sewing reinforcement stitches?????

[stevebo]

Hey guys, I have an off the wall question for you: in circumstances where you want a corner to be reinforced or strengthened, instead of sewing a patch on the area, what would happen if you just ran a series of stitches across the area? My thinking is you are sort of weaving the thread across the area (like a grid), making it stronger? On the other hand, since I have never heard of anyone doing this, it's very possible that there is a big flaw in the way I'm thinking about this! I'm looking for a way to reinforce an area and have a nice smooth distribution of stress across the whole area. Anyway, just curious if this has ever been done before, and if not, why? Thanks!

[Just Bill]

Hey guys, I have an off the wall question for you: in circumstances where you want a corner to be reinforced or strengthened, instead of sewing a patch on the area, what would happen if you just ran a series of stitches across the area? My thinking is you are sort of weaving the thread across the area (like a grid), making it stronger? On the other hand, since I have never heard of anyone doing this, it's very possible that there is a big flaw in the way I'm thinking about this! I'm looking for a way to reinforce an area and have a nice smooth distribution of stress across the whole area. Anyway, just curious if this has ever been done before, and if not, why? Thanks!

It's done on nearly every hammock in existence, or rather on nearly every tree strap. The 'w' type stitch or longer zig zagging lines (vs spaced bar tacks) help spread the load in the manner you're thinking.
Sail makers do it, I've seen some folks sew on reinforcement for tarp corners with radius stitching with debatable success.
If you'd like to be generous with the thought- the three rows of stitching on every gathered end with a sewn channel counts too.

That said, knowing a bit a what I know, it doesn't work that great fer bridges. Grizz has done some corner reinforcements along the way of various types.

Generally though here is the flaw in the thought:
In the case of most applications you're spreading the load out so the THREADS don't tear out. The tree hugger is the prime example. The webbing isnt' going to blow out but your stitching might... so you spread the load over the stitches evenly to reduce the chance of the whole thing zippering open. But the webbing isn't going to tear it self apart if you use the wrong stitch pattern... so the stitches themselves are the weak point to address.

In the case of what you're thinking- the fabric itself is the weak point. Unless you were able to go back to the mill and literally weave in heavier denier thread or additional thread at this stress point... all you're really doing is poking holes in the thing. Also known as 'toilet papering' the fabric. This is why the corner patch on a tarp tends not to go so great... In some cases you can actually concentrate the load onto the stitching resulting in earlier failure.

It's also the reason that very SUL fabrics should not be seam ripped. If a fabric is not self healing (the holes don't smooth back out), then you cannot seam rip it or you will get needle marks at best, or a toilet paper failure at worst.
If you screw up- you're done. If you did it on your tarp or quilt... yar a little seam sealer will clean that mess up... but if you're a vendor or it's a load bearing application then the project should be moved from the production floor to the packaging material scrap bin or sold as a second's quality product.

Laminating fabric to fabric can be one option, but again even in some tarp builds this can simply mean a strong spot next to the spot that's failing.
And while DCF and some stuff does laminate pretty well... most stuff doesn't hold up that wonderful under load. As in real load... not a little tension from your guyline.

Laminating your two ply toilet paper to an extra sheet of two ply generally just means your poopoo paper will just fail next to your patch.
Basically- you just move the load over from the exact corner, to the spot your built up area meets the not built up.

If you were a racing sailmaker... then you can talk about applying this with various layups of dyneema fibers and layers in a computer controlled stress loading diagram that could indeed dissipate the loads across the sail and back to the anchor points. But if you're talking about one ounce bridge fabric failing and it can be solve by using 1.2 ounce fabric instead... the fabric is often lighter than the reinforcement and already woven to spread the load.

In theory- if you laminated a large enough patch you could do it... but Grizz never quite got that cuben fiber bridge to work in practice either.


Might you figure out some magic I have not... sure. I could imagine some things and I have tried some things... but ultimately my feeling is that you are simply moving things around.

The best way I've found is to fix the problem by either bumping up the fabric or fixing the design flaw causing the concentrated load.
A little heavier fabric forgives many sins.
A perfect design allows very light fabric.

Not to be too much of my overbearing cocky self but having said this before I'll say it again:
There is quite a bit you can get away with on sewing stuff up- but there is a big difference when sewing a full load bearing application that most folks don't deal with in normal sewing.
In much the same way we build a tarp that doesn't fail after 40-60lbs of wind thrust... that doesn't really qualify us to build racing sails with thousands of pounds of load on them.

So... it's all relative when talking reinforcement and stitching.

My first bridge was tyvek- that was off the wall- and perfect to illustrate toilet papering

[stevebo]

Thanks Bill! That makes perfect sense. In a perfect world hammock fabric would be like the aluminum skin on a jet aircraft- different thickness at high stress areas. ( but were not quite there yet- maybe someday they will have 3 d printed fabric that would accomplish that!).