An odd source of corrosion identified ?

I have come across fine rust films on one or two newly made steel parts (carefully stored away in my dry workshop), while other stuff in the same drawer was unaffected, and I wondered what was the cause. Recently I made a steel spacer with a polished surface, and cleaned it of polishing debris in my usual way, with a solvent from a spray can of 'brake cleaner'. A few moments later, as I watched, it was hazed over with a very thin brownish film - the dreaded rust, again.

What happens is that the solvent has two effects as well as removing dirt. It removes every trace of grease or oil (which is what you want with a brake cleaner), and as it evaporates it lowers the temperature of the workpiece. This drop in temperature causes condensation, if the day is fairly humid, and there is no trace of protection on the bare metal. Small parts are cooled most, so are most vulnerable. The rust that is produced is very fine and thin - but it could seriously mark a finished tool surface or one on a display model.

The answer, I suppose, is a final quick squirt with an oil product, followed by a thorough wipe, which should leave a thin invisible film of oil and so stop any condensation reaching the bare steel.

Best wishes to y'all,

Tim

Thanks Tim. Good to know that.

John

I'm a great believer in WD40 - solvent, cleaner, lubricant and preservative all in one. And water displacer too.

As apprentices, some of us had dry hands and some had rusty hands. I guess its similar to a dry workshop in a dry atmosphere or a dry workshop with a humid atmosphere.
BobH

Hopper Gummer up of brass as well, Particularly on clocks

Roy

Rather similar effects are noticeable on sand blasted surfaces, they too are very vulnerable to immediate corrosion afterwards.

Brian

Guilty as charged, sir. But I don't mess with clocks or ammo. The WD40'd brass sector arms and knobs on my Versatile Dividing Head have remained a bright shiny brass finish since I made them late last year, through the tropical monsoon season here by the coast. Good enough for me.

Another cause is that all solvents contain water in varying degrees. That is why cheques have a water based colour wash to stop people using solvents to alter them.

Maybe dunk them in metho after using brake cleaner ?

I have used that after using rust converter which needs to be wiped over wth a wet rag to clean off on car panels as it pulls the moisture away from the steel .

That reminds me i need to recharge my moisture absorbent units !

Ian

Warm part with hairdryer before final stage to compensate.

At least one air crash in the 'fifties was attributed to perspiration corroding some wire in a servo. ( I heard this in a lecture at university so might be folklore but not internet fake news)

He who oils his ammo will soon deactivate his firearm!

Bazyle
Many 'Air Accidents' have been caused by inspectors leaving torches and mirrors behind them after an inspection! We had a Vickers Valiant return to Weybridge for major repair as the pilot's urine had spilt out of the bottle and corroded the structure.
BobH

When I did my firearm training in South Africa, we were taught to regularly unload the magazines on our weapons and reload them to make sure there was no crap or jammed rounds in the magazine. Never heard of oiling ammunition.

I worked for the NRA and once had a customer blow up his rifle because, as an air rifle shooter, he had oiled his pellets to give him extra power and flatter trajectory.

Despite advice and warning to the contrary, he oiled .303 bullets to shoot through his Enfield Number Four.

He was lucky not to lose something, finger, eye - life even.

Apologies for going off track