The concrete filled milk jug buoy system, as seen above, is a moderately difficult do-it-yourself contraption to create. The concrete mixture used in this Instructable is lighter than water; therefore, the milk jugs will float. Depending on the experience you have with concrete, the whole project should take 1.5 to 2 hours to complete and a couple of days to let the concrete dry.
Step 1: Supplies
The supplies shown in order are:
milk jug (need 2), rope, 0.5 to 1 mm glass bubbles, 1 to 2 mm glass bubbles, 0.25 to 0.5 mm glass bubbles, white pozzolans (VCAS-140), #16 aggregate, #8 aggregate, flyash, air entraining admixture (AEA) admixture, water reducer, K1, Portland cement, electronic scale, mixing bowl, trowel, funnel, and the lab cement mixer.
The rope can be any length you need depending on the distance swum or paddled.
Step 2: Safety Precautions
• Always wear goggles and a disposable respirator mask, as seen in Figure 1, to prevent irritation in the mouth and eyes from the fine particles used in creating the concrete.
• Gloves may also be worn to prevent any possible irritation of the skin.
• Don’t inhale the strange fumes from the AEA and water reducer. It makes the working area smell bad quickly.
• Keep hands away from the moving parts from the lab cement mixer while in use.
Step 3: Creating the Aggregate
Step 4: Adding the Absorbing Water
Step 5: Creating the Cementuous Materials
Step 6: Mixing Together the Aggregate and Cementuous Materials
Step 7: Adding the Admixtures & Batch Water
The admixtures mixed into the batch should be 7 mL of the water reducer and 0.7 mL of AEA. Add the admixtures together and then slowly add them into the cement mixing bowl.
Figure 4 shows the buttons on the cement mixer to adjust the speed and duration (if needed) of the mixing action. To start the mixer, just press the black “start” button and continue until the concrete looks like what is in the mixer bowl in Figure 5. To stop the mixing action, just press the red “stop” button.
Step 8: Putting the Concrete in the Milk Jug
*If the concrete stops moving, use a rod to shove the concrete down the funnel.
After the milk jug is filled with concrete, cap it and then shake it to help move the concrete into the handle of the jug. After all portions of the jug are filled with concrete, just flip it over and have it standing upside down for the next couple of days, as shown in Figure 6, to allowing the concrete to harden.