Masking is treating a portion of the steel surface prior to hot-dip galvanizing to prevent zinc from reacting with and adhering to the steel. It is not an exact science and is not 100% effective, and as such, additional work may still be required to remove unwanted zinc after galvanizing.
Many different types of products can be used as masking materials, but we recommend the following Gorilla Tape and High Heat Silicon Sealant.
- Gorilla Tape is effective as it prevents the pickling process from occurring therefore preventing the galvanizing reaction from taking place. The tape can be applied to any area of the steel, making it the most user friendly option. It must be applied in a manner that correctly adheres to the steel, otherwise pockets of acid may pool underneath creating a splatter effect and bare spots adjacent to the masked area. The same theory applies to any tails left at the end of a piece. All tails must be cut off to reduce the chance of acid getting trapped underneath.
- A High Heat Silicon sealant is typically applied to smaller surfaces and used on internal threads or threaded holes. It will then be necessary to remove the residue after galvanizing by means of brushing.
If you plan to apply a masking material, consult with Daam Galvanzing to arrive at the best solution for any particular design.