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Methods of Freezing and Drying Books
Home Freezer
If there are just a few wet items, you can use a home chest freezer. Set the temperature to minus 10 or lower.
Freezer drying can take place through dehydration in a freezer with an automatic defrost cycle. The defrost cycle, combined with the movement of air inside the freezer, will pull the moisture out of the item, This takes place very slowly, over a period of months.
Vacuum Freeze Drying
Vacuum freeze drying is considered the safest and most effective method for drying. It's also the most expensive.
Frozen materials are placed in a vacuum chamber.
The water sublimates directly from a solid (ice) state to a gaseous (vapor) state.
There are only a few companies in the U.S. that do vacuum freeze drying.
Books come out of this process very dry--sometime overly dry--because there is no humidity in a vacuum.
Vacuum Thermal Drying
This method uses a chamber but the books are not frozen first, or if they have been, they are allowed to defrost.
Vaporization occurs when water passes out of the books, as a liquid.
Because books continue to react to the moisture as they are drying, they may warp, and the pages may cockle a great deal.
Other problems can occur as well -- like fusing of paper, particularly coated paper. Also, water soluble inks and water soluble adhesives may spread and migrate.
The process is less expensive than vacuum freeze drying. There are more disaster recovery firms that offer this method.
On-Site Desiccant Dehumidification also called "space drying"
This method dries everything in the area--walls, draperies, carpet, furniture, shelving, and books--all at the same time. It is very economical because you don't have to move the books.
It works best when the books are not overly wet and not swelling on the shelves greatly
It is carried out by using heavy-duty dehumidification machinery and lots of air circulation.
Some companies specialize in this form of drying, which has been used for many years for military and commercial applications.
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