Doug fir bench top checking while drying

[sjalloq]

Hi there,

I'm looking for some advice here as I'm new to woodworking and I guess the area I'm most lacking in is understanding how wood behaves whilst it dries.

I've recently bought a couple of thick boards of Douglas Fir to use in a bench build. The main board I have for the top is a length of 12"x4" that I've cut in two 8' pieces. The wood came from a local merchant who said it was kiln dried (but it probably sat in the warehouse for a long time) and after getting it home, the only processing I've done is to cut it in half so that I could fit it in the house. It's currently sat in my lounge and I was planning on leaving it there for a few months until it is fully dry and ready to work.

However, both ends of all boards I have have started to check. The attached photo is one end of one of the thicker boards and the crack that makes it to the edge is 17" long on the surface. What I want to know is:

- how bad is this given all I'm going to do is flatten the boards and stick them on a bench?
- is this due to the wood drying too quickly in my centrally heated house?
- could I have avoided it by drying it first in the garage which doesn't have central heating?
- where do I go now? Do I just use the boards as is or should I try something to stabilise the wood?

Thanks, Shareef.

 

[custard]

If the bench is going to live in your house then store the timber in your house, if it's going to live in your garage then store the timber in your garage.

You're in luck...you're building a workbench, not a fine family heirloom, so a few checks matters not one jot. If they look like they may threaten the structural integrity of the bench then dribble some runny epoxy into the splits.

 

[Bluekingfisher]

If the timber has been kiln dried it it may be suffering from case hardening caused by too brief a stay in the kiln (dry exterior, wet interior). When you cut it in half the exposed and probably still wet interior of the board is exposed.

As custard mentioned, keeping it in a warm centrally heated house may not have done it any favours.

David

 

[sjalloq]

So I'm still not clear from those two answers what I should have done.

I understand that you should keep the wood where it will eventually be used to acclimatise to the environment. So the bench is going to be in a centrally heated room in my house so I've done what is normally recommended.

Given that it has split, would I have been better off trying to leave it in the garage for a month before bringing it inside for another month? I'm assuming here that the humidity in my garage is lower than that of the warehouse it has been sitting so that it would dry more slowly in my garage and there would be less probability of it spliting when brought into the house.

Does that make sense?

 

[Bluekingfisher]

That may have helped a little, however, as the timber is notconsidered a premium wood it would have most probably seen a quick inside of the kiln to prevent major distortion prior to being delivered to the timber supplier.

After all it is mainly a construction grade material so why bother spending time and money drying it out fully. If it is case hardened then drying further could prove difficult.

leave it in the garage for a couple of weeks to let it settle but you will have to expect some further warpage as it dries further

Hope this helps.

David

 

[custard]

As Bluekingfisher said, there's kilning...and then there's kilning.

I doubt a joinery construction timber like Douglas Fir will have been cherished, and even if it did there's every chance it was subsequently stored outside in the rain. It would have been better to stick it in your garage for a few weeks before bringing it indoors, but no harm done, you'll still get a smashing bench out of that timber.

Good luck!

 

[sjalloq]

Yep, understood, thanks all. I hadn't thought about it in terms of the "premium-ness" of the wood but it makes sense that they would try to keep the costs down by kilning it less.

I'll see how it behaves in a month or so.

 

[Aden30mm]

I disagree, I have bought Douglas Fir planks straight out of the sawmill, placed in it stick, and when dry used if for furniture & general construction. I even made up some units for a house in Spain where it has not moved and still looks good some 4 years later. It take a finish well, cuts nicely, and is stable when dry. I do prefer to by timber that has not been kiln dried, but dry by placing in stick outside, then at times using a dehumidifier, and as other commentators have suggested placing the timber in the environment where it will finally rest as a finished piece.

In comparison with timber bought in builders merchants I think its a far superior to much of the softwood they trade out.

 

[RobinBHM]

For a really stable bench I would cut each board into 3 and then orientate then end grain so it is vertical. That way future cupping caused by tangential shrinkage will be minimized as the top would effectively be quarter sawn.

The checking you arr getting is caused by the tension building up as the boards shrink in a tangential direction.

Dug fir is a good quality timber, similar in price to hardwood such as ash or sapele. It is ideal for joinery such as windows or doors. I find it suffers from large resin pockets which tends to run diagonally and therefore appear on the face and edge of a board.

 

[sjalloq]

Thanks Robin but I specifically bought these boards so that I wouldn't have to spend time laminating. I'll try it as is for now and see how badly it cups over time. I'm doing a split top Roubo so if the cupping gets too bad so that I can't flatten it easily then I can always disassemble the top and laminate it.

Thanks again.

 

[AndyT]

Richard Jones - who posts on here as Sgian Dubh - has a really helpful article on his website which may help you understand what is happening to your timber. He also describes a simple test method, using a sample cut from near an end.
Well worth a look.

http://www.richardjonesfurniture.com/Articles/timber-dry-fault/timber-dry-fault.html