Many businesses that have been using steel strapping for years, often wonder if plastic strapping would suit their products, and if so, what would the advantages of changing be.
Well I have the answers. Whilst it's true that steel strapping generally has a breaking strain advantage, PET strapping can still perform as well and has additional benefits.
Let's assume that you are shipping heavy railway sleepers and are using 19mm x .56mm steel strap. It has 200 Mtrs on the roll. It has a breaking strain of 880 Kgs. It is a single strand width roll weighing 15 Kgs. .
Cost of steel roll only approx. $60.00 + GST.
You also have a Reel Holder, a Tensioner, a Crimper and Seals
The most appropriate plastic strapping option is 19mm x 1mm PET (polyester). Comes in a ribbon wound roll with 800 Mtrs on it. It weighs 17 Kgs. Breaking Strain is 710 Kgs. Cost is approx. $180.00 + GST.
Let's say you need the other accessories also, at the same prices.
From the two comparisons we can derive:
a) Plastic is $60.00 cheaper.
b) One roll of plastic equals 4 rolls of steel.
c) Steel equivalent = 100 Kgs. Plastic = 17 Kgs.
OK. So you are trading 880 Kgs of breaking strain (BS) for 710 Kgs BS with plastic. How much breaking strain do you need? How many straps will you use? You are actually constraining the load. Do you think that 880 Kgs of lateral pressure will be exerted on the side of the load every time the truck brakes? If so, then dilute that pressure per strap, by the number of straps to be used.
The next obvious question is flexibility. Steel is not flexible at all. If the load shifts or settles, then the strap is loose. Why do you need 880 Kgs of BS when it isn't even touching the load?
PET has some give. It is a stiff strap, unlike Polypropylene (PP) which has a lower BS and is also more flexible. Not really suited to heavy loads.
Plastic strap is far safer to use. No sharp edges. Easier to thread and conform to shapes. Does not scrape or cut into the goods as steel might.
An argument could be made around security. It is true that plastic strapping can be cut with a knife, but portable disc cutters are in every tradesman's tool box these days.
Let's now look at the method of securing the straps.
Steel crimpers use the cut and deform method to create notches in the sides of the two steel straps, once they have been tensioned together.
Plastic strapping crimpers use a compression method to crimp the seals to the two straps.
Plastic strapping has three options for sealing. Manual using crimped seals as above. Battery to tension, seal and cut, and Air (pneumatic) to do the same.
Battery and air tools do not use a tensioner, crimper or seals, so an initial saving plus a long term saving on seals.
I have found an Air strapping tool to be far superior to Battery in every way - provided you have a 100 psi air line available. It will do the same job as a battery operated unit, but:
a) It has no batteries to run down or recharge.
b) It is far less complex to use. No screens. No dial ups.
c) Easily used with gloves on. Only two levers. One to tension and one to seal, then cut.
d) The friction sealer is much less problematical and less prone to jamming up.
e) It is four times cheaper to buy.
f) It is easy to maintain. Drop of oil and air clean the roller area.
g) No batteries to replace when they die.
h) No electronics to go wrong. No expensive chips to replace.
I know that air is not always practical or available, but if possible, I'd go for it every time.
Most companies have gone away from steel strapping for many of the reasons discussed above.
