Dempster color; and electrolysis

Im attempting to restore an old Dempster irrigation pump that i got and was wondering if anyone knows what color they were originally, and what matches the best. Mine has trace amounts of red in the protected areas. Also im going to try electrolysis on it to loosen some parts and to clean the rust. I've heard that after electrolysis it leaves a slimey residue behind on the part. Is this true? Thanks in advance! Frank Y




some pics

Yes, electrolysis leaves a layer of black crud that needs to be wire-brushed and flushed off. Scotchbrite pads can sometimes be used, too; but, I find that a wire brush works very well. In most cases, this crud is very easy to remove. If I had a pressure washer I'd try it.

I don't know about the layer being slimey. I guess it depends upon the electrolyte. I've never encountered slime.

You should follow up the electrolysis with a product such as Ospho or Metal Prep. It will remove the last traces of rust and passivate the surface, helping to prevent further rusting. You can get Ospho or Metal Prep at paint and some hardware stores.

Having done a couple items by the electrolytic process, I feel a couple things need to be stated here. The "slimey layer" is present immediately upon removal from the electrolytic solution, and is also easiest to remove at that point. Pressure washing works great for this. If you don't have a pressure washer, an alternate removal method is a good scrubbing with water and liquid dish soap. If this slime is allowed to dry, it will be a lot of work to get off the piece. If the iron is immediately thoroughly dried, after removing the slime, no further process is needed before priming. If electrolosys is performed completely, there will be no rust residue left. The process removes all rust, and is far superior to media blasting, as it removes rust down to the molecular level from the poroscity. NO neutralization or passivation is necessary after electrolosys. If surface rust forms due to inadequit drying, or condensation post treatment, this rust can be converted by either phosphoric acid or tannic acid processes. The phosphoric process will yield a coating of magnetite, also an iron oxide, but one that will prevent further rusting. OsPho is a completely unnecessary process post electrolosys, and in my opinion, a waste of money. OsPho will only react with a rusty piece because it is a phosphoric acid process in combination with a polimer.