Moisture meter for assessing "cure"?

[deejayoh]

I bought one of these cheap-o moisture meters at HF a couple weeks ago, thinking it would be useful for checking firewood moisture content

Digital Mini Moisture Meter

It occurred to me last night as I was lighting up the chafing fuel for the first "flame" day of my curing, that the moisture meter might be useful for checking curing status?

I took a couple of readings just to test the theory. It did show that the bricks laid earlier were much drier than those in the arch laid much later - but reading the instructions today I think I had in the wrong mode.

Gonna check again tonight using the "hard materials mode" - but I was wondering if anyone else had thoughts on whether or not this is useful?

[UtahBeehiver]

Re: Moisture meter for assessing "cure"?

Hi Deejayoh,

I use high end moisture meters in my work regularly and IMHO, I think this meter will give you and idea of mechanical water content but probably not chemical water content. Eventhough I am not a the curing stage in my build I suspect the curing is to remove both mechanical and chemical water content. I would interested to hear what other WFOs have to say.

Russell

[deejayoh]

Re: Moisture meter for assessing "cure"?

I was thinking that there is the moisture left in the bricks from sitting out in the rain and running through a wet saw, and the water in the mortar, but not even the google could help me with "chemical water content". Does that mean there might be some water content that is released via reaction generated by the heat of the oven firing?

FWIW, it is a $10 chinese tool - so I am not expecting much

[UtahBeehiver]

Re: Moisture meter for assessing "cure"?

Deejayoh,

Here is some info. But thinking about it more I think this type of water plays such a small role (fire clay) that the mechanical water reading will be a good indicator.

Water within the clay lattice or near the surface within the electrical double layer. This water does not move when fluid is flowed through the rock. In the normal definition used by a log analyst, clay-bound water is not part of the effective porosity and is the difference between total porosity and effective porosity. Clay-bound water is understood to include the interlayer water, although the contribution of the latter to the electrical properties of the clay may be different from the water in the electrical double layer.

In the dual-water and the Hill-Shirley-Klein models, the volume of clay-bound water is related to the cation-exchange capacity per unit volume, Qv, by expressions that depend on the salinity and temperature of the electrolyte in which the clay is immersed. Direct measurement of the clay-bound water volume in the laboratory is difficult.

I am a engineer and I don't understand half of this so have a beer and move on.

Russell

[deejayoh]

Re: Moisture meter for assessing "cure"?

Deejayoh,

I am a engineer and I don't understand half of this so have a beer and move on.

Thank goodness you said that. I was halfway through that and my head was spinning. And as a matter of fact, I am having a beer!

FWIW, I took some quick readings on the right setting and it seems to vary from 0.5% to 1.1% moisture content. Out of curiousity, I will keep measuring it as I cure to see if anything changes.

Edit: I just went back and took readings inside the arch, where the heat has been flowing into the flue - and there the moisture content is 0.0%. Maybe there is something to this.

[Neil2]

Re: Moisture meter for assessing "cure"?

It is the residual moisture in your insulation layers that takes the longest to drive out.

You need patience at this point.

[deejayoh]

Re: Moisture meter for assessing "cure"?

Checking tonight after 3 days of curing, the meter reads between 0.2 and 0.5%. Mostly 0.2-0.3%. It does seem like you can somewhat measure the residual moisture content. At least it's moving in the expected direction

[lwood]

Re: Moisture meter for assessing "cure"?

Keep on firing. It takes a while to drive all the water out. Maybe a week of constant firing will get you close to dry. At that point, forget about it unless it rains on your oven or something, you will never think about it again.

[Nataniel]

Re: Moisture meter for assessing "cure"?

Could you describe, please, how exactly you are going to use moisture meter for your goal? I couldn't figure it out, so far. If I understand it - probably I would be able to help you.