What is the correct way to lubricate clock mainsprings?

[HectorLooi]

I've been watching YouTube and getting more and more confused. I've seen people use machine oil, engine oil, engine oil additives (Slick 50), D5, bearing grease, molybdenum disulphide grease, graphite grease, chain lube, PTFE dry lube....

Some advise putting a thin film, while others really slather on the stuff.

I know @oldhippy always advises using Windle's Clock Oil on mainsprings, but how exactly is it applied and in what quantities? 

TIA

[oldhippy]

There are a lot more oils and grease in the trade for clocks now then when I was clock making.  This is how I went about the job I used a paint brush the sort that an artist would use, first brush around the barrel arbor, I went around the top of the spring when it was in the barrel and a round the few coils to the barrel arbor. Just a few drops to the top and bottom of the barrel. Tommy Jobson who has a youtube channel and is a very high class clock maker likes to use a spray on oil. There is no need to flood the barrel some think the more oil the better which is not recommended because it will just run out and go all over the place.  

[HectorLooi]

1 hour ago, oldhippy said:

There are a lot more oils and grease in the trade for clocks now then when I was clock making.  This is how I went about the job I used a paint brush the sort that an artist would use, first brush around the barrel arbor, I went around the top of the spring when it was in the barrel and a round the few coils to the barrel arbor. Just a few drops to the top and bottom of the barrel. Tommy Jobson who has a youtube channel and is a very high class clock maker likes to use a spray on oil. There is no need to flood the barrel some think the more oil the better which is not recommended because it will just run out and go all over the place.  

In view of the modern lubricants available, would you lubricate a clock movement differently today?

[oldhippy]

I think I would use a spray on oil for springs. 

[Dell]

Surely it depends on the clock , I only usually restore torsion clocks and I only use oil on mainspring ( small amount) but on the few so called normal pendulum clocks I have done I have used mainspring grease as there is more reserves of power than there is in a torsion clock so it is not so critical.

Dell

[oldhippy]

I have always used oil as advised by my master. I expect clock grease has improved a lot over time. One thing I found with old grease on mainsprings is it could congeal causing poor timing because the spring couldn't unwind or wind up properly. 400 day movements run on very little oil the less the better. 

[transporter]

Mobieus 8300

[HectorLooi]

Would it be correct to say that the stronger the mainspring, the thicker the oil should be?

So for a fusee mainspring, should a thick grease be used?