We've all had a trash bag rip open, right? How does it some to be that the hole is almost always near the bottom?

The reason is this: the trash's weight increases the further down you go in the bag. Furthermore, the weight is exerted down, so the bottom is the part that's feeling the most weight. Various sharp things concentrate some of the weight on a small point, making a puncture very likely (they don't have to be very sharp to rip through).

Since the bottom of the bag is under the most stress, why not reinforce bags at the bottom? This will prevent a large number of leaks and indoor trash dumpings.
-- galukalock, Jun 04 2003

Would manufacturing costs go up in comparison to having a single, thicker material?
-- thumbwax, Jun 04 2003


I don't know. But thicker plastic isn't usually found on smaller bags; on the big bags, where it can be found, even it sometimes breaks because, being a bigger bag, it has more stuff in it.

Perhaps some kind of coating could be applied to the lower third of the sheet.
-- galukalock, Jun 04 2003


I dunno. Good idea, but the economics of plastic bags probably preclude this as more trouble than it's worth.

(It still amuses me that all the local supermarkets use ultra-thin shopping bags, presumably because of the cheap price, then double up the bags to load your shopping. If only they'd spend twice as much on the bags, they wouldn't need to double bag. There'd at least be a productivity saving.)
-- DrCurry, Jun 04 2003


The sharp things concept is right, but the concentration of force at the bottom is wrong. Any force transmitted to the bottom of the bag has to be transmitted up to the top of the bag, or it would fall. I've often had the neck of a bag (not grocery store type - trash bags) fail on me.
-- Worldgineer, Jun 04 2003


// I've often had the neck of a bag (not grocery store type - trash bags) fail on me.//

Me too, because a chain is only as strong as its weakest link. Sorry, but I think the physics are wrong here. (-)
-- snarfyguy, Jun 04 2003


The reason I say it's concentrated at the bottom is this: even though the weight is transmitted to the top of the bag, the top doesn't have to deal with irregularly shaped stuff (like sharp corners, etc.) which stretches and weakens the plastic in small, defenseless areas. The top has it nice and easy, for the most part; the force is transmitted neatly to all portions of the upper part equally (I'm speaking generally here; I know it doesn't always happen this way). Also, the top doesn't have to deal with that great bag ripper, the ground.

What all this means is that the overall amount of damage inflicted by all the forces involved is usually higher at the bottom than at the top.

As for having the neck fail, it's happened to me too. Maybe some longitudinal strength-strips would help.
-- galukalock, Jun 05 2003


//Maybe some longitudinal strength-strips would help.// Or make the damn thing thicker. Easy and inexpensive (though they charge more for thicker plastic bags it's not because it costs them much more - plastic is cheeeeap).
-- Worldgineer, Jun 05 2003


Interesting idea.

[World] The strength-strips would be made of the same material as the coating on the bottom, so it could merely be sprayed on. That way you use less plastic (for whatever that's worth).
-- galukalock, Jun 05 2003



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