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A [ Plywood/Epoxy ]
Hot Tub / Swim Spa
Below the 103 degree spa in use mid winter 1988.
It was constructed mainly with 1/2" roof sheeting from
84 lumber, probably B/C. It is 18 feet long,5 feet wide,
and 42 inch side walls with 3 foot deep water. The first
three feet has nozzles and benches for Hot Tub action.
The open 14 ft. section was to have been kept at a
cooler temperature for exercise swimming. I had too many
by-pass leaks to maintain much of a temperature
difference. The disinfectant used was Bromine to
minimize eye irritation.
This next photo shows the completed project with
a prototype working model of an Air Lift Swim Pump
temporarily positioned.. This development was
subsequently abandoned.That is an 18 foot long Roll Out
insulated Lid in the background.
Early fall 1987. These two shots show the two
long sides before backfilling the excavation. The
greenish side is a single layer of six oz. glass filled
with WEST epoxy. It is on the tensil side of the wall
structure.
This photo shows the Drain End and as apposed to
the Nozzle End. The scalloped shape was to reverse the
direction of the flowing swim current. This shape was
strip planked with plywood strips and glassed on two
sides, though incompletely on the back or dry side. The
theory I was working under was to let any moisture which
entered the wood thru the primary barrier should be
allowed to escape much more easily on the dry side. The
Gray color was a WEST pigmented epoxy.
This is a shot of both end structures stacked for
elbow room. The nozzle end houses the pumps, controls
and skimmer. The second shot shows the back or dry side
of the drain end.
The Bottom or floor was constructed first. It was
insulated with loose cellulose insulation, then covered
with 1/2 in. non-marine plywood. That was covered with
six oz glass cloth set in epoxy. This was then used as a
casting table for the outside or dry side of the two
sixteen foot walls. The side wall frame shown was
notched together plywood strips. A polyethylene drop
cloth served as a release barrier on which the
glass cloth and epoxy were laid. A second liquid coat
was applied and the frame set down on that.
Cellulose was used to fill the spaces in the
frame. Plywood was then bonded to the top of the frame
as shown. The photo to the right shows the plywood on
the "wet" side being coated with glass cloth and
epoxy
The finnish "blue" is a two part pool epoxy said
to be good for seven years in direct sun. It was made by
Kelley Technical Coatings, Louisville, KY. and has been
recoated twice plus the original.
These last two photos were taken in June 2003 in
prep for spring cleaning. Fifteen years has elapsed. The
only soft wood that I have found were two places on the
top rim where rain water could enter an unprotected edge
of the plywood.
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