Week 6
About the model
I finished the acrylic box this week. Surprisingly the box didn't leak at all when I finished it. I think this is because the acrylic glue drys out slower than the hot glue, and it does not require heat to melt. Thus I was able to put it at the right place to prevent the water to come out from inside the box. The acrylic glue also has less surface tension, which helps it better stick with the acrylic board.
The other problem I have with the model right now is that the tube for some reason is shorter than the box. I put a lot of glue on the end to attach the tube to the box. The tube is attached but it's still shaking a little bit if I apply force to it.
I applied the glue on the sides and wait for it to dry
The glue is white when first applied and drys out to be clear. You can see the color transition in this picture.
The extra glue I put between the tube and the box to keep the tube in place.
The completed box with the tube in it.
After I've done everything, Rafael checked my work for me. He noticed that connecting part between the tube and the box is not completely circular. He needs it to be exact so he can out the connectors in perfectly. What I did to fix that is I used the circle from the backup piece we printed and glued that between the tube and the box. Another thing I did to keep the box in better shape is I put hot glue on all of the sides. Even though the acrylic glue does a good job to make the box watertight, it is soft even after it drys. On the other hand, hot glue is not as good to keep the box sealed but it is really hard when it's cooled to room temperature. By using the two together, I was able to make the box both watertight and nicely stabled.
The added circular piece in the end.
The completed box with hot glue on all the sides
The next step is to prepare the silicone needed for the model. This time I did it with Rafael. This process what pretty much the same as before except we made a little bit of extra this time. The box was leaking a little bit in the corner when I poured all the silicone in. I think it is because the pressure is way higher when there is a lot of liquid in there compare to when I check the leaks. In general, I worked really well.
Silicone before removing the bubbles.
Completed model in the sillicone.
After leaving the box sitting for two days, I took the box apart. The silicone inside is cured nicely and ready for the next step. I took apart the box and left the model sitting there for another 2 hours before I start dissolving the core inside it.
Removing the glue in the corner to take the box apart
The model without box.
After the silicone is completely cured, I put the model in the water. I come back and check on the model every 15 minutes and try to use the tweezer to remove the partially dissolved part in there. Rafael showed me by using running hot water, the PVA in there can dissolve quickly.
Model when first put into water.
Part of the PVA is dissolved
Using running hot water to remove the PVA
Model after the PVA is removed.
About the 3D design part
I finished the part this week. It is actually easy once I figured how to do everything. I did it in one afternoon. I haven't printed it yet and hopefully it will work the way I wanted.