How Weed Wackers work?
There's a plastic "cutting" string that revolves around, at high speed and whacks the weeds and grass so hard, that they "separate" from one another.
Unlike a mower, there are no "sharp" edges involved.
The lower power corded electric and rechargeable models use lighter plastic string, of around 0.050 or 0.065 inch diameter line (blue or green), that is either "bumped" or automatically fed off of an internal spool of line inside the Weed Wacker's head.
The larger sized machines use fixed line, that lasts longer than the smaller diameter spool-fed line.
The heads used by these larger gas or propane engine powered machines are called some version of "Hassle-Free".
There are one or two pre-cut strings used in the heads, creating from 2 or 4 projecting strings from the various heads.
You even have the option of using standard red or heavy-duty black pieces of line in the heads.
Selection of machine shafts is basically a bend shaft design - for precision whacking closer to your feet than the straight-shaft design - that can trim under obstacles, like bushes, more easily.
It's really a user's preference or choice, more than a requirement.
The engines powering the beasts include 2-cycle gas, 4-cycle gas and propane powered.
Two-cycle engines are commonly used by portable Lawn and Garden tools, like chainsaws, blowers and weed wackers.
They require a special formulated oil to be mixed IN with the gas, in a separate container of gasoline.
Four-cycle engines are used by more complicated engines like lawnmowers and some portable machines - including some weed wackers.
This type of engine uses a separate oil resevoir, complete with dip stick, just like a car or lawn mower engine does.
The gas is kept in a separate can, with NO oil mixed in.
The only requirement is that the gas is relatively "fresh" (less than 2 months old in California).
Propane is the new kid on the block.
It is 40 times cleaner burning than a gas engine.
There is no shelf-life on the fuel.
You can get refill tanks, where ever stout camping cylinders of propane are sold.
Sears non-electric weed wackers include a special "convertible" type of head assembly, that can have different attachment substituted onto the end of the shaft.
This allows ONE engine drive unit to power over a half-dozen accessories out in the yard.
That means only ONE Protection Agreement needs to be purchased!
Accessories include, metal-bladed brush wacker, metal-bladed tree limb trimmer, blower, mini-cultivator, hedge trimmer, pole chainsaw, edger and new power hoe and rake unit.
Weed wackers are tremendous productivity tools for your lawn or garden.
They must be used with caution, including eye protection, hearing protection, closed-toe footwear and long pants are a good idea.
I hope this helps.
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