doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com Rust Removal and Annealing

CLR from your local grocery store works as well as any and is mild and easy clean-up.

OK Men, here goes.
I've been wanting to try this for some time, and, since PB croaked, Now is a good time to open an IMGUR acct for photo hosting.

I have a "barn find" set of fluid steel shotgun barrels, and all I require before proceeding is some washing soda to creat the mild electrolyte.

I already know the chemistry, and am reasonably certain that the outcome will be. I would caution anyone unfamiliar with the chemistry, that changing iron from one state to another, whether by chemistry (a cleaner) or by electricity, can have unintended consequences.

Most of what we do in this arena gives off flammable gas, and must be done outdoors, in a hood, or other well ventilated area.


I will carry out this crude electrolysis experiment, complete with pictures) this weekend, for the benefit of readers.

Electrolysis, as used for common red or brown rust removal, is not a reducing of ferrous oxide to ferric oxide. Common red rust IS ferric oxide, or more accurately, hydrated ferric oxide, Fe2O3.nH2O. The black slime that can be rubbed off the surface of the formerly rusted item after electrolysis is mostly a mixture of iron metal and magnetite, Fe3O4, another oxide of iron... also known as ferro- ferric oxide. This is the same black oxide that forms during the boiling conversion during slow rust bluing. But due to the electric current, it is not bound to the parent metal.

I personally like using the molasses/water solution method of rust removal. It is slow, but very cheap and very effective, without any damage to the sound metal. I just pulled a complete bolt action I recently bought, from my bucket of molasses slop. Scrubbed it off and rinsed it to find that it was totally free of rust, inside and out. The electrolysis method needs an internal anode to effectively remove rust on the insides of items. It took a couple weeks, and since the solution can be re-used many times, it probably cost less than a nickel to clean.

When the molasses solution finally does quit working, you just dump it on your lawn or shrubs. No toxic mess to deal with, and no concentration of explosive gasses. I always keep a 5 gallon bucket of it in my garage, and suspend rusty auction and flea market finds in it. I can forget about them without any fear of damage. The smell is not anywhere near as objectionable as you read about on the internet. I wish I had learned about it years ago.

Lyle Peterson on "Youtubevideomrpete222", did a very interesting comparison of different rust removal methods. It takes a little time to watch, but it is worth it. It was a few months ago and was more than one segment.
Mike

Keith,
what exactly is the molasses/water solution method? Do you just mix molasses and water? what proportions do you use?
Thanks, Pete

sxsman1, you can Google "molasses rust removal" to read all kinds of information and misinformation about it. That's kinda why I'm leery about some of the information on the internet about the electrolysis method. Some of the info is flat out wrong, and can result in a shop fire or creating a toxic mess in your electrolyte bath.

I bought dried molasses in 50 lb. bags for about $16.50 at a local feed store. To make 5 gallons of solution, I mix about 5 lbs. with. a gallon of boiling water to dissolve it. Then I add about 4 more gallons of cold water. Then you simply suspend your rusty iron or steel items by coat hanger wire so they are completly submerged. It is best to knock off any loose rust first since it will just deplete the effectiveness sooner. Pre-clean any oil or old congealed grease because it won't work well under grease or paint. Leave the items in the solution for about a week, and then remove them to check the progress. The rust will turn to a black slimy film. It is a good idea to wear rubber gloves because it stinks and will stain your skin. You will read that it smells like vomit or baby shit, but it isn't really that bad. It does look nasty as it ferments, and it isn't something you'd want to do in your basement. Rinse the items off with a garden hose and knock the loose black slime off with a scrub brush. If any rust remains, put it back in for another week. You will be left with bare iron or steel that will flash rust again very quickly in humid weather, so you need to dry it off quickly and either oil, prime, or paint it.

The process is a chelation that removes the oxygen from rust, and leaves the iron behind. It does not attack sound metal underneath the rust. I have forgotten items left in the bath for months without any harm. You can re-use the solution many times, and it gradually loses effectiveness and takes longer to work. After it is depleted, you can simply dump it on your lawn to give your grass or shrubs a shot of iron.

It works the same as Evaporust, but is slower. It also costs far less, at less than $2.00 for 5 gallons of mixed solution. You can also use liquid molasses if your feed store carries it. Mine doesn't. The mix ratio for the liquid molasses to water is about 5 :1 or 7 : 1. It doesn't seem very critical. Feed store molasses works much better than grocery store molasses, and is also much cheaper. As I said, there is much misinformation on the internet, probably posted by people who never actually used the process. A few people report pitting of machined iron surfaces such as engine blocks or heads, but I think the pits were probably there all along, hiding under heavy rust. The process can't reverse damage... only remove the rust that is there. Don't use it on anything except iron or steel. It works great, and is limited only by the size of the tank you use. Some people line a pit with rubber or visqueen and submerge entire car frames or rusted body parts. I don't know of a better, easier, and cheaper way to safely remove rust. But if you want instant results, try something else.

A few points. Keith is right about the ferro-ferric coating being the result of the electrolytic process. It comes off easily, much like after boiling. I've used the molasses method, it works, but much slower. I find that for light rust on tubes, overnight is usually long enough for electrolysis. Heavy rust on things like wrenches, axe heads, etc can stay in mutch longer. It does create a little hydrogen gas, so I always run my ventilation fan when doing it. I like it because it avoids abrasives, important when dealing with thin tubes.

After any process, when the oxide is removed and I won't be prepping right away I coat with this, the only product I've found that stops oxidation completely, including the coating on Damascus tubes. It's the same stuff I coat bores with before shipping.

theinhibitor.com

I had to go to a large marine cooler for my tank, it's long enough for tubes, with a welded rebar frame inside for the anode. For bores, you have to suspend an anode rod inside the barrel tubes.

Regards
Ken

Just a thought.
If it's going to be engraved after it's current condition is addressed an engraver is going to be needing a smooth surface anyway so whichever order you go about things won't matter.
Jeremy

Evaporust.

I have used all the methods mentioned up to now and I find they all have little problems of their own to overcome. As I have become older I don't want to put a lot of effort into things. So my method of removing rust is as effortless I feel that you can get.
I use Phosphoric acid at the usual high strength sold at 85% yes it is hazardous because the powers that be say so though Tomato growers use it found in some Colas to name just two. Also is the basis of a lot of commercial rust treatment and removal products sold at high prices so if you are sensible it is not like handling concentrated Sulphuric or Nitric Acids.
Its main Benefit is if it is used to treat a rusty surface the resultant layer can be removed with a stiff brush and WATER!!! Then heat the cleaned metal to dry.