Polishing a Cast Iron top

Always a lot of discussion on how to "restore" the new look of the a cast iron top. I have to chuckle because I have yet to get one of my old machines to look like new. Nor do I want it too. Each to his own and what I am about show here could easily be used to restore a top back to new condition if that is what you want.

Here is a before photo of what I started with. A badly rusted and pitted top on a 12" jointer. Obviously has sat outside for many years.

Different people have different methods and I am not saying mine if "The Right Way". This is just the way I like to do it and it works for me. I started the cleaning process by letting the top spend somewhere around 36 hours in an electrolysis cleaning bath. If you not familiar with this technique there are LOTS of web sites on this. Just Google electrolysis and rust and you will find lots of information. Here is the top once it was out of the tank.

You can see the line where the tank wasn't quite submerged. Once dry this top is ready for polishing. I like to paint anything that will be painted before I polish. Then if I have over spray it's simple to take care of it then.

My preffered tool. A Random Orbital Sander attached to shop vac, an assortment of sanding disks and not shown, a good dust mask. The job is simple, you just start sanding and keep the sander moving. I started this job with 50 grit and that is not a typo.

The first picture is after going over the top with 50 grit. Notice there are not scratches? I don't know why but the cast iron does something with the sandpaper and after just a few seconds it started to work more like a polish. After that I go on to 80 grit, which is what I usually start with.

I keep moving through the grits and sanding the top. However after about 120 I don't really notice much difference. I think it might polish it a bit smoother but I really can't tell any difference. This top was so rough to start with I did work all the way though 220 grit just to get it as smooth as possible.

Here is a close up of the top and you can see the pits in it. Most people would panic if their top looked like this. I was more concerned about the costs of the having this top reground. I decided to go the cheap route first and see what the results were. I polished the top and then added a coat of Johnson's Paste wax. I then laid a board on there and slid it around. I quickly decided that there was no reason to have it ground as long as it was flat. The wood slid across there like it was on ice! I will just keep the $300 or more it would have cost to grind these and spend it one some wood for a piece of furniture.