3M 8985L Chromic Acid Anodizing Tape

Starting at $18.2401
Based on the above selections this item has the following specifications:
Display Attributes

3M™ Anodization Masking Tape 8985L has a tough polyester carrier to stand up to chromic acid anodization baths (Type I anodization). It features a non-silicone rubber adhesive to minimize the risk of silicone contamination that could impact downstream processes such as bonding or paint adhesion. This tape provides sharp masking edges, minimizing leakage and the need for rework, and can be used with or without chemical film on a variety of aluminum and other metal alloys. It is supplied on a polyester liner.

This tape can replace complex, messy liquid masking and the unpleasant odors involved. The transparency of the tape makes it easy to position and can be applied in fewer steps; it also eliminates the cure time of a liquid so that overall masking and de-masking can be accomplished up to five times faster*. Ease of application and clean, one-piece removal mean users could save up to 60%* on labor time and associated costs. This tape is transparent purple with a printed backing for visibility and has a liner for easy die-cutting.

Product Features

  • Operates at temperatures up to 200°F/93°C
  • Designed specifically for masking in chromic acid (Type I) anodization baths
  • Masks and de-masks up to 5x faster* than liquid masking, with no cure time
  • Transparent purple tape for fast, accurate positioning and easy identification
  • Provides sharp masking lines and minimizes leaking to reduce the need for part rework
  • Non-silicone formulation helps reduce post-process coating and bonding failures; use on parts where subsequent painting or
    bonding is necessary
  • Rubber adhesive specially formulated to resist the harshest of chemical bath chemistries and provide clean removal when finished
  • Strong polyester backing provides excellent abrasion, tear, scratch, puncture and oisture resistance to help protect surfaces
  • Liner provides added stability for easy die-cutting


  • 4.0 Mil Total Thickness (excludes liner)
  • Roll Length - 72 yards

Recommended Applications

  • Aerospace components
  • Precision machine components
  • Welded assemblies

Application Techniques

Surface Preparation

  • Clean surfaces prior to masking, such as alkaline clean and deoxidize.
  • Improve masking success by chemfilm surface prior to masking.
  • Optimal adhesion is obtained when both the tape and intended surface are within a temperature range of 60° to 80°F (16° to 27°C).
  • To apply the tape, remove a portion of the liner from one end of the tape and firmly tack it down to the surface. Gently pull liner away from tape at an angle as it is being applied by hand.
  • Once the tape has been applied, firmly apply pressure to improve bond strength to surface. Additional tools (wipers, rollers, etc.) may be needed to achieve proper bond.
  • Squeegee out any air bubbles that may be trapped between the tape and the surface paying special attention to masking edges for better sealing from chemicals.

Removal Techniques

  • Allow masking tape to dwell greater than four hours after part processing before removal.

*Up to 5x faster and up to 60% reduction in labor time both based on 3M internal data.

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