Joining Dissimilar Materials

Joining Dissimilar Materials to ATS FXP™ with ChemBond™

ATS ChemBond™ can be used to bond ATS FXP™ duct to itself or to other types of plastic or metal ductwork. The most common plastic ducts are conventional polyester and vinyl ester fiberglass reinforced plastic (FRP), polyvinyl chloride (PVC) and polypropylene (PP). Metal ducts are either usually made of stainless steel (SS) or galvanized steel (GS). Below are the methods that we recommend to achieve both a chemical and/or mechanical bond to these materials. Refer to the ATS installation guide for the recommended glass widths, the number of glass reinforcement layers and the correct methods for handling and using ATS ChemBond™ resin.

Note: For butt joint connections, ATS can manufacture H-Collars with one end made special to fit the I.D. and O.D. dimensions to accept the non-ATS duct. (See H-Collar Installation Instructions, page 141 of Reference Guide.) Before making the connection, follow the preparation procedures for the non-ATS duct as described in the paragraphs below.

Non-FM Regular FRP

Non-FM Regular FRP duct typically is supplied with an exterior surface that has a slick gel coat finish or an intumescent (fire-protective) coating. These exterior finishes must be removed by lightly sanding the surface to expose the inner glass fibers of the duct structure prior to the application of the ATS ChemBond™ resin and the glass reinforcement materials. After the area to be bonded has been sanded, the surface must be cleaned with a solvent-based agent to remove the surface dust and any wax added to the exterior resin for curing purposes.


Although ATS ChemBond™ resin will bond ATS FXP™ duct directly to PVC, it requires sanding to achieve a good bond. A simple solution is flange to flange.

PP (Polypropylene) and PPs (Polypropylene “Schwerentflammbar”)

The exterior surface of the PP must be carefully heated with a high wattage heat gun or a propane torch. Only apply enough heat to change the shiny surface of the PP to a dull, discolored texture. A test to measure the appropriate amount of heat is to heat until the endpoint of a paper clip can be thrust into the surface approx-imately 0.020 in. (0.5 mm). Be careful not to melt and deform the plastic structure. The surface is prepared properly when water “sheets off” evenly on the PP surface (instead of beading). At this point, the ion structure of the surface has changed and the ATS ChemBond™ resin will bond to the PP surface. Coarse-grit sanding will increase the mechanical bond strength.

Stainless Steel & Galvanized Metal

The outer surface of the metal must be cleaned with a solvent agent to remove protective oils and foreign particles. The surface of the metal should then be coarsely sanded before applying ATS ChemBond™.

For more detailed information, please contact the ATS Products’ Engineering Department at +1-510-234-3173.