PLASTIC POST AND CHAIN

AS YOU SAW THE GARDEN STAIRCASE.A CUSTOMER WANTED TO HAVE 2 FT POST WITH CHAINS ATTACHED TO GO AROUND BORDER OFF GARDEN.I SUGGESTED WHY NOT SQUARE RAINWATER DOWN PIPE WITH PLASTIC CHAINS ATTACHED.WITH END CAP ON TOP OF POST.AS I SUGGESTED THESE ARE GUARANTEED FOR LIFE?AS IF YOU HAD WOODEN 4X4 POST THEY WILL ROT IN A FEW YEARS.WITH RAINWATER PIPE 2 FT APART X 10 POST,THEN ADD CHAINS BETWEEN THEM.SO ALL HE WOULD NEED IS 2FT.6 INCH SQUARE RAINWATER PIPE GOING  6 INCH IN THE GROUND.WITH A FANCY CAP ON TOP.THEN THE PLASTIC CHAINS BETWEEN WITH A PLASTIC COATED HOOK. ON EACH POST..POST DONT HAVE TO BE 2 FT 6 THEY CAN BE ANY HEIGHT,BUT THEY WILL LAST A LIFETIME COMPARED TO TIMBER POST.PRICES MAY VARY FROM DIFFERENT PLASTIC COMPANYS.BUT IF YOU WANT TO START YOUR OWN LITTLE BUSINESS? BUY IN BULK THE PIPE AND CHAIN.AND SEE HOW IT GOES.THESE WERE THOUGHT OFF 40 YEARS AGO AND IF I RECALL THEY CALLED THEM RANCH POST!! .COST ALOT OF MONEY IN THOSES DAYS AS PLASTICS WERE ONLY JUST STARTED TO BE USED FOR OUTSIDE WORK.AND ORNAMENTAL WORK .NOWADAYS ITS USED EVEYWHERE,BUT IT MAYBE ONLY PLASTIC RAINWATER PIPE BUT ITS BETTER THAN TIMBER POST??NEVER NEED PAINTING OR STAINING,JUST WIPE OVER ..