I too thought bottles of mortar or concrete would work but made my hooks in a bending jig for wire. Refer to the youtube video titled: "Adjustable Bending Fork & Jig for Blacksmiths" I also used wire that had cross pieces that I cut off to form a small cross for the bottom of the wire to make an anchor at the bottom of the bottle. I had a bunch of tomato cages I cut up for the wire hooks. If you do not have salvaged fence wire to use, one could use the wire bender to make hooks for the anchors. I cut off the top of the bottle to make a larger opening to insert the mixed mortar, used a funnel to pour in the mortar, and then inserted the wire with the hook already in the upper end, and let it set over night and a few days more before using. I presently use a 5 pound brick with clothesline rope to attach them to each corner of the tarp to cover pallets of firewood. And, I intend on replacing these with the bottles, with no clothesline rope then needed. Each 16 oz. bottle is about 2.5 pounds when filled with mortar and mortar mix is much cheaper than the cement mix in this video. It does take more time to mix the mortar and I mix it in a plastic tub. I mix enough mortar to fill about 4 plastic bottles, then repeat. Bags of mortar mix comes in 80 pound bags for less than 20 bucks. One should be able to get about 30-16 oz. bottles for weights from an 80 pound bag of mortar. Sooo, the only cost to me without purchasing the wire is for the mortar.
I too thought bottles of mortar or concrete would work but made my hooks in a bending jig for wire. Refer to the youtube video titled:
"Adjustable Bending Fork & Jig for Blacksmiths"
I also used wire that had cross pieces that I cut off to form a small cross for the bottom of the wire to make an anchor at the bottom of the bottle. I had a bunch of tomato cages I cut up for the wire hooks. If you do not have salvaged fence wire to use, one could use the wire bender to make hooks for the anchors. I cut off the top of the bottle to make a larger opening to insert the mixed mortar, used a funnel to pour in the mortar, and then inserted the wire with the hook already in the upper end, and let it set over night and a few days more before using. I presently use a 5 pound brick with clothesline rope to attach them to each corner of the tarp to cover pallets of firewood. And, I intend on replacing these with the bottles, with no clothesline rope then needed. Each 16 oz. bottle is about 2.5 pounds when filled with mortar and mortar mix is much cheaper than the cement mix in this video. It does take more time to mix the mortar and I mix it in a plastic tub. I mix enough mortar to fill about 4 plastic bottles, then repeat. Bags of mortar mix comes in 80 pound bags for less than 20 bucks. One should be able to get about 30-16 oz. bottles for weights from an 80 pound bag of mortar. Sooo, the only cost to me without purchasing the wire is for the mortar.