Great Rust Removal Process (Incredibly Simple)...
Here's something I wanted to share with y'all. I tried a new rust removal technique using molasses. So the formula is this: 1 part (feed-grade) molasses - to 8 parts water. Drop in your most rusted parts for a couple days and whamo! No more rust. Then, throw away the mixture - right on your lawn! (the iron is good for grass).
Here is my South Bend's tailstock hand wheel. It has a fair amount of surface rust. And I let them soak for just 2 days. The "after" pictures speak for themselves. At $6 per gallon, it's WAY cheaper than Evaporust (although I have a LOT of love for that product). And it's way easier than electrolysis. And...the mixture lasts up to 6 months (from what I hear). Check out YouTube for videos.
I've tried molasses once. I wasn't terribly impressed with it, but the stuff I got was from a grocery store, so it wasn't the "feed grade" type. The grocery stuff has sulfates removed from it, or something of that sort. The feed grade is just straight mollasses with no additional processing done to it.
- it's cheap
- you can mix a lot of it for working on large parts. one guy on youtube is soaking whole automotive panels.
- it's slow. sometimes you have to soak for a week if the rust is more heavy.
- it smells kind of weird
- it does leave the converted rust residue, which looks kind of black/gray. So additional scrubbing/sanding is required to get shiny metal out of it.
- the part should be grease/paint free. But same goes for Evaporust.
By the way, have you ever tried muriatic acid for rust removal? You can get this stuff at Lowe's. It's basically diluted hydrochloric acid. This stuff will remove rust almost instantly. You dip the part in, you take it out, and the rust is gone. Then you throw the part in some clean water to neutralize the acid. The speed of the process is very impressive. However, there are downsides because it's dangerous to work with. You don't want to get this stuff on your hands, and you don't want to breathe the vapors in. So good chemical gloves are a must, and working outside is a must. Another thing I read is that the acid removal methods, like muriatic acid, molasses or naval jelly, can effect the steel, and lead to "hydrogen embrittlement". Search the net for more information on that. Apparently the acid can get absorbed inside the steel and make it brittle.
Anyways, the point is that it might be a better choice to use more than one rust removal method, depending on the type of part one is trying to derust. Each method has it's pros and cons. The molasses is great for large parts, electrolysis for medium to large parts, Evaporust for small parts, naval jelly for parts you can't soak, muriatic acid for small to medium parts for instant rust removal at the expanse of working with a not so friendly acid. Then there are always abrasives when all else fails. And if you can't get the rust off, well then paint over it with some POR-15.
Thanks, Brad, nice tip; probably need to do that for some of my tools as well
Pressure blasting would be an abrasive and deserves some publicity. No chemicals to work with and no messy liquid cleanup and disposal problems. Not always so good for sheetmetal, but the best for chunky shapes.
Originally Posted by iron_junkie
I was just thinking, a thin veneer of rust isn't necessarily a show stopper except for cosmetics. After reading what Iron Junkie said, I'd hate to have any side effects of brittle metal. I've seen some mainline rails, laid before WWII on the old Pennsylvania Railroad, now CSX, in Washington, DC that have had trains rolling over them for 80 years and the rails never rusted through
Well yeah, it is cosmetic. But that's the idea when restoring a lathe. I'm not at all worried about leaving my metal parts soak for 2-3 days in molasses. In fact, you might be able to remove thin surface rust with a bucket of this molasses mixture and a scrub brush - by hand. Sort of like a cleaner.
Originally Posted by SE18
I poured some (straight - undiluted) molasses on my Bridgeport bed and left it sit for 2 minutes while I was filling up the bucket with 8-parts water. When I was slowly pouring the water into the tank, I began to use a brush to help mix the molasses as the water was coming in. The areas where the molasses sat, BRIGHTENED up the metal - totally cleaned it.
Got me thinking....
I can just hear Billy Mays... "thats the power of Molasses Clean"!!
About Hydorgen Embrittlement, it only occurs on parts harder than about Rockwell C 32. So considering test variation, and production hardness variation, most production shops consider RC 28 a practical upper limit. Still, many hardened and unhardened parts get treatment in acid, for example during plating. So if the part is over RC28, you need to bake at 400 degrees F, IIRC, for 1 hour within ~10 minutes of the acid treatment.
For South Bend parts, I think most steel shafts, gears, etc are well below Rc28 (verification required), so hydrogen embrittlement wouldn't be a problem. Acid dip might be a good alternative for parts like these. The only hard parts on a South Bend are the spindles, I think. Might not want to use acid dip on hard parts like tool holders. I personally wouldn't use it on cast iron, becasue the acid might dwell up in pores of the castings and continue to be corrode metal after the paint goes on. Maybe I'm being overly cautious though.
Thanks for the tip on molasses, I'll have to try it.
Someone mentioned Pressure Blasting. Has anyone tried Soda Blasting and what were the results?
PS Gonna need to make some molasses cookies this weekend. I need the extra iron
That's a good tip on the molasses but on something like a hand wheel Scotchbrite and WD40 will take that off in about five seconds.
I think soda blasting will remove paint, but not rust
I use vinegar and salt overnight. Non-toxic and easy to clean up. Whatever be sure to oil or paint immediately or the rust will be worse than when you started. 1/4 cup salt to one gallon brown vinegar. Start with a quart and give it a try. Save the stuff. It does keep for a little while. Don't use on aluminum.
Soda blasting works well for delicate parts and won't roughen the surface of your work.
Originally Posted by wb2vsj
The best part is that there's no grit to get into oil passages, between gears, etc. I used it to clean the bodies of some vintage Weber carburetors which have some very small diameter passages. It cleaned up the outside without removing the 50-year patina, removed the varnish in the bowls left by old fuel, and cleanup just took a few shots of compressed air. I used a cheap Harbor Freight plastic bottle type gun and had no problems. Non-toxic, easy cleanup, and cheap.
I think it's also used on larger thin-wall panels, but I'm not sure.
Feed grade molasses can have different stuff in it. The closest farm and ranch supply has urea in it as a protein source. Another suppliers does not. I have use the one with urea as fertilizer, so when your done do not pour it down the drain, dilute and fertilize something. Ask the supplier about the formulation he has. One may work much better than another, who knows till you have tried several.