1. Use the ButtTaper System with a backer board (required) between studs and joists. Use a 4" to 6" strip of plywood or OSB board (the wider the better) on the Backer Board. Space the drywall screws every 4" with the 1st screw about 1/2" to 3/4" from the board edge.
2. Leave a space of 1/16" to as much as a 1/4" between the butt joint.
3. Using the spray bottle, spray a liberal amount of water into the butt joint. Wait 15 seconds for the water to absorb and soften the board edges before using the ButtTaper tool.
4. Roll the ButtTaper tool up and down in the drywall joint gently at first and apply pressure until the tapered edge is formed.
5. Apply a setting compound into the tapered edge with a standard finishing knife.
6. Let dry and apply the 2nd coat of setting compound.
7. Let dry and apply the 3rd coat with a joint or setting compound using an 8" or 10" finishing knife.