How to sew a hammock underquilt – DIY, with down filling

If you’ve decided on a project to make a hammock liner with down or feathers, you’re in for a lot of fun. All you need is patience and be prepared for a cloud of flying down, and after a few hours of work, you’ll achieve top-class insulation!

There are two basic techniques for attaching down to the fabric: quilting or baffles. The difference between them lies in the shape of the compartments in which the down is packed. In quilting, we create compartments by stitching the fabric with a straight seam. At the seam, a so-called cold spot forms, which slightly reduces thermal comfort. If, instead of a seam, we sew in a wall connecting both materials, we create a three-dimensional baffle, providing a tight insulating layer without cold spots at the seams. For our liner, we opted for the quilted version. However, if someone is considering a baffle version, they can be made using our nylon mesh.

Material selection

The best materials are down-proof, lightweight, and breathable so that the down can loft properly. Tear strength is less important because, unlike a hammock or tarp, there aren’t significant stresses involved. Ultralight calendared nylons coated with DWR work very well for this purpose.

The calendaring process, in simple terms, involves pressing the fabric to create a smooth, more “plastic-like” surface, which effectively prevents down from escaping. This is why down-proof fabrics have a shiny appearance.

DWR (Durable Water Repellency) prevents water from soaking in, such as from light rain or dew.

However, if greater water resistance is desired and the liner won’t function as a quilt or be in direct contact with the body, a compromise can be made by combining a less breathable, down-proof polyester material on one side of the liner with nylon on the other. The advantage of this solution is increased water resistance, while the nylon layer ensures down breathability and allows for washing.

Required Materials:

Additional information:

• 4 m of fabric: Ripstop Ultra Light Marine Blue, 10D nylon
• 850 CUIN down – 400 g
• 10 m of polypropylene cord ø3 mm
• Talia threads matched to the fabric

Tools:

• Measuring tape
• Tailor’s chalk
• Scissors
• Sewing machine
• Bodkin or another tool suitable for stuffing down
• PVC tube

• Ready DIY Kit – Hammock underquilt
• Estimated completion time: approx. 4 h
• The liner is designed for a person 180–185 cm tall

Step 1 – Cutting the pattern

Cut 2 layers of fabric with the dimensions shown in the picture:

Step 2 – Drawing the quilting diagram

After cutting the fabric, we draw the quilting pattern. In our case, we filled it with 25×25 cm squares. This is a reliable design that prevents the down from shifting. Narrow tunnels also work well, but filling them and “measuring out” the down can be more difficult.

Step 3 – Preparing the tunnels for the cords

Before we started stuffing the squares with down, we decided to prepare and sew the tunnels for the cords. Why did we do this separately? The width of the Ripstop Ultra Light Marine Blue roll is 150 cm. We didn’t want to reduce the dimensions of our underquilt and wanted to keep the full 150 cm of down filling. However, nothing prevents you from making a version 20 cm narrower (this solution is also used in our DIY liner product). This allows the entire piece to be made from 4 m of fabric. If you have other ideas for the tunnels, share them in the comments below.

Cord tunnel for the hammock cover.

The cord tunnel for the hammock cover has been sewn.

Step 4 – Quilting and stuffing with down

Once the tunnels are sewn in, we can move on to the most exciting part: quilting and filling with down 🙂 At home, all you need for this is a tube of the appropriate diameter (depending on how wide the tunnels you’ve chosen are). You can find a wide selection of PVC or metal tubes in any hardware store. In the end, a cardboard roll from paper towels will also work. To make the filling easier, we used a kitchen tool with the wonderful name *KOPYSTKA*. For thinner tunnels, another kitchen tool with an interesting name, such as *KWIRLEJKA*, might work better.

The principle of quilting is simple. We sew the square along the previously drawn lines, leaving an opening of about 8 cm. The width of the opening should be adapted to the filling tool. Place the tube on a scale and fill it with the measured amount of down. Insert the filled tube into the opening and push the down into the square using the *kopystka*. Then sew up the opening and move on to the next square.

This part is definitely the most time-consuming, depending on how densely you draw the squares. In our cover, there are 40 squares and we have 400 grams of down. That gives about 10 g per square. After sewing, we were surprised at how much and how quickly the down expanded. Probably, in the next project, we would try an even smaller amount. Packing more than 10 g per square would only reduce the down’s ability to expand, and therefore also the insulating capacity of the padding (see the article on down).

Step 5 – Threading the cords through the tunnels

In the end, it’s enough to pull the lines through the tunnels. For shorter tunnels, you can use an elastic cord with a stopper; we used whatever was at hand, namely a 4 mm rope. The easiest way is to attach such a rope to a mop handle and neatly push it through the tunnel.

Now for the most enjoyable part… field testing in the lowest possible temperature 😉 We’re curious about your results and tests, let us know how it went and if there’s anything you would do differently.