Cross Cut Blade

Description

Additional or replacement cross cut blades for adhesion and flexibility tests to meet the standards of the ASTM test method D-3359. Part of the cross cut test kit from Precision Gage & Tool.

Cross Cut Blades

Our cross hatch cutter blades come in 6 different blade configurations with a gap between teeth ranging from 1.0 mm up to 5.0 mm.

Testing Materials and Procedure

The information below is taken from the included cross hatch cutter adhesion test kit instructions and is also available for download here.

Materials

As mentioned above, our cross hatch cutter adhesion test kit provides everything you need to perform adhesion and flexibility tests to meet the standards of ASTM Test method D-3359. In the kit, you’ll find a blade, a blade holder/handle, a hex wrench for changing blades, an extra clamp screw, a small flaking and cleaning brush, a lighted magnifier, and a roll of test tape. You’ll also need a rubber eraser on the end of a pencil.

Test Specimens

In the field, you’ll test the actual coated structure or article you want to evaluate. In the lab, you may apply the materials you’re testing to panels of the appropriate composition and surface conditions. Either way, the testing surface must be flat. You can check flatness with a straight edge such as a steel rule.

Procedure

1. 1. Make sure your specimen is at room temperature (or other mutually agreed upon temperature) and placed on a firm base.

   2. Select an area free of blemishes and minor surface imperfections. Under the illumination of the magnifier, use the cross-cut tool to make parallel cuts as follows:

   3. For dry film coatings of thickness of 2.0 mils (50 μm) or less, use a fine blade (1.0 mm spacing). For coatings having a dry film thickness between 2.0 mils (50 μm) and 5 mils (125 μm), choose a medium (1.5 mm spacing) or coarse (2.0 mm spacing) blade.
   4. Make the first cut about 3/4 in. (20 mm) long. Cut through the film to the substrate in one steady motion, using just enough pressure to reach the substrate.
   5. After making the cut, gently remove any detached flakes or ribbons from the film with your kit’s brush.
   6. Next, make a second cut at 90 degrees to and centered on the original cuts to create a grid pattern in the film.
   7. Brush the area again and inspect the cuts to make sure you’ve reached the substrate. If not, make another grid in a different location.
   8. Remove two complete laps of your kit’s test tape and discard. Remove an additional length at a steady rate (don’t jerk it) and cut a piece about 3 in. (75 mm) long.
   9. Place the center of the tape over the grid and smooth it into place. To make good contact with the film, rub the tape firmly with a pencil eraser. The color under the tape helps you determine when you’ve made good contact.
2. Wait about 90 seconds, then remove the tape. Seize the free end and quickly (without jerking) pull it back upon itself as close as possible to a 180 degree angle.
3. Using the kit’s illuminated magnifier, inspect the grid area for coating removal. Rate the coating’s adhesion according to the test results classification chart below.

Report

Report the number of tests, their mean and range, and where the failure occurred—i.e., between the first coat and substrate, between the first and second coat, etc. Note the substrate used, the type of coating and the method of cure. If the adhesion strength of the tape has been determined in accordance with ASTM Test Methods D-3359-17, report the results with the adhesion ratings. Otherwise, report the specific tape used.

Precision and Bias

Use the following criteria to judge the acceptability of your results.

Repeatability — If adhesion is uniform over the surface being tested, results obtained for two measurements by the same operator should not differ by more than one rating category.
Reproducibility — Test results obtained by different operators (each the mean of two measurements) should not differ by more than two rating categories.

Bias cannot be established for these test methods.