Dick Allen said:

> I've been making my frames from 3/8 inch plywood.

Wow, you must have a lot of time on your hands up there
in Alaska - we crank out lots of other woodenware on a table
saw, but frames are the one thing we have never bothered to make.
we can't justify the time that would be required.  Maybe you have
a design that makes for a much more simple frame, and faster
fabrication.  Can you post a sketch?

> Someone, somewhere once told me they thought plywood resin,
> even after being cured, could still give off vapors or volatiles or
> whatever they are termed. I don't quite buy it.

You should buy it.  It is 100% true.  "Outgassing" happens with ALL
plywood and Oriented Strand Board (OSB) variations.  The stuff being
outgassed is one of two types of formaldehyde, not very nice stuff to
have near wax and honey, and not nice for people to breathe, either.

> Does anyone in the science community out there know anything
> about that?

Well, I can't claim any in-depth knowledge, but I do know this much,
as I was forced to sit through lots of chemistry lectures, and I wire
houses for Habitat For Humanity:

a) Veneered plywood and particle board are loaded with a nasty
    urea-formaldehyde glue, and they are almost always coated
    with a formaldehyde emitting clear finish.

b) Formaldehyde is a "suspected" carcinogen, meaning that it
    causes cancer in actual lab tests, but the building materials
    industry has been able to pay off enough politicians to enjoy
    the same "protection" as the tobacco industry enjoyed.

c) Construction-grade (meaning "exterior") plywood and oriented
    strand board use a far less noxious phenol-formaldehyde resin glue.

d) What blows my mind is that cheaper "exterior" grades of sheet
    stock (ply/OSB) use the phenol-formaldehyde, while the more
    expensive "interior" sheet stock use the urea-formaldehyde.
    So the stuff you use "outside", where there is lots of ventilation,
    is the less toxic version.

e)  When I wire houses for Habitat, I open windows, even in the
     depths of winter.  I can smell the fumes, even though the
     only plywood in a Habitat house is the plywood subfloor.
     If I do not open the windows, I get a nasty headache, and
     I am not "sensitive" to most pollutants.

> What are the chances that I'm contaminating my honey?

Much higher than if you were plywood-free, for sure.

The outgassing goes on for years, not days, not months.
Do a web search on "plywood outgassing", and you can read
about it.  Again, I can't point to any specific beekeeping-oriented
reference, but both types of formaldehyde certainly can be taken
up by wax, and it is reasonable to infer that it can contaminate
honey if the plywood frames are less than 4 years old.

The bad news is that elevated temperature and humidity causes
higher rates of outgassing, so the interior of a beehive would be
the "best" place to see plywood outgass, even if one allowed it
to "age" at ambient temps for a few months.  At any one
temperature, the plywood only outgasses to a certain point, which
is why builders will often "cook" a new house by turning the heat
up to very high temps for a few days.  Their only concern is the
smell - they want it gone, and it still smells bad even after the
normal multi-month delays of mill, lumberyard, and the entire
period of construction.

> Although the archives had some discussion on plywood hives,
> I didn't see any mention about using it for frames.

I'm not sure a comparison between plywood hives and plywood
frames would be "fair":

1)  A plywood hive would present planar surfaces to the bees, while
     frames would present lots of edges.  All those edges expose the
     glue layers directly.  The glue is the problem here.

2)  A plywood hive would have both "interior" and "exterior" surfaces,
     and, assuming that the internal hive temp would be above ambient,
     the outgassing would tend to be driven outward, given the general
     direction of the heat flow (heat loss through the wood to the exterior).
     The frames would outgas 100% of their fumes into the hive.

3)  Even with a well-ventilated hive, think of the airflow, and you have
     the possible fumes being directed over capped cells and uncapped
     nectar and honey.  As one goes "up" in the hive, one has the possibility
     of the combined outgassing of the frames below, which would elevate
     the possible formaldehyde level for the uppermost frames where your
     crop sits.

4)  I don't know about you, but my super frames get much more wear and
     tear than my brood-chamber frames, and must be replaced more often.
     This means you may have more "newer" frames in supers than in
     brood chambers.

Testing for formaldehyde is not very difficult.  Any decent high-school
chemistry teacher should have the equipment and skills required.
You don't need a High-Performance Liquid Chromatograph, or a
Gas Chromatograph, but they would be able to detect smaller levels
of contamination, down to parts-per-million (GC), or parts-per-billion (HPLC).

        jim

        farmageddon (a circa 1922 brick structure)