Accelerating drying of a precious piece

[Lou Jacobs]

My forestry school class’ 50th reunion will be in August and I’m hoping to donate a bowl for the fundraising auction they have every year. I’ve done this before with a piece from local (Maryland) wood, but I thought it would be more special to make a bowl from wood from the school forest in the Adirondacks. The powers-that-be liked the idea and agreed to send me a block of cherry that was cut to fit in a large USPS priority mail flat rate box. It is a hair under 12”x12”x5 1/2”. I received the piece a week ago, and quickly rough turned it. There was one surface crack, you may be able to see in the photo, which turned off, and as I opened it up, a couple of defects that look like the bark was scarred in two succeeding years about a decade or so ago. I filled them with thin and then medium CA, and have coated the end grain with Anchorseal. The bowl is now in a paper bag.
The challenge: I need to have this ready by late July to go to the reunion. I don’t want to risk putting it in my homemade drying “kiln” as the process, while usually successful, isn’t perfect. I wonder what is the best way to dry this a bit quicker than usual, while ensuring I won’t lose the bowl to cracks? I realize I could a) go the Robo Hippy route and just once turn it and let it move however it wants, b) quick dry it and if it cracks, fill the cracks with black CA or turquoise, or some other medium. I have silica gel which I haven’t used for a while. I could try this. I could also turn off the Anchorseal and bury it in shavings in the paper bag. Thoughts? Thanks in advance.

 

[hockenbery]

I found paper bags dried bowls quicker than anchor seal by a couple of months.
I switch dry bags for damp ones every day until the bags are dry. About 5 days.
Then leave it in the bag for 6 months then out of the bag and put it on a shelf.
In a drying room with 50% humidity and average temp 70 degrees the wood will reach 9% Mc
Still takes 8-10 months until the moisture meter reads under 10%.

What I would do is go the paper bag route until July. Then microwave it.

I had my students in a class that met once a week microwave 10” bowls. We had great success in roughing a bowl one week, drying in the microwave as homework, finish turning the next class.

40% power then Something like 3 minutes in the oven followed by 20 minutes resting. Repeat.
Do need to watch as wood can catch fire

You can find articles in the journal.
Also a forum thread. For a few other recipes.

Microwaving Bowls

Brand new to this hobby and have been doing a lot of research. I eventually plan on building up a stock of rough turned bowls that have slowly dried, but until then I have been trying my hand at microwaving. I have been developing some small cracks on a few of the bowls that are rough turned...

www.aawforum.org

 

[Don Wattenhofer]

You could also put it back on the lathe and turn it down to about an 1/8" wall removing all of the Ankorseal, then because it is cherry put it into a paper bag without the Ankorseal and weigh & change bags daily. The bottom near the base can be thicker without any problems but the areas where you get into end grain should be fairly uniform thickness. The surfaces inside and out should be as smooth as possible to eliminate the need for excessive sanding when dry and it will distort. After about a week the weight should stop changing indicating that it is dry. I have been using an electronic scale set to grams that reads to one decimal place and eliminates the confusion of ounces and pounds.

 

[Leo Van Der Loo]

The best way is to put it in the brown paper bag, no anchor seal and no shavings in with it.

Return the piece now to 8% rather than the 10% that is mostly used, not necessary with plain Black Cherry, that will reduce the time needed to dry it.

Make sure you check that wood over carefully, to make sure there are no checks and splits in there already, if you find any, now is the time to soak thin CA in those small splits.

 

[Richard Coers]

You are closer to the pith than I like with cherry. Also a couple of the defects are close to the rim and likely going to be an issue too. I use yard waste bags because they are double layer. I change bags every other day, no Anchor Seal or curls. Good luck.

 

[Randy Anderson]

I have had good luck boiling large black cherry hollow forms to speed up the drying process and reduce cracking risks.

 

[Bob Brown]

Does anyone use alcohol anymore?

 

[Michael Anderson]

I agree with Randy. Boiling the roughout is the best way to go.m to speed p drying and preventing crack formation.

 

[Dave Bunge]

My experience with 12" cherry bowls is they will dry enough for final turning in less than 6 months. That's dried in brown paper bags, no anchorseal, probably 1" initial thickness. Usually 4 months of drying is enough. So I'd say don't do anything out of the ordinary now...keep it it brown paper bags (change them out every day or two until they stop filling moist), weigh it occasionally and see where you're at by mid June. If it hasn't stopped losing weight by then, try the microwave procedure that Al recommends.

 

[John Dillon]

I do something similar as @Leo Van Der Loo

I will rough-turn bowls sometimes 3 times if I'm in a hurry for a special order.

I turn them to the 10% thickness then bag, or cardboard box, for about a month (maybe a little more depending on the time of year) until it starts to warp from losing weight (I also weigh before bagging/boxing it up) Check periodically for any cracks, mold, etc. I don't use shavings in the bag/box.

Then I re-turn it to "about 5% of diameter thickness". In your case you would go from initially about 1.25" then down to about 5/8". Then let it sit out on my basement floor as it warps some more and until it's almost found it's equilibrium (based on where you live and rate of weight loss). You can tell when its almost dry. Shouldn't take more than another 4-6 weeks.

Then I turn to final (maybe 3/8" for a 12" bowl) and sand it, but do not finish the foot (or apply any finish) until it's had time to stabilize itself over another couple of weeks. At this point it will probably only have lost an ounce or two of weight and we know it's "dry enough". Yes, it might warp a tad more, but will hardly be noticeable and besides, you've already sanded it. Then I finish the foot so it will sit flat.

Seems like a lot of work to mount it on the lathe 3-4 times, but it definitely speeds up the process from letting it sit at 10% thickness. Entire process takes about 3 months.

Individual results may vary - especially based on where you live and relative humidity, etc.

 

[Rusty Nesmith]

A friend of mine microwaves them then sets them on the concrete floor over night. The next day he will anchorseal them and put them on the drying shelf. He said they dry in half the time that way. I don’t know his process yet but will be learning it soon.

 

[Kent Jaffrey]

I’m in northern VA and have done a lot of cherry. Typically after I rough turn I coat the bowl with pva glue and then let them sit in a stack of other roughed bowls. For black cherry they tend to dry pretty well and quickly just sitting in my non climate controlled shop. I did a bunch of cherry in later July and most of the bowl blanks are ready to turn now so I don’t think any extraordinarily measures are needed.

 

[Lou Jacobs]

Thank you all for the terrific advice! I remounted it this morning and turned off the anchorseal. Took it down to about an inch. While the initial blank was 12” square, it’s now about 11.25” and will get a bit smaller when it’s finally turned. I like the idea to take it a bit below 10% thickness and keep watching and re-turning a couple of times. It’s in a paper bag and I’ll monitor weight and change daily until the bags are no longer showing moisture. I like the idea of boiling the bowl, but never having done it before, I’ll experiment on another piece. Again, thanks for all the wisdom!