Microwave drying...?

[Doug Rasmussen]

So far my experience has been good, but in the year or so on this forum I'm not sure I've seen any mentions of the process.

Fresh cut wood, small bowl turning. Put in microwave for 15 seconds or so on high heat. Put the piece on a cold surface and observe condensation under the bowl. Let cool, repeat until no condensation under bowl. I've also used the postal scale method to determine when the moisture content stabilizes.

I'm impatient, the rough turning, air dry and re-turn cycle is not my favorite.

As I said small bowls, 6" diameter more or less. How about larger bowls, special issues with them?

Any general concerns to be aware of with microwaving turnings?

[Bob Bouis]

Drying with the microwave can cause discoloration of some woods. Walnut in particular, if turned green, with not end up looking good if it goes straight into the microwave. I've never tried it with a piece that had some time to oxidize. I had a similar experience with sweetgum.

[John Keeton]

I have nuked roughed out bowls as large as 10" by doing 30-60 sec sessions. Couple of cautions - sneak up on the time and be aware that wetter portions of the bowl will get hotter than drier areas and can crack. I have not had this happen, but I am aware that pieces can actually scorch and/or catch on fire. Again, sneak up on the time and it sounds like you have that down pat.

[Fred Belknap]

I put my bowls in a plastic bag when I microwave them. I like to get them hot enough that the water is close to boiling. When I take them out I cover them with an old coat to keep them from cooling down to quick. Just leave them in the plastic bag but open it up to let the steam out. How long you keep them in the microwave depends on the size of the bowl and the power of the microwave. A turn table would be good but mine in the shop doesn't have one. The one in the house is larger and has a turn table hummmm, maybe when the wife goes to work. If you melt the bag you have left it in the MW to long. DAMHIKT

[John Keeton]

A turn table would be good but mine in the shop doesn't have one. The one in the house is larger and has a turn table hummmm, maybe when the wife goes to work.Not a good plan for some woods, such as catalpa! Apparently, Ms. Keeton does NOT care for the lingering aroma.

[Barry McFadden]

I have microwaved quite a few green bowls. I turn them to about 1/2" thick and put them in the microwave at 40% for 3 or 4 minutes. Let them cool and repeat one or two more times. The next day I finish turning them. Haven't had any problems doing it this way. I use the old microwave we used to have in the kitchen.

[Peter Blair]

I have experimented with this process for several years, I have two microwaves in my shop stacked on top of each other so I can do quite a bit. I use the defrost cycle and my latest was a set of four nested bowls made from newly cut Silver Maple. The smaller three dried very quickly but the larger 12" dia started to crack at the top edge. I wrapped it with stretch seal and have it in a bag. I may have tried to dry it too aggressively. I don't like to have wood sitting for a year or so as I have a problem remembering where they are and exactly what I had planned. For me the thinner the better but as is stated above they can burn from the inside out. I make it a practice never to leave the shop with one in the Nuker!!!!

[Leo Van Der Loo]

So far my experience has been good, but in the year or so on this forum I'm not sure I've seen any mentions of the process.

Fresh cut wood, small bowl turning. Put in microwave for 15 seconds or so on high heat. Put the piece on a cold surface and observe condensation under the bowl. Let cool, repeat until no condensation under bowl. I've also used the postal scale method to determine when the moisture content stabilizes.

I'm impatient, the rough turning, air dry and re-turn cycle is not my favorite.

As I said small bowls, 6" diameter more or less. How about larger bowls, special issues with them?

Any general concerns to be aware of with microwaving turnings?

I used “microwave” in the "search forum" and got lots of hits on that, here is a couple of them,

http://www.sawmillcreek.org/showthread.php?235390-Norfolk-Island-Bowl-up-in-smoke-any-ideas&highlight=microwave

http://www.sawmillcreek.org/showthread.php?232930-24-Hour-Turnaround&highlight=microwave

http://www.sawmillcreek.org/showthread.php?216293-Drying-wood-in-microwave&highlight=microwave