Birch wood is a popular wood to work with and Pentacryl (or Wood Juice) will stabilize it effectively. Due to the soft bark, we have found that the birch wood absorbs Pentacryl into this area more readily than other types of wood. This extra absorption plus the lighter color, will leave the bark slightly darker.
This photo shows the left side of a birch log treated with Pentacryl and dried for 2 months. The bark is a grey color compared to the untreated right side.
In the photo above, the bark of the same log was cleaned with odorless mineral spirits and air dried for 2 days. However it still remains slightly darker with a yellow tint.
Another cleaning method tested was to “wash” the surface. We used a mild dish detergent and applied it directly to surface with a soft brush or cloth. Then lightly rubbed it on the bark with our fingers. Note, as to avoid scratches, do not scrub the surface. The wood was then rinsed off with HOT water, patted down with a towel and air dried over night.
As you can see from this picture, the treated and washed area looks cleaner and almost the same color as the untreated bark.
When treating birch with the bark on, Pentacryl can be applied directly to the wood itself. This would mean using the brushing method (not soaking) to avoid the absorption into the bark area.
If you do soak your wood, the above “washing” method is effective for cleaning any bark that becomes discolored.
The birch logs for this table by John & Gigi Designs, were treated with Pentacryl. Once dried, the natural colors of the wood were enhanced.