how can i fix the warped faded bars on my garden bench?

If the bench seat is like mine wood slats and cast iron side sections then remove the slats sand them down the grey color is surface only then coat them libraly with teak oil until they won't absorb anymore oil. Lay them bow up on flat surface close together, cover with plastic sheet then a board like piece of hardboard put weights on the board in centre of bow they should gradually drop flat again. Done it so know it works only with two slats though. Coat it at least twice a year....Sprng or later if not needed............Autumn essential to keep out winter damp. Tip if any wood screws or any bolts involved coat them with vaselene especially the threads of the botls and screws. coating with vaselene on wood screw threads make it easier to remove them when rusty. Another is screw that won't budge in wood heat up red hot old screwdriver place that on the screw head the heat transmitted down screw makes wood sweat and usually you can ease out the screw.

Bob
January 2011