Application of Molding polyurethane

Processing procedure:

Preparation of master-model. Master-model should be thoroughly cleaned and dried. Use release agent for porous surfaces (gypsum plaster, concrete, clay, etc.). You can use wax-base paste or grease as release agent. A moderate quantity of release agent is applied both on a surface of master-model and on the inner sides of a casing. Too much of release agent can cover some fine details of master-model. Let release agent dry for at least 10 minutes before pouring polyurethane.

Mixing components.

  1. Mix component B thoroughly.
  2. Weigh the equal quantities of component A and component B in separate containers. It is recommended to measure components by weight, however due to specific weight of material it is possible to measure by volume.
  3. Mix components A and B gently in the third container, which should be larger than the first two ones. Mixing should be done slowly and carefully in order to avoid formation of a large number of air bubbles. Mixing should be carried out not less than 3 minutes.
  4. It is recommended to degasify material to achieve complete absence of bubbles. Injection casting technology with the use of autoclave also leads to almost complete absence of bubbles. Tools and containers used while working with polyurethane compounds should be clean and made of glass, metal or plastic. Do not forget to capture material from side walls and bottom of containers while mixing.
  5. Use mechanical mixers when mix large amounts (over 7 kg). Mixing with mechanical mixer should also be performed within 3 minutes. Then mix by hand carefully as it is described in p.2 and p.3. After that pour to a new clean container and repeat the procedure.   

Casting polyurethane compound.  To achieve additional reducing of bubble amount it is recommended to cover master-model surface with a thin layer of polyurethane with a brush and only then pour the remaining material. OR when casting target polyurethane at one point trying to hold container with polyurethane as close to master-model surface as it is possible. It is recommended to cast polyurethane at height not less than 1.3 cm from the highest point of model surface.

Storage. Uncured polyurethane compounds are sensitive to moisture which can affect material quality that is why it is recommended to work with material only in the rooms with low humidity in order to prevent polyurethane from absorbing moisture from air. The storage time of unused polyurethane compound after opening original packaging is greatly reduced. Plastic packaging is intended for transporting and short-term storage. When storing the material for more than a week it is recommended to pour it to a glass jar or metal container.   

Shelf life is 6 months.