Thread: Microwave.

When I first dried timber in the Microwave I had to buy her a new Microwave but I was allowed to keep the old one

Use shorter heating times, especially with small pieces. Sometimes an extra 10 seconds is the difference between success and failure. Start at 20-30 seconds, add more only when needed.

There's no Undo button on a microwave.

Cheers,
Joe

I use a small low powered microwave with no turntable. Smaller pieces I set on about a minute, run 15 seconds, open, feel, turn, repeat until it feels warm to the touch. I take it out or leave it in the microwave with the door open. In an hour or two, repeat.

I leave the piece near the microwave and stick it in and give it a warm when I think of it, over a period of days or weeks.

I live alone so I don't have the "significant other" problem.

One can sometimes find bad looking but still working microwaves in junk stores that could be taken to the shed and used to give a piece a zap when you think of it.

A dead microwave with a light bulb inside would make a dry kiln. Use the size
bulb that gives you about 100 F - 55ish C inside.

The piece below was a soppy wet root / stump given to me out of a friends wood pile. Sap wood was punky and partially rotted. I roughed it, nuked it off and on for 3 - 4 weeks, soaked the punky part with CA, and filled a crack that opened with epoxy mixed with copy machine toner, then finish scraped, sanded, and oiled with linseed oil, sanded again and used tung oil. As I didn't use a sanding sealer it was darker than I liked. I lightened the photo to better show the figure.

It is small, about 6 inches across and probably was not worth the effort. I did learn a lot, drying with the microwave, stabilizing the soft part with CA, filling the crack, dealing with grain running every which way.

Then I gave it to the guy who gave it to me, because he admired the crazy figure.

Try putting a mug of water in with the piece and keep changing it as the water boils.....works for me

G'day,
I have had the best results using very thin bowls and the like - mine are usually desert timber which seem to take the process better than soft wood. Like others have suggested - pulse the m/w till the piece is about as warm as a cup of coffee, take out and leave till cool ( I turn mine up side down to dry as the base is the thickest and steamiest and takes the longest to dry) I do that about 3 times then leave it for a couple of hours, remount on the lathe and true it up then finish it off.
Good luck.
Bruce.

Hi C ookie48,
Many years ago, a Chap I knew, worked out the way to M/Wave Green Timber.
You have to weigh the timber, & you use 1 Min. for every 100Grams. on High.
So Weigh, write with Texta the Weight, M/W, let cool, & repeat the process, until the weight has Stabilized, & it should be fine.

There could not be one recipe to suit all; there are too many variables.
1. The power of the microwave
2. The type of timber
3. The size/thickness of the timber
Some timbers will crack, some wont. Remember, the microwave heats things from the inside out. You can alter the power of the microwave; eg high, med high etc and I would suggest more time on Medium setting rather than less time with higher setting. I agree with Issa, weighing the timber is a good idea. I would take things slow and steady and it really is a matter of suck-and-see. Experiment but not on good pieces of wood.

Microwaves are very handy devices in the workshop. I now have two, both picked up cheaply at garage sales. I would never use my domestic M/W for drying timber as they can taint food with a woody flavour; not good.

the secret is to take it easy.....it is a misconception that a microwave heats from the inside out.

Timber will not get warm all the way thru till it is well dry.

It is a must to weigh the timber as you go... you can see progress and you know when it is dry.

What you are looking for is a piece of wood that is warm to touch but not excessivly hot.

rest the items between nukings, this allows the moisture to equalise in the timber and for some of it to transpire and evaporate.

Best if the material is a bit dry to start with.

for damp rough turned bowls and the like, I stuff the voids with crumpled news paper and then wrap in the same....it slows down and equalises the drying process for damper items

some use the defrost function for harger loads, but I have not tried that.

for things like pen blanks and low mass narrow items, stacking them like a sty works well and makes the process more managable.

some things have taken me a couple of days to dry out between other things.... but it is certainly quicker that waiting like normal.

If you overdo it failures are guaranteed....even just pushing it a bit hard can ruin the character and colour of the timber.

cheers

Try defrost mode as it goes through a stop start mode but do it on the lowest setting and weight.

As has been said, the main things are weighing and short bursts in the 'wave, with adequate cool-down time between.

Another helper is to place the timber in a plastic bag and "twist it" closed.

For wet wood, the first few treatments you should stop the 'wave as soon as the time is up (with my 'wave, practice has shown about 30-40 seconds is best) or the bag begins to balloon - whichever comes first.

After a few treatments the bag stops ballooning - which usually indicates that you're past the "danger zone" where the wood may split.

As a bonus, the bag helps keep the other half from knowing what you've been up to when she's not looking.

Well what we learn when we ask. It cost me lots today to replace a used microwave with a new one. I have taken in to account all that is said above. Wiser now I will take my time and let things go slowly. Thankyou all for the info. Only thing now is to go out and buy a set of scales as I am not allowed near the kitchen.

How many turners, carvers,etc. out there have considered vacuum drying small quantities of wood? This, combined with "nuking", can be quite effective and sometimes results in less cracking although it does take longer.
I have used a small old vacuum cleaner (the least efficient method) and various compressors. A small refrigeration compressor connected to one end of a siutable diameter plastic pipe with a small bleed valve on the other end that allows a small amount of air to enter through a small canister that is packed with a desicant of the type frequently used in packaging to absorb moisture. The bleed valve is needed so the moist air from the process can be sucked into the vacuum pump and expelled.
A negative pressure inside the tube results in faster removal of moisture from the wood core. Heating the piece prior to vacuum drying will open the wood pores and aid evaporation of the moisture.
Commercial sizes of vacuum kilns are quite common and ,generally, work on the same principal.

Yup, what everybody else said, take it easy, keep opening it & feeling the heat build up & keep weighing it til it stops loosing weight.

I have had some luck freezing the timber first & then microwaving.

The freezing bursts the cell walls to allow the water to escape.

Originally Posted by kcam

Try putting a mug of water in with the piece and keep changing it as the water boils.....works for me

Not to sure this is a good idea check this link for boiling water in microwave.
Boiling Water In A Microwave, Read This Before Trying To Boil Water In Your Microwave

Not trying to be an alarmist but I saw a report on tv were a woman got scolded heating water in the microwave.