Grade Application 203: Discoloration and Defects

In 203, you will learn all about how to apply various discoloration characteristics to the NELMA grades.

Syllabus

Grade Application 203: Pitch

Pitch is an accumulation of resinous material.  The chart below shows the limitations of Pitch in each grade. Watch the video below for a visual example of the various accumulations of pitch that are found in the NELMA Eastern White Pine grades.

 

Grade Limiting Provision
C Select Medium 1/3 the face on a clear board
D Select Medium 2/3 the face on a clear board.  One small streak (1/12 the width x 1/6 the length of the board) of Heavy Pitch
Finish Medium
Premium Medium
Standard Heavy
Industrial Not limited by grade

 

Grade Application 203: Pith

Pith is the small soft core in the structural center of a log.  See below for the limitations of Pith in each grade.  View the image to the right as a refresher on identifying pith in a board (Click on the image to enlarge, then click on the “x” to return to the course page)

 

Grade Limiting Provision
C Select Not permitted in grade
D Select Not permitted in grade
Finish 1/10 the length
Premium Not limited by grade
Standard Not limited by grade
Industrial Not limited by grade

 

Grade Application 203: Seams

A seam is an area of ingrown bark.  A seam is often ingrown at a knot and is sometimes independent of a knot. Seams are often surrounded by an accumulation of heavy pitch; the heavy pitch must be included within the measurement of the seam.  Click on the image to the right as a refresher on identifying Seams in a board (Remember: Click on the image to enlarge, then click the “x” to return to the course page). The chart below shows the limitations of seams for each grade.  For a complete tutorial on identifying and measuring seams watch the video below.

 

 Grade Limiting Provision
 C Select Not permitted in grade
 D Select Not permitted in grade
 Finish Seams partially surrounding a knot are permitted up to a maximum size of one 1/8″ x 1/2″ per board
 Premium Seams partially surrounding a knot are permitted up to a maximum size of one square inch (for example: 1/4″ x 4″, 1/3″ x 3″, 1/2″ x 2″). One maximum sized seam or equivalent is permitted per 8 surface feet.
 Standard Any Seams not seriously weakening the piece, limited to 1/6 the length
 Industrial Not limited by grade

 

Grade Application 203: Stain

Stain is a discoloration of the wood.  Blue and  Brown (Coffee) stains are treated the same, based on the limitations of the grade. The following chart quantifies these limitations for each grade.  View the image to the right as a refresher on identifying Stain in a board (Click on the image to enlarge, then click anywhere outside the image to return to the course page). Watch the video below for a visual representation of Blue Stain.

 

Grade Limiting Provision
C Select Medium (Blue or Coffee), not to exceed 1/3 the face surface area in a clear board, equivalent larger area of light stain; less if present in combination with other characteristics
D Select Medium (Blue or Coffee), not to exceed 1/3 the face surface area in a clear board, equivalent larger area of light stain; less if present in combination with other characteristics.  OR, Heavy up to 5% of the face surface area on an otherwise clear board
Finish Medium (Blue or Coffee), not to exceed 1/2 the face surface area
Premium Medium (Blue or Coffee)
Standard Heavy
Industrial Not limited by grade

Important Note: In practice, Blue or Brown Stain is not typically accepted by the consumer.

 

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