Drying wood in freezing temperatures

[AndrewPritchard]

Here in Nova Scotia, we often have daytime freezing temperatures for 3+ months of the year and my workshop is unheated when I'm not working there. If I'm drying turned bowls in there how will this effect the wood?

I'm assuming the drying will be non-existent during that time?

If I move them into my temperature controlled apartment, am I asking for them to dry faster and possible cause more splitting and checking?

NB This is a cross post from the turner's corner

[CandorLush]

If you are just talking about bowls, the tried and true method of stuffing them in a paper bag with shavings from the bowl should work just fine. 

 

Also, for what it is worth, the guy who taught me how to turn kept the blanks he wanted to keep "green" in a big chest freezer (without a "frost free" system)

[AndrewPritchard]

4 minutes ago, CandorLush said:

If you are just talking about bowls, the tried and true method of stuffing them in a paper bag with shavings from the bowl should work just fine. 

 

Also, for what it is worth, the guy who taught me how to turn kept the blanks he wanted to keep "green" in a big chest freezer (without a "frost free" system)

I'm assuming then, even in paper bags and shavings, the cold temperatures will slow or completely arrest the drying?

[CandorLush]

Yeah, sorry, that was in reference to your question if you would be ok bringing them inside

[Jean [Fr]]

My two cents : drying means evaporation. So you need water to be at the liquid state. Sure it will dry faster if the temperature is higher and the moisture in the air low, but since it's no more ice, it's drying. I would keep the workshop over 5°C (40°F) and everything gonna be alright.

[Marmotjr]

I know some turners will microwave blanks to dry them faster.  Weigh the piece, microwave for a few minutes, let it cool so you can handle it, and weigh it again.  Once the weight stops changing, it's dried enough to finish turning.  I've done it with a few spindles with good results. 

6 minutes ago, Jean [Fr] said:

My two cents : drying means evaporation. So you need water to be at the liquid state. Sure it will dry faster if the temperature is higher and the moisture in the air low, but since it's no more ice, it's drying. I would keep the workshop over 5°C (40°F) and everything gonna be alright.

Some shops, like mine, can't be climate controlled, even above freezing. 

[AndrewPritchard]

1 hour ago, Marmotjr said:

I know some turners will microwave blanks to dry them faster.  Weigh the piece, microwave for a few minutes, let it cool so you can handle it, and weigh it again.  Once the weight stops changing, it's dried enough to finish turning.  I've done it with a few spindles with good results. 

Some shops, like mine, can't be climate controlled, even above freezing. 

Microwaving sounds like rather rapid drying. Won't that warp and split the bowl?

[Woodenskye]

I have also heard of the microwave idea.  The other thing I have heard which is slower, but along the same line is using the oven at a very low temp.

[Marmotjr]

1 hour ago, AndrewPritchard said:

Microwaving sounds like rather rapid drying. Won't that warp and split the bowl?

 

16 minutes ago, Woodenskye said:

I have also heard of the microwave idea.  The other thing I have heard which is slower, but along the same line is using the oven at a very low temp.

It can split the bowl, but so can the oven, and air drying.   Sometimes you want a warped bowl though. 

 

[Pondhockey]

12 hours ago, Woodenskye said:

I have also heard of the microwave idea.  The other thing I have heard which is slower, but along the same line is using the oven at a very low temp.

I think this is your winner.  The USFS uses ovens to dry more quickly for their experimentation.  I've done this in my outdoor grill, also for experimentation (my grill uses indirect heat; I wouldn't do this on a direct flame!)

[AndrewPritchard]

I've also been reviewing mini-kilns. One guy was using an old dishwasher, with both grills to hold many bowls, and a 100w non-CFL bulb to heat. Wrap the whole thing in pink insulation and he was saying he can get his rough turned bowls dry in 2 weeks

 

 

[Pondhockey]

On 7/29/2017 at 5:25 AM, AndrewPritchard said:

Here in Nova Scotia, we often have daytime freezing temperatures for 3+ months of the year and my workshop is unheated when I'm not working there. If I'm drying turned bowls in there how will this effect the wood?

I'm assuming the drying will be non-existent during that time?

If I move them into my temperature controlled apartment, am I asking for them to dry faster and possible cause more splitting and checking?

NB This is a cross post from the turner's corner

In response to the direct question, I believe that even in freezing temperatures, if the relative humidity is low there will be "sublimation" and your wood will do some amount of drying.  Not sure about the humidity levels in Nova Scotia in the winter (or anytime!)

[Sawdustdad]

On 7/30/2017 at 12:53 PM, Pondhockey said:

In response to the direct question, I believe that even in freezing temperatures, if the relative humidity is low there will be "sublimation" and your wood will do some amount of drying.  Not sure about the humidity levels in Nova Scotia in the winter (or anytime!)

This is exactly it. Sublimation will provide some drying, albeit at a substantially lower rate.  Think about those shrinking ice cubes left in a freezer for a long time.  

[Eric.]

Yep.  Even snow evaporates.   Give the wood the time it needs.  Air drying requires patience.  No point in rushing it.

[Coop]

5 hours ago, Sawdustdad said:

This is exactly it. Sublimation will provide some drying, albeit at a substantially lower rate.  Think about those shrinking ice cubes left in a freezer for a long time.  

Sounds like the definition of climate change! Actually, I've never measured the cubes from conception to consumption, so didn't know there was a difference. 

[Brendon_t]

Looks like the actual question has been answered but for conversation sake, I don't think bringing them into the house would cause more rapid evaporation than air drying in temperate (read as not up in Nova Siberia). If you have a utility closet or storage space you could load up a few drying bags in, you should be good to go.