You can buy plastic storage bins and plywood sheets at any home improvement store.
Choose a drill bit that has an equal or slightly larger diameter than the 1. 25 in (3. 2 cm)-long bolts you’ll be inserting, so that the pilot holes are large enough to accept the bolts. Either prop the plywood up on blocks or low sawhorses, or place it on soft ground. That way, you won’t drill into the floor of your garage, workshop, or driveway! Drill a total of 20 pilot holes—2 per bin, 1 per handle.
So, on one side of the plywood, each piece of duct tape will cover one bolt head and one washer that’s pinned between the bolt head and the plywood. The other end of each bolt will be sticking out of the other side of the plywood. Galvanized bolts are rust-resistant and will hold up better on the water.
Finish tightening the bolts with a ratchet that has an extension attached to it, or with a power drill that has an extended ratchet bit attached to it.
For instance, to create an 8 ft × 8 ft (2. 4 m × 2. 4 m) raft, place 2 smaller rafts together long side to long side. Then use 2, 8 ft (2. 4 m) long pieces of 2 in × 4 in (5. 1 cm × 10. 2 cm) lumber to connect the decks along their short sides. Drive in at least 1, 2. 25 in (5. 7 cm) galvanized screw per linear 1 ft (30 cm) of 2 in × 4 in (5. 1 cm × 10. 2 cm) lumber.
The plastic bins provide ample buoyancy for this raft. However, overloading the raft makes it more likely someone will fall off, so stick to 2-3 people per 8 ft × 4 ft (2. 4 m × 1. 2 m) section. Make sure everyone has a life vest on at all times. This raft is OK for slow-moving water (such as a lazy river), but keep it out of fast-moving or rough water.
“Medium grit” generally refers to sandpaper with a grit number between 60 and 100. [10] X Research source
Repeat this process with the other 7 end caps and pipe ends. You’ll find small (separate) cans of PVC primer and PVC cement in the plumbing supplies section of any home improvement store. Work in a well-ventilated area to dissipate the fumes created by the PVC cement, and wear work gloves to keep it off of your hands.
This step isn’t absolutely necessary, since the PVC cement should provide a lasting watertight seal. However, the caulk does provide extra insurance. Use a caulk that is labeled as water-resistant.
In reality, then, your rectangle will have 4, 1 ft (30 cm)-long “tails” of PVC pipe sticking out beyond its corners.
Make the pilot holes with a drill bit that has a slightly smaller diameter than the 2 in (5. 1 cm) brass screws you’ll be inserting.
You’ll be doing this for all the screws, but work one-at-a-time. You can buy tubs of silicone gel at your local home improvement store.
Dip the brass screws into the silicone gel as before. If you can’t find a large enough sheet of plywood—some stores carry a maximum size of 8 ft × 4 ft (2. 4 m × 1. 2 m)—attach 2 more 5 ft (1. 5 m) pieces of lumber to the PVC pipes, spaced out evenly between the 2 at the ends of the raft. Then, cut 4 sheets of plywood to 5 ft × 2. 5 ft (1. 52 m × 0. 76 m) lengths and secure them side-by-side over the 4 supports.
To add some extra buoyancy, you can glue sheets of rigid foam insulation to the underside of the plywood deck. Pick a glue intended for use with rigid foam. Even with this extra buoyancy, though, keep this raft on calm water.
