Asym Diamond Tarp Tutorial
This tutorial is based off a hammockforums.net thread started by member nacra533 on 8-23-2010. I'm just attempting to explain and repeat the steps that I use in hopes that it may help others.
3.5 to 4yds - SilNylon or other suitable tarp fabric.
9yds - 5/8" or 7/8" Grosgrain ribbon.
2 - 3/4" D-rings
2 - lineloc 3 adjusters
Note - I've found it easier to use a fairly stiff tape measure to do this because the tape is much easier to move around when extended this far out.
1. Lay fabric on a large flat surface with lots of elbow room to move around.
2. Place a mark in one corner of the fabric. This will become one end of the ridgeline. I use a red Sharpie marker for this.
3. Measure 132" on a diagonal to the opposite edge. Keep adjusting the angle until 132" reaches the opposite edge. This is the other end of the ridgeline.
4. With the tape measure in place, put a piece of masking tape on the fabric at the halfway point (66") of this measurement. Mark a small "X" on the masking tape.
5. Measure the width by extending the tape measure to 88". Lay the tape across the fabric, keeping the 44" point on the tape measure exactly on the "X" you marked in Step 4. Adjust the angle until "0" is on one edge of the fabric and "88" is on the other edge.
6. Mark the 0" and 88" points on the edges of the fabric. These 2 points determine the diagonal width of the tarp.
7. These 4 points to make the parallelogram shape of your tarp. Now you need to decide if you want to cat cut your tarp edges or keep them straight.
8. If you want straight edges, Connect and mark the 4 points on your tarp and skip to Step 11.
9. If you wish to cat cut your tarp edges, now's the time. With your tape measure, find the center point of each of the tarp edges. Measure in the amount of curve you desire on each edge. On my tarps, I use 1" on the short sides and 1.5" on the long sides.
10. I use an old fiberglass tent pole to mark my cat cuts by placing the pole along the tarp edge and bending it until the curve reaches the mark placed in the center in Step 8. Carefully hold the tent pole steady and mark out each edge.
11. Cut out the tarp outline along the lines you've marked.
On a couple of tarps with grosgrain edging, I chose to leave off these corner reinforcement patches, instead using a continuous loop of grosgrain ribbon. This places much of the force on the edging instead of the fabric. If using folded webbing or grosgrain ribbon for the tie-outs, you probably should add the reinforcements.
1. Layout and cut two 12" to 14" square pieces of material. You can use the leftover tarp fabric or even better yet, some uncoated ripstop nylon in a complementary color.
2. Cut each square in two, creating 4 triangle shaped pieces.
3. Measure and mark diagonal lines for corner reinforcement alignment. I measured 7" up on each side on this one. It's best to use masking tape or painter's tape for this. If you use a marker, your lines will likely show through the tarp fabric. Be prepared to fight with the tape if you're using it on Silnylon because it'll peel off when you least expect it.
4. Stitch top edge of triangle to the tarp keeping the edge aligned with your masking tape edge.
5. Remove the tape and fold the triangle piece down over the corner of the tarp.
6. Sew 1 row of stitches close to the top edge of the triangle and 2-3 more rows evenly spaced down the triangle.
7. Turn the tarp over and trim the excess fabric off the reinforcements.
Note - There's some debate about whether it's better to hem the edges before stitching on the grosgrain ribbon. I've done it both ways and have never had a problem either way. If you prefer to do it this way, go for it.
1. Carefully fold the ribbon lengthwise for 2-3" and press down with your iron"s polyester setting. Fold the ribbon another 2-3" in front of the iron and hold a finger on it while you advance the iron those 2-3". Fold, iron, fold, iron until you reach the end.
2. Starting at one corner, insert the edge of the tarp fabric into the folded ribbon and run a row of stitching along the edge. Work 8-10" at a time until you get a rythumn going.
3. When you reach another corner, trim the ribbon and seal the cut with a flame. Continue until you've gone around the entire tarp.
4. Run a 2nd row of stitching around the edges, offset slightly from your 1st row.
1. Cut 4 pieces of your leftover folded grosgrain ribbon approx 6" long.
2. Run 1 row of stitching down the side to close it up.
3. Fold over and insert into the D-ring or Lineloc 3.
4. Run a row of stitching as close as you can to the edge of D-ring or Linloc 3. You may have to use a narrow or zipper foot to get close enough.
5. Insert the tie-out onto the tarp with one piece over and one piece under the tarp. You will likely need to pin and double, triple check that the 2 ends of the grosgrain ribbon line up on top of one another.
6. Stitch a "Box X" or your preferred pattern.
Disclaimer - This is maybe not the best way or the only way. It's just the way I do it.