Rust Removal Techniques...

[Curt A]

I don't have any problems removing exterior rust on parts, but recently I disassembled a Columbia BF feedscrew 2/4 min adapter which had rusted inside the feedscrew tube. I managed to free up the feedscrew by soaking it in kerosene for 2 weeks and then tapping it out. The feedscrew has cleaned up fine, but is there a good way to remove the rust from the inside of the tube...? I crimped a piece of sandpaper to the end of a coat hanger kind of like a gun cleaning tool and attached it to my cordless drill running it in and out of the tube. A lot of the rust went out with this method, but I still have some residual rust to deal with...

[CarlosV]

I have had good results with formic acid, sold in form of gel. I pasted the gel on the rusted surface, left it for a day and the rust came off with the gel. You may need a cotton tip on your coat hanger similar to reach the inside of tube.

[De Soto Frank]

Is the part nickel-plated, or plain steel ?

If not plated, I've had great results with Evapo-Rust, available from Hartbor-Freight, Tractor Supply, and other retailers.

It works on the chemical process of chelation, and the solution reacts only with iron oxides (rust). Once the rust is reacted, action stops - the Evapo-Rust will not "eat-into" the good metal.

I like to soak in one-hour intervals, removing the part, brushing under warm water, then repeating as necessary.

Have not used it on talking machine bits yet, but have had good results on old rusty tools, mechanical parts, etc.

If you want to know more details, let me know.


Frank

[Curt A]

Thanks, guys for the info on formic acid and Evap-O-Rust...

[Phonofreak]

Another product is Crud Cutter. You can get it at any good auto or hardware store. What I like about it is that water based for easy clean up.
Harvey Kravitz

[De Soto Frank]

Curt -

I have used Evapo-Rust on nickel-plated tool hardware, as well as Japan-black cast tool bodies ( saw filing guides, bench and jack-planes ).


If the plating or coating is on sound metal, the Evapo-Rust does not seem to effect it. If the rust has crept-under the plating or coating, the Evapo-Rust may not attack the plating or coating itself, but may dissolve the oxide underneath, resulting in some flaking of the plating or coating.

What I really like about the stuff is that does not remove metal or detail ( such as mechanical methods like wire-wheel or sanding ).

Probably worth testing on a similar object before dunking a rare part.



Best,

Frank