Method of making hollow elastomeric bodies

Claim 1

A method of fabricating a smooth, hollow pinhole free elastomeric body with an integral flange attached to each end thereof, each said flange having a cylindrical peripheral surface, comprising the steps of: a. attaching a flange forming end cap to each end of a mandrel having an exterior male form corresponding to an internal surface of said hollow body, each cap having an interior surface portion surrounded by a peripheral flange edge member, disposing said edge members toward said mandrel, each cap having a diameter larger than said end and defining a flange forming cavity, at least one of said caps being releasably attached to the mandrel; b. independently heating the mandrel; c. disposing the mandrel horizontally and dipping 10-70% of the heated mandrel surface into a solution of elastomeric resin; d. recirculating the elastomer solution through a heat exchanger to control the temperature thereof; e. rotating the mandrel while in the solution an integral number of revolutions, to apply a layer of elastomeric resin to said male form and against inner surfaces of said edge members; f. removing the mandrel from the solution; g. drying the coated layer; h. repeating steps (b) to (g) until the desired thickness is achieved;

Claim 2

A method of fabricating a smooth, hollow pinhole free elastomeric body with an integral flange attached to each end thereof, each said flange having a cylindrical peripheral surface, comprising the steps of: a. attaching a flange forming end cap to each end of a mandrel having an exterior male form corresponding to an internal surface of said hollow body, each cap having an interior surface portion surrounded by a peripheral flange edge member, disposing said edge members toward said mandrel, each cap having a diameter larger than said end and defining a flange forming cavity, at least one of said caps being releasably attached to the mandrel; b. independently heating the mandrel; c. disposing the mandrel horizontally and dipping 10-70% of the heated mandrel surface into a solution of elastomeric resin; d. recirculating the elastomer solution through a heat exchanger to control the temperature thereof; e. rotating the mandrel while in the solution an integral number of revolutions, to apply a layer of elastomeric resin to said male form and against inner surfaces of said edge members; f. removing the mandrel from the solution; g. drying the coated layer; h. repeating steps (b) to (g) until the desired thickness is achieved;