Page 19 - WEB-S3 Sealants and Supplies

FHC SEALANTS AND SUPPLIES SECTION 4
FHC Backer Rod
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FHC Backer Rod Guidelines for
Properly Moving Dynamic Joints: DO’s and DON’Ts

Prevents Adhesions on Three Sides
The sealants inability to bond with the joint’s underside will
increase movements (Figure 2).

Control the Sealants Bead Depth
The sealant bead conforms to the manufacturer’s design recommendations,
enhancing the sealant’s capacity for movement (Figure 2)

Provides Resistance to Tool Against
When tooled, the sealant is pressed against the backer rod, ensuring optimal
adhesion to the joint’s side walls (Figure 3). To achieve this, the backer rod
must be intentionally oversized, ensuring a secure fit within the joint (Figure 4).
DO DON'T

A Sealant Ensure that the minimum A Sealant A deep sealant bead
hinders flexibility and
A to B ratio is 2:1. movement.
B B
C A and C dimensions FIGURE 1: C Excessive sealant depth
must not be less than
leads to slower curing.
1/4".
Regulates the B dimension exceeds
The joint surface should Sealant Bead Depth the suggested 3/8"
have a concave tooling. maximum.
It is recommended that
dimension B does not
Backer Rod exceed 3/8". Backer Rod
Silicone Silicone
Weather-Seal Weather-Seal
Sealant Sealant
Glass Glass Glass Glass
Silicone FIGURE 2: Silicone
Structural Structural
Adhesive Prevents adhesion on Adhesive
three sides.
Backer The silicone weather No Backer The silicone
Structural Rod seal bead hovers Structural Rod weather seal bead
Spacer above the backer rod, Spacer remains immobile
as it is adhered to
Mullion enabling maximum Mullion the joint’s bottom.
movement.
Sealant
Spatula FIGURE 3: Uneven gaps
Offers resistance between the
sealant and the
To ensure uniform when using a tool. Sealant wall result in an
strength and irregular joint,
adhesion along leading to weak
the bond line, No areas in the
the sealant is Backing bond line that
pressed firmly and Material are prone to
evenly against the failure under
sidewalls using a stress.
spatula tool.
RECOMMENDED BACKER ROD DIAMETER SIZES
Sealant JOINT WIDTH FHC CLOSED CELL FHC OPEN CELL
FIGURE 4: 3/16" 1/4" ---
An oversized 1/4" 3/8" ---
rod keeps 3/8" 1/2" 5/8"
things in 1/2" 5/8" 7/8"
position. 5/8" 3/4" 1-1/8"
3/4" 1" 1-1/8"
1" 1-1/4" 1-1/2
Open Cell Backer Rod 1-1/4" 1-1/2" 2"
1-1/2" 2" ---
Visit fhc-usa.com to search for
Backer Rod FRAMELESS HARDWARE COMPANY LLC
P.O. Box 1906 South Gate, CA 90280
Enter the Item Number or scan QR code with Toll Free: (888) 295-4531 | Direct: (323) 968-2031
your smartphone for complete product details WS17
Fax: (323) 336-8307 | fhc-usa.com