Method of making molds

Claim 1

A method of making a low-cost precision mold comprising the steps of providing a pattern of a product to be made in the mold; orienting said pattern on a surface plate within a plaster retaining perimeter dam; applying a release coating to the pattern, the surface plate, and the plaster retaining perimeter dam such that the finished mold may be easily separated from said pattern; applying a thin resin layer to the pattern and the surface plate to form a mold surface; placing magnetic inserts on the thin resin layer as dictated by part geometry and size, to hold load spreading metal inclusions during part molding which will provide attachment points for the finished part; applying a double layer of chopped strand glass fiber reinforced tooling resin to the thin resin layer and the magnetic inserts; curing said tooling resin for one hour; applying a layer of epoxy-dry plaster mix to the fiber reinforced tooling resin wherein said mix acts as a binder coat to adhere to both the cured tooling resin and a bulk casting plaster; immediately pressing a layer of continuous strand glass fiber veiling into the surface of the uncured epoxy-dry plaster mix to provide bonding tooth for the bulk casting plaster; inserting a metal mold-reinforcing framework with external attachment projections into the plaster retaining perimeter dam; pouring bulk casting plaster into the plater retaining perimeter dam to totally engulf the mold-reinforcing framework; and applying a final layer of continuous strand glass fiber veiling to the bulk casting plaster to prevent surface drying cracks; and allowing a sufficient time for curing and drying of the mold.

Claim 2

A method of making a low-cost precision mold comprising the steps of providing a pattern of a product to be made in the mold; orienting said pattern on a surface plate within a plaster retaining perimeter dam; applying a release coating to the pattern, the surface plate, and the plaster retaining perimeter dam such that the finished mold may be easily separated from said pattern; applying a thin resin layer to the pattern and the surface plate to form a mold surface; placing magnetic inserts on the thin resin layer as dictated by part geometry and size, to hold load spreading metal inclusions during part molding which will provide attachment points for the finished part; applying a double layer of chopped strand glass fiber reinforced tooling resin to the thin resin layer and the magnetic inserts; curing said tooling resin for one hour; applying a layer of epoxy-dry plaster mix to the fiber reinforced tooling resin wherein said mix acts as a binder coat to adhere to both the cured tooling resin and a bulk casting plaster; immediately pressing a layer of continuous strand glass fiber veiling into the surface of the uncured epoxy-dry plaster mix to provide bonding tooth for the bulk casting plaster; inserting a metal mold-reinforcing framework with external attachment projections into the plaster retaining perimeter dam; pouring bulk casting plaster into the plater retaining perimeter dam to totally engulf the mold-reinforcing framework; and applying a final layer of continuous strand glass fiber veiling to the bulk casting plaster to prevent surface drying cracks; and allowing a sufficient time for curing and drying of the mold.

Claim 3

A method of making low cost matching closed mold sets, having a self-aligning taper lock feature, comprising the steps of providing a pattern of a product to be made in the mold; orienting said pattern on a taper lock pedestal on a surface plate within a plaster retaining perimeter dam; applying a release coating to the pattern, the surface plate, and the plaster retaining perimeter dam such that the finished mold may be easily separated from said pattern; applying a thin resin layer to the pattern and the surface plate to form a mold surface; placing magnetic inserts on the thin resin layer as dictated by part geometry and size, to hold load spreading metal inclusions during part molding which will provide attachment points for the finished part; applying a double layer of chopped strand glass fiber reinforced tooling resin to the thin resin layer and the magnetic inserts; curing said tooling resin for one hour; applying a layer of epoxy-dry plaster mix to the fiber reinforced tooling resin wherein said mix acts as a binder coat to adhere to both the cured tooling resin and a bulk casting plaster; immediately pressing a layer of continuous strand glass fiber veiling into the surface of the uncured epoxy-dry plaster mix to provide bonding tooth for the bulk casting plaster; inserting a metal mold-reinforcing framework with external attachment projections into the plaster retaining perimeter dam; pouring bulk casting plaster into the plaster retaining perimeter dam to totally engulf the mold-reinforcing framework; and applying a final layer of continuous strand glass fiber veiling to the bulk casting plaster to prevent surface drying cracks; and allowing a sufficient time for curing and drying of the mold; orienting the fully cured mold on a support plate; placing the pattern on the cured mold to define a part forming cavity; placing a plaster retention dam at the edges of the mold; applying a mold release coating to the pattern, the cured mold, and the plaster retaining perimeter dam such that the finished mold may be easily separated from said pattern; applying a thin resin layer to form a mold surface; applying a double layer of chopped strand glass fiber reinforced tooling resin to the thin resin layer; curing said tooling resin for one hour; applying a layer of epoxy-dry plaster mix to the fiber reinforced tooling resin wherein said mix acts as a binder coat to adhere to both the cured tooling resin and a bulk casting plaster; immediately pressing a layer of continuous strand glass fiber veiling into the surface of the uncured epoxy-dry plaster mix to provide bonding tooth for the bulk casting plaster; inserting a metal mold-reinforcing framework with external attachment projections into the perimeter dam; pouring bulk casting plaster into the plaster retaining perimeter dam to totally engulf the mold-reinforcing framework; and applying a final layer of continuous strand glass fiber veiling to the bulk casting plaster to prevent surface drying cracks; and allowing sufficient time for complete curing and drying of the mold.

Claim 4

A method of making low cost matching closed mold sets, having a self-aligning taper lock feature, comprising the steps of providing a pattern of a product to be made in the mold; orienting said pattern on a taper lock pedestal on a surface plate within a plaster retaining perimeter dam; applying a release coating to the pattern, the surface plate, and the plaster retaining perimeter dam such that the finished mold may be easily separated from said pattern; applying a thin resin layer to the pattern and the surface plate to form a mold surface; placing magnetic inserts on the thin resin layer as dictated by part geometry and size, to hold load spreading metal inclusions during part molding which will provide attachment points for the finished part; applying a double layer of chopped strand glass fiber reinforced tooling resin to the thin resin layer and the magnetic inserts; curing said tooling resin for one hour; applying a layer of epoxy-dry plaster mix to the fiber reinforced tooling resin wherein said mix acts as a binder coat to adhere to both the cured tooling resin and a bulk casting plaster; immediately pressing a layer of continuous strand glass fiber veiling into the surface of the uncured epoxy-dry plaster mix to provide bonding tooth for the bulk casting plaster; inserting a metal mold-reinforcing framework with external attachment projections into the plaster retaining perimeter dam; pouring bulk casting plaster into the plaster retaining perimeter dam to totally engulf the mold-reinforcing framework; and applying a final layer of continuous strand glass fiber veiling to the bulk casting plaster to prevent surface drying cracks; and allowing a sufficient time for curing and drying of the mold; orienting the fully cured mold on a support plate; placing the pattern on the cured mold to define a part forming cavity; placing a plaster retention dam at the edges of the mold; applying a mold release coating to the pattern, the cured mold, and the plaster retaining perimeter dam such that the finished mold may be easily separated from said pattern; applying a thin resin layer to form a mold surface; applying a double layer of chopped strand glass fiber reinforced tooling resin to the thin resin layer; curing said tooling resin for one hour; applying a layer of epoxy-dry plaster mix to the fiber reinforced tooling resin wherein said mix acts as a binder coat to adhere to both the cured tooling resin and a bulk casting plaster; immediately pressing a layer of continuous strand glass fiber veiling into the surface of the uncured epoxy-dry plaster mix to provide bonding tooth for the bulk casting plaster; inserting a metal mold-reinforcing framework with external attachment projections into the perimeter dam; pouring bulk casting plaster into the plaster retaining perimeter dam to totally engulf the mold-reinforcing framework; and applying a final layer of continuous strand glass fiber veiling to the bulk casting plaster to prevent surface drying cracks; and allowing sufficient time for complete curing and drying of the mold.

Claim 5

A method of making a low-cost presision mold comprising the steps of providing a pattern of a product to be made in the mold; orienting said pattern on a surface plate within a plaster retaining perimeter dam; applying a release coating to the pattern, the surface plate, and the plaster retaining perimeter dam such that the finished mold may be easily separated from said pattern; applying a thin resin layer to the pattern and the surface plate to form a mold surface; placing magnetic inserts on the thin resin layer as dictated by part geometry and size, to hold load spreading metal inclusions during part molding which will provide attachments points for the finished part; applying a double layer of chopped strand glass fiber reinforced tooling resin to the thin resin layer and the magnetic inserts; curing said tooling resin for one hour; applying a layer of epoxy-dry plaster mix to the fiber reinforced tooling resin wherein said mix acts as a binder coat to adhere to both the cured tooling resin and a bulk casting plaster; immediately pressing a layer of fibrous reinforcement into the surface of the uncured epoxy-dry plaster mix to provide bonding tooth for the bulk casting plaster; inserting a metal mold-reinforcing framework with external attachment projections into the plaster retaining perimeter dam; pouring bulk casting plaster into the plaster retaining perimeter dam to totally engulf the mold-reinforcing framework; and applying a final layer of fibrous reinforcement to the bulk casting plaster to prevent surface drying cracks; and allowing a sufficient time for curing and dyring of the mold.

Claim 6

A method of making a low-cost presision mold comprising the steps of providing a pattern of a product to be made in the mold; orienting said pattern on a surface plate within a plaster retaining perimeter dam; applying a release coating to the pattern, the surface plate, and the plaster retaining perimeter dam such that the finished mold may be easily separated from said pattern; applying a thin resin layer to the pattern and the surface plate to form a mold surface; placing magnetic inserts on the thin resin layer as dictated by part geometry and size, to hold load spreading metal inclusions during part molding which will provide attachments points for the finished part; applying a double layer of chopped strand glass fiber reinforced tooling resin to the thin resin layer and the magnetic inserts; curing said tooling resin for one hour; applying a layer of epoxy-dry plaster mix to the fiber reinforced tooling resin wherein said mix acts as a binder coat to adhere to both the cured tooling resin and a bulk casting plaster; immediately pressing a layer of fibrous reinforcement into the surface of the uncured epoxy-dry plaster mix to provide bonding tooth for the bulk casting plaster; inserting a metal mold-reinforcing framework with external attachment projections into the plaster retaining perimeter dam; pouring bulk casting plaster into the plaster retaining perimeter dam to totally engulf the mold-reinforcing framework; and applying a final layer of fibrous reinforcement to the bulk casting plaster to prevent surface drying cracks; and allowing a sufficient time for curing and dyring of the mold.