Any tips on removing old paint from a blued Sten MK V barrel?

[Freeland]

Lately I have picked up an original Sten MK V at a good price, unmolested and with all numbers and stamps in place.
The gun had a serious amount of dust caked to the finish so I first gave it a good diesel soaking bath and took off all woodwork to give it a thorough "revival". All steel parts came out quite alright afterwards, appearing to have most of its original blueing still in place. The only thing I noticed was that the barrel end had old red paint on it, mainly in the area where the bayonet attaches.
Some pieces were still coated with a thin film of brownish stuff (I gues a mixture of dried oil, fly rust and dust) so I have put them in a soaking bath of old milspec cleaning oil (the thin summer version, gets everywhere) and the first results look promising. I hope this treatment will soften up the red paint on the barrel so it can be scraped off with a soft piece of plastic but in case this does not help, does anyone have other suggestions on how to remove that paint?


Many thanks!
Using either paint stripper or thinner would be my very, very last resort...

Information

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[lawrence_n]

Depending what kind of paint it is, lacquer thinner has always worked well for me and doesn't harm the bluing. After, I use 4 zero or 3 zero steel wool to gently polish off any residue. Since they are more of a polishing agent than an abrasive, they leave a nice clean finish. One little trick I've learned, wrap a powerful magnet (neodymium or rare earth magnets as they are called) in a piece of linen, and pass it over the metal work. It will pick up all the stray bits and pieces of the steel wool.

[Peter Laidler]

We scrape odd paint splashes off optical lenses with a thin piece of thin brass shim. If it won't scratch a glass lens it ain't going to scratch your Sten gun.

A red ring around a barrel indicated Z-UF to Armourers Unfit to Fire. So double check the barrel as well.

[Vincent]

Magnesium wool soaked in oil.



It removes rust, paint, etc without damaging the bluing.

The oil is important. You have to keep it soaked in oil or it will damage the bluing.

It’s pure magic!

Same as this stuff - Big 45 Frontier Metal Cleaner

[Seaspriter]

All good advice so far.
I keep a container of the following available -- testing each to see what works: (sometimes it requires a chemical plus bronze or steel wool)
- acetone
- lacquer thinner
- xylene
- paint/varnish remover
- heat gun (don't use it in conjunction with the above chemicals unless you have death wish)
- fibre pad (Scotchbrite, etc)
- bronze wool (doesn't leave steel shards to rust, available at a boat store)
- steel wool (000 or 0000)

Always start with the least harsh/abrasive, and work up.

[Flying10uk]

Methalated Spirit can work depending on the type of paint and is much less severe than paint stripper. The paint stripper available today in D.I.Y. outlets intended for Joe Public is very "watered down" compared to professional paint strippers used in industry.

[Freeland]

Many thanks for all your suggestions!
Good tip on the magnet Lawrence, I have one available in case it comes down to steel wool after all.
I am hoping the oil bath softens up the paint so it can be scraped off. Next step would be warming up the particular spot bmo a hairdryer to see if that helps, or maybe gently warming up the full barrel in the convector oven.
@Peter, thanks for the tip on trying copper; I have some scraps lying around so I could give it a go if the above does not help. As for the red "Z-UF" paint I did not know that. Might be a good addition to your book on the Sten Carbine (I own a copy, very useful information indeed). Optically the barrel inside looks good and shiny but I should X-ray it to make sure it is fit for firing. However, the gun will be on display only...
@Vincent, nice result! I never heard of magnesium wool but it looks it should be part of my kit from now on. I will add it to Seaspriter's suggested lineup. I could use it to tidy up the pieces that are still somewhat brownish.
Good suggestion Flying10uk; in case I initiate the "chemical path" this sounds like the most harmful way to start with.

I will let you know what in the end helped remove the paint.

KR
Marco

[Peter Laidler]

But don't forget that ANY rust present is telling you that the protective outer surface has broken down and the atmosphere has leeched in. That's a chemical fact of life. And blueing, browning, blacking, painting etc etc is simply a surface protector. Don't be misled by the 'term 'surface rust' either It's ALL surface rust until it goes through like it does on your old English cars, then it's called 'terminal rust'.

If you have visually inspected the barrel of the gun and it is good, then don't waste time and money X-raying it.

[Flying10uk]

Incidentally, any-one who has a Bren Transit chest with the stencilled writing over painted with a grey paint, as a lot seem to have been when they sold off, can remove the grey paint without damaging the white stencilled writing below using very fine wire wool soaked in Meths. Just rubbing over very lightly with the Meths soaked wire wool will reveal the stencilled writing below.

[Freeland]

@Peter
Yes, I am aware that any rust signs mean the dreaded but irreversible process has initiated. My basic approach:
- a diesel bath to remove any dirt and old grease
- then a 14-day thin, gun cleaning oil bath
- followed by a good rubbing down and airblowing of parts
- finally a light coat of a mixture of non-acid grease/milspec winter oil to seal off all surfaces

All guns are stored in display cases each equipped with a dehumidifier keeping the space dry. So far this has worked for me. As for the x-raying; I am lucky to have a good friend working at police forensics where they keep such equipment. Another way to have your tax money working for you...

Back to the subject: the oil bath did not do anything to the paint. It did however fully remove the brown "film" from the MKII barrel nut, leaving a very nice blued surface. I now hope this bath has worked similarly for the remainder of the Sten's parts, will check this tonight at the workshop.
Next step was heating up the barrel in the convector oven (up to 90 degrees C.). The paint did become somewhat "gummier" but I was not able to remove it with the plastic spudger. I then turned to my girlfriend's eco- and skin-friendly nail polish remover, working the spot with some cotton swabs and balls. This worked out just right! The paint came off slowly but surely while the blueing remained completely intact. The blued part from underneath the paint even came out a little less "used". Altogether I am very pleased with the result, I will post some pics later on.