User:KkeanJHU/sandbox/conservation restoration of waterlogged wood

conservation restoration of waterlogged wood

History

History will explain why and how wood gets waterlogged. Go over briefly the biology behind wood as a material. Where waterlogged wood is prominent. What environments create waterlogged wood, how do museums or objects look waterlogged (examples include shipwrecks, archaeological findings).

Agents of deterioration

Relative humidity and temperature

What is relative humidity and temperature. How does RH and temperature affect waterlogged wood.

Pests

What are pests, what pests specifically target waterlogged wood.

Light

What is light exposure as a agent of deterioration. How does it affect waterlogged wood or treated waterlogged wood.

Pollutants

The liquid inside of waterlogged wood might not always be completely fresh water. How do different pollutants affect waterlogged wood.

Physical

What are physical agents of deterioration, how do they affect waterlogged wood.

Preventative conservation

Environment

Waterlogged wood should be in the environment that it is found in until a stable treatment proposal is found. Explain how environment must be keep the same without dehydration, which causes the cell walls of the wall to collapse when waster or liquid is removed quickly.

Storage

Discuss environments that do not promote mold/bacteria/pest growth. Add proper handling skills.

Conservation treatment

The problem with conservation treatments to waterlogged wood and to stabilize the materials has been changed throughout the course of time. Some treatments include the Polyethylene Glycol (PEG) method, Sucrose method, Acetone-Rosin method, alcohol-Ether method, Camphor-Alcohol method, freeze drying, and silicone oil treatment. One of the largest issues with treatment on waterlogged wood is finding a way to remove the water in the wood but keep the water that is part of the material. Preserving the cell walls of the wood represent the largest struggle in treatment.

Evaporation/displacement/replacement of heavily waterlogged wood

PEG Treatment: purpose: to remove water while simultaneously bulking wood. Waterlogged object is placed in ventilated vat with a solution of PEG and a solvent of water and alcohol. Additional percentages of PEG are added to the solution and through this process the water and alcohol are able to evaporate bringing wax into the waterlogged wood as a form of displacement. I have handled objects like this before (wooden pea barrel lid from a shipwreck) and the object still felt wet or slimy.

Sucrose Treatment: Identical to PEG treatment process but sucrose is used.

Acetone-Rosin Treatment: Treatment used on dense wood that cannot be penetrated by PEG. Goal is to replace cells of wood with natural rosin.

Dehydration

Alcohol-Ether Treatment: replace cells with alcohol, the dehydrate cells/object.

Camphor-alcohol Treatment: similar to alcohol ether treatment but slowly replaces cell walls with camphor which goes from a solid to a gas state over time, keeping walls of cells bulked.

Resources

NPS Handbook

Conservation sources

Case studies

Alexandria Ship Project

January 2016 a mid 18th century ship was discovered on the waterfront of Alexandria, Virginia. Conservation efforts include keeping the wood submerged and wet since the wooden framed was waterlogged. the conservation history of this ship is ongoing. When the waterlogged wooden frame was originally removed from the archaeological site, the timber frames were stored in fresh water vats until June 2017. The framed structure was then packaged and sent to the Conservation Research Laboratory at Texas A&M University for conservation. Documenting and conservation included laser scanning, modeling, X-ray, and wood degradation analysis before the treatment using polyethylene glycol and vacuum freeze drying.

References

http://nautarch.tamu.edu/CRL/Alexandria/conservation/index.html#work

Conservation and restoration of shipwreck artifacts Maritime archaeology

https://www-sciencedirect-com.proxy1.library.jhu.edu/science/article/pii/S1296207412000544