Accelerate drying of bowl blanks

[delbs]

Hey all.

Been a while since I've posted on here. I've decided to expand my turning horizons and branch out from pen turning which I never said I'd do. I still really enjoy pen turning but something about bowls and all sorts of other objects have caught my attention.

So I recently picked up a whole tree of manchurian pear locally. I've got it all cut up and air drying. There's already some surface checking occurring so I want to know the best way to store it to prevent further checking or complete cracking throughout (I've heard paint the ends) and also if there is anything I can do to accelerate the drying or do I just have to leave it for a few years?

A friend from the forums said that if I turn it green then place it in a box of saw dust and leave it that will accelerate it. I'm just not sure if it will warp or reduce the chance of it cracking. Any advice on this would be great

Also, for all those Canberrans out there. Is anyone sitting on a stock pile of bowl blanks I can buy a few from? Or even interstate guys I can pay postage if your willing to post them for me. I've just picked up 2 camphor laurel and a Blackwood blank from Syd wood show and bought 3 jarrah blanks from eBay but want to build up a stock pile of dry ready to turn bowl blanks. They don't have to be round already I've got a bandsaw etc to cut down.

Thanks for all the advice. I've been watching Brendan stemp videos a lot recently. Man they are worth every second!

Cheers
Nathan


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[Robson Valley]

You face the typical issues that wood carvers have. It is completely unreasonable to expect every last chunk to air dry
without a crack. Collect 50 chunks each year for the next decade. Each year, rough turn 50, each year, finish 50 if you can.
Don't fall in love with any of it.

The "plumbing system" of wood is cut wide open in the ends. The game is to try to equalize the speed
of water loss from the sides and the ends. Paint the ends with anything = old crappy paint, glue, hot wax, whatever.

Get the bark off ASAP. Bugs love the juicy most nutritious growth just under the bark.

Under cover, outdoors, not cooked in a shed, the general rule of thumb is that wood air dries about 1" of thickness per year.
Drying all around, a 2" diameter stick might settle down in 12 - 18 months. That equilibrium Moisture Content will be approx 12 - 14%.
Fact: some woods air dry more successfully than others.

The result is a great inventory of wood, drying for a long time. I have 3 piles out back and 3 more piles in the cool workshop.
Mostly western red cedar shake blocks as large as 24" x 12" x 8".

The rustic furniture shop down my street went for harvesting last week. They brought back 4 cords of diamond willow sticks
from 1" - 4" diameters. They expect 6" loss to cracks in every 8 foot piece. The biggest pieces went into the 2018 bin.
The rest went into a 2017 bin.

I did a big dish in Alder. 8" x 8" x 20". It was coming along really well. I heard it explode in the night. 3/4" crack down the entire length.

[NeilS]

A friend from the forums said that if I turn it green then place it in a box of saw dust and leave it that will accelerate it. I'm just not sure if it will warp or reduce the chance of it cracking. Any advice on this would be great




Having tried most methods, this is the one I settled on.

Accelerating the drying process is not a priority for me, but maximising the survival rate of blanks with the least effort is far more important. Cutting up fresh felled logs (for which you have to drop everything and do immediately) and carting the load back to the workshop is quite an investment of time for which you need a good return in usable blanks.

Pre-turning green blanks definitely speeds up the drying process, but more importantly it reduces splitting by allowing the wood to move without tearing itself apart.

The trade off is you get warping instead of splitting. But, if you pre-turn the blanks thick enough the warp can in most cases be eliminated when re-turned, but splits are forever!

I'm happy if I can get a 70-80% survival rate.

Removing the pre-turned blanks from the wet shavings before the blanks become mouldy, but not too soon, can be tricky. My process is too bury the blanks under the wet shavings on the floor as I turn and leave them there for a week. That allows the the shavings to dry out a bit. Then I pack the blanks surrounded with shavings into cardboard boxes and leave for a few more weeks. Then I repack the blanks tightly together without shavings and monitor from there. I usually do this with a bottle of CA at hand to dab onto any signs of a developing cracks. If caught early they can often be prevented from extending any further. At some stage I stack the pre-turned blanks on open shelves.


350026

If you get a particularly nice blank you can increase its survival rate by sealing it on the outside (only) by whatever method, eg putting gladwrap around the outside of the blank. Splits in pre-turned blanks always start from the outside, like the buttons popping off the tight shirt on a fat man. By slowing down the drying/shrinkage of the outside relative to the inside you equalise the tensions inside the blank.

Others will swear by other methods and their experience may be different, but for me this method works best.

PS - You don't always have to remove the warp; a warped bowl has its own aesthetic appeal.

[Dalboy]

Having tried most methods, this is the one I settled on.

Accelerating the drying process is not a priority for me, but maximising the survival rate of blanks with the least effort is far more important. Cutting up fresh felled logs (for which you have to drop everything and do immediately) and carting the load back to the workshop is quite an investment of time for which you need a good return in usable blanks.

Pre-turning green blanks definitely speeds up the drying process, but more importantly it reduces splitting by allowing the wood to move without tearing itself apart.

The trade off is you get warping instead of splitting. But, if you pre-turn the blanks thick enough the warp can in most cases be eliminated when re-turned, but splits are forever!

I'm happy if I can get a 70-80% survival rate.

Removing the pre-turned blanks from the wet shavings before the blanks become mouldy, but not too soon, can be tricky. My process is too bury the blanks under the wet shavings on the floor as I turn and leave them there for a week. That allows the the shavings to dry out a bit. Then I pack the blanks surrounded with shavings into cardboard boxes and leave for a few more weeks. Then I repack the blanks tightly together without shavings and monitor from there. I usually do this with a bottle of CA at hand to dab onto any signs of a developing cracks. If caught early they can often be prevented from extending any further. At some stage I stack the pre-turned blanks on open shelves.


350026

If you get a particularly nice blank you can increase its survival rate by sealing it on the outside (only) by whatever method, eg putting gladwrap around the outside of the blank. Splits in pre-turned blanks always start from the outside, like the buttons popping off the tight shirt on a fat man. By slowing down the drying/shrinkage of the outside relative to the inside you equalise the tensions inside the blank.

Others will swear by other methods and their experience may be different, but for me this method works best.

PS - You don't always have to remove the warp; a warped bowl has its own aesthetic appeal.

This is the same method I use, When I first get the log the first thing I do is seal the ends if I can't convert it straight away but I normally manage to this within 1 to 2 weeks and the sealing helps to stop splitting before this happens

[delbs]

Thanks for the replies, I will turn off the bark initially and leave the blanks in the pile of shavings for a while while the shavings dry out.. Seems ive got a few methods to try, Thanks for your responses.