Yesterday afternoon I set up my electrolysis rust removal system. The reversal of the plating process. This consist of a 12 amp 24 volt adjustable dc power supply, a plastic tub from the dollar store and some scrap iron to use as the sacrificial anode. I keep the workpiece slightly raised off the bottom of the tub with a couple of bricks. The electrolyte solution is simply tap water with sodium carbonate (washing soda). Hook the negative lead to the workpiece and the positive to the sacrificial anode. I like to keep the battery clips out of the solution as the negative lead will lose it's plating and the positive will rapidly erode if they are submerged in the solution. The electron flow is from negative to positive, and the electrons will scrub off the oxides, paint and anything else coating the workpiece. The byproduct is rusty water with old paint and hydrogen gas. Yes, this does produce some hydrogen gas, so only do this in a well ventilated area. Avoid any sources of sparks or flame while running this process, and of course, No Smoking. You shouldn't be smoking anyway unless you happen to be on fire. A day or two in the "soup" will usually result in a perfectly clean part ready for primer after a vigorous cleaning with a green pad and tap water. This process is only for ferrous metals and should not be used on yellow metals or aluminum as they will disolve away. Rusty water with sodium carbonate is not particularly nasty for the environment on its own, but since I don't know what may be in the paint, I like to let the water evaporate and then dispose of the rust and paint in a well sealed plastic bag for the trash. I also avoid using stainless steel for the sacrificial anode as it contains chromium which is toxic to the environment.
The helpful folks at Original Saw Company were able to decode the serial number on my GR and determined this machine was made in 1948. A well deserved thank you goes out to the helpful folks at Original Saw and Wolfe Machinery for making the parts that help keep these great old machines running.
Since I always enjoy sharing things from our life and my various projects, I have decided to start documenting these things in a blog. I am currently working on refurbishing a DeWalt model GR radial arm saw. I found this saw on Craigslist and went to have a look as it was identified as a model GP in the ad. A model GP is an older 12 inch saw that is a very nice size for a home shop. Heavy duty iron castings and plenty of power for most projects. Once I had a chance to look the saw over I discovered it to actually be a Model GR; a much larger industrial machine, with a 14 inch blade capacity and 3 phase, 3HP motor. I was not sure of the actual age of this machine, but it was clearly from the 1940's or early '50's at the latest. A deal was struck and I was the new owner for $225.00. One thing I would like to do is begin documenting the actual cost of my little projects and see just how deep in the hole I have to go to resurect some old iron. Disassembly revealed a broken miter index on the column and a poor fitting replacement elevation handle. A quick search of some of my favorite old woodworking machine sites secured an elevation handle $25.00 and column $100.00. Totals so far are $350.00. I spent most of yesterday welding closed all the extra holes in the saw frame that have been drilled over the years. Here are some pictures for your enjoyement.