Watering plants is a therapeutic activity. It allows for people to relax and get physical activity. However, people who are disabled are not able to operate a watering can. They lack the necessary strength and fine motor skills to be able to use a watering can. The goal of our project was to engineer a watering can that is able to be used by people who are disabled and lack strength and fine motor skills to operate standard watering cans.
Step 1: Gather Materials
The first step to constructing a watering can for people who are disabled is to obtain the necessary materials.
1. Oil Based Clay https://www.utrechtart.com/Plastalina-Modeling-Cla... $14.49 for 4.5 lbs.
2. Rebound 25 (2 Trial Sizes) https://www.smooth-on.com/products/rebound-25/ $64.42 for both
3. Plasti Paste II (1 Trial Size) https://www.smooth-on.com/products/rebound-25/ $35.65
4. Polymer Resin (1 Gallon) https://www.smooth-on.com/products/rebound-25/ $91.86
5. Thi-Vex (1 Ounce) https://www.smooth-on.com/products/rebound-25/ $3.30
6. Easy Release 200 (1 Can) https://www.smooth-on.com/products/rebound-25/ $12.45
7. Rubber Stoppers (1 Per Can) https://www.walmart.com/ip/RSTPK2-2LB-Stopper-Asso... $18.46 for several.
8. Fishing line (Roughly a foot per can) https://www.walmart.com/ip/Stren-High-Impact-Fishi... $7.90 for several feet.
9. Wood Paint Sticks (Half Per Can) https://www.amazon.com/dp/B076BXLDQN/ref=asc_df_B0... $12.86 for 25 wood sticks
10. Eyelet (1 Per Can) https://www.joann.com/eyelet-outlet-eyelets-washer... $2.69 for 50 eyelets
1. Plastic Cups
2. Wooden Sticks
4. Power Sander
5. Wire Cutters
Step 2: Clay and Styrofoam
The second step is to mold the watering can. This can first be accomplished by cutting the styrofoam. Then, clay can be placed on the styrofoam to form a smooth finish. It is important to make the clay as smooth as possible because all imperfections will be shown in the final watering can.
Step 3: Silicon Mold
The second step is to form the silicon mold. This was done by mixing equal parts A and B into a plastic cup and then stirring the cup. Then, the silicon was applied in five layers using a brush. The first three layers being thin and the second two, thick. The thick layers had Thi-Vex a few drops of mixed in. These layers needed about half an hour to reach a slightly solid but sticky state and another six hours to solidify. The next layer should be applied when the silicon is sticky but not coming off the mold after being touched.
Step 4: Plasti Paste
Plasti Paste was applied to the top of the silicon. It was put on in two layers. Each layer was very thick and the mold was well-covered. The Plasti Paste hardened and the mold was supported. The Plasti Paste was mixed in a large container to prevent it from spilling. The Plasti Paste hardened after about two hours. The Plasti Paste was applied using a knife and a brush.
Step 5: Remove the Clay
At this point, the layers should have all been formed around the clay. The clay should be removed and the mold should be trimmed to prepare it for formation. Our mold was formed on newspaper so we had to remove any paper that was on the silicon. However, once it had been removed the mold was ready for formation. We found it was easiest to remove the mold by first removing the spout and then removing the body and last, the handle.
Step 6: Rotocasting
The can was then rotocasted. The molds were attached using clamps. The plastic resin was mixed and poured into the watering can, and the mold was moved up and down and rotated so that resin would get everywhere. Three layers were applied and the plastic was pooled in the feet to solidify them. It is important to get plastic everywhere in thick layers. to allow for the next steps and to form a sturdy watering can. It is also important to make sure that the molds align properly before spinning.
Step 7: Sanding
Now that the watering can has hardened and solidified in plastic, it is time to clean up the design. At this point it is important to sand out any undesired imperfections in the watering can to prepare it for the implementation of mechanisms. These can be sanded out using regular sandpaper, but we used a power sander.
Step 8: Implementing Mechanisms
Next, the mechanisms were implemented. The trigger mechanism and the spring were added to keep the watering can working. The spring was put in the spout and using a peg was held in place. Then, the trigger was put in the handle by cutting a hole in the handle using the wire cutters and putting the trigger through the handle. Then the handle was attached to the stopper and the stopper to the spring using fishing line. The stopper is placed right where the spout meets the body.
Step 9: Improvements and Extensions
The principle improvement to this project would be to clean up the mold a bit. There are a couple of imperfections that exist in the final design Also, there could be more work done with the alignment of the molds which can be difficult to work with. Also, if possible it would be interesting to try vacuum forming which may create a cleaner final design. Similarly, the group ultimately decided to adhere two half molds, and then rotocast. It may have created different results if we decided to rotocast with two separate halves first and then adhere.
Step 10: Resources and References
There are many available places for more information about rotocasting and watering cans for disabled people in general.
Videos about rotocasting and molding and casting in general:
References for more information about people that are disabled and watering cans and different plastic formation methods:
The Best Watering Can (Outdoor and Indoor). (n.d.). Retrieved February 27, 2018, from https://thewirecutter.com/reviews/the-best-wateri...
FAQs Frequently Asked Questions. (n.d.). Retrieved March 02, 2018, from http://www.fiberpad.com/faqs.ph
Injection Moulding. (n.d.). Retrieved February 27, 2018, from http://www.fiberpad.com/faqs.php Monosoff, T. (2005, October 23).
Creating a Product Prototype. Retrieved February 27, 2018, from https://www.entrepreneur.com/article/8067
Plastic Moulding Techniques. (n.d.). Retrieved February 27, 2018, from https://www.entrepreneur.com/article/80678
Plastic Reference Tables. (n.d.). Retrieved February 27, 2018, from https://www.entrepreneur.com/article/8067
Systems, J., & Jaycon Systems. (2017, August 01). All You Need to Know About Rotocasting – Jaycon Systems – Medium. Retrieved March 25, 2018, from https://www.entrepreneur.com/article/80678
Thrive. (n.d.). Watering Cans for People That Are Disabled. Retrieved February 27, 2018, from https://www.entrepreneur.com/article/80678
Vacuum & Pressure Forming. (n.d.). Retrieved February 27, 2018, from https://www.entrepreneur.com/article/80678