Drying Blanks

[Dudley]

If you put the blank in and follow all of the instructions for drying a rough turned bowl, can you dry a spindle blank in a microwave (before turning)?

I would think it would take longer, but if the pith is out and enough excess in length is left for a check, would this work?

 

[MichaelMouse]

It'll work, but it's a long time, and the effort hardly seems justified by the benefits. Face grain takes ten times as long to get water out as end grain, and doubling the thickness demands more than three times as long to dry the interior. Weigh this against the dangers of lighting off SWMBO's microwave and the ratio of tangential to radial dimension loss, and it hardly seems worth it.

Rough and then dry, re-turn for circular if desired, is still the best way to go. Treat all wood over two inches thick as green wood, and you'll have less pain from unanticipated warp. With the progression of seasons, there's really only a couple times a year where you can expect the moisture to be constant throughout, unless you keep your wood in a constant humidity environment.

 

[Dudley]

MichaelMouse,
That makes sense. Thank you. I have been trying to come up with a way to dry some slabbed green wood so I can turn candle sticks and maybe a box or two. Seems that turning rough, then microwaving would work in both of these situations as long as I leave enough wood to true up when dry. Am I correct in thinking this?

 

[MichaelMouse]

I've done it, and since they will be long-grained, the stains from water and extractives boiling out the ends won't be an eyesore. That's why I don't do bowls.

I'm a lower power setting, longer cycle time microwave guy. After you take the blanks out, cover the ends with a couple pieces of paper toweling so they'll stay damp with evolving vapor. If you know there's a knot in there by the sweep of the grain, microwave with care. Wood's a good insulator, and a dry knot in the middle can build heat and light off pretty easily.

 

[Andy Coates]

microwave seasoning

I would agree. Short, repeated cycles on defrost setting and wrap the endgrain whilst cooling. Another technique is to put your blank in a microwavable plastic bag. After each cycle remove it, turn the bag inside out and allow to fully cool before the next cycle. It's amazing to see the released water condensing on the inside of the bag!

I would also agree that care needs to taken. I rushed a piece once and it burnt quite badly. The microwave smelt like a fish smoking house for hours and took some cleaning up.

Andy