WD 40 for padlock or sewing machine oil?

What's the problem with never getting the lock off? ; -) kidding aside, sewing machine or mineral oil is best for keeping moving parts lubricated whilst WD40 is a penetrating oil and will displace moisture for when things get stuck and corroded.
Either will do what you want, if the lock get wet, dry it and apply some more.
I wouldn't worry too much, a good quality lock can put up with a lot, assuming it's going to get some use!
We have a padlock for our garden shed that is exposed to the harsh weather conditions we have in north Scotland and it's usually ice forming in winter that prevents it working.

 

Don’t use WD40 it’s not really for locks.
I know graphite base lubricants are usually used for locks. I’m not sure of their anti rust properties though.

I don’t know anything about sewing machine oil.

Oils used for firearms may work as they have to be light weight and stay on. Otherwise not sure.

 

Tri-flow. Available at locksmiths.
No doubt that this is the best.

 

TBH the padlocks and security screws we've used over the last decade or more have never been lubricated and so work perfectly

 

Interesting idea. I have oils developed for use on guns but the best I have found on them is Mobile One. Should work for locks as well.

 

I've had the opportunity to see how well it has worked and don't envisage doing so for some time. But I am following a suggestion on this site trying filling the keyhole with vaseline, which will hopeully both prevent water access and protect the metal from oxidation.

 

S

Superglue will keep the hole free from any foreign objects

 

I’m not saying do that. Just that it’s where I’d look.
Personally I’m with Disciplined Boyfriend in that my own opinion is don’t use anything unless you have an issue.

Oils can collect dirt and dust. Guns are disassembled and cleaned, locks aren’t, I only suggested gun lubes as they are high quality, dissipate water and stick well. Folks have to weigh that vs the potential problems of dirt and such.

 

Tri-flow.

 

I'm sure there are some on here that would do it, or want it. But no, I was being a bit flippant.