BUILDING PLYWOOD AND EPOXY GROW OUT SYSTEMS
The students were out looking in construction dumpsters. Mikey found a large piece of plate glass that had been taken out of the store window, so he asked the owner if he could bring it over to the school for them. Now they have to design an aquarium for the hatchery that uses that piece of glass, so they're going to learn to make wooden aquariums and coat them with epoxy paint.
This month we will continue with our series of articles on building your own reef farm equipment. We have made these plywood aquariums for over 40 years, and they are very sturdy. LeRoy built an entire saltwater fish store in Boise in 1972 from plywood and epoxy paint. These tanks lasted more than twenty years. We use swimming pool paint that is sold in two parts. We purchase one gallon of paint and it comes with one gallon of curing agent. We use white or light blue because it reflects light and the paint is stronger when you use less color.
You can use these plans to design any size aquarium system you want. A good size reef farm can be started by building two of the 140 gallon brood stock aquariums and three of the four by two foot grow - out aquariums.
BASIC GROW - OUT TANKS STACKED THREE HIGHThese aquariums can be used as a flow through system or each tank can be set up as one system.
Drill all holes in the aquariums before you paint them. Make all overflow pipes at least two inches. It is much better to have the pipes too big. You may decide to use a larger pump later and if the holes are too small you will have problems.
We use two by four lumber to construct the stands and it is important to paint all of the stands with water proof paint. White paint reflects light and it saves energy. Several of these three tank systems can be attached to one central sump. This will save money, but if something bad like algae gets into one tank it can spread to the others. We are certain that separate systems are better in many reef farms.
The distance between the tanks is important! We always make certain that a five gallon plastic bucket can be poured into the lower aquarium. After years of hatchery work we have learned that this simple thing can save time almost every day.
140-GALLON GROW-OUT TANK
- (1) Length: 96 inches (94.5 inches inside)
- (2) Width:24 inches (22.5 inches inside)
- (3) Height: 16 3/4 inches (16 inches inside)
- (4) Water capacity (.75-inch freeboard): 140 GALLON
The most important thing is to have safety gloves and safety goggles when you're cutting glass.
1. Measure and mark the glass with a straight line. A grease pencil works very good or a felt marker. A drawing board and a T square works best for us.
2. Put a little bit of oil on the glass cutter so it has a coating of oil on the wheel.
3. Hold the glass firmly and make sure that it's flat.
3. Take the glass cutter and apply slight pressure and score the glass carefully along the lines.
You want to be sure that you don't miss an area, and do not go back over the scored line
The secret to cutting glass is the perfect score. The secret to the perfect score is firm, even pressure perpendicular to the glass. Hold it tight and then make a good, clean cut.
4. Place the glass on the edge of the table and snap the glass using a firm push down. You can easily break the sheet of glass along the cut if there is enough glass on each side of the cut to get a firm hold on. If not put it into one of the notches on the shank of the glass cutter and you can then easily break it off.
5. When you cut a sheet of glass the edge left by the cutter will be slightly rough. To smooth it up and round off the corners rub it on a whetstone, that is any kind of a coarse stone on which you have poured a little water. A better way is to grind it on a grindstone if you have one.
TANK IS A 2-3 PERSON PROJECT
- a. 1- portable or table power saw
- b. 1- screw gun, with Phillips bit
- c. 1- orbital or belt sander, with medium grit
- d. l-caulking gun
- e. 4- 4-inch paint brushes, one for each day of painting [ KEEP BRUSHES IN FREEZER TO REUSE ]
- f. 2- 16-inch stanchions (May be boxes, or anything of this height, used to support the plywood pieces during
- g. 3-6 Various containers for mixing glue, putty, and paint
Materials List (Sufficient to build two  tanks)
- a. 3- 4-foot by 8-foot sheets, 3/4 inch, AC EXTERIOR plywood
- b. 2- 94-inch by 14-inch glass, 1/4-inch plate
- c. 1.5-pounds, 2-inch drywall screws (Approx. 240 count)
- d. l-two-can container, Resorcenol waterproof glue
- e. l-gallon, autobody putty w/ hardener
- f. 5- gallons, two-part epoxy paint
- g. 2-tubes, silicon caulking, non-toxic aquarium suitable
- h. l-gallon, Xylene glass cleaner
- i. 1- pint, commercial glass cleaner
- j. 6-sheets, 120 grit sandpaper
- k. 2-sheets, 220 grit sandpaper
- l. 2-packs, paper towels Sufficient for more than two tanks
Plywood Cut List (Sufficient to build two  tanks)
- a. (2) 24-inch by 8-foot (bottom panel)
- b. (2) 16-inch by 8-foot (backpanel)
- c. (4) 3-inch by 8-foot (upper & lower face frames)
- d. (4) 3-inch by 10-inch (left & right face frames)
- e. (4) 16-inch by 22 1/2-inch (endpanels)
- f. (2) 12-inch by 22 1/2-inch (top brace)
A clean, dry work area is needed, indoors if necessary to insure cleanliness, out-of-doors if possible. Secondary, well ventilated, warm area for final tank drying after construction.
Single Tank Construction Procedure, Tank Assembly
a. Inspect all plywood pieces for rough or flawed edges, which might later affect tank integrity. Sand as needed.
b. Lay bottom panel on the 16-inch stanchions.
c. Apply glue along all four edges of bottom panel, sufficiently heavy to accommodate the edges of the backpanel, endpanels, and face frame.
e. Raise backpanel up under bottom panel, mating long edge of backpanel into glue along edge of bottom panel. Insure that edges are flush, and that they make a 90-degree corner.
d. Turn bottom panel over, glue side down, centered on stanchions so that all edges of bottom panel are accessible.
f. Using screwgun, screw backpanel to bottom panel, inserting 2-inch drywall screws at 3-inch intervals along entire length. INSURE THAT ALL SCREWS ARE FULLY SEAlED, AND TIGHT.
g. Apply glue along one 16 inch edge of each endpanel.
(h) Raise each endpanel up under bottom panel, and screw
tightly to both bottom
panel and backpanel. Place drywall screws at three inch intervals.
i. Apply glue along inside edges of face frame, where they will mate with the endpanels.
Raise lower face frame up under remaining edge of bottom-panel, and screw into place to bottom panel and endpanels.
j. Use three (3) screws in each end, and normal three-inch intervals along length. Insure that all edges are flush, and tight, after final tightening of screws.
*** WIPE EXCESS GLUE FROM ALL JOINTS AFTER FINAL TIGHTENING, AS IT IS VERY DIFFICULT TO CHIP OR SAND AWAY AFTER IT IS HARDENED. ***
k. Turn partially-completed tank right side up on stanchions for inspection. At this point, all panels screwed together should rest on the bottom panel, for the strongest possible base.
is not the case, quickly disassemble the pieces before the glue sets, and reassemble properly.
1. Turn the tank face-up on the stanchions.
m. Apply glue to FRONT exposed edges of endpanels.
n. Lay upper face frame in place, and screw to edge panels, using three screws in each end.
o. Check short face frame pieces for proper fit, sanding if necessary. THEY MUST FIT TIGHTLY WITHOUT SPRINGING UPPER AND LOWER FACE FRAME PIECES APART.
p. Apply glue to ends of short face frame pieces.
q. Lay short face frame pieces into place, and screw firmly
to end panels, insuring that the outer edges are flush with the ends of the tank.
r. Recheck all work, wiping away excess glue, and insuring that corners are square, true, and not pulled open by later construction.
s. Allow to dry overnight if possible, though this is not critical.
Single Tank Construction Procedure, Painting --
Precautions FOR ALL PROCEDURES INVOLVING EPOXY PAINT, THE FOLLOWING PRECAUTIONS MUST BE ADHERED TO.
- 1. NO SMOKING
- 2. DO NOT LET BRUSHES DRY
- 3. DO NOT BREATH FUMES
APPLY PAINT IN A WELL-VENTILATED AREA, PREFERABLY OUT-OF-DOORS, AND MOST ESPECIALLY AWAY FROM THE AIR SUPPLY INTAKE. THE FUMES ARE HIGHLY TOXIC, AND MAY RESULT IN SERIOUS RESPIRATORY PROBLEMS IN HUMANS IF THEY ARE CONCENTRATED AND EXPOSURE IS PROLONGED.
a. Apply epoxy paint to all exposed wood surfaces of tank.
b. Make coat of paint as thin as possible, while covering the wood surfaces completely, because the paint runs easily.
c. Allow coat to dry overnight.
d. Fill all cracks and holes with autobody putty, making as smooth a surface as possible.
e. Sand entire surface, using 120-grit paper or power sander, and apply second coat.
Again, insure that the coat is as thin as possible, to avoid running paint.
Use the 120-grit sandpaper for sanding the first two coats of epoxy paint.
220-grit for sanding the third coat, in preparation for the fourth or final finish coat.
(If power sander is used. then the sanding pressure applied would be less for the last coat.)
Repeat procedure in steps until four (4) coats of the epoxy paint are applied.
Allow tank to dry in well-ventilated, warm area for 24 hours before proceeding.
Glass Installation Single Tank Construction Procedure, Glass Installation --
a. Turn tank face down on level, flat surface, insuring that entire face frame is supported.
b. Use 220-grit sandpaper to rough up a two-inch strip of the epoxy paint on the inside of the tank, around the glass opening. This rough area will serve as a bonding area for the silicon glue.
c. Sand or file all corners of the glass panel, to avoid later injury to either workers or fish.
d. Clean entire surface, and edges, of glass panel with Xylene cleaner, and then commercial glass cleaner.
e. Apply 1/2-inch bead of silicon caulking around entire opening in face frame, on inside of tank. The bead should be approximately one inch from edge of opening, except along the top, and there the bead should be approximately one-half inch from edge of opening.
f. Install glass on inside of tank, insuring that the lower edge of the glass is resting full-length against bottom panel of tank for support.
g. Press evenly on glass to remove all bubbles and gaps from silicon caulking seal.
h. Recaulk glass, along all edges. pressing caulking with finger firmly into the corner formed by glass and face frame. Final caulking seal should be smooth, rounded, and gap and bubble free. Wipe any excess caulking away after seal is finished.
Single Tank Construction Procedure, Final Assembly Points
a. Using three screws for each end of brace, install tank top brace, centered, spanning from top, inside edge of backpanel to top inside edge of upper face frame.
b. Apply heavy bead of silicon caulking into all interior corners of tank, again smoothing the seal with finger, removing all gaps and bubbles, and wiping away excess caulking when finished.
Allow tank to dry for 48 hours in warm, dry area before adding water.
This is absolutely the most important part of any plywood fish tank
made, and the least researched by the vast majority of aquarium DIY people.
A tank coating that doesn't poison fish.
The only sealer/coating that is qualified for use in an aquarium is a TWO
PART EPOXY FOR POTABLE WATER TANKS. This coating is used to seal the
interior of several thousand gallon community drinking water tanks, as a
coating for holding tanks in fish farms and as a liner for large public
aquariums. These coatings are NSF 61/USDA/ANSI/AWWA and FDA certified and
approved. Further, epoxy coatings are highly resistant to salts and
corrosion and are recommended for marine
Some brand name coatings that can be used are:
----- carbolene brand "891" epoxy with color choices one of which is
----- dupont brand "epoxide hs tank lining"-------
----- sherwin williams brand "tank clad hs epoxy"-----
----- rustoleum brand "9200" system epoxy with color choices one of which
is "9271" dunes
These epoxies contain no solvents or volatile organic compounds and
are usually composed of 100% solids. Additionally, solvents and thinners
are not recommended for use with this epoxy because they would defeat the
purpose of using a non-toxic coating. There are other manufacturers of epoxy
and many of them have nsf 61 approved epoxy for potable water. Further, if
one finds an epoxy that is not recommended for use with potable water, not
nsf 61 certified, I suggest against using it.
This potable water epoxy may
cost a little more than a different coating but on the other hand, IT IS NOT
POISONOUS TO FISH. From what I have read, I could suggest against using as
a tank liner; enamel, acrylic enamel, urethane, fiberglass, gel coat and
polyester resin, all of these release/outgass poisonous volatile organic
compounds, VOC's. On a side note, in my opinion, only the part of the tank
that touches the water needs to be coated with this epoxy. The outside of
the tank can be coated with a less expensive paint, maybe a urethane.