Preservation Solutions

Stabilizing a Cross-Cut Section of Wood with Pentacryl

Stabilizing a cross-cut section of wood, also known as a "cookie", is challenging since this type of cut has the most tension in it. The wood will crack from the outside edge as the tension increases farther from the pith, forming a pie shaped crack.

There are 2 key factors for achieving success when using Pentacryl:

  1. Completely saturate the wood.
  2. Dry it SLOWLY.
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If you will not be treating the wood immediately, it is recommended to wet it down lightly with water and wrap in plastic until it can be treated (not longer than 1 to 2 weeks). This will prevent it from drying too soon. Apply a small amount of Lysol concentrate (dilute per instructions on bottle) to the surface of the wood to avoid mold growth.

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This cross cut section of lodge pole pine is 7" diameter x 3" thick with a moisture content above 40%

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There are 2 methods to treating the wood with Pentacryl; 1. soaking or 2. brushing. When soaking, use a plastic, fiberglass or stainless steel container only. Do not use other metal containers as they will react with the Pentacryl and darken the wood. Place the wood on stickers to keep it off the bottom of the container.

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A large plastic kids pool is ideal for treating this 5 foot diameter by 12 inches thick maple cookie. The cookie is sitting on small stickers between the plastic so the Pentacryl can soak in evenly. Since this piece is too large to turn over, Pentacryl is also being brushed on from the top.

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The wood does not need to be completely submerged in the Pentacryl as it will “wick-up” from the bottom into the wood. Generally, the wood will be saturated within 2-3 days, however, larger pieces should be soaked longer.

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Cover the exposed wood in the soak with plastic to prevent the top from drying too soon.

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Often times you will see a "white film" or residue on the wood. This is the water being displaced.

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When using the brushing method, apply Pentacryl liberally with a paint brush. It is recommended to lay plastic down underneath the wood (again with small stickers between the wood and the plastic)

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Cover the wood with plastic to allow the Pentacryl to soak in and prevent the wood from drying too soon. Repeat the brushing (to both sides) and wrapping in plastic method until the wood is completely saturated. Try to complete this process within 1 week so the plastic can be removed to prevent mold growth.

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Drying the Wood
Once the wood is saturated with Pentacryl, let it drain and proceed to drying it. The treated wood needs to dry slowly and naturally in an area away from air movement, direct heat source, sunlight, etc. A basement is ideal. If the piece is small enough, you can put it in a cardboard box and loosely close the top. Be sure to stand the piece on end so that it can dry evenly on both sides.

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We also recommend cutting rounds of cardboard and taping them to both sides of the wood. This will prevent rapid drying especially in dry climate areas.

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For large pieces, 2+ feet in diameter and 3+ inches thick, we also recommend applying an End Grain Sealer prior to applying the cardboard. This will slow down the surface drying even further.

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When drying wood in high humid areas, lightly spray a coat of Lysol to the surface. This is recommended to prevent mold from growing while drying in the cardboard. If mold does form, the spores are only on the surface and can be treated again with Lysol.

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The Lodge Pole Pine cookies shown were both dried for 8 weeks in a cool basement. The one on the left was treated with Pentacryl and dried in cardboard. After drying, the moisture content was 14%. The piece on the right was left untreated.

Since these pieces were cut in winter (the dormant period), when the sap had stopped running and the wood hardened off, there is a good chance that the bark will stay on.

The treated wood is now ready for sanding, staining, gluing and/or finishing.

There has been good success with treating cross-cut sections with Pentacryl. The species stabilized range from soft to hard wood with sizes up to 6-7 feet in diameter. Do not rush the drying, or all your efforts will be wasted on cracked wood.

Occasionally you will have a cross-cut piece from a dead standing tree where the wood is almost dry, in this case, it is recommended to use Wood Juice, a stabilizer for drier wood.

We gladly offer free technical advice to those customers who need it. If you have questions as to which product to use, contact us via email or phone: 303.642.3060.