Sunday, February 18, 2018

Fly for a small tent (parrt 1)

We have two small, inexpensive tents that we purchased years ago.  They're simple and easy to set up.  Best of all, they're very lightweight.

But sadly, the rain fly is way too small.  Since it seems that no really suitable tents are on the market, I set about making a replacement fly.

Based on some quick measurements of the tent, the basic idea is that there are four panels.  The front panel is split with a zipper.

The panels lay out on about 6 yards of fabric on a 60" wide roll.

Here's the bill of materials:
  • 6 yd of ripstop waterproof nylon.  I'm using 1.1 oz weight, which should lead to about a total of 7 oz.
  • 3 foot zipper
  • seam sealer
  • 4 peg tiedowns

First, I chalked out all of the pieces on the fabric to make sure that everything fit nicely.
The front panel (with the zipper) is handled first so that I can compensate for any issues with the front panel size.  The zipper seam is a little complicated.

I figure that if the overlap (v above) is more than three times the zipper half width (z above), it will be fit nicely.  This means that the seam allowance ought to be about 2 v + 1.5 z.  For my zipper, this was around 5 inches.

Here are the two panels to be zipped together.

Forming the pocket for the zipper.

Sewing the zipper into its pocket.

Completed seam.

The pocket folds over the zipper and is sewn in place.

Duplicated on the back as well.

The zipper doesn't open all the way to the top, so the front and back pockets are pinned together to close the front panels together.

Completed zipper pocket.

Since ripstop nylon is slippery stuff, each of the main seams is sewn in two steps.  (I was trying this seam as an alternative to the usual felled seam.  I did three of the main seams as below, and the last as a felled seam.  The felled seam was much easier, but perhaps wasn't as well aligned.)

First, the fabric is pinned...  (use lots of pins!  the fabric is quite prone to sliding!)

... stay-stitched flat...

... then folded, re-pinned, and final stitched.

Here is the tent with the fly at this point. 

The fly is a bit floppy, but this is not surprising.  Shaping still needs to be done, and guying is critical. The attachment points for the guys are determined experimentally with the tent pitched.

Still to come:
  • Guy lines
  • Stitch the bottom edge
  • Shape the top
  • Clean up loose thread ends
  • Seal the seams
  • Add a nice zipper pull