Originally Posted by Winston S.
The rugged twill I don't think is treated with anything, whereas the tin cloth is treated with oil. The rugged twill also feels like a heavier fabric to me.
Filson's Tin Cloth, so-called because garments made from it are as waterproof and wear resistant as if they were made of tin, has long been recognized in the Northwest as setting the standard for protection and wear resistance. The material, a 100% cotton duck, is offered in two distinctly different finishes, an oil finish and a dry finish, and now in both the traditional 12.5 ounce Duck and the newer lighter weight 8.5 ounce Shelter Cloth, named after military shelter tents. Shelter cloth is softer than the Tin Cloth, and does not require breaking in as does the stiffer Tin Cloth material.
The oil finish provides the greatest protection and wear. The cotton duck is impregnated with a paraffin-based wax, creating a finished 12.5 ounce fabric that is highly water repellent and wind resistant. The greater wear resistance of the oil finish is accounted for by the wax reducing internal wear in the fabric as threads slip against each other. The oil finish Tin Cloth (12.5 ounce) and Shelter Cloth (8.5 ounce) have not been preshrunk and may shrink with repeated soaking in the rain. If you intend using your oil finish garment primarily as wet weather gear, order one size larger than normal to accommodate shrinkage. If you intend using it under dry conditions for its great durability, your normal size will be better.
Filson's Rugged Twill Luggage is made from a special 22 ounce 100% cotton twill, a heavier and stronger version of the legendary oil finish Tin Cloth. It is durable and breathable, impregnated with wax to make it water resistant and protect against wear.