Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D1309-93 – Standard Test Method Technical Guide
📐 Test Apparatus and Specifications
This test method, designated as D1309-93 (Reapproved 2015), simulates pigment settling that traffic paints may experience during storage. The following apparatus is required:
| 🟦 Component | 📏 Specification |
|---|---|
| Container | 500 mL (1 pt) friction top can, 85.5 ± 1.5 mm diameter, 98.5 ± 1.5 mm height |
| Spatula | 45 ± 1 g, square-end blade 125 mm length, 20 mm width |
| Freezer | Maintained at -21 to -23.3 °C (-5 to -10 °F) |
| Oven | Maintained at 71 ± 1 °C (160 ± 2 °F) |
| Lid Clips | Four clips to secure the can lid during cycling |
⚙️ Accelerated Settlement Procedure
Paint is mixed thoroughly and filled to within 13 mm of the can top. After sealing with lid clips, the can undergoes a two-week exposure cycle as shown below:
| ⏰ Time Period | 🌡️ Action |
|---|---|
| Monday to Friday: 8:00 a.m. | Place in freezer |
| Monday to Friday: 10:00 a.m. | Transfer to oven |
| Monday to Friday: 2:00 p.m. | Transfer to freezer |
| Monday to Friday: 4:00 p.m. | Transfer to oven |
| Friday 4:00 p.m. to Monday 8:00 a.m. | In oven continuously |
| Monday 8:00 a.m. | Place in freezer and continue cycle |
Each time the can is removed from the oven, give it one sharp “spank” on the table, exerting a force equivalent to 2.27 kg (5 lb). After two weeks, allow the paint to cool at room temperature for 4 hours.
⚠️ Warning: Due to residual vapor pressure, open cans slowly and carefully after the exposure cycle.
📊 Evaluation and Reporting
The degree of settling is evaluated per Test Method D869, using a scale from 1 (hard settling) to 10 (perfect suspension). The result is reported as the “accelerated settling rating” for specification compliance.
💡 Tip: For consistent results, calibrate the spanking force periodically using a scale set to 2.27 kg.
❓ Frequently Asked Questions
🔍 What is the purpose of the accelerated settling test?
This test simulates 12 months of storage settling in 2 weeks, allowing rapid assessment of pigment suspension properties in traffic paints.
💡 How does the temperature cycle work?
The cycle between -21 °C and 71 °C accelerates settling by thermal expansion and contraction, mimicking natural aging processes.
⚡ Why is the spank force specified as 2.27 kg?
It standardizes the mechanical shock encountered during handling, ensuring reproducibility across different laboratories.
📌 How do I interpret the settling rating?
The rating from Test Method D869 ranges from 10 (no settling) to 1 (hard sediment), with higher values indicating better storage stability.