Successes and Failures

Our first test of the mold we 3D printed totally failed. It was easy to reuse the chicken wire reinforcement we made for it though because the concrete didn't cure at all or stick to the wire. Our informed guest is we used contaminated sand that somehow stop the concrete from curing. This thought us that for future pours and concrete tests we need to have control/test pieces that can show what's wrong with the concrete. If the test piece also fails we know its something wrong with the concrete not the mold. 

Our initial mold design is a straight cylinder which after conversations with other groups and our collaborators will make it difficult to take the cured concrete out of the mold. If we have to destroy the mold we can sacrifice it, but a final design needs to be reusable. This could be done with a tapered shape that makes it easier to remove the duct tape or a design that we can disassemble to remove from the mold. 

Today in our lab we broke two blades of the scroll saw as we were trying to cut a circle for our concrete mold. The lab techs had begun to get upset with us by the end of our time in the shop and stopped being as helpful. 

After spending all the time cutting the wood we realized it would've been better to have a thinner piece of wood that match our desired thickness of concrete.  Instead, we had to leave a small gap and compress the concrete into the mold. 

After a week of watering a letter our concrete dry, one of the test pieces we made was too large to be compared to the other test pieces. The piece was poured way too thick and didn't allow us to test it against the other test pieces. 

One of our test pieces with a high density fiberglass mesh failed immediately, which could also be consider a success! Since it taught us it won't be a great method for creating a strong piece of concrete. 

After one of the first pour tests we did of our design we noticed that the concrete didn't stick to the duct tape we used to tape a bag over our mold to prevent sticking. After some research, we found that some contractors swear by duct tape for their forms to prevent concrete from sticking. We decided to cover our mold with duct tape to see the feasibility of using it as a way to prevent the concrete from sticking. The duct tape can also be combined with motor oil to insure the concrete from sticking to the mold. 

After discussions with our collaborators and looking into the heating need of our school, we decided that the best course of action for their cooking needs should be a more efficient wood cooking stove instead of fully-solar electric setup. Andrew, one of our collaborators, recommended the company MASRCORP that builds cook stoves in Uganda. We forwarded this information to our contact with the school, Elwyn, who was able to get an initial quote of £1,500. This cost could hopefully be decreased with a stove designs that better fits the school's needs and cheaper solar panels. 

One of the biggest issues we've been facing with using the mold design for our concrete is that we have trouble fitting the concrete into the small gaps of the mold. In our last lab we tried using a massage gun to vibrate the concrete and settle it into the mold. This worked surprisingly well as the concrete when it was being vibrated easily fell into the vertical part of our mold and worked much better by packing it by hand. More research will have to be done about the best methods to vibrate concrete and how it could be done in Uganda. Once we take the concrete of our mold we will have to see the strength of it after the vibration. A concern of using vibration to settle it into the mold is that it also causes our aggregate to settle unevenly along the bottom of our mold. More information can be seen on the Concrete Molding section of our website. 

We were able to design a testing method for our test pieces of concrete and achieved useful results from the test. We found that the concrete with a loose concrete mesh was able to withstand the most force from dropping a metal rod on it. 

We poured two more larger pieces of concrete that will hopeful get us closer to our final design and tell us more about create thin concrete circles. We did this by making wood molds using our Red Tags! Along with a lot of great teamwork. 

We've had success getting into contact with our multiple collaborators for this project. There's difficulty, because everyone lives in a different part of the world, but we've received information on what the meals look like for the school. We can use this information to start thinking about what ISEC would be able to do for the school's needs.