Both Trevor and Nick point out that CCA treated lumber should be painted.
Do either of them know whether specific guidelines as to quality and type of
paint were developed?

Because of the ease of use, water soluble latex based paints seem to be
used frequently.  Depending on their grade, some are by no means
impermeable. The amount of material, vapor, water, and dissolved solids
which are allowed to migrate from the hive body to the interior surface is
relevant to both disease and preservatives.

Comments regarding grade and type of paint used in the field would be
appreciated.

> Work done in the 1970's in the USA showed that timber (lumber) treated with
> CCA (copper chrome arsenate) could give a residue in hive products.  This was
> for timber used in boxes and not painted.  Even though the CCA formulation is
> supposed to have the arsenic bonded in an insoluble form by the chromium,
> trials have shown that there is still a certain amount of leaching of the
> arsenic.  This would be the case inside a beehive, particularly if there is
> condensation.

> The opinion of our wood chemists here in Australia at the time was that by
> painting the exposed surfaces of the timber, you would stop any leaching of
> the arsenic.  It should not bleed through the paint if the timber is dry.

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Richard Yarnell, SHAMBLES WORKSHOPS | No gimmick we try, no "scientific"
Beavercreek, OR. Makers of fine     | fix we attempt, will save our planet
Wooden Canoes, The Stack(R) urban   | until we reduce the population. Let's
composter, fly tying benches        | leave our kids a decent place to live.

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