DiyProject

How to Make a Keystone Cushion With a Backer Board

X-HT-300102

In many v-berths, there is a cushion that can be added for extra sleeping space, or removed for standing room. This helpful cushion is referred to as the keystone cushion. The keystone cushion in the v-berth on our Regal Ambassador 245XL powerboat was attached to a backer board. In this video, we'll show you how we re-covered that board to create a new keystone for our cushions.
Video Chapters:
  • Patterning Plate – 0:39 min.
  • Making Boxing – 3:38 min.
  • Sewing Piping to Plate – 5:39 min.
  • Sewing Boxing to Plate – 7:22 min.
  • Cutting Foam – 13:16 min.
  • Attaching to Backer Board & Finishing – 14:50 min.
  • Materials List – 20:18 min.
Materials List:
  • Dura-Skrim® Patterning Material – #122463
  • Marine Upholstery Fabric
  • Tex 70 Polyester Thread – we used Derby Navy, #103795
  • Medium 5/32" Welting Cord – #107035
  • Seamstick 1/4" Basting Tape for Canvas – #104167
  • CushionRite® Dry Fast Antimicrobial Foam
  • Cushion Underlining Fabric – we used Beige, #103934
  • 21 Gauge 1/2" (12mm) Staples 10,000/Box (Stainless Steel) – #8012SS
  • Morbern® Seabrook 3/4" Hidem Gimp – we used Lite Glacier, #120132
Tools List:
  • Sailrite® Canvas Patterning Ruler – #107040
  • Multiuse Pins – #102985
  • Grease Marking Pencil Yellow – #111002
  • Gingher® Scissors Right Handed – #19104
  • Sailrite® Clear Acrylic Ruler 6" x 24" – #102400
  • Sailrite® Ultrafeed® LS Walking Foot Sewing Machine – #311502
  • Sailrite® Blade Foam Saw V2 with Carrying Case – #121244
  • Sailrite® Long Nose Staple Gun – #121411
  • Tape Measure, Marker
How to Make a Keystone Cushion With a Backer Board Video 2

To make a keystone cushion with a backer board, you will sew together the top half of the cushion, which will then be fitted over the backer board and stapled in place. We patterned the shape and size of our keystone cushion on the boat when we patterned the rest of the v-berth cushions. You can see that process in our "How to Make Forward Berth Cabin Cushions" video. Since our cushions use a patterned fabric, we made sure to line up the patterns when cutting the fabric for our keystone cushion for a cohesive look. Cindi carefully explains that process in the video.

With the keystone cushion being removable, we wanted the back of the board to be neat and nice-looking, for times it was removed and stowed. To do this we added a layer of cushion underlining fabric to the underside of the board and hid the raw edges of the decorative fabric with hidem gimp. This is an optional step, but one that does add a nice finished touch.

In this video you’ll learn how to pattern your fabric, sew on boxing and piping, cut the foam, and staple the assembly to the backer board.

This project is part of our Regal Ambassador 245XL Powerboat Makeover series. 

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