Hello Dan,

Apologies in advance if I was unclear ... Since lots of posters dislike
anything but short answers, it can be a challenge at times to be concise on
complicated issues. I've been hammered before for long answers, so I'm a wee
bit gun shy. :-0

Cured wax emulsions remain vapour permeable, allowing moisture vapour to
pass through, albeit at a greatly reduced rate. Wax emulsion sealers are
specifically formulated to control the rate of moisture loss in green
timber, by forming a durable wax membrane between the exposed end/side grain
and the surrounding ambient atmosphere.

Think of it like this... A freshly sawn endgrain section is like on open
super-highway. Moisture vapour can move freely out of the log as there is
nothing to hinder its natural movement. (Let's assume no environmental, or
other controls for sake of discussion) When a endgrain sealer is added to
the exposed endgrain surface, it's like a speed limit has been added on the
super-highway. Moisture vapour can still move out, but at a greatly reduced
rate.

The goal is not to prevent moisture vapour from moving through the wax
coating, but instead to retard the rate of moisture evaporation, thereby
helping to prevent steep moisture gradients from forming and reducing
subsequent drying defects like end grain checking and warping. It's a common
misconception that end grain sealers *stop, or prevent* moisture loss
through the cured coating, this is incorrect. They simply limit the loss,
but do not and can not prevent the loss of moisture vapour.

If you have any questions, please do not hesitate to contact me. Take care
and all the best to you and yours!


On 9/12/06 9:08 PM, in article
, "Dan Bollinger"
wrote:

Steve, Didn't you mean to say 'vapor impermeable' ? The problem with latex
paint is that it is vapor permeable. Dan

Cold wax log sealers like Anchorseal are paraffin, or microcrystalline based
emulsions that dry, forming a flexible, yet vapour permeable membrane that
is much more resistant to movement than latex paint.


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