D3918-11 – Standard Test Method Technical Guide

📘 Surface and Cure Terminology

This section defines terms related to surface imperfections and cure conditions in pultruded products. Barcol hardness is measured using a Barber Colman impresser, providing a relative measure of cure (Note 2 states values can differ with additives). A blister is a rounded elevation, often gas-filled, resembling a human blister (Note 3). Fiber blooming appears as white fibrous prominence, easily buffed without structural issue (Note 4). Undercure blooming is a dull bleached color from insufficient surface cure (Note 5). Crater is a small shallow imperfection. Craze includes fine cracks; hairline craze exceeds 1/4 in. (6.4 mm) without penetrating reinforcement, while resin craze is from shrinkage (Note 6). Discoloration is any color change, and dry fiber indicates incomplete resin encapsulation. Dullness is lack of gloss, often from undercure (Note 8).

⚙️ Structural and Dimensional Defects

This section covers dimensional deviations and structural separations. Bow and