Weld tape, also known as weld backing tape, is used to support the molten weld pool from the backside of the joint, ensuring a clean and consistent weld. The application involves positioning the tape's fiberglass strip in a convex shape away from the backside of the weld area for best results.
While the provided reference mentions the Aquasol Welding brand and a convex positioning technique, a more comprehensive understanding requires expanding upon the steps involved in using weld tape effectively. Here’s a detailed guide:
1. Preparation:
- Clean the base metal: Ensure the surface where the weld tape will be applied is free from dirt, rust, oil, or any other contaminants. Use a wire brush, grinder, or solvent cleaner as necessary.
- Select the correct tape: Choose a weld tape compatible with the welding process (e.g., GTAW/TIG, GMAW/MIG, SMAW/Stick) and base metal. Different tapes are designed for different heat inputs and materials. Consider the joint geometry (butt, fillet, etc.) and required weld quality.
2. Application:
- Cut the tape: Cut the weld tape to the required length, ensuring it extends beyond the weld joint on both ends. This provides adequate support and prevents burn-through at the start and end of the weld.
- Position the tape: Carefully align the weld tape on the backside of the joint, centering the fiberglass or ceramic strip behind the intended weld path. According to the reference, positioning the fiberglass strip in a convex shape away from the backside of the weld area is suggested for optimal results. The backing material should be in direct contact with the base metal.
- Secure the tape: Firmly press the adhesive side of the weld tape onto the clean metal surface. Ensure there are no air pockets or wrinkles. For wider gaps or irregular surfaces, consider using multiple strips of tape or a wider tape. Some tapes are designed to be used with additional clamping or fixturing.
3. Welding:
- Adjust welding parameters: Welding with weld tape may require slight adjustments to welding parameters (e.g., amperage, voltage, travel speed) to compensate for heat transfer differences. It is generally recommended to consult with a welding expert to determine the ideal parameters for the specific application.
- Weld as normal: Proceed with welding, keeping a consistent travel speed and maintaining proper arc length. Monitor the weld pool and adjust parameters as needed to avoid excessive heat buildup or burn-through.
4. Post-Welding:
- Remove the tape: After the weld has cooled sufficiently, carefully peel off the weld tape.
- Inspect the weld: Examine the backside of the weld for any defects. A properly applied weld tape should result in a clean, uniform weld bead with good penetration.
- Clean the area: Remove any adhesive residue left behind by the tape.
Key Considerations:
- Material Compatibility: Choosing the correct type of weld tape for the base material is vital to prevent unwanted chemical reactions and ensure a sound weld.
- Heat Input: Control heat input to prevent the tape from burning or deteriorating excessively.
- Proper Surface Preparation: Adequate surface preparation is critical for the tape to adhere correctly and provide effective backing.
- Storage: Store weld tape in a cool, dry place to maintain its adhesive properties.
By following these steps, you can effectively use weld tape to improve weld quality, reduce the need for back gouging, and increase welding efficiency.
