Cast iron work surface pitted.... Filler????

[Chill Wills]

Interesting read.
I fixed the table on a old Rockwell drill press that was worth fixing! The table was ...well. You know! It had that smile.
But the price to me was right!
Someone has No Respect for Tools!

Anyway.
This was not shallow pits like your project so I blocked the bottom and filled with J B and leveled with the random orbit sander.
All the above is old news in this thread but what you may want to do now is apply Johnson's past wax for a slick protection.
I like my CI tops slick. Makes moving stock across it easy! And, keeps rust away.

[Col4570]

Mix Cast Iron Filings with Salamoniac and Water to make a paste.Clean out your Pitting and Holes spread the paste into the depressions and allow to rust and Dry,clean off the surface.This was a method of cast iron repair when I was an apprentice and it did work.Very often someone would leave the feed on the Radial Drill Press and Make a Hole in the Bed,The filling was done to hide the accident from the powers that be.

[W.R.Buchanan]

All of these other "Methods" are fine but the good way is to go buy a can of Devcon with Steel or SS filings in it.

Prep the surface with grit blasting if possible, if not then acetone until it is clean.

Mix the Devcon thin and add acetone to thin it out a little,,, not too much you just want it to flow so it fills the holes completely.

You pour the stuff on from one side of a hole to the other, and it will expel the vast majority of the air bubbles. Use a needle to probe holes to remove air bubbles.

Make sure you overfill the holes so that when dry the material is proud of the surface.

Then use a large file to get the surface close to fair, then an orbital sander to finish it. This is as good as it will get.

I say Devcon because it is the best stuff available and it isn't that expensive. If you can't afford $10 for materials then you shouldn't do the project.

In order to fill the holes with brazing rod you would need to preheat the entire table to about 900 F, then use Silicon Bronze Brazing Rod with Heliarc to braze in the holes shut.

Done a bunch of this stuff and as long as you preheat the work it won't warp unless you are trying to fill a hole that is really big,,, like an inch or so wide.. Then when the weld shrinks as it cools, the warpage will happen.

Good luck.

Randy