myself, and I read mixed information on this online. The conclusion I came to was to not varnish the underside at all. From my experience looking at pieces of furniture the underside or non visible areas are never finished to the same smooth varnished or waxed effect top or outer surfaces which made me google if I needed to. The conclusion I read up on from serverl sources lead me to believe, that regardless to being varnished, the same amount of moisture and shrinkage would come from the wood.

If I can make anything I can sell that would be a bonus. This example went to a relative. But I've had a request for a six seater version.

 

[Ttrees]

It is a nice looking table. Probably part of its interest is that it is an unusual design. But there's a reason it is unusual !

Ideally, you want to design your furniture in such a way that it is flexable enough to cope with any movement, without bringing it to attention.

IMHO, designing and building stable pieces from a material that will always be on the move is the essence of woodwork. It's what distinguishes working with wood from other materials. The traditional designs are worth studying, because they rely upon the grain directions along which the wood is fairly stable, whilst allowing for movement across the grain which is much larger. The trick is to take on board those ideas but without losing the creativity and making rather boring furniture (as I usually do).

Well written Tony
Agreed, the design might certainly prove a real headache if your going to a commission based on it ...
Looks like their could be manys a tableworth in your future
Good luck

 

[ColeyS1]

I don't think it'd need to be as smooth as the top but I'd definitely think it would benefit from a lick of something. What you're trying to do is get it as dry as the environment it might go into. When it's at this point, I'd have thought to keep the wood stable you'd want to completely encapsulate it. - this would mean varnishing the board all the way around ( including the edges) so that moisture changes don't cause the wood to move as much.
If you're going for an oiled finish then what I've just said isn't as relevant as the wood can still breathe.
My advice would be thoroughly dry it then seal it as much as possible, or alter the design....

Coley

 

[custard]

You can make a chevron design out of solid wood by having the chevron pattern as panels that float within a solid wood frame.

To do a table of that size you'd probably need a a frame with four panels, so you could do a "diamond" type chevron design, or an "X" shape, or the "arrow" style chevron that you used in your table. You make the grooves in the rails and stiles fairly close to the top edge, so that the chevron panels are flush with the surface of the rails and stiles.

Good luck!