BERNINA Skillbuilder Sew Along: Blocks 7 & 8

Welcome back to the BERNINA Skillbuilder Sew Along with Sweet Potato Quilts! I’m Christina, the quilt pattern designer behind Sweet Potato Quilts. If you’re just joining, you can catch up HERE with all links to past blog posts and PDF patterns in one place.

This week we’re making Blocks 7 and 8, and they’re some of the most fun in the whole sampler. Block 7 introduces the disappearing block, where simple cuts transform half-square triangles into a brand new design. Block 8 builds on our HST knowledge with quarter-square triangles and on-point piecing, which open up even more design possibilities.

Download the PDF Pattern for Block 7 here:

Download the PDF Pattern for Block 8 here:

Materials

For Blocks 7 and 8, you’ll need:

• Fabric 1–5 and background fabric pieces (yardage requirements and instructions provided in the Pattern Introduction PDF from Week 1)
• Ruler (12 ½″ square ruler recommended for larger units)
• Rotary cutter + mat
• Starch spray (helpful for bias edges in Block 8)
• Optional: Wooden clapper or seam roller for pressing seams without heat

Skill Highlights

Block 7 introduces disappearing blocks, which start with simple half-square triangles but transform into entirely new designs with just a few cuts and rotations. I personally love this method because the process shows you the possibilities that open up simply from starting with a simple unit.

In Block 8, you’ll move on to quarter-square triangles, which build directly on your half-square triangle skills. Make sure to watch the video tutorial to figure out how to trim them accurately while keeping the center point exactly in the middle of the unit. You’ll also work with on-point piecing, a technique that places blocks on the diagonal to create dynamic layouts. Again, we are working with bias edges, so starch and careful trimming will be my biggest recommendation for success. Finally, both blocks emphasize pressing and trimming techniques that protect your seam allowances, keep your points sharp, and ensure your quilt top comes together smoothly with nested seams.

Instructions to Sew Block 7

Step 1. Make Half-square Triangles

• Pair Fabric 1, 2, 3, and 4 squares with background squares using the two-at-a-time HST method.

• Sew ¼″ seams on both sides of the drawn diagonal line, cut apart, and press toward the darker fabric.

Step 2. Trim HSTs

• Trim to 8″ square using a large 12 ½″ ruler. Keep the 45° line on the seam for accuracy.

Step 3. Slice and Transform

• Cut each 8″ HST in half both directions at the 4″ mark.

• Rotate and rearrange units to form arrow blocks.

Step 4. Piece the Disappearing Block

• Sew units into rows, then join rows together.

• Follow pressing arrows in the pattern for nesting seams.

Finished Block 7: 16 ½″ × 16 ½″ (unfinished).

Instructions to Sew Block 8

Step 1. Make Half-square Triangles

• Pair HST 1 squares (Fabrics 1–4) with Fabric 5 HST 2 squares.

• Use the two-at-a-time HST method.

Step 2. Turn HSTs into QSTs

• Pair each HST with another square, right sides together, with diagonal lines perpendicular to the existing seam.

• Sew ¼″ on both sides, cut apart, and press.

• Trim to 4 ¾″ square, keeping the center point 2 ⅜″ from each side.

Step 3. Prep Background Triangles

• Spray starch before cutting to stabilize bias edges.

• Cut smaller background squares once diagonally; cut the large background square twice diagonally.

Step 4. On-point Piecing

• Add background triangles to QSTs, aligning edges and letting tips extend past the points.

• Press away from QSTs. Trim dog ears for clean edges.

Step 5. Assemble the Block

• Lay out the full block before sewing to double-check fabric placement.

• Piece rows, nest seams, and join together.

Finished Block 8: 16 ½″ × 16 ½″ (unfinished).

Want More?

If you’ve been enjoying this sew along, I think you’ll love my Mix & Match Block Membership at the Sweet Potato Quilt Club. Each month, members receive a new quilt block pattern with video tutorials, plus access to hundreds of layout possibilities using mix-and-match designs. It’s like continuing this sew along all year long, with a community of quilters sewing right alongside you. Visit my site today to learn more about the Quilt Club!

Don’t Forget

✅ Download the PDF patterns for Blocks 7 and 8
✅ Share your progress with #BERNINASkillbuilderSAL to stay eligible for our fat quarter bundle prize
✅ Follow me @sweetpotatoquilts on Instagram and Facebook for more quilting tips and inspiration

We’re almost at the finish line! These skills are building toward a beautiful sampler quilt, and I can’t wait to see your progress.

Let’s get sewing! 🧵❤️