Mull Strip Test

Overview
            How to properly test mull strips for strength and quality.
 
Definitions
 
Procedure

1. With a razor blade, cut the nail fin off each piece of vinyl being mulled.
2. Measuring 3 inches from the edge of the mull rebar, drill 1/4" holes every 12 inches into your mull rebar. Alternate these holes between the 2^nd and 4^th channels.
   1. All rebar (even the smaller units) needs at least 3 holes drilled. Add an additional hole in the middle of smaller units, if needed.
3. Attach the mull strip to the rebar with 1” of overhang on each side.
4. Apply mull tape to the mull strip.
5. Remove the paper from the mull tape.
6. Apply a dime sized ball of silicone on top of each of the holes in the mull rebar.
7. Apply a bead of silicone in the 1^st and 5^th rebar channels.
   1. Apply enough silicone to fill the channels and create a 1/8” amount of crowning.
8. With mull epoxy, fill the center (channel 3) mull rebar cavity.
   1. Apply enough mull glue to fill the channel and create a 1/8” amount of crowning.
9. Place the mull strip on top of vinyl being mulled.
   1. Make sure the vinyl and the mull strip sit flush.
10. With a drill, attached 8 X ¾” bugle head screws into all holes of the mull rebar.
11. Repeat steps 4, 5, 7, and 8 to the other side of the mull rebar.
12. Use clamps to secure the two pieces of vinyl and mull rebar together.
    1. Place a clamp on each end and every 18” in-between.
13. Leave the clamps on for 2 hours.
14. Time stamp the unit and let them cure for 2 hours before moving them.