Timber movement

Woodmatt · 1 Aug 2018

Hi All,
Over the last number of years I have made most of the furniture in my home but despite bringing the timber into the house for some time am still having a problem with timber shrinkage,fielded panels have not been a problem having made allowances within the frame and grooves but most of my pairs of doors now have huge gaps between them due to shrinkage.My hydrometer in the workshop generally reads relative moisture at around 64%,so some weeks ago I brought the meter into the house expecting the level to drop but it still reads about the same so what do members think is going on and how do I fix the problem,thanks

Yojevol · 1 Aug 2018

Are the gaps now stable? Do they come and go with the seasons? When they are stable, all you can do is add some more timber to either fill the gaps or cap over them.
Brian

Sgian Dubh · 1 Aug 2018

Woodmatt":3mucv5bm said:
Hi All, My hydrometer in the workshop generally reads relative moisture at around 64%,so some weeks ago I brought the meter into the house expecting the level to drop but it still reads about the same so what do members think is going on and how do I fix the problem, thanks

It's possible the shrinkage that occurs does so primarily during the winter because RH in most British houses tends to be lower during the winter and spring months than the summer and autumn months. Much depends on your location (wet Wales I see) and the construction, insulation and climate control measures you have. However, readings I've gathered for internal conditions in my house(s) show typical summer/autumn builds up to and hovers around 65% RH, and winter/spring values as low as about 45%.

It's hard to work out why the gaps get wider but then later fail to close up again without being able to examine the situation in more detail. There may be something else at play other than RH that hasn't been factored in, but at this stage any other suggestions from me would be speculative. Slainte.

profchris · 1 Aug 2018

Once wood shrinks, it usually expands again to less than it's previous size. This goes on for a few years, then stops. Thereafter it still expands and contracts, but less so.

Musical instrument makers are very conscious of this - for example, on a new fretted instruments the fret ends will probably stick out late in its first winter. Level them back again, and two winters later they probably need levelling again. Maybe never thereafter.

You could build your cupboards in low humidity, say 45%, but then the doors would stick for the first few summers.

So there's no real solution I'm afraid.

mbartlett99 · 1 Aug 2018

Its annoying for sure - I've a house in Savannah Georgia where things really move but here in Herts I haven't really noticed anything apart from the cheapo pine panelled doors which have been here since 1984 where the paint has cracked on a few. Is it only your doors that are moving? What wood are they made of and was it kiln dried when you bought it?

I work so slowly that any of my timber has ages to acclimatise inside (under the bed is currently the space of choice. I suppose its a blessing working at a glacial pace sometimes. I'm pretty careful on the timber I buy too and when going from rough sawn to final dimensions.

Woodmatt · 1 Aug 2018

Thanks for your comments guys,Im glad Im not the only one who runs into this problem.I think the cabinets of most concern are now stable so I may well add a piece to one of the doors to fill the gap,I might even use a contrasting timber so that it looks more like a feature rather than a repair.
I am more concerned really with how I can reduce the problem with future pieces,any suggestions. My last piece I kept the timber indoors for about three months to acclimatise the timber but then it took me another couple of month to make the piece so the timber was back in the workshop adjusting again to the conditions in the shop.