Help with submerged timber preservation

[P.ALLEN]

So, I have some timber that I salvaged from an old bridge (it floated free while I was fanning out debris around it(tons of coins in the cracks)) so I took it home to make some walking canes from. I didn't want it to go to waste. It's sitting in a kiddie pool of fresh water in the backyard (I hosed it down good then fully submerged it). Does anyone know about preservation of cut timber like this? I know if it dries out right now it will just get brittle and fall apart, but I want to use it. HALP! Merci beaucoup.

EDIT: Important info; it's been submerged for around a hundred years +/- 10 years I reckon.

 

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[Jason in Enid]

POLYETHYLENE GLYCOL (PEG) METHOD
Polyethylene glycol (PEG) is a synthetic material that has the generalized formula H2OCH (CH2OH2) CH2OH. The low molecular weight PEGs (300 - 600) are liquids, the intermediate members (1000-1500) are semi-liquids or have the consistency of Vaseline, and the higher molecular weight PEGs (3250-6000) are wax-like materials. The various PEGs are now designated by their average molecular weight. What was once called PEG 1500 is now called 540 Blend (it is equal parts PEG 300 and PEG 1500), PEG 1540 is now called PEG 1500, and PEG 4000 is now called PEG 3250. Although the PEGs have some of the physical properties of waxes, they are distinguished from true waxes by the fact that they are freely soluble in alcohol (ethanol, methanol, isopropanol), as well as water. PEG 4000, which has a melting point of 53-55°C, was once the most commonly used PEG because it is the least hygroscopic; its large molecules, however, prevent it from penetrating dense wood. Now PEG 1500 and the 540 Blend are more commonly used.


The PEG conservation process was the first reliable method for treating waterlogged wood that was also relatively simple to perform. This method removes excess water while simultaneously bulking the wood. After preliminary cleaning to remove all surface dirt, the waterlogged object is placed in a ventilated vat containing a solution of PEG and solvent (water or alcohol). The vat temperature is gradually increased until, after a period of days or weeks, it has reached 60°C. During this time, the PEG percentage of the solution increases as additional increments of PEG are added while the solvent evaporates. During the conservation process, the wax slowly permeates the wood, displacing the water. At the end of the operation, the wooden object is covered with 70-100 percent molten PEG, depending upon the nature of the wood. The object is then removed, the excess wax wiped off, and the object is allowed to cool. After cooling, any excess wax on the surface of the object is removed with a hot-air gun or with hot water.


In most instances, the wood to be treated is placed in a vat of water containing a small increment of PEG (usually 1-5 percent. The vat is kept at a constant temperature of approximately 52°C. If the solution is not heated, it will solidify when the concentration of PEG in the solution reaches 20-30 percent. Over a period of months (or even years), the PEG percentage of the solution is increased in small increments until a minimum concentration of 70 percent is reached. If this minimum concentration is reached, the wood will remain stable. In some instances, if the percentage of PEG in solution exceeds 70 percent, water may be drawn out of the well-preserved heartwood without being replaced by PEG; this will cause the wood to collapse. The size of the PEG increments is dependent upon the condition, size, and specie of the wood being treated.


An additional method of treating waterlogged wood that is only appropriate for small objects and thus is seldom used in practice involves using a container in which the PEG concentration is increased solely by the evaporation of the solvent. When performing this procedure, it is important that the dimensions of the container be such that the amount of PEG in solution will be more than enough to cover the object at the end of the process.


It has already been noted that PEG is soluble in both water and various alcohols. Water is generally used in PEG solutions for large objects, as it is considerably cheaper than an equal volume of alcohol. When using PEG in water it is necessary to add a fungicide, such as Dowicide 1 (ortho phenylphenol), at .05 to .1 percent of the weight of the PEG used. During the conservation of the 17th-century warshipWasa, a fungicide consisting of seven parts boric acid and three parts sodium borate (1 percent of weight of PEG) was used (Barkman 1975:82). For smaller objects, it is often more convenient to use alcohol in the PEG solution. This considerably reduces the overall treatment time, and the finished product is lighter in both weight and color. To further reduce treatment time, the additional step of dehydrating the wood in at least three baths of ethanol before placing it in the first PEG/alcohol solution is recommended. However, it is not critical that all the water be removed from the wood prior to treatment, as PEG is soluble in both water and alcohol. Alcohol treatments save time but are less cost-effective and always pose the risks inherent in heating alcohol. Since all alcohols are fungicidal, no fungicide is required when using alcohol in PEG solutions.


Before a decision is made to conserve wood with PEG, it is important to consider the fact that PEG is corrosive to all metals, especially iron. For this reason, PEG treatments should not be used on wood that will be in contact with any metal (e.g., gun stocks).


Treating small waterlogged wood artifacts with PEG in the laboratory is a simple and straightforward process. Small vats (stainless steel or glass) are readily available and they can be placed in a thermostatically controlled oven to maintain the correct temperature; furthermore, only a small amount of PEG is required. In contrast, when large pieces of wood are treated, there is a considerable investment in PEG (sometimes measured in the tons). A substantial vat must also be constructed with the capability to heat and circulate the solution. Laboratories that intend to conserve large pieces of waterlogged wood must be prepared to make major investments in both equipment and chemicals. Of all of the wood conservation methods discussed in this section, any of the various PEG treatments with water is the most utilized because of its reliability and low cost.

copied from Wood Conservation - Conservation Manual - Conservation Research Laboratory - Center for Maritime Archaeology and Conservation - Texas A&M University

 

[P.ALLEN]

Thank you much, I got looking into the PEG and also found an alternative, Sucrose Method.

http://nautarch.tamu.edu/CRL/conservationmanual/File6.htm

Same folks, different article, really though thank you for the information