Restoring rusty metal

Jeff Horton

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The Heart of Dixie
I am not expert by any means, but I thought I would toss out a couple of things that might interest to some of you on rust removal. This can apply to most any ferrous metal, not just restoring old machines. It could be used on hand tools such as planes for example.

I will start with my favorite rust removal tool. A wire brush. Nothing fancy or high tech about it but it works. I have used a wire wheel mounted in one of side of a standard bench top grinder for a long time. I just made this up a couple of weeks ago.

bench_grinder.jpg

This is an old motor I had laying around with a built in switch in the base. Perfect for this application. I mounted it to scrap piece of pine so I could take it where I was working, my temporary saw horse bench in this case and clamp it down. Then I store it out of way when I don't need it.

This is a Craftsman 1750 RPM motor. The lower motor speed make it safer in my opinion since it has no guards. It doesn't seem to grab as hard and try to pull your hand into it. It has a couple of arbor adapters on it and medium stiffness wire brush on one side and a scotch bright pad on the other.

Since there are no guards I like the softer wire brushes. They don't clean as aggressively but they don't tear up your skin nearly as bad either. And if you use this you are going to hit your hand with the wire wheel. If I have a tool rest I like the stiff brush because it cleans faster.

On the other end is something I just started using. A scotch brite wheel. I found this at the local surplus store. I like it so much I am going back and buy an bunch and stockpile them! They will polish up a machined surface very nicely. They remove the rust too, I am just used to the wire wheel so I use it for that.

wb-example1.jpg wb-example2.jpg

This is rusty piece of cast iron off my jointer I am restoring. I spent 2 or 3 minutes cleaning the small area. Probably takes 5 minutes to do the whole part. You can see the amazing difference the wire brush made. That surface it now ready for primer. I took the scotch brite wheel to the machined surfaces to clean them up an polish them when I finished it.

I don't have pictures but on large pieces I use a knotted wire wheel or knotted cup brush in an angle grinder on them. Same principle, just a larger scale.

Electrolysis, a very effective method of cleaning old rusty parts. It just takes a dumb battery charger*, a tank of water and and some soda to make the water more acidic. It's probably the best method around but it's not nearly as quick as the wire brush. I will skip the details as there are lots of web sites with the details. Just Google something like "Electrolysis rust removal" Be sure and include rust of you get a lot of unrelated things like hair removal. :rolleyes:

*Dumb Battery Charger is one without the automatic controls. You don't want one that shuts down when the battery is charged. You want one that is dumb and just keeps supplying power till regardless. This usually means the cheaper ones.

Here are a couple of photos of my latest tank. I have used small plastic boxes and commonly use the storage containers. I even made one on the trailer out of concrete blocks and plastic sheeting for a large DeWalt radial arm saw base.

tank.jpg tank-in-action.jpg

The second photo shows what happens after about 36 hours. Smaller parts won't take as long, but this is the top of the 12" jointer. It is ready to be taken out and swapped end of end since the tank was not quite large enough.

There are other methods, these are just my favorites.

Jeff
 
Yep, wire wheel on my 8" high speed bench grinder (no guards) works great, and the angle grinder with the knotted cup wire brush is a close second!

One thing I do hate, is those busted off wires get EVERYWHERE..... :rolleyes:

I'll be pulling them out of my coveralls for weeks after I use the wire brushes......... :D

Oh well, they do work well, and the electrolysis sure works great too! :thumb:
 
Hey Jeff, :wave:
Heard anything good about vinegar and rust?
Shaz

I didn't see much results from vinegar, but Citric Acid works real well, (If you can find it). Take the piece out as soon as the rust is cleaned though so it won't turn the metal dark, (like a lot of acids do if you leave the metal in the solution too long).
 
Jeff,

Would the wire wheel (on a bench grinder motor) work for old rusty hand saws?

I have a knotted wire brush for my 4in angle grinder but I think that might be too harsh.

thanks!
 

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Sean from what I have read, and I have yet to do a saw but I have one laying around. The way to clean them is electrolysis. That won't damage the etching from what I read. Plus the saws are small so it's easy for find or make a tank.

Personally I would be afraid of knotted brush. I wouldn't use a straight wire brush on one with etching. Just give them a bath. Wouldn't teak 24 hours.

Jeff
 
Sean from what I have read, and I have yet to do a saw but I have one laying around. The way to clean them is electrolysis. That won't damage the etching from what I read. Plus the saws are small so it's easy for find or make a tank.

Personally I would be afraid of knotted brush. I wouldn't use a straight wire brush on one with etching. Just give them a bath. Wouldn't teak 24 hours.

Jeff


Jeff,

What kind of battery charger do you use? I was looking on HF's site for a cheap one, but most seem to have an automatic shut off or a trickle charge.
 
Any dumb battery charger will do. Mine is an old 10 amp from Wally World I think? They are getting harder to find without the shut off.

A low voltage DC power supply will work too. 5-10 amps. Less amps work, just takes longer. I have heard of people, Stu I think did this, using computer power supplies too.

I am watching for a good power supply as much as I do. Just haven't found one yet.

Jeff
 
i have 5 saws cooking at present in molasses and water and they are coming along nicely. Takes times (6 weeks approx) but only removes the oxides not the metal.

Electrolysis is a lot quicker, but who needs speed. If you need speed try orthophosphoric acid and electrolysis. I forget the dilution rate but i started off with a 500ml bottle of concentrated acid. As you probably know, the acid is the one they use in making rust converters (oxide to phosphate).

I always wonder about using steel brushes as it seems to be too easy to leave a polished surface of rust that is unless you give it more elbow and then it comes out ok (unless there are those internal corners - which is where soaking and/or electrolysis gets a toe in front).

Stuart agree with you about looking like a porcupine after using the brush, especially those cheap ones. Though there is something really purposeful about a big cupped brush in an 8.25" angle grinder.

Tom
 
Jeff,

Using a battery charger for electrolysis doesn't hurt the battery charger does it?

I was thinking about borrowing my Dad's to give this a try, but I don't want to kill it on him. :eek:
 
Nobody has mentioned brush-on, rinse-off, phosphoric acid-based rust removers like Naval Jelly or Rustoleum Rust Stripper (see this link for an alternate packaging look).

Are these products considered too aggressive for tool restoration? I understand that they do a bit of etching as well as rust removal, but I would think the etching could be kept to a minimum by rinsing sooner rather than later (and reapplying if all the rust wasn't removed the first time).

I only have experience with the Rustoleum product. It worked well for me, although I didn't use it on anything "fine" like hand saws ... just hand-crafted steel bits for mounting luggage and gauges and stuff on a motorcycle.
 
Nobody has mentioned brush-on, rinse-off, phosphoric acid-based rust removers like Naval Jelly or Rustoleum Rust Stripper (see this link for an alternate packaging look).

Are these products considered too aggressive for tool restoration? I understand that they do a bit of etching as well as rust removal, but I would think the etching could be kept to a minimum by rinsing sooner rather than later (and reapplying if all the rust wasn't removed the first time).

I only have experience with the Rustoleum product. It worked well for me, although I didn't use it on anything "fine" like hand saws ... just hand-crafted steel bits for mounting luggage and gauges and stuff on a motorcycle.

Kerry,

For handsaw blades anyways....I think the reason that the acid based rust removers were not mentioned was that it might remove/distort the manufacturer's etching on the blade. Same thing with a wire wheel.

However for something that was not as sensitive to surface etching, those products would probably work.
 
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