Datasheet

3M
™
Scotch-Weld
™
Epoxy Potting Compound/Adhesive
DP270 Clear and Black
- 7 -
Surface Preparation
For high strength structural bonds, paint, oxide films, oils, dust, mold release agents
and all other surface contaminants must be completely removed. However, the
amount of surface preparation directly depends on the required bond strength and the
environmental aging resistance desired by user.
The following cleaning methods are suggested for common surfaces:
Steel
1. Wipe free of dust with oil-free solvent such as acetone, isopropyl or alcohol
solvents.*
2. Sandblast or abrade using clean fine grit abrasives.
3. Wipe again with solvent to remove loose particles.
4. If a primer is used, it should be applied within 4 hours after surface preparation.
Aluminum
1. Alkaline Degrease: Oakite 164 solution (9-11 oz./gallon water) at 190°F ± 10°F
(88°C ± 5°C) for 10-20 minutes. Rinse immediately in large quantities of cold
running water.
2. Acid Etch: Place panels in the following solution for 10 minutes at 150°F ± 5°F
(66°C ± 2°C).
Sodium Dichromate 4.1 - 4.9 oz./gallon
Sulfuric Acid, 66°Be 38.5 - 41.5 oz./gallon
2024-T3 aluminum (dissolved) 0.2 oz./gallon minimum
Tap water as needed to balance
3. Rinse: Rinse panels in clear running tap water.
4. Dry: Air dry 15 minutes; force dry 10 minutes at 150°F ± 10°F (66°C ± 5°C).
5. If primer is to be used, it should be applied within 4 hours after surface
preparation.
Plastics/Rubber
1. Wipe with isopropyl alcohol.*
2. Abrade using fine grit abrasives.
3. Wipe with isopropyl alcohol.*
Glass
1. Solvent wipe surface using acetone or MEK.*
2. Apply a thin coating (0.0001 in. or less) of 3M™ Scotch-Weld™ Metal Primer
EC3901 to the glass surfaces to be bonded and allow the primer to dry 60 minutes
before bonding.
*Note: When using solvents, extinguish all ignition sources, including pilot lights,
and follow the manufacturer’s precautions and directions for use.