A neighbor of ours had an old iron framed park bench sitting in a pile of junk in his backyard for years and one day I mentioned that I thought it would sure look nice in my yard. He chuckled and said, "look nice? it is broken! You can't even sit on it." I told him that, all the same, it was a beautiful antique bench. So, in exchange for a beer, he gave it to me. The picture above was taken after I had assembled as much as I could with the mangled pieces that remained. The problem now was to finish it, make it sturdy and useable, and yet not destroy the antique look.
To do this type of restoration you need:
1) a jigsaw
2) and angle grinder or a hacksaw
3) a drill
4) a sander and also some sandpaper for hand finishing
5) a pile of old boards
6) measuring tape
Step zero is to rip off all of the old and rotted pieces of wood that are still hanging to the iron frame. If there are pieces that are salvageable you should keep them since the wood coloring will be the same as the wood that remains.
Step 1: Fix the Salvageable Pieces and Take Measurements
The first step is to repair the wood that is not too rotten to be saved. In my case, this meant using wood filler to fix cracks and holes as well as replacing loose screws with thicker ones that fit more tightly. As you can see in the photos, the way I did this was to find screws that were thick enough to fit snuggly into the existing holes and then cut them off with an angle grinder (or hacksaw) so that they were short enough (the same length as the old screws that I removed) so they would not push through the boards. If there were screw holes that were too rotted to make a secure fit I would remove those boards. One could use wood filler and then screw into the dried wood filler, but I think if the wood is that rotten, the whole board should go. Plus the way the cast iron pieces are built you cannot change the position of the screw hole.
Now set up the bench as best you can, which may entail having someone help you hold it or prop it up the way that it should look when it is finished. This way you can measure the exact length of the spaces where boards are missing. In my case I needed to replace the board that runs along the top of the back of the bench as well as one of the side boards on the back. The side board measurement could be gotten from measuring the equivalent board on the other side but the board from the top of the back was missing and so it needed a precise measurement of both the length and the width.
Step 2: Find Some Similar Wood, Choose a Design, Cut, and Sand
For a project like this you don't want to use new wood unless you plan on replacing it all and then staining or painting the entire thing. I wanted the bench to look old since I live in an old house and it would look out of place with a modern looking bench. So I had to rifle through piles of old boards until I found some of the same thickness and the same color as the old wood still remaining on the bench.
The side piece that was missing was quite straightforward to replace since there was a piece on the opposite side to take measurements from.
The top board on the back of the bench was also missing and so I needed to design a shape for it that looked appropriate. One side had to fit into the cast iron of the back of the bench which you can see by the picture is quite curved. So I had to begin with a board much wider that the finished product so that it could be cut to fit the mold as one solid piece. For this I laid the back of the bench on some packing paper and traced out the design with a pencil. I then cut this design on the board with a jigsaw and attempted to fit it to the cast iron. It didn't fit precisely so I had to go back and forth from the bench to the jigsaw until the board fit to the cast iron like a glove.
Then I chose a curved design for the top of the board and cut it -- also making several trips to the bench to make sure the symmetry worked out.
Then I power sanded all of the jags remaining from the jigsawing and also rounded the top edge, finishing it off by hand sanding to make it smooth and uniform.
Step 3: The Finished Product
After shaping the piece the way I wanted I attached it to the bench and it was finished. There are a few spots where it was sanded that don't have the same discoloration as the rest but I am confident that this will change after a few months of weathering.
I realize that this was quite a simple project and didn't need any extra clever techniques to accomplish, but hopefully seeing the finished product may inspire someone to notice the next time they see an old broken cast iron bench sitting in some neighbors junkpile and to take the time to bring it back into use. They really are beautiful and have much more character than a new bench.