Air Dried or Kiln Dried - utterly confused!

[JonnyW]

I am so so so sorry to drag up a much discussed topic, however after searching and reading, and searching and reading on this forum. I hate to admit it, but I'm still none the wiser.

Now this is just probably me being my usual stupid self, so I apologise.

I am still trying to work out if it would be worth me investing in a small kiln - to be installed in my new garage extension. Sorry I call it my garage, but it's not had a car in it for years and never will.

I'm a DIYer (served my time as a joiner years ago, but have been sitting on my fat behind in an office, longer than I was on site), but have dreams of trying furniture making - as a hobby etc.

Now I've worked in many houses on finishings and have seen a lot of hard work bend, twist, shake, split, mitres open - the list goes on. And that's not just my joinery, I've seen it in many houses. I've lost count how many tall OG skirtings that have been nailed in lovely, then a month later after the central heating has done its work, the skirting boards are bowed/scooped off the wall, and now look like they've been installed by a 6 year old child. It's becoming an obsession of mine, on how you season wood or acclimatise wood before you stick it in the house -I've had varying successes.

Anyway to cut a long story short; should I venture into the world of furniture making, I'm going to have to get the seasoning of wood issue sorted.

I live on a small island off the north coast of Scotland, where in the summer we regularly see relative humidity levels in the high 80%. I think this summer, it fell to its lowest at 67% humidity. This obviously rises during the winter months.

I've not bough a moisture meter (I intend on getting one soon), so I've not checked the humidity levels in my garage (approx. 58 square metres), but I wouldn't think my unheated garage would be any different to the ambient humidity levels outside. So my limited understanding of lowering the moisture content of wood (to an acceptable level to work on and bring into a heated house) would lead me to believe that air drying in Shetland (my home island), is completely pointless.

So am I right in saying, that for me, the best option would be to build a kiln in my garage/workshop?

Sorry for my ramblings.

Thank you for your input and help.

Confused.com

Jonny

 

[custard]

Hello Jonny, I make furniture commercially and I even own a few acres of woodland, but I've never felt the need for a kiln. Then again I've plenty of timber yards close by who are far more expert on the complex technical challenges of kilning than I'll ever be.

Couple of points to consider.

You'll hear lots of people talk about the virtues of air dried timber, I think that's a bit romantic, I've known logs that were part kilned (the thicker boards) and part air dried, and working them both was really very, very similar. I'm not saying there's no difference, but for all practical purposes it's fairly small. I suspect some woodworkers might be swayed by the experience of working partially air dried, but still fairly wet wood; that indeed does work like a dream, but to use it in that state is just storing up a heap of problems down the road.

For many projects you'll need a combination of different thickness boards. The thicker the board the harder it is to get it dry and the more complicated the kilning process. Once you get over about 50-60mm thick I'm sceptical that you can ever air dry in this country to useable interior furniture standards, no matter how long it's stored in stick.

You can spend a life time learning how to kiln, and some people never get there! I regularly see examples of poor kilning. Take oak for example, look closely and you'll often see yellow patches or streaks, alternatively you'll find paler blotches on the wood. Both of these are common kilning faults. Then there's honeycombing and checking, again unfortunately very common. You could argue doing it yourself will safeguard against these faults, equally you could say if the professionals get it wrong so often then what chance the layman with only rudimentary facilities?

If you're selling furniture, especially more complicated pieces with moving parts (doors, drawers, etc) veneering onto man made sheet materials becomes very attractive. And if you saw cut your own veneers and use exactly the same boards for lippings, legs, etc then there's a lot to be said for it. If you're making furniture for yourself then no problems, you're always on site to fix any problems!

Good luck.

 

[JonnyW]

Custard, thank you very much for the reply. I see your location is the southeast; can I ask you what the climate is like where you live? it must have an effect on what you do with your wood when you harvest it.

This has always been such a source of confusion. You are right, my furniture making will be for family members only and won't be for sale (at the moment, I would probably need to pay someone to take a piece of my furniture).

We have a CO2/moisture metre here in my office (folk complaining about lack of ventilation - long boring story). Anyway, the humidity levels inside today are reading 44%. That's in a lovely dry office. Outside today it's 82% (MET office).

If I was working out of my garage, then the moisture content of the piece of furniture would obviously be much much higher than inside our office. So, I would've thought that when the piece is moved into a house, the movement associated with drying would be catastrophic or pretty ugly at best.

I didn't realise kiln drying was so difficult to master - showing my complete ignorance of the processes.

So maybe for me it should be suck it and see. I'll try a test piece of furniture made with wood that has sat and air dryed in my garage for a few months, and take it into the house and watch what happens.

Thanks again for your reply.

Jonny

 

[Phil Pascoe]

I'll try a test piece of furniture made with wood that has sat and air dryed in my garage for a few months, and take it into the house and watch what happens.

No. Take the wood into the house for a few months before you make the furniture. Much better chance of success.

 

[JonnyW]

I have done that Phil when I've been doing work in the house; I've stuck things like skirtings and facings in the house to acclimatise before I've installed them. Certainly helps.

I just can't see 'she who must be obeyed' living with lengths of wood inside the house, when I have a 'bloody huge man-cave in her lovely garden' as it is - her words not mine.

Although it's not a bloody huge man-cave when there is things being done inside it for the inside and outside of her house. (that's another discussion).

Jonny

 

[Phil Pascoe]

If I had the chance to choose, I always got skirtings etc. with the heart facing outwards so when they were fixed through the middle they pulled against the fixing rather than cupped away from the wall.

 

[JonnyW]

I agree Phil. Most of the skirtings I've installed have been bought pre-machined with the round or the OG pre moulded. I did run my skirtings for my own house myself, and did exactly what you've just said. I also ran a couple of horrendously big rebates at the back of the skirting to lessen the thickness of the stock to help keep it pulled in tight.

I've never understood why they don't check the crown/heart pre-maching, to at least give the buyer of the skirtings some chance of keeping it on the wall. I've also seen skirtings with the rebates at the back of the boards, and they've still cupped away from the walls.

I could go on!

Jonny

 

[custard]

I see your location is the southeast; can I ask you what the climate is like where you live?

Anyway, the humidity levels inside today are reading 44%. That's in a lovely dry office. Outside today it's 82% (MET office).

The climate, from a wood processing point of view, probably isn't that different between us. We both live in a maritime climate dominated by Atlantic weather. I check the humidity in my (centrally heated) house and in my (heated and dehumidified) workshop, both bounce around but are almost always in the range 40-60%. What we don't get are the killer continental climate of central Europe or large parts of the US, where hot and humid summers alternate with bone dry freezing winters. In other words, we're not that badly placed for making furniture! I wonder if your bad experiences in the past are due to getting poorly stored timber? It happens more than it should, interior graded softwood that's actually been rushed through the kilning process then stored outside in the rain.

Regarding conditioning furniture indoors. Even if you can't get away with loads of timber you might be able to get away with some critical components tucked out of sight under a bed. Drawer sides for example need really careful handling, quarter sawn, straight grained, stable wood, and then kept in stick 1 or 2mm over thickness.

 

[JonnyW]

Thanks Custard. Yes you are probably right. Similar climate here.

Thanks for excellent advice and comments - all noted.

Now to find a secret wood stash location under the bed!

Jonny

 

[gregmcateer]

I'm pretty sure I read an article by Alan Holtham about making a kiln. I think he used an old refrigeration lorry as the container.

Here's a link or two to his book, poss in your library?

http://woodworkersworkshop.co.uk/ep...ectPath=/Shops/eshop814530/Products/GMC_17880

http://www.amazon.co.uk/How-Season-Dry-Your-Wood/dp/1861086415

Plus poss useful;

http://www.woodworkersinstitute.com/page.asp?p=760
http://www.woodworkersinstitute.com/page.asp?p=4035

and on ukw forum;

https://www.ukworkshop.co.uk/forums/kiln-making-t77935.html

HTH

Greg

 

[JonnyW]

Nice one Greg. Thanks for that.

I've ordered the book! And will have a good look over the institute article. Iooks like an excellent read.

Thanks again

Jonny

 

[Droogs]

Hi JonnyW,
Here's a fairly decent write up about a solar kiln if that interests you

http://www.instructables.com/id/Solar-kiln/

 

[JonnyW]

Thanks Droogs. Appreciated.

Jonny

 

[jimmy_s]

Jonny

I am also originally from Shetland, some of the timber that is sold up around the isles is of dubious quality to begin with.

I would think you could make a kiln if you can get some sort of control on the RH of the air circulating. Preventing the timber drying too quickly is probably the biggest challenge.

 

[JonnyW]

Hi Jimmy. You hit the nail squarely on the head there. The quality of timber here is absolutely atrocious. I was in B&Q in Aberdeen a few months ago with my wife. While she was looking at sinks! I nipped into their timber store. I was taken aback at the quality of timber there - much more superior to the suppliers in Shetland - and that's B&Q of all places! So it had me wondering what the hell kind of quality of timber you'd get from a reputable 'timber' merchant that specialises in 'timber'.

I made a playhouse on stilts for the kids this spring, and had to concrete in extra legs as three of the 95x95 legs had developed deep shakes in them. Two of them to the point where I thought their structural integrity had been compromised. Absolute shocking quality. The finished treated boards that I jointed together for the split doors, I had to put lengths back as they had twisted and warped to the point that I couldn't use them - and that was just the boards drying out in my unheated garage!!!!!

I'm thinking about asking a well know local furniture maker here, where he gets his timber from and what exactly he does with it. The quality of the pieces he produces is excellent.

But as you well know living up here, you just have to deal with what you've got or be prepared for the delivery cost.

Jonny

 

[Nelsun]

If it's Cecil you're meaning, I think it's DITT they get their wood from. I'm a noob to wood but did speak to a guy I kinda sorta know who works with him. It was certainly DITT he recommended. It could've been Tommy he said was the man to talk to... but then I'm no good with names. There's certainly a Tommy there.

FWIW, Hays has some ash (in main wood store up the back on the right) and LBC keeps lumps of rough oak. I think DITT has the odd bit of live edge stuff tucked away but it was maybe being kept for Cecil.

 

[JonnyW]

Hi Nelson. Thanks for that. Yes it was Cecil I was going to speak to.

I think the problems here are mainly due to the conditions the wood are stored in. Internal joinery being kept in large damp, unheated stores that have their doors open to the elements all year round. Relative humidity levels reach the mid 80's in the summer, so it's no wonder your damp skirting boards go like boat propellers when you stick them inside hot houses.

Thanks again Nelson. I'll nip along DITT for a look.

Cheers

Jonny