Gravel Bag Test Results

Table 1 compares test results of the two versions of Ivan Carper’s design and the fruit picking bags. The MTDC bag proved to be most efficient. Fruit picking bags would be adequate for lightweight jobs.

Table 1.—Packstock Gravel Bag Test Results

POINTS CONSIDERED

DESIGN THAT WAS TESTED

"Carper" Design - MTDC Fabricated

"Carper" Design - PWOA Fabricated

Fruit Picking Bags

Construction
  • 16-ounce (455 gram) nylon Cordura™ sewn seams;
  • Tubular nylon release strap;
  • 3/16-inch (4.76 millimeter) steel hoop
  • 18-ounce (510 gram) polyester with PVC resin truck tarp;
  • Riveted seams;
  • Manila release rope;
  • 3/16-inch (4.76 millimeter) steel hoop
    		•
  • Wells & Wade #80 Super picking bag;
  • Citrus bag with rope hoop;
  • Treated canvas;
  • Lightweight metal hoop;
  • Sewn seams

    • Approximate Cost
    • No current manufacturer—small lot fabrication costs about $80 per bag
    • No current manufacturer—small lot fabrication costs about $80 per bag
  • $22-$27 per bag, plus freight

    • Load Carried
  • Average 160 pounds (72 kilograms) per bag;
  • Easy to overload
    		•
  • Average 160 pounds (72 kilograms) per bag;
  • Easy to overload
    		•
  • Approximately 80 pounds (36 kilograms) per bag

    • Best Feature
  • Direct flow up to 4 feet (1.2 meters);
  • Lightweight 5.5 pounds (2.5 kilograms);
  • Quiet;
  • Easy to roll up and pack;
  • Tubular nylon worked well
    		•
  • Direct flow up to 4 feet (1.2 meters);
  • Lightweight 5.5 pounds (2.5 kilograms);
  • Quiet;
  • Easy to roll up and pack
    		•
  • Economical;
  • Able to direct flow somewhat;
  • Lightweight 2-3 pounds (.9-1.4 kilograms) each;
  • Quiet;
  • Easy to roll up and pack away

    • Limitations
  • Chain rattled when bag was empty;
  • Tubular nylon sometimes caught in chain (fixed in final design)
    		•
  • Chain rattled when bag was empty
    		•
  • Metal rim not heavy enough, tendency to collapse;
  • Small opening made loading harder;
  • Limited capacity;
  • Had to get close to animal and lift load to release hooks

    • Observed Wear
  • Stitching in bottom of one bag wore out, but repairable
    		•
  • Two tops came undone at rivets, but repairable
  • 1/4-inch manila ropes wore out...replaced with 3/8-inch (9.5 millimeter) manila;
  • Fabric tore on one bag, but repairable
    		•
  • Top side of one bag ripped out, but repairable

    • Comments
    • Final strapping design modified so it will not catch on chain;
    • Nylon Cordura™ held up well but more expensive than polyester with PVC resin truck tarp;
    • Sewn construction stronger than riveting
    • Fabric held up well and costs less than nylon Cordura™, so it is recommended for final design;
    • Riveted seams not as strong as sewn seams
  • Bags not designed for gravel but serviceable for light duty use, especially when cost and quick availability are most important

    • table of contents

    next

    This page last modified October 1, 1999