MTS Boilermaker’s Chalk (Soapstone)

MTS Boilermaker's Chalk, also commonly known as Soapstone, is a natural mineral marking tool (talc) used extensively in welding, metal fabrication, and blacksmithing. Unlike traditional blackboard chalk, soapstone is highly resistant to heat and remains visible even when subjected to the extreme temperatures of a welding torch or plasma cutter.

Technical Specifications

• Material: Natural Steatite (Talc)
• Form: Rectangular strips (typically 100mm x 10mm x 5mm)
• Heat Resistance: Stable up to approximately 1100°C
• Pack Size: Usually sold in boxes of 10 or 50, or as individual sticks.

Key Features

• Heat Stability: The white marks will not burn off or disappear under the intense heat of an oxy-acetylene flame or arc welding.
• Non-Contaminating: Soapstone is chemically inert. It does not react with the metal or contaminate the weld pool, which is critical for maintaining the structural integrity of a joint.
• High Visibility: It leaves a clear, distinct white line on dark metals, rusted steel, and cast iron.
• Easy Removal: While the marks withstand heat, they are not permanent; they can be easily wiped or brushed off the metal surface once the job is complete.
• Removable Sharpness: You can "sharpen" the flat edges of the chalk against a rough concrete floor or with a file to achieve a fine line for precision layout work.

Common Applications

• Welding Layout: Marking cut lines, center points, and weld start/stop locations on mild steel and stainless steel.
• Pipe Fitting: Drawing "fish-mouth" templates or wrap-around lines on piping.
• Blacksmithing: Marking metal that is about to be placed in a forge.
• General Fabrication: Temporary marking on any rough or dark surface where a pencil or felt-tip pen would fail.

Usage Tip

For the best results, use a Soapstone Holder. These metal sleeves protect the brittle chalk from snapping in your pocket or tool bag and allow you to use the entire stick right down to the last fragment by sliding it forward as it wears.