Hemp canvas is bought by weight and sewn by patience. The two decisions that matter are made before the machine is switched on: the gsm, and the needle.
The settings that stop a domestic machine skipping stitches or snapping needles.
| Weight | Needle | Thread | Stitch length | Machine |
|---|---|---|---|---|
| 200–280 gsm | 80/12 | All-purpose polyester | 2.5 mm | Any domestic |
| 320–400 gsm | 90/14 jeans | Topstitch or upholstery | 3.0 mm | Domestic, slowly |
| 450–550 gsm | 100/16 jeans | Upholstery, bonded | 3.5 mm | Heavy domestic or walking foot |
| 600 gsm + | 110/18 leather | Bonded nylon | 4.0 mm | Industrial, or hand-stitch |
Hemp shrinks 3–5% on the first wash. A bag made from unwashed canvas that then gets washed will pull out of square at the seams and never recover.
Hemp creases willingly and holds a press beautifully, which makes it far easier to sew accurately than cotton canvas. Use the crease rather than fighting it.
The weave is directional and a piece cut off-grain will twist over time. Mark the warp direction on every piece as you cut — on plain undyed canvas it is genuinely hard to tell later.
Hemp frays enthusiastically at raw edges. Overlock, bind or fell every seam that will take stress; a raw edge inside a bag is a seam with a countdown on it.
Hemp felt is needle-punched rather than woven, so it has no grain, does not fray, and can be cut in any direction and left raw. That makes it far quicker to work with and much less strong: it tears rather than resisting, so it wants seams that spread load rather than concentrating it.
Where it earns its place is padding, liners, plant pots, cases, and anything that wants thickness without weight. Where it does not is straps, handles, or anything carrying a point load.
Almost always the needle — too fine, blunt, or the wrong type. Fit a fresh jeans needle one size up, lengthen the stitch, and slow down. If it still skips, the layers are moving and you need a walking foot.
Yes. Rub a wax bar over the surface, work it in with a hairdryer or a warm iron through paper, and repeat until it stops absorbing. Do it after sewing — waxed cloth is unpleasant to feed through a machine and clogs the needle.
Undyed, natural-dyed and piece-dyed are all available, though the range is narrower than cotton. Undyed is the most common and takes dye well yourself, which is often the better route for a small run.