We need believable fake wrought iron bars to cover a bay window. Ideas? Jeannette

Thats railings and bars.  Typing problems here.

Is the iron meant to be decorative only?

If that's so, then I've used with some success a product that is sometimes referred to as "backer rod" and sometimes as "foam rope caulk saver" depending on what part of the country you're in, or which hardware store you frequent.

It's a grey-colored foam rubber shaped like long tubing; it comes in a packaged roll about 25 feet long and is manufactured in different diameters from 3/8" thick to 3/4" thick.

You can use pdavis' suggestion of building a simple frame with wooden dowels and slats, then attaching lengths of foam rod in decorative swirls and designs. Simply cut duct tape into thinner widths (about 3/4") and wrap them (gently!) around the foam to secure to itself (if you're making scrollwork) or to the framework (if you're building arches or other shapes).

Wads of duct tape can be shaped and added as ball finials (if you're making a brass bed headboard for example) or "arrowheads" (if you're building a gate or fence).

Give the whole thing a solid coating of black spray paint (or other metallic paint - again, if you're making a brass bed or something).

I've created quite a few convincing "wrought iron" pieces using this method. It's amazing how elaborate you can get as the material is quite flexible. I even tried "twisting" the foam to create the spiral look of some fences, but once painted, such an effect is lost on the audience sitting several feet away and I sadly realized I had wasted a colossal amount of time. (It looked great, though!)

I even built a rustic chandelier using foam rope, and cardboard toilet paper tubes as the candles. Sturdy wire (coat hangers) was needed to help it maintain its shape, but the whole thing was feather-light and needed no special rigging to hang.

Unfortunately this method is not useable if your wrought iron needs to support ANY kind of weight (such as a burglar or somebody climbing through the window). It's purely decorative, and should anybody come into contact with it on stage, it wobbles like rubber (which it is!) and spoils the illusion.

Just go to lowes/home depot etc... cheaper and easier.. Some times it really is just easier to use the real deal... Or if your project is too big, go with the dowels... you could mount plastic/cardboard tubes, but dowels will take the paint better...