"Unless you plan to use stainless steel or any other type of non
metal, the grommets will rust and eventually eat away at the canvas.
keep in mind, even if they don't rust, you risk the fraying of the
around the grommets since they are not sewn within the grommet area."
"No matter how well you install grommet, it'll compromise the
of canvas. "
Guys, **brass** grommets (the cheap hardware store kind) are COMMONLY
used on boat canvas, __under stress__, or at least FAR more stress
than an awning draining a bit of water. "Weather cloths" (USA term)
or "Lee cloths" (Brit) are the canvas (usually Sunbrella) that are
strung on the lifelines to the sides of a sailboat cockpit to protect
the sailboat operators from (cold) winds and/or spray. They are
typically strong enough so that sailboaters often use light string to
hold the bottom edge, in case a boarding wave (from the side) strikes
the boat. That way the bottom edge of the weather cloth comes loose,
so that the (stainless) stanchions holding the lifelines don't
**Normally**, those grommets are put through a double layer of
Sunbrella, with maaaaaybe a layer of webbing, but that is because boat
owners like to pull weather cloths TIGHT. For __weather cloths__,
those extra layers around the grommet are justified. For water
drainage, no extra layers are needed.
FWIW, MAINsails (which develop enough power to push a 12,000 pound or
more boat at 7 or 8 mph) usually have *brass* grommets (the strong
kind), though some with have stainless grommets (more difficult to
set, but look nicer for the customer who prefers stainless steel). In
main sail applications, the luft (front edge of the sail) is usually
several layers of resinated sailcloth, and most usually with a stretch
rope sewn in as well.
Hand-sewn grommets for the luft attachment of a main sail are
**reportedly** stronger than set grommets, but to the best of my
knowledge no one makes them anymore (the rings are available, but the
*brass* sleeves that protect the sewing thread from chafe are not).
FWIW, last week I hand-sewed a 1-1/4" tack (front corner attachment)
to a used sail for a customer (to shorten it a needed 2", because the
sail was longer in the vertical measurement than advertised). It is
time consuming, but the alternative is some expensive equipment that
only dedicated sailmaking shops have. It DOES look salty, however.
It also took $60 worth of die setting tools, a concrete surface and a
2# hammer. The only mainsails I have ever seen with hand-sewn
grommets on the luft (leading edge) were OLD sails.
Cheap grommets (without extra layers of awning material) will work
just fine for water drainage. It is commonly done on certain kinds of
main sail covers which collect rain (which most main sail covers
BUT, if you're really worried about grommet corrosion, you can unlay
(unwind) a small diameter nylong rope, take one of those strands and
twist itself back on itself to form a small circle, cut a small hole
(Exacto knife) in the canvas, then sew around the rope/hole, one
stitch close (on the outside), the next stitch out a bit, continuing
around the rope/hole until complete, two ropes/holes sewn somewhat
close together, then sewn (kinda) to each other. Rope handle attach
points on canvas water buckets were once commonly made that way. I
did it once, just to say I did it. Now, I use machine sewing and
pressed grommets, or a sewn on canvas handle.