Managing wood movement in thin solid pine furniture

[Giovanni Rinaldi]

Dear all,

I'm planning to renew my office's furniture, moving from particleboard to solid wood.

The reasons for this switch are many, but the most relevant is that plywood (my material of choice) got quite expensive here, and I can get solid fir (I live in Italy, it probably is subalpine fir) for less than half the price of melamine PB, which in turn costs half the price of plywood. Sure, it will likely be that kind of wood you use for roofing, but for that price I may want to gamble (meaning I won't be able to use some planks). Of course I may be using other materials for something like the back of a cabinet etc...

Now, having only used PB, MDF, plywood and different grades of fir I think I know what I'll be missing, but I really feel the urge to go for fir, accepting the fact that I will definitely have to deal with wood expansion, shrinkage, cupping, twisting, bowing and all sorts of pain that this wonderful material has to give.

So far I have considered a few things I could do to avoid disasters, which are:

- Never joining two pieces of wood with their grains crossing each other

- Limiting the amount of metal fasteners which may damage the wood during its movement

- Always giving some more room to the wood joints so they can accommodate any movement.

- Using a solvent based finish so that the wood does not absorb too much water.


I am pretty sure there is more that I can do, so it would be nice to know more if you'd like to share but so far my biggest obstacle is the wood's thickness... 3/4", which in fir's language means warpfest, one solution would be going for a bigger thickness, but I have found that I can get 3/8" planks and glue them together, making it 9/8" "plywood"... Well... Sort of...

Would that be a good idea? Would it reduce warping and dimensional movement just as real plywood does? (I've never got any, even with cheap 5 layers ply with allsorts of cracks and voids in the core)

Would 3 layers be enough to give me any meaningful advantage?

Many thanks in advance, if anything just for getting to this point!

[Wayne Lomman]

Giovanni, I have made furniture out of fir from Europe by recycling packing crates from imported steel and heavy machinery. I have some in storage at the moment. What I have found is that you need to let the timber dry for a while. This is because framing and packing material is not usually dried to furniture standards. I would purchase your timber now and get it into your shop as soon as possible. I would also saw it to your rough sizes and stack it with spacers between layers. Being fir it will dry pretty quick.

If you get your timber stable, you are much less likely to get cupping etc and therefore wouldn't need to layer up panels. Laying up the panels is a good idea, just thinking about saving work. Sorry, just realised you can get 3/8 planks. If do, laminating them is a good way to go. Looking at the end grain, make sure you alternate the curve of the growth rings on adjacent pieces.

Finishing with a water-borne coating should not be a problem if you coat both sides. Cheers

[Giovanni Rinaldi]

Thank you! Thank you! Thank you!

I hope I won't need a planer... I've only got a hand one.

And yes, I can either get 3/4" or ply 3/8" planks.

[Wayne Lomman]

If you don't have a planer, spend time in the timber supplier store(if they will let you) and select good straight timber. Some loose knots etc won't matter as they can go in inner layers but straight is important. Then when you get back to your workshop and stack it, strap it moderately firmly into a bundle so that each plank stays straight as it dries.

European fir is nice to work with. At least good enough for Stradivarius. Cheers