Progress Report: Materials Testing ManoTech Associates Jina Kim Forrest Liau David Lin Teresa Wang

Review of Project Goals Fulfills two criteria:  Low-cost materials  Anatomically user-matched Does not include:  Detailed hand aesthetics (color, texture, etc.)  Articulating joints

Progress Overview Interview with Charles Mathis “Clay Block” Materials Reversible Glove Possibilities

The 4-Step Process

Interview with Charles Mathis ManoTech met Charles last Thursday, 3/9 Watched and practiced making wax molds

Wax Advantages  Gives better detail and shape of hand in final mold  little shrinkage  Is relatively easy to use  Allows for mistakes Disadvantages  Must be maintained at 120 degrees F in a larger pot or deep-fryer

Kidz EZ Cast Mold Advantages  MoldGel sets in 4 – 5 min.  Works at room temperature Disadvantages  Lumpy mixture  Water leaks from bottom  Air bubbles reduce detail

5-Minute Molding Putty Advantages  Not messy  Takes ~10 minutes to set at room temperature Disadvantages  Requires significant amount of material  Difficult to mold exactly around the hand and maintain shape

Mini Casting Kit Advantages  Comes in a kit Disadvantages  Vapor and powder is toxic  Requires 4 – 8 hours for mold to set around hand Cannot be used

Gypsum-based Plaster of Paris Advantages  Cures at room temperature in 1.5 hours  Retains detail of initial mold Disadvantages  Hardened material is brittle, easily cracked  Transfers bubbles and cracks to solid hand

Brushable Latex Advantages  Brushes on easily  Reversible  Maintains shape  Able to use leftover latex Disadvantages  Needs ~10 coats with a 20-minute incubation between coats

RTV Polyurethane Advantages  Very elastic  Potential to be reversed Disadvantages  30-minute pour time  Messy  By dipping, creates non-uniform layer  Dipping twice gave a thin coat that rips

Summary of Materials Initial Mold Solid Hand Reversible Mold Wax EZ Mold Molding Putty Casting Kit Plaster of Paris Brushable Latex RTV Polyurethane Prosthetic Hand Silicone Rubber Polyurethane Foam

Schedule TODAY

Future Plans Procedures  Improve reversible mold-making method Materials Optimization  Solid hand mold  Prosthetic Hardness & Elasticity Testing  Underlayer: silicone rubber  Reversible material: latex, RTV polyurethane