Resistance tester Model 435

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Description
Surface marks and metal-impressions can degrade the appearance and function of coated or polished substrates. The Mar Tester Model 435 provides a reproducible method to quantify the force at which a visible mar or a metal mark appears on a test surface, allowing objective evaluation of surface resistance.

Design and function
The marking element is a lockable test disc (special plastic or metal) mounted on a screw and preloaded by a helical spring. The device applies an adjustable force in the range 0–20 N. Three exchangeable springs provide three test ranges:

• Test range 1: 0–3 N — sensitivity 0.1 N
• Test range 2: 0–10 N — sensitivity 0.5 N
• Test range 3: 0–20 N — sensitivity 1.0 N

Note
Test discs wear at the contact point. After approximately 100 tests, rotate the disc to expose a fresh periphery point (about 2 mm). Mark the initial use point with a scratch for reference.

Method of operation
Select and fit the appropriate test disc for the required test:

• plastic disc for mar-resistance tests;
• copper or other special disc for metal-marking tests.

After tightening the screw so the disc cannot turn, set the spring to the estimated force. Place the instrument perpendicular to the surface until the guide wheels contact it, then move the instrument a few centimetres in a quick rolling motion. Record the spring force (N) that produces a visible mar (no crack) or, for metal-marking, the force that produces a black/grey mark.

Scope of delivery

• Mar tester, Model 435 S
• Test disc made of steel
• 3 force springs
• Carrying case

Standards
DIN 55 656

Accessories (selection)

• Test disc stainless steel (Ø 16 mm, R 0.5 mm)
• Test disc Duroplast (Ø 16 mm, R 0.5 mm)
• Test disc copper (Ø 16 mm, R 0.5 mm)
• Spring 0–3 N
• Spring 0–10 N
• Spring 0–20 N

Technical specifications

• Model: Model 435
• Order number: 00960131
• Drive: Manual
• Testing force: 0–20 N
• Scratch/profile discs: Steel, Duroplast, Copper
• Test ranges/sensitivities: 0–3 N (0.1 N); 0–10 N (0.5 N); 0–20 N (1.0 N)