Budnick Converting ®
3M
421
Lead Foil Tape
3M 421 is a 6.3 mil. lead foil backing with a rubber adhesive used as a maskant in electroplating and chemical milling and as a moisture and radiation barrier in certain applications. 421 tape has very good conformability, easier and faster to work with than linered lead foil. It also has good thermal properties and will perform over a wide variety of temperature conditions (-65°F to 225°F). It has been used at higher temperatures for shorter durations. Tape is electrically and thermally conductive. Elevated lead levels in water may result from long term submersion of this product. Best results are obtained when applied to a clean and dry surface above 32°F. Also, by "feathering" the edges, rubbing the tape down with a smooth edged plastic piece (or similar object), the tape can be made to better conform to the substrate. This is especially important if the tape is to be used as a "thief" in electroplating where the edges must fully contact the metal base. To obtain best performance, use this product within 12 months from date of manufacture and store under normal conditions of 60°F to 80°F and 40% to 60% relative humidity in the original carton. Disposal and sfety considerations: *Wear protective gloves and/ or wash hands after working with tape. *Lead will slowly leach into water when submerged, leaching will accelerate as acidity increases. *This material, when disposed of separately, is classified as RCRA hazardous waste, please consult applicable Federal, State and local regulations for proper disposal.
Converting Services
- Precision Cutting
- Die Cutting
- Slitting
- Printing
- Laminating and Coating
- Spooling and Finishing
- Consulting & Process Audit
- Prototyping
- Inventory Management
At Budnick, we specialize in custom converting these materials into labor saving, user-friendly parts.
| Backing/Carrier | Lead |
|---|---|
| Adhesive | Rubber |
| Thickness | 6.3 Mils |
| Tensile | 15.00 lbs/in |
|---|---|
| Elongation | 14.00% |
| Adhesive Activation | Pressure |
| Adhesion (unwind) | 31 oz/in |
| Min. Application Temp | 50° F |
|---|---|
| Min. Service Temp | -65° F |
| Max Short-Term Temp | 225° F |
| Max Long-Term Temp |
Product Features
- Lead foil backing blocks x-rays
- Has excellent protection
- Is electrically conductive
- Is malleable and heavy
- Green rubber adhesive has good chemical resistance and good solvent clean up
- Dark silver tape
- Water vapor transmission rate: 0.1 gms H2O/ 100 sq. in./ 24 hrs.
- Weigth: 0.06 lbs./ yds./ in./ width
- Permits masking of x-ray film
- Protects parts from water, dust or chemical damage and radiation
- Minimizes tape edge printing build-up ("thieving action")
- Conforms to surface
- Provides balance with little mass
- Minimizes undercutting resulting in a straight masking line
- Reduces clean up labor
Adhesive Tape Applications
- Electroplating
- Radiation barrier
- Moisture barrier
- Chemical milling
- X-ray plate masking
- Maskant during paint stripping
- Add weight (balance) to equipment parts (golf clubs, tennis rackets, etc.)
Adhesive Tape Colors
- Silver
Data provided by Budnick Converting, Inc.
The physical properties listed are typical values and are not to be considered as specifications. Our suggestions for use are based on tests we believe to be reliable. However, the purchaser must carry out their own tests to determine the suitability of the product for their internal use. Information is given in good faith, but without warranty.
It is essential, as with all pressure-sensitive tapes, that the surface to which the tape is applied be clean, dry and free of grease and oil.
Shelf life from date of manufacture is based on the product being stored at 70°F(21°C) / 50% relative humidity out of direct sunlight.
Specification compliance is dynamic and should only be used as a general guide. Always confirm that the tape you are interested in currently complies with all specification requirements. Please verify that the product number that you select is available in the proper size and color to meet your specification.