Replace Sponge for Office Chair

You can replace the sponge of an office chair by following these steps:

I. Prepare Tools and Materials

1. Tools: You need to prepare scissors, a utility knife, screwdrivers, an Allen wrench, pliers, a hammer (a rubber hammer is best), a stapler, or strong glue (choose according to the original fixing method). If the old sponge is fixed with staples, you need a staple remover; if it is glued, you need special glue.
2. Materials: Choose high-density sponge (with a density of 25 - 35KG/M³ or higher). The thickness should be selected according to body weight: for those under 50kg, choose 6 - 8cm; for those between 50 - 75kg, choose 8 - 10cm; and for those over 75kg, choose 10 - 12cm.

II. Remove the Old Sponge

1. Separate the Seat Cushion from the Base: Turn the chair upside down on a soft-padded floor. Use an Allen wrench to unscrew the fixing screws (usually 4) that connect the seat cushion to the five-star foot or chassis, separating the seat cushion from the base.
2. Disassemble the Fixing Structure: Observe the edge of the seat cushion and use a screwdriver to remove the screws that fix the U-shaped iron bar or plastic baffle. For some models, you need to first remove the large screw below the backrest adjustment lever and lay the backrest down.
3. Peel off the Old Sponge: If the old sponge is fixed with staples, use a screwdriver or a staple remover to pry up the staples; if it is glued, use a utility knife to cut through the adhesive part and then peel it off.

III. Measure and Cut

1. Measure Dimensions: Use a soft tape measure to measure the length, width of the chair surface, and the required sponge thickness multiple times, and take the average to ensure accuracy.
2. Cut the Sponge: Cut it slightly larger than the actual size (about 1 - 2cm) for easy installation and adjustment. The excess part can be trimmed later. If you need to stack sponges (such as stacking two layers of one-inch-high pads), ensure comfort.

IV. Install the New Sponge

1. Fixing Method:
   • Staple Fixing: Start from the edge of the sponge and staple every 5 - 8 centimeters to ensure a flat edge.
   • Glue Fixing: Apply special glue evenly on the chair surface, press the sponge and press it firmly to ensure a firm bond and a wrinkle-free surface.
2. Check Flatness: After installation, check if the sponge is flat to avoid local bulges or depressions.

V. Reinstall the Seat Surface Reinstall the seat surface with the new sponge onto the chair frame and tighten all the screws with a screwdriver. Check if the sponge is firmly installed, sit on it to adjust the comfort, and ensure there is no looseness or abnormal noise.

Precautions:

• Before operation, ensure that the air pressure rod of the chair is at the lowest position or completely deflated. When turning it upside down, pad it with a soft carpet or cardboard to prevent scratches.
• If the chair has a complex structure or a special fixing method, it is recommended to take photos to record the disassembly process for installation reference.