How to Bond Plexiglas to Steel

Plexiglas is the brand name for a line of clear plastic panels made of polymethyl methacrylate (PMMA). Transparent, shatter-resistant and unaffected by certain types of otherwise corrosive chemicals, Plexiglas conduit tubes are sometimes used for chemical engineering projects (in conjunction with steel flanges as connectors). To ensure a proper bond between Plexiglas and steel, you'll need an acrylic-based binary epoxy.

Things You'll Need

• 220-grit "very fine" sandpaper
• Tack cloth
• Acetone
• Cotton cloth
• Masking tape
• Acrylic-based binary epoxy (i.e., 80 percent methyl methacrylate monomer (MMA) resin)
• 2 G-Clamps
• 2 bar clamps
• 2 1-gallon paint cans
• 2 short-nap epoxy rollers

Instructions

1. Use the sandpaper to thoroughly sand the area of the steel you plan to bond. Dust any particles off of the steel's surface.

2. Go over the sanded area with the tack cloth to remove any remaining dust.

3. Saturate the cotton cloth with acetone and scrub the sanded area.

4. Allow the steel to air-dry for about 20 minutes.

5. Create a 4-inch-wide masking tape border around the area of the Plexiglas that you plan to bond.

6. Pour the epoxy resin and the catalyst into separate paint cans.

7. Saturate one of the short nap epoxy rollers with resin and the other with catalyst.

8. Apply a thick layer of resin to the bonding surface of the Plexiglas.

9. Apply a thin layer of catalyst to the bonding surface of the steel.

10. Press the two coated surfaces against one another and secure them with the clamps. If you're attaching a steel flange to a Plexiglas tube, use two G-Clamps at the 12 o'clock and 6 o'clock positions of the tube's circular cross section. If you're attaching flat surfaces, simply place the two bar clamps an equal distance from the center of the bonded area.

11. Remove any excess epoxy that squeezes out of the bond seam.

12. Let the clamped assembly dry for 24 hours before removing the clamps.

13. Remove the masking tape from the Plexiglas.

References

• Ridout Plastics: Weld-On Product Line Usage Guide (PDF)
• IPS Corp.: Weld-On 10 Instructions (PDF)
• IPS Corp.: Structural Adhesives