wood drying question

[Hugh]

I am in a mental fix right now. I have a question or two for all you tinkerers.

In the middle of June of this year I cut down a madrone tree (part for firewood and the trunk for turning). I took the turning chunks home and rough turned them into open bowls, and then boiled them for 3 -4 hours. I took them out the next day and started to let them dry. I checked for cracks and put a little CA glue on the cracks that appeared over the next 2 -3 weeks. Then everything seemed to be stable. The bowls have been on the floor of my shop all this time. Then about July 30, I decided to weigh the roughed out bowls. Wrote the weight on the bowl with the date. I have weighed them every couple of days since then. I use an accurate scale - to the gram. Over the last couple of days the bowls have not lost any weight and are only about 5 grams off the original weight.

Question - Do you think they have dried?
Thanks
Hugh

 

[Owen Lowe]

When I weigh my drying blanks, I check them, at most frequent, on a weekly basis. I think waiting for only a couple days between is too short to see if they are continuing to lose water.

I go 2 months after boiling before checking and then every couple weeks or whenever I remember. When they're stable within a few tenths of grams - or even gain a little, I finish turn.

Patience, my man, patience.

 

[n7bsn]

I am in a mental fix right now. I have a question or two for all you tinkerers......
Question - Do you think they have dried?
Thanks
Hugh

My best guess, no.

If I recall Dale Larson (noted Madrone turner in Portland) waits more like 4 months before final turning

TTFN
Ralph

 

[Hugh]

The reason for the question in the first place is that I had a hard time believing that the wood had dried as quickly as a month and a half. I normally rough turn a bowl and then let it sit for a year before I put it back on the lathe. That way I know it is dry. For some reason I weighed this set of bowls and found that they were not loosing any more weight. I thought this was unusual, and I wondered if anyone else had had a similar experience. Therefore the question.

I have boiled a couple of other woods and it still seemed to take a while (months) for the bowl to dry. I am going to keep weighing this set of bowls and see if they continue to loose moisture. In a couple of weeks I may re-turn a bowl and see what happens - just for the fun of it. I would like to finish up some of the larger ones for a sale in October. There may be enough time.
Hugh

 

[MichaelMouse]

How thick they were, how humid it is and was where they were drying is what counts. Thinner dries much faster, humid now may mean they're at 20%, which will certainly spoil your day come winter at 6.

They've reached equilibrium when they stay about the same for a week. If the humidity is something that equates to a reasonable moisture content, go for it.

At about an inch, most hardwoods reach equilibrium in the 15-8% range in less than two months in my circumstances. "Inch per year" is for planks, and not even correct there, but it's one of those urban legends we keep repeating.

 

[Vince Welch]

Hi Hugh,

You can always turn one piece and see how much the piece moves. Maybe it moves a little maybe a lot... but this way you know. Especially if you have multiple pieces of this wood. Simply turn one and find out!

Vince

 

[Hugh]

Thanks Everyone for the answers. I think I will try turning one after a couple more weeks at an even weight. I am not in a super hurry to get these re-turned. It is just that I boiled the wood and then weighed them after about 1 1/2 months. I just have not had any bowl blanks dry that fast where I was paying attention. Maybe I just was not paying attention and just figured I would leave the blank about a year. I have been tripping over these blanks as I have them on the floor of the shop. Did I just admit to a messy shop?????

MM - The blanks were turned the normal 1" - 1 1/4" thick. I am in California just north of San Francisco about 50 miles. Humidity happens most mornings this time of year with the incoming fog - then burns off and runs up to 90 degrees. Actually it is pretty nice wood drying weather.

Thanks for the thoughts Everyone. Sometimes it is just fun to think about how this stuff works and why it works that way. And it is always fun to get advise from others. Have to keep the brain cells working also.
Hugh

 

[MichaelMouse]

Morning and evening isn't spread enough. The relative humidity over the long term, just as the constant weight over a longer term is the key. If you're near the coast you may find that the RH averages 80% except in the heat of the afternoon. That's 16% by weight as things go, and nearly twice what you'd want for a 20C 50% human comfort room. It's also not too far from the ~30% FSP where wood starts to shrink.

I was at Beale, and I remember how unfriendly this time of year in the valley was to curing wood. Hadn't been for the swamp cooler it would have turned into toothpicks! Sonoma Co shows 80 and more as average on NOAA for this time of year.