Advice on weighing blanks please.

[Hobbyshop]

I am new to turning and have obtained several logs (of unknown species) to practice on.
I have rough turned a few pieces into shapes that approximate to bowl-shaped :lol: and am currently watching them dry and distort before remounting and finish turning them.

I have read about recording the weight of the items and re-weighing them occasionally until there is no further reduction in weight.
My question is, how often is occasionally? I haven't been able to find anything that is specific about this.
How long would you suggest waiting between subsequent weight checks to be happy that a stabilised weight really is just that.

Thanks,

 

[CHJ]

Honestly the answer is a bit like the one for "how long is a piece of string"

1. How green was the wood when turned, was it freshly harvested, was it harvested in summer growth or dormant winter?
2. How big (diameter) are the items, how thick have you left the walls and base?
3. Have you masked the external surfaces at all to help control the moisture loss gradient?
4. Where have you stored them whilst drying?
5. Do you have any images of roughed out turnings?

Just some of the variables involved, drying to local ambient moisture level can be anything from a couple of weeks to six months dependant on timber type and storage conditions, shortest time being more risky, longer times being safer regarding likelihood of splitting.

 

[finneyb]

Kevin,

I thought the drying time calculation was approx 1in/year. So if you've left the bowls 1in thick it will likely take a year to dry naturally. So if you want to weigh them about 1-2 months seems about right. I understand that if you draw the graph you see a noticeable drop in the line.

Alternatively, you could throw them in a cool dark place and wait until next spring chances are they will be ready by then. Which is what I would do.

HTH

Brian

 

[CHJ]

I thought the drying time calculation was approx 1in/year. ......

This is the general rule for slabbed/planked wood stored in stick for natural air drying.
The times can come down considerably when drying turned items stored in domestic/workshop conditions,
Here's an example of some green Beech which dropped to below 12% moisture within a couple of weeks.

 

[Jacob]

Weigh them as often (or as little) as you like but put the results on graph paper. When it starts levelling out you know it won't get much drier

 

[Dalboy]

Whatever you do when trying to work out timing to re-weigh. I roughed my blanks weighed them even took a moister reading with my moister meter sealed the outside. So far so good placed them in area for storage again no problem. Read this post and soon realised that I had not put the date I rough turned them. This does help for keeping track but at least I can still check the readings which I will do tomorrow.

 

[Hobbyshop]

Thanks for the advice everyone.
I begin to understand why I couldn't find a simple instruction.

I will start charting weights monthly and hopefully with experience will begin to get a feel for what is happening.

 

[Bodrighy]

It also depends on what wood it is and when it was harvested. Some woods are much more likely to warp split etc than others. I have to admit that as I get a lot of green wood form various sources I just leave and if it splits it splits. Drying wood is a dark art quite frankly and you can get a wood down to about 12% moisture and find it still splits in a centrally heated room. For example, wood that I had turned several years previously in Cornwall split badly when I moved to Wiltshire.

Pete

 

[CHJ]

Yes it only takes a day with a radiator turned up on a cold winter day or a couple of hours exposed to sunlight through a window to modify a piece more than every you expected.
How much cringe factor can you repress when someone tells you they have put your gift in pride of place in the conservatory!!

 

[Tazmaniandevil]

I rough turned half a dozen bowls in various timbers today. My favoured method is to put them in a paper bag (Primark or Lush) with the wet shavings and place on a shelf or in a cabinet, weighing every 2 weeks. You can write the timber type, date, and weight on the outside of the bag with a sharpie.

 

[Vic Perrin]

It also depends on what wood it is and when it was harvested. Some woods are much more likely to warp split etc than others. I have to admit that as I get a lot of green wood form various sources I just leave and if it splits it splits. Drying wood is a dark art quite frankly and you can get a wood down to about 12% moisture and find it still splits in a centrally heated room. For example, wood that I had turned several years previously in Cornwall split badly when I moved to Wiltshire.

Pete

Totally agree Pete, I turned a large Monkey Puzzle bowl that had pretty much dried out and had been on show in my centrally heated house here in the Midlands for well over 6 months. My son who lives in Kent claimed it when he was up here on a visit . Within a fortnight it developed a major split !

Vic

 

[Grahamshed]

Makes you wonder why we bother