There are some who think that a silage bag and a grain bag are one and the same. Although the methods of filling are similar, offloading and the stresses that occur during the application are not.

When a grain bag is filled the final shape is dependant on the type of product being stored. Some will maintain a round shape while others will take on a more oval or elliptical form because after filling, the grain will slowly settle within the bag creating a shape that is specific for each product. This results in a flatter bag having more stress on the top of the bag. But, when a silage bag is filled under compression the material becomes self supporting allowing the bag to maintain its original shape with little further stress applied to the plastic.

As a grain bag is emptied it is used to pull the offloading equipment forward while simultaneously high tension is applied to the bag as a result of the lifting and pulling action of the off loader. A grain bag with its low level of stretch and high strength will prevent the plastic from thinning and eventually tearing during offloading. Present day silage bags, due to the materials used to produce them, have a high level of stretch causing the plastic to become thin and more prone to tearing during offloading with grain bag equipment.

A silage bag only undergoes stress when being filled, after which, due to the nature of the silage compaction, it is self supporting. What`s more a silage bag is not always emptied at one time; it is cut into and emptied using front end loaders. The requirement here being the bag should not split further once sliced open, especially in cold weather. These properties achieved by using plastics that have a high level of elasticity (the technical term that describes stretch).

In contrast, the grain bag not only has to withstand the pressure while being filled but be able to withstand the stresses incurred while settling of the product takes place and then again while being unloaded. This is achieved by using plastics with high strength and low elasticity (stretch) in the grain bag making process to give the optimum properties necessary. Grain Bags Canada new Heavy Duty formula grain bag incorporates both a higher gauge product and a grain bag specific formula to help achieve the best possible performance in both filling and extracting of grain bags.

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