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Leneta Company, Inc.
15 Whitney Rd.
Mahwah, NJ, 07430 USA

Toll-Free: 800.663.6324
Phone: 201.847.9300
Fax: 201.848.8833
Toll-Free: 800.663.5154

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Leneta Anti-Sag Meter Method
(See ASTM D4400)

A. Equipment

  1. The Anti-Sag Meter
  2. Adjustable Straight Edge, Item SE-1
  3. Drawdown Plate-Regular, Item DP-1
  4. Drawdown Charts, Form 7B Black and white, for light colored paints. Form WB plain white, for dark colored paints.
  5. Catch-Papers, Form CP-1
  6. Pre-shear equipment with the Low Range Anti-Sag Meter, a flat glass surface is preferred.

B. Preparation of Coating

  1. Stir well and adjust to 23°C (73.5°F)
  2. Pre-shear in accordance with one of the methods described in the attached Pre-Shear Method  and test immediately thereafter.

C. Application of Coating

  1. Attach the Straight Edge to the drawdown plate in a suitable position.
  2. Place a test chart on the drawdown plate under the clip.
  3. Place the Anti-Sag Meter on the chart adjacent to the clip, with its open side toward the operator and its shoulder against the straightedge. Position the Catch-Paper.
  4. Place a suitable quantity (8 - 10 mL) of pre-sheared paint directly in front of the blade, and drawdown uniformly at about 6 inches (150 mm) per second.
  5. Promptly fasten the drawdown to a vertical surface, with stripes horizontal like rungs in a standing ladder, left edge (thinnest stripe) at the top, and allow to dry in that position.

D. Rating the Drawdown

  1. Note the notch numbers marked on the Anti-Sag Meter and identify the corresponding stripes accordingly.
  2. Ignore the leading and trailing edges, and observe only the central 5-1/2 inches (150 mm) of blade path, corresponding to the black area of Form 7B.
  3. The lowest (thickest) stripe that does not touch the one below itself is referred to as the index stripe, and its notch number is the Anti- Sag Index of the paint.
  4. For a more precise Anti-Sag Index, add to the index stripe number the product of the post-index clearance step and the fractional degree to which it has failed to merge with the next lower stripe

The fraction is estimated in accordance with the following table:

Degree of Merger Fraction Unmerged
Complete
Somewhat more than half
Approximately half
Somewhat less than half
0
0.25
0.50
0.75


E. Practical Interpretation of Ratings

This is empirical and strongly subjective. It should be emphasized that the Anti-Sag Index is not a wet film thickness; it is the clearance of the index groove expressed in mils, and as such, approximately twice the wet film thickness of the index stripe with emphasis on approximate. Neither the Anti-Sag Index nor the estimated corresponding wet film thickness is to be construed as calling for a specific thickness in practice. It is solely a numerical comparator and acquires practical significance only on the basis of experience. When a coating is perceived as having optimum sag resistance by actual application, the Anti- Sag Index is then measured and thereafter becomes the sag control value for that particular formulation.

The correct Anti-Sag Index for one product might be quite different than for another. Latex paints, for example, would normally have much higher index values than solvent borne coatings. The following qualitative judgments were based on observations of a series of trade sales type alkyd gloss enamels, and are given here as examples only. They are not to be considered as definitive.

Anti-Sag Index Sag Resistance
3
4
5
6
7
8
10
12
Very Poor
Poor
Poor-Fair
Fair
Fair-Good
Good
Very Good
Excellent

The above indices cover the range of the Standard Anti-Sag Meter, but many coatings require lower or higher index measurements. These requirements are met with Low, Medium, and High Range instruments, making it possible to measure Anti- Sag Index values from 1 to 60.

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