WD40 - when to use?

Personally, I have a world of hate for people who use WD40 as a lubricant.

It is shit at lubricating as it leaves a lot of guck behind that will clog up the item even worse.   We have a strong law on the farm that if one uses WD40, one must clean out the thing with an oil or grease after.  

I admit my bad experience with WD40 goes so deep, I have never used it in my adult life.  

And here we are.  A bottle of WD40 next to a rusty thing.  Well, two things rusted together.  Normally I would use penetrating oil but that is a whole drama for another day... Instead, all I've got is WD40 Penetrating oil substance.

Is there anything I need to know before I spray?  

Or is there anything (I might have on hand) that would work better at penetrating the rust?  

Depending on what you have rusted, vinegar will derust things.
WD 40 doesn't eat rust at all.
It makes things move easier.
I'd vinegar, then WD 40 once it's broken up a bit

I don't like it either, but end up using it sometimes too.

r ranson wrote:Or is there anything (I might have on hand) that would work better at penetrating the rust?  

The non-toxic method of breaking loose rusty parts is the "heat it and beat it" method. Basically you torch the part, causing the metal to expand as it heats and contract as it cools, thereby breaking loose the frozen parts. Then you beat on it with your tool of choice.

As for alternatives to WD-40, PB Blaster works amazingly well for breaking apart rusted parts, but I think it has lead in it in addition to all the other toxic ingredients. I've also heard Kroil works quite well but I've never used it.

These are very fine (and expensive to replace) parts on a sewing machine.  They are stuck on the machine so I don't want to do anything too large.

I THOUGHT they were stainless steel, but I have never seen that rust before.  But some of the parts like screws probably aren't so galvanic action?  

I'm trying to find the least invasive thing to try next.  I did some sewing machine oil and heat which usually does the trick.

The other thing that often happens is there is old oil that gucks up, but I don't think that's what happened.  

Yeah. Liquid Wrench is another penetrating oil spray that works better than WD-40.
The physical plant guys at college HATED WD-40! , students would "fix" their squeaky heater fans themselves with some WD-40... Truth is, it is a better cleaner and solvent than it is a lubricant, so the oil-filled bronze bushings in the heater fans would have what little oil was remaining in them dissolved and flushed away by the WD-40. They'd go from squeak to squeal in a few days, at which point it was a crap shoot as to whether oil could save the fan.

In a pinch, it sure is better than dry, but it won't last and should be replaced with the correct lube on moving parts.

Aha! I see that I'm cross-posting... stuck sewing machine screws? It's likely that they are not stainless steel... probably highly polished or plated steel. Sewing machine parts need to be hard to not wear out, and that gets expensive to make in stainless. (You can sniff out stainless with a magnet, no attraction, or weak attraction, is or could be stainless)

One thing I always have to remind myself is that penetrating oil takes time... it's not a magic wand to spritz on with immediate results. Tiny screws are easy to break or strip if forced. One last thing, sometimes a screw won't budge when trying to unscrew it, but there could be just a little more that it can be tightened... which breaks it free to be unscrewed and/or allow the oil to penetrate further/faster. It's tricky working with delicate parts. Patience.

1940 technology in this machine.

Body is mostly cast iron.  Considering how long this has been damp, I'm amazed it's not more rusted.  I always assumed the parts were Stainless or some other sort of steel.  They do love lots of oil.

I'm going to try to get a bit of wood I can use to tap the place where I think the rust is worst.  Put the wood against it, then tap with a light hammer.  

If that won't do the trick, WD40... sigh.  

This is like the most delicate part of the machine.  Once I get that off, I can assess what needs to happen next, but any scratch or burr here will make my life hell later.  

...

New question.  Vibrating bath for removing rust?  Useful?  Amazon has some cheap.    

WD 40 gets a bad rap. I think folks just try to make it do things it was never intended to do. It was designed to displace water and inhibit rust.
W= water
D=displacement
40= batch number of the final mixture

I had an older pickup truck that the model year was notorious for rusting out the bottom seam of the doors. A biannual application of wd 40  did a good job of protecting and preventing my truck from ever suffering from the dreaded rot. My doors still were rust free right up until the transmission blew up.

I can verify that Kroil is amazing stuff! Works wonders on 30 year old extremely rusted tractor and Jeep bolts.

Others have given all the advise you need to succeed, but I will repeat and stress BE PATIENT!  It will be far more frustrating to strip or break the screw and then have to drill and retap the hole.

Good luck!

Tests have shown automatic trany fluid and acetone work great together for penetrating rust.
Tough on some plastics.

There is some stuff that you can soak metal in and it will dissolve just the rust.
Can't think what it's called "rust dissolve"?
It's just some acid like citric acid or something. Pretty friendly stuff.

I think navel jelly is phosphoric acid and meant to remove rust.

RR   I found this for your consideration: attached
and strongly vote for PB blaster to loosen the frozen parts. The only problem I had was to dispense small amounts through the straw. Let it work overnight.
Blessings on your project.

craig howard wrote:Tests have shown automatic trany fluid and acetone work great together for penetrating rust.

All the car restoration guys I know swear by ATF + acetone. These are guys who can afford anything, so if they say it works I take them at their word.

Personally, I use ATF by itself. It takes the tiniest amout -- don't over-apply -- and it works its way into every nook and cranny. A litre lasts me for years and years. A single drop off a tranny dipstick is often all it takes.