May 2025
I am a proponent of bivy sacks. I like sleeping under the stars. However, what I like most about bivy sacks, is that I don’t have to pack up a tent in the morning.
Design
I was originally hoping to purchase an ultralight bivy from Borah Gear. However, they’re an American company; after the currency conversion and various fees, it was going to cost close to $300 to get one. This felt like a little much to say the least.
So, I endeavored to make one. Thankfully Borah Gear makes this fairly easy; though I’m not sure if this is really their intention. Their website lists rough dimensions and the exact materials they use. I ordered all the same materials and created a sewing pattern by measuring myself. I figured if I was making a one-off, I might as well make it perfectly suited to me.
The pattern is below. A few notes about it:
- The measurements are based on someone who is 5’9″ and quite slim with narrow shoulders
- The pattern is too narrow. It’s quite tight when using a CCF pad and it’s a coffin when using any inflatable pad. If you plan to use this pattern; measure your shoulder width, then add roughly eight inches in width to the cut line
- The pattern is also too short. Measure your height, then add four inches to the cut line
- Don’t pay too much attention to getting perfect 5″ radii in the corners. It’s probably easier to just use a bowl that is close in size to trace the corners
- The pattern is split into two parts. An upper that is mesh and a lower that is some sort of breathable fabric. Both parts can be put together to form the pattern for the bottom
- The pattern assumes a straight zipper in the middle
Given that all the dimensions are slightly off, you’ll need to make your own modified pattern based on the provided drawing.
Materials
When selecting the materials, the most important thing is the top fabric be breathable and the bottom fabric be waterproof. I selected the materials based on what is listed on the Borah Gear website.
- Mesh: 0.67 Oz Noseeum Mesh
- Top Fabric: Argon 90
- Bottom Fabric: 1.1 oz Silpoly PU4000
I used a cheap Amazon zipper; after 1500 km of use, it was the only thing that had failed. I would recommend using a #3 YKK zipper instead.
Construction
The construction is relatively straight forward; unfortunately I don’t have any pictures. The steps are essentially as follows.
- Use the pattern to cut the bottom piece
- Cut the various top pieces
- Stitch the top pieces together
- Stitch the top and bottom pieces together
There are a few tips that I think are useful.
- Use a 1″ seam allowance. This sounds big, but the fabric is very slippery and very thin. The larger seam allowance allows for a bit of misalignment
- Newspaper between fabric layers can help with slippage. I used this trick with all the corners
- Don’t worry too much about having a perfectly even seam allowance the whole way around, you can always cut off excess fabric before finishing the seam
Gallery
Action shots. I guess I like camping under trees.
