By Ken Filipiak
Salmon growing up in a
The science teacher at the school where my
wife works (West Ottawa Macatawa Bay
School in Holland, Michigan) called me for
help with his leaking aquarium which had
flooded his classroom. This was no ordinary
aquarium; it was one he had custom built to
show a progressive ecosystem - a brook to a
stream to a pond for raising salmon.
After reviewing what was there to work
with, we decided to scrap the original tanks
and build new ones. It was a good winter
project we could complete in our shop and
The science room counter top is 24' long and
the assembled tank would span approximately
21'. The tank system needed to clear
the overhead storage and be assembled between
sinks and plumbing fittings. A riser
system allows access under the tanks for
clean up, and provides an air space to help
keep things dry. The risers also let us place
shims to level and align the tanks.
Dry fitting the tanks in the shop. The tanks are built of 1"-thick, 16-ply birch-faced plywood.
A scraper designed to clean out excess epoxy from the groove that holds the "O" ring. The "O" ring seals the joint
between the separate tanks.
It was important to be able to keep the load
(water, tank and seascape) off the bolts
which would hold the tanks together, and
maintain the pressure on the seal at the
pass-through. The bolts, washers and nuts
are stainless steel. Reinforced rubber washers
are placed between the stainless steel washers
and the epoxy coated tank to prevent marring.
We used 1"-thick high-grade (16 ply) birch
faced plywood to construct four tanks. Each
was 63" long, approximately 12" front to
back and varying from 8" to 15" deep. There
were cut-outs in the ends of the center tanks
allowing the fish to pass-through to swim
upstream against the re-circulating water
pumped from the deep end back to the shallow
tank. All the tanks were built to accommodate
any lay-out the class may want by
capping the pass-thru. They could also separate
species by using a screen at the pass-thru
as a barrier-this would allow a cascade of
water for filtering.
Individual tanks were edge glued with WEST SYSTEM 105 Epoxy Resin and 205 Fast
Hardener thickened with 403 Microfibers.
Stainless steel screws held the panels in position
while the epoxy cured. Generous fillets
were added in the corners of the panels to
improve strength. The open end grain on the
plywood panels were allowed to take in as
much epoxy as they could to keep the exposed
edges sealed. Then we gave the entire
tank three to seven coats of epoxy to be sure
there would be no unsealed surface where
water might penetrate.
We paid special attention to the tank end
panels. They had five bolt holes, and alternating
tanks had an O-ring groove for sealing
off against the proceeding tank. Before
assembling the tank, we cut the O-ring
groove with a router. The groove was sized
for a ¼" O-ring stock and cut oversize to allow
for epoxy build up to seal the exposed
edge grain. The groove was cut at 9/32" wide
and ¼" deep; the epoxy build up on the
groove walls set up the proper compression
for the O-ring seal. We made a scraper to
help square the walls of the groove and control
the depth after coating. The outer surfaces
of the tank were sanded flat, this also
helped set the depth of the O-ring groove
and allowed the tanks to be bolted tightly together.
The bolt holes were drilled oversized
and given a generous coating of epoxy to
seal exposed end grain. The holes were all
located inside of the O-ring seal path to reduce
the risk of leakage.
Tempered glass was required for the front
panels. The glass was sealed in place with
aquarium silicone seated in a groove around
the facing of the tank and held in with epoxy
coated hardwood retainers. The retainers
were sanded just below flush and coated separately.
This allowed for servicing the glass
and silicone seal.
We asked a couple of the local businesses to
help out with supplies and Glass Enterprise
and Gentex Corporation stepped up. We appreciate
their support to help make this project
The tank has been in service since late February.
The salmon were released the first week
of June at a length to give them a good
chance of making it to Lake Michigan from
the local stream. We hope to see them back
The bolt holes were all
located inside of the
O-ring seal path to reduce
the risk of leakage.
Holes were drilled oversized
and given a generous
coating of epoxy to
seal exposed end grain.
Filipiak assembling and
leveling the finished
tanks. The tempered
glass face was sealed in
place with aquarium silicone
seated in a groove
around the facing of the
tank and held in with
epoxy coated hardwood
A pass-thru blocked by
stones keeps the salmon
from getting into the
The finished assembled
tank, an operating progressive
flows from a brook to a
stream to a pond.
Epoxyworks 29 / Fall 2009
Copyright© 2009, Gougeon Brothers, Inc. All rights reserved.
Reproduction in any form, in whole or in part, is expressly forbidden without the consent of the publisher. EPOXYWORKS, Gougeon Brothers, WEST SYSTEM, Episize, Scarffer and Microlight as used throughout this publication, are trademarks of Gougeon Brothers, Inc., Bay City, Michigan, USA.