moisture readings

[wallace]

I have been planning some redecorating work for a couple of years and have had my orders off the lady of the house that not another machine resto until I use said machines to do some work. I plan on making some new interior doors, skirting, architrave and dado from some ash I got a few years ago. The ash came from a big door making factory that was relocating, incidently the same place I got my first wadkin lump. I presume it would have been kiln dried, its been in my work shop for a good 3years. I have a cheapo moisture meter and went round poking various bits. I was getting variances from 10.5 to 14%. I have sorted through the timber and done some cutting to rough lengths. When I checked end grain of a fresh cut it was 8%. What is a good reading before I start planing stuff to size?
Another query is I wish to stain the ash a brown similar to the colour of the brown you see on church pews. How can I achieve this?

 

[woodbrains]

Hello,

Kiln drying has nothing to do with the timber's current moisture content, which depends on the storage conditions since you have had it. 8 percent is a fine starting point, but I'm wondering why you are reading as much as 14 which is not. Can you get the wood into the location it will eventually reside for a few weeks? I would plane and thickness a bit oversize, move it to its final location, laying flat with stickers between each board, and let it acclimatise for a few weeks, if you think the place it is now stored is not at a low enough humidity, which seems likely if the timber is as high as 14%.
Then plane and thickness to final dimension, where any wood movement will be corrected.

Staining depends on the type of finish you will use on the final project. A dye-stain will work well on ash, such as Colton wood dye. It can be finished in and oil or polyurethane, or other finishes if given a seal coat of shellac.

Mike.

 

[wallace]

Thanks mike, I mentioned the kiln dried bit because I heard /read somewhere that being kiln dried can affect the timbers future capacity for moisture content. It may be Horlicks though.

 

[dzj]

+1 what Mike said.

The inexpensive moisture meters shouldn't be taken too seriously.
EMC depends upon where you live. In some places it goes up to 18%.
It can make problems, particularly if you have climate control inside.

 

[Sgian Dubh]

Thanks mike, I mentioned the kiln dried bit because I heard /read somewhere that being kiln dried can affect the timbers future capacity for moisture content. It may be Horlicks though.

It's not "Horlicks" because the ability of wood cells to adsorb moisture after it's been dried to a low moisture content is ever so slightly compromised. To give an example, let's say a piece of wood is dried from green (30% MC and above) to 15% equilibrium moisture content (EMC), which is not necessarily the same as a reading of 15% MC which is an average moisture content. Then dry it some more to say, 5% EMC. Subsequently, return the piece of wood to the same RH conditions it was in when it dried down to 15% EMC, and leave it long enough to adsorb moisture to reach EMC again. In all likelihood the wood won't quite reach that 15% EMC number, and it will be a tiny fraction of a per cent short of that. What you will have demonstrated is one form of hysteresis that wood displays. Interestingly, the more often wood adsorbs and desorbs moisture as it adjusts to changing RH conditions, the less responsive it becomes to those cyclical RH changes. Admittedly, the phenomenon is pretty small in most cases, not all, but it is measurable ... which keeps some wood scientists busy, and I suppose quite happily employed, ha, ha. Slainte.

 

[custard]

I have been planning some redecorating work for a couple of years and have had my orders off the lady of the house that not another machine resto until I use said machines to do some work. I plan on making some new interior doors, skirting, architrave and dado from some ash I got a few years ago. The ash came from a big door making factory that was relocating, incidently the same place I got my first wadkin lump. I presume it would have been kiln dried, its been in my work shop for a good 3years. I have a cheapo moisture meter and went round poking various bits. I was getting variances from 10.5 to 14%. I have sorted through the timber and done some cutting to rough lengths. When I checked end grain of a fresh cut it was 8%. What is a good reading before I start planing stuff to size?
Another query is I wish to stain the ash a brown similar to the colour of the brown you see on church pews. How can I achieve this?

Are you able to rough cut the wood then temporarily store it, in stick, inside the house? You won't do better than letting it acclimatise in the very environment where it will reside. Give it a few weeks at least, plane and thickness to dimension, and then put it back indoors.

I'd also sort through your timber stack and identify the straightest grain boards that are closest to being quarter sawn. You could earmark these for the jobs where stability is most critical, like the stiles and rails for your interior doors.

It sounds like your wood is just a few percentage points above the level where it will average once it's installed, so not too bad. You can plan in advance for some of the movement that will take place, for example if you have a flat sawn board where the end grain is curved, then the curve will try and straighten out as it dries, so for a skirting board it might be better fitted with the "convex" side of the curves towards the wall, that would avoid a gap opening up between the top and the wall as it dries that last little bit.

 

[wallace]

Ta very much Sgian, Custard I have cut a load of timber for stiles and rails and brought them indoors. Wife not impressed about having 30 lengths of ash in the hallway. I'm hoping when I rip to size the offcut will be big enough to make the architrave. Can anyone recommend some spindle tooling for making interior doors.

 

[woodbrains]

Hello,

Wot Richard Jones says is correct, but the short answer is, kiln dried initially or not, does not prevent the wood absorbing moisture into the cells, when humidity becomes high. It is the moisture adsorbing in and out the cells which causes the wood movement, so keeping the wood in the vicinity it will spend its life as a finished article is likely to minimise problems. Wood will always move with seasonal changes, and whether the swing becomes less pronounced with time does not have much bearing on practical woodworking practices. Acclimatisation of the timber and good joinery, which allows for seasonal movement is essential, whether the wood is kiln dried, or air dried. I have never had a moisture meter, but following these good practices has never let a piece of mine fail yet.

Mike.

 

[AndyT]

Picking up on the stain question, one option is to use Potassium Permanganate. This was traditionally used on mahogany but works on other woods as well, and seems quite controllable in use. See here for some experiments on ash, plus discussion of buying it from the chemist to treat smelly feet. I found it on eBay.

https://www.ukworkshop.co.uk/forums/post726117.html#p726117

 

[Sgian Dubh]

Wot Richard Jones says is correct, but the short answer is, kiln dried initially or not, does not prevent the wood absorbing moisture into the cells, when humidity becomes high. Mike.

What you say is true Mike. I should have perhaps briefly discussed and emphasised the need to allow for wood expansion and contraction during the construction, because in most cases the reduced ability of wood to respond to changes in RH is quite small, whether time dependent or not. Slainte.

 

[wallace]

I had thought of PP Andy. I have some that I use for my koi. What top finish would you recommend.

 

[AndyT]

I had thought of PP Andy. I have some that I use for my koi. What top finish would you recommend.

Apart from the sample in the thread I linked to, I have not yet used the stained ash on anything. But as it's a chemical alteration to the wood, I reckon anything you like would be ok, whether water or spirit based. For inside work I'd probably use hard wax oil again, like I did on the chair - easy to apply and tough.

 

[whiskywill]

Another query is I wish to stain the ash a brown similar to the colour of the brown you see on church pews. How can I achieve this?

I don't know what shade of church pew brown you have in mind but for reference this brown was done with two parts of Colron English light oak to one part of Jacobean dark oak.

 

[wallace]

This is the colour I want to achieve.