Here's How

• Step 1: Place mirror face down on a protected workbench and undo screws. With a piece of cardboard between hammer and back of glass to prevent direct impact, gently tap frame with a hammer to remove, keeping hammer adjacent to glass.
• Step 2: Measure mirrored glass (ours was 2300 x 760mm). Clean, cover and set it aside.
• 
  Step 3: To cut rebates in back of frame, stand any 1 frame length on edge and clamp to workbench. Set cutting depth on power saw to 43mm. Set guard to cut in 8mm from back face then rip along length of frame. Always cut from 1 direction. Depending on workbench, you may need to unclamp, reposition timber and continue cutting. Repeat step for other 3 frame lengths.
• 
  Step 4: Clamp any 1 frame length to workbench, back face up. Set saw guide rail to cut along 43mm line at a cutting depth of 8mm and rip along lengths. Repeat for other 3 frame lengths.
• 
  Step 5: For mitred corner joints, mark in 86mm from each end of any 1 frame length, rebate face up. Set compound saw to 45° and cut from mark outward. Repeat for each length, adjusting direction of 45° cut as necessary.
• 
  Step 6: Working with top and bottom lengths, use a square to measure and mark 20mm and 50mm guidelines from long point of cut edge, squaring off 45° cut. Repeat for each end of top and bottom lengths.
• 
  Step 7: Clamp top length to workbench on its edge. Using guidelines, drill clearance holes at 20mm and 50mm marks. Repeat for bottom length. There is a total of 8 holes.
• Step 8: Lay frame lengths in frame position on workbench, front face up. At each corner, check for square. Predrill through clearance holes into side lengths.
• 
  Step 9: Working on 1 corner at a time, apply PVA to join, press together and clamp to workbench. Check for square. An offcut wedge placed under rebate side of frame will help face of frame sit flush. At 20mm mark, drive in a 32mm screw. At 50mm mark, drive in a 75mm screw. Repeat for each corner.
• 
  Step 10: Flip frame over. Run a bead of silicone along rebates.
• 
  Step 11: With someone helping, place 1 edge of mirrored glass into frame and carefully lower, pressing it into silicone at edges.
• 
  Step 12: Using snips, cut four 60 x 80mm brackets from a sheet of flat galvanised bracket.
• 
  Step 13: Place a bracket at each corner and fix with 20mm galvanised screws. Use washers, if necessary.
• 
  Step 14: Measure and mark centre position along length of mirror. Centre brace on mark, then predrill, glue and screw with 32mm screws – 2 at top and 2 at bottom.
• Step 15: Coat back of frame with Woodshield. Let dry. Flip mirror and coat front. Let dry.
• 
  Step 16: The split batten makes it easy to hang the mirror from a fence. Rip a 45° angle on long edge of each 300mm length. With long point facing down and away from frame, screw 2 lengths to top of back of frame, 100mm from outer edges. Fix other 2 pieces to fence with long point facing up , corresponding to pieces on back of mirror. Slot mirror into place.