A bit off target.

Epoxy fumes are negligible and not, to my knowledge, affected by any air quality
regulations in California or elsewhere.

Polyester amd vinylester resins, when used in open molds, give off significant
amounts of styrene vapors. This is the distinctive smell of these resins. Air
quality regulations in California and more broadly are greatly reducing
permissible levels of emission of styrene and other solvents for all but the very
smallest commercial boat builders.
Some quality-oriented builders (e.g., Tartan) have switched to epoxies, while
others are switching to a process called infusion.
In a typical infusion process, the reinforcement materials are laid up dry in an
open mold, then covered with a vacuum bag. In a small part, a vacuum is drawn
from one end of the part while catalyzed resin is supplied, at atmospheric
pressure, to the other end. The resin is drawn across the part, wetting out the
reinforcements. When the part is fully infused, the resin supply is closed, and
the vacuum compacts the layup for the duration of the cure. A byproduct of this
method is that, once the process is debugged, quality levels are improved over the
wet-layup process, with fewer boids and higher glass-resin ratios.
Production boatbuilders, particularly those whose price-quality position can't
justify the benefits of epoxy, really have no choice but to go this way. For
one-off amateur builders, I've only heard of infusion being used by a few
ambitious multihullers.


"William R. Watt" wrote:

"Meindert Sprang" ) writes:

Fumes? from epoxy?

California has environmental laws which prohibit releasing fumes from
curing resins into the atmosphere. Boat shops have to have elaborate
ventilation systems. Some have left the state. Someone has developed a dry
vacuum bagging process to contain the fumes from curing resins. The hull
is vacuum bagged dry and the resin is pumped in so it is never in contact
with the atmosphere.

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