2 Moisture testers - 2 different readings..sigh

[Mike H]

Many thanks for all the help and advice. This forum is amazing.

 

Open spaceman - I'll give it a try.

 

Best wishes, Mike

[aspenarb]

Could you not check calibration by dipping the end in water?

 

Bob

[openspaceman]

Could you not check calibration by dipping the end in water?

 

Bob

 

I doubt it as it would depend on the amount of electrolyte (mineral salts) dissolved in the water, pure water is non conductive.

 

The resistive type meters use the conductivity of any sap left in the wood as a surrogate for moisture, I don't know how capacitance based ones work but none actually measure water.

[logdog212]

Waste of time moisture meters are experience is better, when you bang the logs together they should ring not a dull thud

[aspenarb]

I doubt it as it would depend on the amount of electrolyte (mineral salts) dissolved in the water, pure water is non conductive.

 

The resistive type meters use the conductivity of any sap left in the wood as a surrogate for moisture, I don't know how capacitance based ones work but none actually measure water.

 

I purchased a cheapy like this [ame=http://www.amazon.co.uk/diy/dp/B0036PSX0K]Moisture Meter - Moisture Detector for wood, building materials (screed, concrete, wall) and other materials - With switch button to select material: Amazon.co.uk: DIY & Tools@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41oGRJ7YzVL.@@AMEPARAM@@41oGRJ7YzVL[/ame]

which is used a general moisture meter, it gives a reading in just about anything so I assumed for example when its poked into a damp wall its measuring between the probes as a percentage its water content. When I find it I will give it a swimming lesson and let you know the reading.

 

Bob

[Hodge]

What did cave men do to test the moisture content or Henry the 8th?? Fire has been around for thousands of years, it's been used for cooking and heating since the dawn of time, long before any fancy moisture meters. People are getting brainwashed by stove company's and the likes.

[aspenarb]

What did cave men do to test the moisture content or Henry the 8th?? Fire has been around for thousands of years, it's been used for cooking and heating since the dawn of time, long before any fancy moisture meters. People are getting brainwashed by stove company's and the likes.

 

I agree but when selling timber the question does get asked and answers are needed.

 

Bob

[Hodge]

I agree but when selling timber the question does get asked and answers are needed.

 

 

 

Bob

 

 

Why? I sell logs, they are seasoned and burn just fine, I know this because I burn them on my burner and I have the chimney cleaned every year and there is very little spot or build up according to my sweep. People are brainwashed into moisture content, just like they are brainwashed into the soft wood is crap vibe.

[Mark Bolam]

That's a fair point Hodge.

 

A local stove place here recommends 'logs of 11% mc or less'.

I have some bits that have been in a barn for over 10 years that come in at about 16-17%.

 

 

Sent from my iPhone using Arbtalk

[openspaceman]

It's not just microwaves, this happened to us a few yrs ago, left one in the Esse to dry out, came back a few hrs later after walking the dogs, house full of smoke and a nice bit of charcoal in the oven

 

But was the charcoal burning?

 

The phenomenon you saw was pyrolysis with heat provided from the atmosphere in the oven gradually heating the log up to the point where the mixture of wood chemicals start splitting up and then the products of that reacting with each other within the wood.

 

In the microwave case the ambient temperature of the oven is near room temperature and the surface of the wood can lose heat to the atmosphere, the heat that drives the drying process is water molecules within the wood being vibrated by the electromagnetic waves and then releasing their excited state as heat deep inside the log, the outside of the log remains cool but the inside gets hot enough to form char and oxidise it.

 

Now imagine if your oven were a big kiln with recirculating fans to get the heat in and moisture laden air out quickly, supplied to dry kindling on a strict shedule to do it quick enough and then finish before the wood got too hot, then imagine if the kiln owner decided to try logs instead of kindling and to get the moisture content down he ran the kiln cycle twice...

 

Then imagine what you would do if you noticed a bit of smoke coming from the kiln, sensible people might peep in the door and then close it again and block off all poorts whilst cooling everything down with water.

 

Other people might fling the door wide open and run away schnell and allow the whole thing to end up in flames.