One cubic foot? Sledge hammers and nuts come to mind. I’m having trouble visualising both the bags and the perceived problem. Can you show a picture?

Zip ties.

@armoured zip ties are an option, but a bit of a hassle to clip them off, particularly if you want to reseal the bag after partial use. What you want is something the size of a zip tie that can easily be removed and re-attached.

@floral_uk z.8/9 SW UK I added a photo to the original post.

Depending on how heavy the stuff you intend to keep in that bag is, why not use a heavy duty plastic clip meant for keeping bags closed?

Heavy round clip

@Esther-B, Zone 7a one cubic foot of stone weighs about 100 pounds. I do not think a plastic clip is going to hold the bag shut if it falls over in the back of a truck during transit.

OOOOOHHHHHH....I did not know the bag's contents was going to be so heavy. I think you'll end up using a piece of stout twisted wire.

@Esther-B, Zone 7a I was imagining something like a very thin noose that use a choker with a built in clamp. Push down on the release and the choker slides. Release pressure and it locks in place. Something like that.

@Esther-B, Zone 7a I think that bread and bagel clip is still worth trying, for less than $10 not much to lose. Do you know anyone who makes a larger version of that? Actually, I am going to just buy it and if I need a larger hole in the middle I can just try to drill that out.

What you are describing is a PARACORD BARREL LOCK. I was just about to suggest that!

Bungee cords?

@Gargamel I cannot see a bungee having much gripping strength.

Maybe a heavy duty contractor garbage bag over the top of it and bungeed around the girth...?

The heavy duty crocodile clip I suggested above would do the job. Plenty available via a simple google.

@floral_uk z.8/9 SW UK Could you point to a crocodile clip that you think would do well for this? Here is a heavy-duty one for an 80 amp line:

https://www.altecautomotive.co.uk/insulated-80amp-crocodile-clip---------------br--pair-of-red--blackbr--altfbc80br-4875-p.asp

I think you can probably google as well as I can. Look also for tarpaulin clips or clamps. There are lots.

My brother left here once with all my bungee cords, and took them to the dump, after informing me that bungee cords are one of the leading causes of eye injury. Gee, I miss my bossy brother.

6 inch spring clamps: https://www.amazon.com/Spring-Clamp-Large-Super-Heavy/dp/B01MV6RKVF/

These grip very well. and open around 2.5 inches. Bought them to hold down greenhouse shades/covers to my metal tube canopy. HD also has them for a $1 a piece.

Or get heavy duty reusable zip ties. You can get 100 pound rated tensile strength or even more.

Or heavy duty long twist ties. These are very convenient - also available at HD/Lowes.

I use the heavy duty lidded plastic tubs available at any box store for storage and transport of any bulk gardening materials. But I rarely have much need for bulk rocks or stone - I use them mainly for soil mixes and amendments. Bulk mulch or compost I have delivered and just leave it in its pile until used/dispersed, covering against the weather as necessary.

@floral_uk z.8/9 SW UK I went for these electrical clamps.

@gardengal48 (PNW Z8/9) I have cracked many a $50 big-box-store giant plastic container trying to haul stones in them. They work fine for compost. But any kind of granite or garden people weighs about 2700 pounds per cubic yard, roughly 100 pounds per cubic foot. Those made-in-china plastic containers do not survive long with that kind of load.

I guess I don't understand the need for trying to keep them in a bag. Once onsite and the bag opened, just leave them in a pile in an out of the way location to draw on as needed. It's not like they are going to be spoiled by weather :-) Then use your wheelbarrow to transport them to wherever needed.

At the top of this thread you referred to ‘one cubic foot bags’. How big can a one cubic foot bag be? Now you’re talking about cubic yards. Which is it?

@floral_uk z.8/9 SW UK One cubic yard = 27 cubic feet. One cubic yard of stone weighs 2700 pounds, therefore one cubic foot of stone weighs 100 pounds.

The bags most wholesale rock suppliers use are one cubic foot bags.

@gardengal48 (PNW Z8/9) The problem is not what to do when the bags of stone are at the final destination. The problem is how to safely transport the material in a car or truck from the wholesale supplier to the job site. In our area, you get to a wholesale supplier and they give you empty one cubic foot bags and a shovel. It is self-serve. Once the bag is full, how do you secure it so that when a 100-pound bag of stone falls over, you do not get loose stone everywhere in the car or truck?

Invest in a couple of collapsible but flat bottomed totes like these:

They won't fall over and you do not need to fill them. Just load in as much as you can handle.

You put a tote in your trunk. You put the bag in the tote. If the bag falls over in transit the tote catches the spills. You don’t have to lift the tote so there’s no chance of it breaking. How complicated can you make it?

For some reason I assumed you were talking about a cubic foot of soil...not rocks. I doubt there is anything which would keep a cubic foot of rock closed if it tipped over in the back of your truck/car...?

@gargamel At least you understand the question now. I am looking for a fast and convenient way to secure a loose opening on a bag that holds a significant amount of weight. I think this is a harder problem than people want to believe at first glance. But I think it can probably be solved, hence my persistence. :)

@gardengal48 (PNW Z8/9) Are those handles rated for 100-pound loads? Can you point me to the product online?

@floral_uk z.8/9 SW UK Fine on putting the bag in a tote as a fail-safe to catch spilling rocks.... But the objective is not to spill the rocks in the first place, hence my question.