Anyone tried drying wood in a microwave?

[Mark Gottesman]

I have a Black (Wild) Cherry tree that just came down. Thinking of trying to use some to build a Ukulele. Anyway, I plan to try and split or saw off some thin slabs, and if that works then sticker and weight them down. Small enough to keep inside on a shelf. Plan to melt wax over the ends.

However, I was wondering about drying in a microwave. I've seen several web pages devoted to this and wonder if anyone has tried this recently on wood of the 1/4 x 9 x 12 size. Looking through past threads the objects were usually pen blanks or rough bowl turnings.

 

[FlyingRon]

Microwaves aren't tremendously good at drying things so I'm dubious. It will make any water content HOT however. Perhaps if you have one that's a combination convection oven and microwave (speedcooker).

 

[KenOfCary]

I don't know from experience but I would expect the water in the cells would boil and explode the cells of the wood, possibly with extremely exciting results.

I wouldn't try it, but YMMV.

- Ken.

 

[CDPeters]

See "Exploding wood" thread :rotflm::rotflm:.

Seriously, if I had to try to accelerate drying, I think I would lean toward trying the conventional oven set on it's lowest temp (~150 F).

C.

 

[kommon_sense]

Given how microwaves work, I don't think it is a good method to dry wood. You would get more predictable/reliable results putting the wood in a toaster or convection oven.

 

[CrealBilly]

I've dried lots of over sized pen blanks in the nuker - it works very well if done right. As a matter of fact I have a microwave in the shop just so I can dry pen blanks, the wife got tired of me using the one in the kitchen. I dry 16 at a time in a 4x4 configuration separated with wooden popsicle sticks and held together with rubber bands. Air circulation and end grain sealing is the key to success.

Don't just throw a hunk of wood in the nuker and punch in some numbers and hit start, you'll mess up good wood. Do your research and be careful - the wood can catch fire pretty easy, be especially diligent during the last few cycles as the fire risk increases.

 

[Bugle]

See "Exploding wood" thread :rotflm::rotflm:.

Seriously, if I had to try to accelerate drying, I think I would lean toward trying the conventional oven set on it's lowest temp (~150 F).

C.

I have a 10" x 10" x 2" piece of ambrosia maple that I would like to dry. How long to you think it would take in a 125-150 degree oven? Would you stack it on something?

 

[CDPeters]

Never actually done it Preston, probably a better question for one of the kiln operators like Scott maybe.

Being employed as a lab manager, I would use one of our precision balances and do a test - weigh, dry one hour, weigh again - then calculate the % loss over one hour. If you know the starting MC, you could then calc how long to dry.

Sorry I couldn't be more helpful :dontknow:

I just bought some nice Ambrosia myself this past weekend.

C.

 

[ehpoole]

Never actually done it Preston, probably a better question for one of the kiln operators like Scott maybe.

Being employed as a lab manager, I would use one of our precision balances and do a test - weigh, dry one hour, weigh again - then calculate the % loss over one hour. If you know the starting MC, you could then calc how long to dry.

Or, if you lack the equipment to determine original moisture content you can continue drying the sacrificial sample until no further weight is lost (0%MC) and calculate the original MC from the weight differential (wet vs. dry). If you record the weight every hour you can even create a drying chart that will tell you how long to cook (at a given temperature) to reduce the MC by any arbitrary amount. However, some species may need higher or lower temperatures to speed or slow their drying to prevent unwanted checking.

Another option, place the wood in a vacuum chamber and pull a strong vacuum on it -- you can boil the water out of the wood at room temperature with no risk of fire and minimal energy investment. You can also do vacuum dye infusion and other interesting effects with such a setup.

 

[scsmith42]

All wood has a maximum safe daily drying rate based upon its species, thickness, and initial moisture content. These rates differ based upon whether the drying method is a combination of temperature, RH% and Air flow, or vacuum.

You can dry wood a lot of different ways, and it will be suitable for woodworking projects as long as you do not exceed the maximum safe drying rate. Once wood has dried below 25% MC it is much more forgiving.

If you dry it too quickly, it can case harden on the outside, which will substantially reduce the future drying rate, or it can honeycomb on the inside; destroying its integrity or it can severely check on the outside, or a combination of all three.

Length and width of the boards is not a factor in the drying rate - only the thickness.

1/4" cherry should have a fairly fast drying rate, as 4/4 black cherry can be dried as fast as 7% reduction per day. With 1/4", you can probably shoot that up to 20% or more.

Bugle, the maximum safe daily drying rate for 8/4 soft maple is 2.8% per day; for hard maple it is 2% per day. If you leave it in an oven at 150 degrees for very long, unless it is almost dry you will most likely damage your wood.

 

[Greeker]

It would have to be for 10sec at time I would think< I talked to guy in SC that said he has used a microwave for bowls and turnning planks. Am not a turnner so I would not know.

 

[zapdafish]

well, put some hot dogs in there too long and they come out like sticks of wood.

hrmm, I might have just come up with my next pen blank, :gar-La;