Light Duty: General welding, light sparks, and spatter. Not recommended for stress relief.
Medium Duty: Heavier welding applications, sparks, spatter, and light slag.
Heavy Duty: Heavy sparks, spatter, slag, and molten metal.
Extreme Duty: Extra heavy spatter, slag, and molten metal.

Use only non-coated materials in a welding blanket that is designated for stress relief.

Coated Material: Stiffer and allows spatter and slag to easily roll off. Offers good abrasion resistance.
Uncoated Material: Softer and more pliable allowing for easy coverage and wrap of materials for stress relief.

Stiff materials are coated to allow spatter and slag to roll off easier. This weight and coating will provide better protection and longer burn through time.

Vertical application materials can be lighter weight and have lower melt temperatures. Flat application materials need to be heavier weight and higher melt temperatures.

See the different kinds: https://jtillman.com/products/blankets/

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