MTS Boilermaker’s Chalk Group

MTS Boilermaker’s Chalk, commonly known as Soapstone, is an essential marking tool for welders, fabricators, and boilermakers. Unlike standard blackboard chalk, soapstone is a natural mineral (talc) that is highly resistant to heat, making it the industry standard for marking metal surfaces that will undergo welding, cutting, or heating.

Technical Specifications

• Material: Natural Soapstone (Steatite).
• Form: Rectangular strips or round sticks.
• Standard Size: Typically 125mm x 12mm x 5mm (Flat).
• Heat Resistance: Withstands temperatures up to 1100°C without burning off or fading.
• Color: White / Natural Grey.

Key Features

• High Visibility: Leaves a clean, distinct white line on dark metals, rusted steel, and cast iron.
• Heat Stability: The marks will not disappear, char, or melt under the intense heat of an oxy-acetylene torch or a welding arc, ensuring the fabricator can follow the line throughout the process.
• Non-Contaminating: Soapstone is chemically inert. It does not react with the metal or contaminate the weld pool, which is critical for maintaining structural integrity in high-pressure boiler or pipe welding.
• Low Dust: It is much denser than regular chalk, meaning it produces very little dust and won’t crumble easily under pressure.
• Removability: Marks can be easily wiped away with a damp cloth or a wire brush once the job is completed, leaving no permanent stain on the workpiece.

Common Applications

• Welding & Fabrication: Marking out cut lines, weld joint positions, and fit-up points on structural steel.
• Pipefitting: Layout marking on large diameter pipes for miter cuts or branch connections.
• Blacksmithing: Marking hot steel during the forging process.
• Textile/Industrial: Used in some heavy-duty textile applications where a heat-stable mark is required on thick canvas or rubber.

Usage & Maintenance Tips

• Sharpening: For high-precision layout work, you can sharpen the edge of the flat chalk using a bench grinder, a file, or even by rubbing it against a concrete floor.
• Chalk Holders: To prevent the chalk from snapping in your pocket or during use, it is highly recommended to use a Mechanical Soapstone Holder (available in flat or round versions). This protects the brittle mineral and allows you to use the piece down to the last centimeter.
• Storage: Keep soapstone in a dry place. While it is a stone, excessive moisture can make it slightly “mushy” or cause it to leave a feathered, less precise line.
• Surface Prep: For the best visibility on very oily or greasy steel, wipe the surface quickly with Herschell Clean Up Spray before marking.