Microwave Baking Samples

[steveST]

Anyone have luck using a microwave to bake their samples? It doesn't seem to make sense to me to have one's oven running for days on end during 90 degree weather.

[Den Socling]

You can use a microwave. A turntable makes it easy. My old microwave doesn't have one but I get by. Just heat for a minute or so, then open the door to let the samples cool. When you don't see condensation in the microwave, start weighing. When the weight stays steady, it's oven dry.

I can spend an hour doing it this way as I may open to cool or restart the oven whenever I happen to walk by.

[kilndry]

And watch for the telltale puff of smoke as you near 0% m.c., it is a good indicator that you are about to ignite your wife's microwave...

[Ianab]

As Den says, yes it work well.
Things to watch, keep the power settings low untill you get the hang of it. I use the 20 or 30% power setting. Take it out every couple of minutes and weigh it. If it's too hot to pick up, let it cool a bit and/or reduce the power setting. Dont let it get too hot and start smoking, that will foul up your measurement and your microwave  :D
I think it works so quickly because the microwaves are absorbed directly by the water INSIDE the wood, and converted to steam directly. After the first few 'nukings' the sample will be warm and steaming when you take it out.
And the microwave will smell of wood for days after... so it might be best to use an old one in the shed  ;)

Ian

[shopteacher]

What kind of scale do you guys use for weighing the samples?  Was thinking of using the one I use to weigh out Ole Butchs dog food, but he went and rigged it so as not to weigh anything under 5 pound. :D

[Ianab]

Hi Teach

Best scales is good digital ones that are super accurate. Being a cheapskate I use budget scales that are "semi-acurate". ;) Mine only measure to 2 gram accuracy, but with a 200 gram sample thats good to 1%. If you need to know if it's 15% or 25%, then 1% accuracy is plenty. If you NEED to know if you wood is 7.9% or 8.1%.. then you need real scales.

[woodmills1]

Yes, micro works for drying samples, but as stated use low power and short times or it WILL smell up the kitchen.  What the H#$% did you have for lunch said my lovely wife.  I use a triple beam balance for my weights.