Description

#257 BLACK PITCH is a semi-hard temporary cement used for a variety of blocking applications. #257 BLACK PITCH is commonly used for blocking together a series of lenses or work pieces that need to be edged or profiled. Other applications include Blanchard wheel work, spot blocking, surface protection, and a variety of uses where semi-hard, high tack materials are desired.

Application

Depending on application, #257 BLACK PITCH can be applied in two basic methods:

1. Pre-melt #257 BLACK PITCH in a controlled heating vessel, and apply or pour molten pitch to blocking plate or lap, and then mount the workpiece.
2. Pre-heat the blocking plate or lap and work piece, and wipe the pitch across the heated tool and mount the workpiece.

#257 BLACK PITCH can be removed from the parts by using UPI’s UNICLEAR or UNICLEAR II. For best results, please consult with UPI technical staff to recommend optimal processing conditions.

Benefits

• Unaffected by water and coolant
• High dielectric constant
• Lack of porosity
• Works well with diamond tooling
• Very dense and viscous material preferable for medium to thick bonding layers

Physical Characteristics

• Appearance: Solid Black
• Softening Point (°C): 54 ± 4
• Melting Point (°C): 78 ± 4
• Ball Penetration Test (70F, 500 g weight, 1hr) (in): 0.0010 ± 0.0005

Availability

Additional Product IDs

PB0257, PB0257NS