[Nhcoll-l] Wooden storage cabinets

[Callomon,Paul]

Wood is a better thermal insulator than metal, so if the temperature in your space fluctuates significantly then the atmosphere inside tightly-sealed wooden cabinets will tend to react less to that. Metal cabinets react much faster, and if humidity is high this can lead to condensation issues such as mold and rust as the cabinets can be the coldest things in a humid, warming room.

Tightly-sealed wood cabinets are nevertheless hazardous for Byne's because acetic and formic acids are volatile at room temperature, so they will migrate out of the wood and go in search of things to eat regardless of atmospheric conditions. Lower humidity within the cabinets mitigates this problem to some degree, but does not solve it, and some woods such as oak are known to exude a lot of acid. It may be possible to mitigate this with the equivalent of the "sacrificial anode" on a wooden ship (that is, place a tray of hygroscopic alkaline material in the cabinet that is more attractive to the acids than the specimens) but I have not seen this done.

On the other hand, powder-coated metal (not painted) exudes no VOCs (we tested; see https://www.researchgate.net/publication/267271211_A_grand_scale_rehousing_the_mollusk_collection_at_the_Academy_of_Natural_Sciences) and of course resists fire over long periods better than wood, which burns. For short fires, however, the thermal insulation qualities of a wooden cabinet might actually protect the contents better than metal. How good are (a) your fire brigade and (b) your institution's disaster plan?

Finally, the wood used to make cabinets will originally have been kiln-dried to a low water content (5% or less) to make it stable enough for joinery and finishing. If it was then varnished or painted, its water content is not likely to have risen much since - and in many buildings it will actually have continued to dry and shrink, especially if they are heated.


Paul Callomon
Collection Manager, Malacology and General Invertebrates
________________________________
Academy of Natural Sciences of Drexel University
1900 Benjamin Franklin Parkway, Philadelphia PA 19103-1195, USA
prc44 at drexel.edu<mailto:prc44 at drexel.edu> Tel 215-405-5096 - Fax 215-299-1170

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