Electric arc spray coatings, also known as twin wire arc spray coatings, are a form of thermal spraying whereby 2 feedstock/ consumable wires are fed into the spray gun. The wires are subsequently charged and an arc is created between the two wires. The heat generated from the arc melts the feedstock wire as it is “fed” into the gun. The melted wire droplets are propelled by an air jet through the nozzle of the gun. The particles impact (splat) on the surface of the component forming the coating
Arc spray coatings tend to have very wide plumes of coating which makes masking an important task.
Electric arc spray coatings are commonly used in industries such as Aviation/Aerospace, Energy (Industrial Gas Turbines), Semiconductor (Parts Cleaning), and Marine (corrosion resistance). Common applications corrosion resistant coatings from sprayed aluminium or zinc, conductive coatings, and coatings for wear resistance.
Why is Masking Necessary?
When a component is masked in preparation of thermal spray, it must first be grit blasted. Those areas where coating is required, must be grit blasted first. It is important to protect the areas where coating (and first abrasive blasting) is not desired. A grit blasted surface will quickly oxidize when left exposed. Hence masking is essential. The masking also prevents potential damage in the case of sensitive components. Ideal masking will offer a 1 step solution. In the case of Taconic thermal spray masking materials, the tapes, fabrics, and compounds are designed to withstand the abrasive blasting and coating process with one application.
Masking Options…Finding the Better Way
Contamination Free Surface: Taconic thermal spray masking tapes, fabrics, and compounds are designed to leave no residual silicone adhesive nor fluid on the component surface.
High Abrasion Resistance: Taconic thermal spray masking materials are designed to withstand the high abrasion associated with the abrasive blasting process as well as the spraying of abrasive coating particles (ie. Carbide particles). In most applications, abrasive blasting can potentially break down masking faster than the coating process. For this reason, abrasive resistance is critical.
Flexibility & Conformability: Taconic thermal spray masking tapes, fabrics, and compounds are designed to conform to challenging profiles without lifting, sagging, or moving. These traits make Taconic materials idea for critical masking tasks.
Peel Adhesion: Taconic pressure sensitive tapes offer industry leading adhesion to metal and face-to-back adhesion. The situation of tape lifting during coating can be catastrophic. For this reason, Taconic tapes are used to ensure the masking survives the coating process consistently.
Finding a Better Way to Save Time & Money While Improving Masking Efficiency…
Use Strong Tape & Apply Fewer Layers of Tape – The stronger the masking tape, the fewer layers of tape that are required. Each layer of tape adds time and cost increasing the overall cost associated with a masking job. Using a strong tape allows you to mask in 1-2 layers which.
Reusable Masking – Silicone coated Fabrics and silicone rubber compounds have the ability to speed up masking – to cover and/or large intricate areas quickly. Masking tapes are always single use – they are thrown in the garbage after use. Silicone fabrics and rubber compound molds can be used over an over.
Post Coating Properties – After the abrasive blasting process is complete, the maskant must remain in place and retain its heat resistant properties and structural integrity. Put simply, the maskant must be strong enough to withstand the forthcoming thermal spray coating.
What does the above mean for coating shops?
- Reduces time
- Reduces tape consumption
- Reduces overall spend
- Improves throughput
- Reduces clean up
- Eliminate Rework
Taconic PSA Tapes:
6605-07-HP: Basic single sided glass cloth tape suitable for non-critical Abrasive Blasting masking. A good choice for single layer secondary masking.
6525-08: All purpose Abrasive Blasting masking tape. Tape is suitable for grit blast and air plasma applications. Construction is silicone rubber coated fiberglass complete with silicone adhesive.
6525-20: Double Layered masking tape. Double Layer allows for single layer application for each job. In cases where 2 layers of standard tapes are required, the 6525-20 can reduce masking times by 50%.
Taconic Coated Fabrics:
7322W: All Purpose thermal spray masking blanket constructed of silicone coated fiberglass fabric. This fabric is ideal for secondary masking of large components for most spray styles.
7422W: Heavy silicone coated fiberglass fabric for more demanding jobs requiring protection of large surfaces. This fabric is more abrasive resistant and more suitable for primary masking jobs (as well as secondary).
TacMold Masking Compounds:
TacMold (A2023-A / A2023-B) masking compound is a 2-part silicone putty which is designed to withstand all forms of thermal spray including GF-HVOF and LF-HVOF. This putty is intended to assist with masking holes or complicated intricate profiles. In some cases, the compound is reusable.