Moisture Content suitable for working hardwoods

[Davidadew]

Having read various books, including Alan Peters, I'm wondering what other people think about the best moisture content for working hardwoods.

I'm working in oak, ash, beech, cherry, walnut etc. and I buy kiln dried then put in not so warm garage so obviously MC goes up, so I cut to over sized then bring into house to dry before working it, and store inside overnight etc.

I'm waiting until down to less than 10% MC at the moment before working it - and ensuring it has been indoors for at least a week.

I only make smaller items (boxes, stands etc.) so no large expanses of wood, but is what I am doing OK and will prevent warping later on in life?

 

[jimi43]

I am watching this thread with interest as I have often thought that air dried wood cut from local stock was something I needed to get into....

I have some billets drying slowly under cover from an old cherry tree which my neighbour cut down and the moisture content is currently at about 26% so interesting to see a) how long before it is useable and b) what the final mc needs to be....

Jim

 

[woodbloke]

Percieved wisdom is that timber ought to be at around 10% or lower MC when used in a centrally heated home. Air dried timber will generally take a year per inch of thickness and will eventually settle at around 20%MC, depending on how well it's been dried (under cover, well stickered and out of direct sun)
If your timber is at say 20%, then bringing it into the house for a week isn't going to achieve much...a far greater time frame would be needed. If it's already at 10% and at approx the right dimensions, then a short spell indoors won't do any harm.
I usually use air dried if I can get it, and dry it for a couple of months in the 'shop (insulated and heated) I then machine it to approx dimensions and leave it for another month or six weeks, after which it's brought down to final sizes. I do a lot of stuff in Elm which I really like but the stuff will warp and twist at the drop of the proverbial :evil: so I like to be cautious rather than jump staight in - Rob

 

[Alf]

fwiw, referring to the notes from a friend of mine who used to teach this stuff for a living, he said:

22-15% - Usual limit for thoroughly air-dried timber. Very unlikely to be 15% unless in a long, dry summer.
20% - Dry rot safety line
16% - Outdoor furniture
15% - Joiner's work in new buildings, church work.
12 - 14% - Bedroom furniture with only occasional heating
11 - 13% - Living room furniture with normal heating, including reasonable central heating.
9 - 11% - Flats/offices with continuous high degree central heating.
8% - Radiator shelves, etc.

Mind you, that would have been the 80s at the latest, and our ideas of heating may have altered somewhat.

 

[devonwoody]

I have been making boxes and some furniture as a hobby for 7 years now and can honestly say I have not had any warping or distortion of any item in my home since starting.

I am very lax regarding moisture control, the first couple of years I even stored some boards on the floor below the bed, but dont now.

Unless you are working in very extreme damp conditions I wouldnt be too concerned.

 

[Davidadew]

Thanks for all your replies.

The kiln dried I bought and have stored for some months in unheated workshop in UK has only got up to about 10% - 13% MC which is fortunate - so when bringing it in doors am not having to do too much too it. As all items I make require small parts and as the surface area to volume ratio is high, they aren't taking too long to dry thankfully (few weeks - correction from initial posting) - but think I'm going to leave them in longer so they season properly as I have had some pieces both bend and crack (at the ends).

I also have acquired a walnut tree from down the road - it was very wet has had been stored outside, uncovered, in rain. Slowly am cutting it up - but it is only taking a few months for quartered sections (none of which were too big) to go down to 20% or so now I've cut into working pieces hopefully will take a month or so to go down to 10%.

I have a database on my computer now where I store when wood is cut, and layed out for drying etc. so it helps me to manage things better.

We have done quite a lot of work on workshop though to make it more water tight - it wasn't at start - when it rained, water came it floods under door, so built new doors for it, and new windows for similar reason. Now the roof needs replacing... think a job for someone else this time though.