ADHESIVE-ANCHORING SCREEN TUBES
AUTHORIZED SIMPSON STRONG-TIE DISTRIBUTOR
Screen tubes are vital to the performance of adhesive anchors in base materials that are hollow or contain voids, such as hollow block and brick. Screen tubes are used in hollow base material applications to contain adhesive around the anchor and prevent it from running into voids.
The Simpson Strong-Tie® Opti-Mesh® screen tube provides the economical advantage of a plastic screen tube while providing performance comparable to steel screen tubes and better than competitive plastic screen tubes.
Simpson Strong-Tie® steel screen tubes are specifically designed to precisely control the amount of adhesive that passes through the mesh. This results in thorough coating and bonding of the rod to the screen tube and base material.
Caution: Screen tubes are designed for a specific adhesive type. Epoxy screen tubes must be used with SET or ET-HP formulations (for instance) and acrylic screen tubes must be used with AT-XP adhesive (and other acrylic adhesives). Do not use SET1.7KTA with screen tubes.
ACRYLIC SCREEN TUBES – PLASTIC
EPOXY (SET AND ET-HP) SCREEN TUBES – PLASTIC
See load values for installations with SET inUnreinforced Brick Masonry Walls and in Hollow CMU. See load values for installations with ET-HP Epoxy in unreinforced masonry. Not for use with SET1.7KTA.
BEHIND THE FACE SHELL COMPARISON
The photo on the left shows the Opti-Mesh® screen tube installed in a hollow CMU block. The extra collar of adhesive created by the open-mesh collar results in increased bearing area and higher load values. The typical screen tube shown on the right relies on the bond between the relatively small amount of adhesive in contact with the face shell of the block for its holding power.
MESH SIZE MATTERS
The Simpson Strong-Tie Opti-Mesh screen (top) features formula specific mesh designed to control the flow of adhesive out of the screen. The result is uniform coverage of adhesive on the rod. The standard screen (bottom) utilizes mesh which allows adhesive to flow freely out of the screen when the rod is inserted. Too much adhesive is pushed out of the screen, leaving a large portion of the rod unbonded. This unbonded rod will pull out of the screen at a much lower load than a rod installed with an Opti-Mesh screen.
TOP: Opti-Mesh screen completely bonds the anchor rod.
BOTTOM: Competitor’s screen leaves portion of anchor rod unbonded.
Drill holes to correct diameter and depth as specified in the load tables. When drilling into hollow concrete block or brick, the drill should be set to “rotation only” mode.
Once the hole is drilled properly, remove dust from the hole with oil-free compressed air. Dust left in the hole can reduce the adhesive’s holding capacity.
Clean the hole with a nylon brush and blow out remaining dust.
Dispense a bead of adhesive off to the side to check for proper mixture (a uniform gray color)before filling the screen. Fill the screen completely, starting at the bottom to avoid air pockets.
Close the cap and insert the screen into the hole.
Anchor rods must be clean and oil free. Insert the rod, turning slowly until it contacts the bottom of the screen. Do not disturb during cure time.
Caution: Screen tubes are designed for a specific adhesive type. epoxy screen tubes must be used with SET-XP or ET-HP formulations (for instance) and acrylic screen tubes must be used with AT-XP adhesive (and other acrylic adhesives). Do not use SET1.7KTA with screen tubes.
ACRYLIC SCREEN TUBES – 50 MESH STAINLESS STEEL
EPOXY SCREEN TUBES – 60 MESH CARBON STEEL
Note: Not for use with SET1.7KT or SET1.7KTA.
Sources: ASTM Standards for Mechanical Fasteners and Related Processes 2nd Edition, Inch Fastener Standards 8th Edition, Simpson Strong-Tie Anchoring and Fastening Systems for Concrete and Masonry, StrongTie.com
Note: All material included on this page is informational only, and should not be used as one’s sole source for design purposes. STS Industrial, Inc. and its affiliates do not guarantee the accuracy of the information on this site, and retain no liability for the use or misuse of the information contained on this site.