Harris Bridgit® Burn Resistant Paste Soldering Flux

Flux must remain chemically active long enough to remove and prevent surface oxides while the joint reaches soldering temperature. When conventional flux is overheated or exposed to heat for too long, it can decompose and leave carbonized residue on the joint surfaces.

Harris formulates Bridgit® Paste Flux to resist this thermal decomposition. Because it remains active across a broad temperature range up to approximately 800°F, it provides additional working time during larger connections and other installations where the joint may require a longer heating cycle.

The burn-resistant formulation helps reduce black carbon formation that may interfere with solder wetting and contribute to voids, incomplete joints, or leaks.

Modern lead-free solders can require different working temperatures than traditional lead-bearing plumbing solders. Bridgit® Paste Flux remains active across a wide temperature range, allowing it to cover the soldering temperatures required by many common lead-free plumbing solders.

It is an especially strong companion product for Harris Bridgit® lead-free solder but can also be used with many other compatible solder compositions. Always verify solder, flux, base-metal, and service compatibility before use.

1. Cut and properly deburr the tubing.
2. Clean the outside of the tube and inside of the fitting to remove oxidation, dirt, oil, and other contamination.
3. Apply a thin, even coating of Bridgit® Paste Flux using a suitable flux brush or the applicator supplied with the selected package when applicable.
4. Avoid excessive flux that could become trapped inside the tubing or connection.
5. Assemble the tube and fitting completely.
6. Heat the connection uniformly with an appropriate soldering torch.
7. Apply the selected solder when the joint reaches the proper soldering temperature.
8. After soldering, allow the joint to cool appropriately and remove flux residue.

Harris recommends removing Bridgit® Paste Flux residue after soldering to help reduce the potential for long-term corrosion. After the joint has been completed, clean the exterior of the connection according to current Harris instructions.

Removing residual flux and surface contamination helps leave a cleaner completed solder joint and is an important part of proper soldering practice.

A major advantage of Bridgit® Paste Flux is its ability to remain active during a longer soldering heat cycle. This is particularly valuable when working with larger plumbing fittings or lead-free solders that may require more time and heat to bring the complete connection to proper soldering temperature.

Its paste consistency also makes controlled application easier and allows the installer to place flux directly on properly cleaned tube and fitting surfaces.