Sep 27, 2011 at 6:57 am #1279860
@ware4Locale: Northwest Georgia
For this project, my goal was to construct a footprint for my Nemo Obi 1P tent from a 36” roll of Tyvek HomeWrap. For reference, the ‘stock’ footprint for this tent costs $45 and weighs in at 7.6 oz
Here I cut the material to length using a sharp pair of scissors and my drywall square. I choose the length and width of the raw material to be the dimensions of the tent plus 6” (3” per side). The additional 3” of material will be used to reinforce the corners. A tent footprint should always be somewhat smaller than the tent floor. The ‘offset’ is accomplished when the edges are seamed in Step 5
Because my tent is 39” wide at the widest point, I needed a 45” material width. As I am working with a 36” roll of Tyvek, I marked two pieces of material for a 1” overlap (one on the printed side, the other on the blank side) and applied water-based contact cement. I let the adhesive set for 15 minutes, then flipped 1 piece of material and joined the two sheets. I found it quite handy to have a laminate seam roller close by to ensure a flat, tight seal.
Here I sketched the tent profile on the sheet (exactly as measured from the tent floor), allowing a 3” square at each corner for reinforcements. I also added a line 1-1/2” inside of the cut line. This will be my fold-to line for the seam (creating a 3/4” seam).
Cut out the profile!
Fold over the 3/4” seam and trim the excess from the corners so that a 3” x 45 degree corner reinforcement is created. The material will be 3x as thick at the corners to support the shock cord that I will use to attach the footprint to the tent poles.
I cut a couple of small pieces of Tyvek to mimic the corners of my footprint. I used these pieces to test two different methods of attaching the shock cord. In the first, I cut a small 45 degree angle across the corner fold, then opened corners and put a couple of stitches through the shock cord to hold it in place. I glued the corner shut with contact cement, then stitched the cord down through all 3 layers of material. I tried using the sewing machine for this, but found it difficult to work with.
For the second sample, I glued down the corner straight away. Then, I punched a hole in the corner and added a 3/8” grommet. I bought a pack of 25 grommets at Michael’s for $3. I could easily have gotten by with a paper hole punch, but I had this punch set and it allowed me to get a nice tight fit so that the grommet could be placed accurately. I tied a knot in the shock cord and fed it up through the bottom of the grommet.
Both methods worked quite well. In the end, I decided to use grommets for the footprint, as they will allow me to replace the shock cord if necessary.
Ok, back to Step 6.
Final construction step – Glue down all of your seams and corner braces. Add all of the hardware (shock cord only, or shock cord and grommets). Once the glue is thouroghly dried, crumple everything up in your hands…like wadding a piece of paper. Pull it out flat, and crumple it again. I was really amazed how much the feel and properties of the material changed by doing this, almost like transforming it from paper to fabric.
Fold it, roll it, and evaluate it. Mine came in at 4.5 oz and around $7.50 in materials!
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