Conditioning hardwood before use

[Dave S]

Is there a rule of thumb for conditioning hardwood? In other words, if I were to buy 25mm air dried boards and store them in the house (centrally heated), how long would it be before they would be safe to use?

Most of what I've found by googling talks of using moisure meters - these aren't a necessity, are they?

Finally, any recommendations for a book (or website, for that matter) which covers this topic?

cheers
Dave

[opener]

Hi Dave

I don't know any rule of thumb but I do know that Alan Peters used to cut up the timber (air-dried) for future jobs and stack it between stickers in the upstairs area of his heated workshop for several months to effectively kiln dry it. Without a moisture meter the longer you can leave it the better.

I trust someone else will come along and be more helpful.

Cheers
Malcolm

[engineerone]

i think the other piece of useful advice is to cut the pieces slightly oversize for the specific project, ie 10 % over length and width
and depth, if you are buying wood to be machined this is will allow it to move and show you the weaknesses.

the problem for the amateur is being brave enough to take this step as well as trying to ensure that where possible the bits match.

for instance it is often mentioned that you should keep a grain pattern going round say the apron of a table, but the benefit of cutting is that the overall movement is reduced. the grain will of course not match totally, but will seem to flow.

this is also often used with drawes that slide into the apron of a desk, cutting the whole out of one piece makes it easier to match.

you have to consider where the piece is going to live, and also what season you are buying the wood in. now for instance you need to try and keep the wood in the centre of the wood so that all around it gets acclimatised to the ambient temperature and moisture. during the summer the conditions are of course different but in general i have been told about 3 months is a good time to leave it in stick, if it is par.

hope that also helps

paul

[dom]

Rule of thumb is a year per inch thickness, but indoors this would probably be less and suggest regular checks with a good meter should be made.
Drying air dried more quickly is not always a good idea it will be prone to cupping, warping etc.

[nickw]

If you have access to accurate scales then you can stack'n'sticker your timber in the conditions in which t will eventuallly be deployed. Weigh one of your pieces (or an offcut) at weekly intervals until it no longer changes in weight (caveat seasonal changes, but in modern central heating conditions that should be relatively minor). It will then have reached equilibrium and is fit for use.

Alternatively, cheapy moisture meters can be had that should be good enough for the job.

[Dave S]

Hmm - sounds like a slower process than I had hoped I'd come across the 1 year per inch guide before but was hoping the last bit indoors might be a bit quicker than that. But no point in rushing the process and ruining the timber.

Most of the furniture I've built so far has been from softwood or sheet material. My goal this year is to make my first piece from hardwood, and to try to push my abilities in the process. Sounds like I should look for kiln dried or I'll be waiting until next year to start!

As to moisture meters, the ones I had seen in the past were quite a lot of money so I had dismissed them as beyond my means. Hence my asking about a rule of thumb. Just had a quick look around and found this one. Would this 'cheapy' be good enough for the job?

cheers
Dave

[engineerone]

dave don't be too down hearted, it is not as difficult as you imagine.

i think the axminster one will do whilst you are starting out,
the important thing is to consider it as a guide to what you are
doing, not the ultimate answer.

as an amateur, you need to consider all your needs, and the important thing is how long do you think it will take you to make a piece after you have bought the wood?? sounds silly, but what are you designing and what wood effect are you looking for in the finished product. if to start with, you are not too worried about really flamboyant wood, then you can look buy it from the woodyard, after they have told you how they condition it,
then keep it for 3 months or so in your workshop, then see about it after that.

so far much of the stuff i have finally used so far i have had about 12-18 months, and so far have been lucky, but then have only used oak and cherry, plus some cedar. most of it was either waney,(the cherry) or rough cut, (the oak) and so far it is pretty stable and does what i want. a lot i think depends on the
sizes of the pieces you are making.

however there is another thing to consider for a really large flat surface there is still much to be said for using veneered mdf, which is then surrounded by the hard wood.

paul

[nickw]

That cheapy one will do. Don't rely on it giving you an absolutely correct result, but if the answers don't change over a period of time you will know that the timber has reached equilibrium with its surroundings, and that is the important thing.

[Dave S]

nickw said:

That cheapy one will do. Don't rely on it giving you an absolutely correct result, but if the answers don't change over a period of time you will know that the timber has reached equilibrium with its surroundings, and that is the important thing.

Good point, Nick, and one which seemed to be lost on some of the sites I visited.
I think I'll have a look at Ally Pally, and if I don't see anything there I'll purchase the Axminster one.

cheers
Dave

[Dave S]

Paul,
not really down hearted - just rethinking a little.

I have North Heigham Sawmills near to me, and have quite a lot of kiln dried timber. Time to go and investigate, I think.

cheers
Dave

[9fingers]

Has anyone got one of these moisture meters?

tinyurl.com/2jvxjc

As nick has said there is little need for accuracy just repeatability for basic use.

TIA

Bob

[Dave S]

9finger said:

Has anyone got one of these moisture meters?

tinyurl.com/2jvxjc

As nick has said there is little need for accuracy just repeatability for basic use.

TIA

Bob

Funny, I saw that one as well. Love the 'Chinglish' :
'This moisture meter is a delicate device, easy to use,

which used to measure the containing water of wood.' ;D

Dave

[9fingers]

daves said:

9finger said:

Has anyone got one of these moisture meters?

tinyurl.com/2jvxjc

As nick has said there is little need for accuracy just repeatability for basic use.

TIA

Bob

Funny, I saw that one as well. Love the 'Chinglish' :
'This moisture meter is a delicate device, easy to use,

which used to measure the containing water of wood.' ;D

Dave

Well I decided to buy one after a google search showed many vendors selling these under their own names so I figured they shouldn't be complete junk and worth a punt for £10.99 delivered from Hong Kong.

It seems pretty consistent with consecuitve measurements in the same piece of wood reading within 1% variation.

Most timber lying around the workshop reads between 15 and 16%

Some oak that was stacked outside and brought into the shop before Christmas read 15% too whereas some of the same oak brought inside 2 weeks ago is currently at 19-20%

Some second hand Iroko sealed with varnish for years read 5-6%
and some beech from the same source, also sealed read 2-3%

I have nothing to calibrate the meter against but it seems to be repeatable and can differentiate between wood that has been indoors for sometime and wood that is still drying out.

On that basis I reckon it is not a bad buy.

I assume it works by measuring electrical resistance between the probes. Interestingly some MDF - unsealed - measured 0%. I guess this is more to do with the structure of mdf and the amount of insulating resin it contains rather than it holding no moisture.

Plenty more of these on ebay being sold by 'service369'

and it comes in a zip up protective case too!

HTH

Bob

[Dave S]

Bob, thanks for that review. It sounds like it is repeatable enough for basic use - as you and Nick pointed out, that is more important than the absolute measurement at this level.

At that price I think I might get one too.

cheers

Dave