Lithium grease, silicone grease & axle grease: I keep coming accross
these three. Can anyone clarify what the first two are appropriate
for? Presumably situations where good old axle grease is not
appropriate, yes?

Thank you,

RickyC

Well, grease is an oil which has been "solidified" by mixing it with a
thickener, so that it doesn't run away through clearance gaps.

Mineral oils are cheap and are good lubricants for metals. However they are
also a bit biologically active so you try to keep them away from food and
skin. Lithium greases are made from mineral oils and have a relatively high
melting point, so are good for things like car wheel bearings which get warm
because of the high speeds, and the proximity of brakes.

Silicone oils are more expensive and are poor lubricants for metals, but
good lubricants for plastics. They will also ultimately withstand higher
temperatures than mineral oils (and don't catch fire). You make silicone
greases from a mixture of shorter and longer chain silicone molecules.They
are biologically inert so are good for lubricating plastic fittings (such as
drinking water joints, taps).

Axle grease is too loose a term. In olden days (carts with wooden axles)
they would have been made from animal fats.

In article , Newshound wrote:
You make silicone greases from a mixture of shorter and
longer chain silicone molecules.They are biologically inert
so are good for lubricating plastic fittings (such as
drinking water joints, taps).

Just what I need - is there a trade name. Until I read your post I
sort of assumed that grease was grease.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm

On Wed, 16 Feb 2005 21:24:53 -0000, "Newshound"
wrote:

Well, grease is an oil which has been "solidified" by mixing it with a
thickener, so that it doesn't run away through clearance gaps.

Mineral oils are cheap and are good lubricants for metals. However they are
also a bit biologically active so you try to keep them away from food and
skin. Lithium greases are made from mineral oils and have a relatively high
melting point, so are good for things like car wheel bearings which get warm
because of the high speeds, and the proximity of brakes.

Silicone oils are more expensive and are poor lubricants for metals, but
good lubricants for plastics. They will also ultimately withstand higher
temperatures than mineral oils (and don't catch fire). You make silicone
greases from a mixture of shorter and longer chain silicone molecules.They
are biologically inert so are good for lubricating plastic fittings (such as
drinking water joints, taps).

Axle grease is too loose a term. In olden days (carts with wooden axles)
they would have been made from animal fats.

Very informative - thank you! I undestand that mineral oils (and
gease) rots rubber. What about silicone grease? Is that safe to use on
rubber? And then there is neoprene (as often used nowadays in place of
rubber for seals and o-rings. Which greases are safe to use on that? I
think you might know the answer.

Thanks again,

RickyC

In article ,
Tony Bryer wrote:
In article , Newshound wrote:
You make silicone greases from a mixture of shorter and
longer chain silicone molecules.They are biologically inert
so are good for lubricating plastic fittings (such as
drinking water joints, taps).

Just what I need - is there a trade name. Until I read your post I
sort of assumed that grease was grease.

The trade name would be: silcone grease...

You can get silicone grease from lots of places. Universally used
in diving equipment (where there is no contact with high pressure
oxygen). Although it seems to be extortionately priced.

I have a small tub of "Hi Tack" silicone which is good for keeping and
O rings in-place (and lubricating) push-fit pipe fittings, etc. (Which
I think I got from BES)

Check stuff like:

Spray:
http://www.screwfix.com/app/sfd/cat/...13662&ts=47358
1Kg tub for £71.49 (told you it was extortionate)
http://subaqua-products.co.uk/
you'll need to search for it though, their sites isn't that good.

Actually, compared to the O2 compatable "grease" we use, it's not that
bad... (£26 for a 28g syringe)

http://rswww.com/ RS have "plumba grease", 423-7155, £3.83 for a small
tube. Suitable for potable water systems.

Enjoy!

Gordon

In article ,
RickyC wrote:

Very informative - thank you! I undestand that mineral oils (and
gease) rots rubber. What about silicone grease? Is that safe to use on
rubber? And then there is neoprene (as often used nowadays in place of
rubber for seals and o-rings. Which greases are safe to use on that? I
think you might know the answer.

Divers have been using silicone grease on rubber, etc. for
decades... Whether that makes it suitable or not, who knows, but it's
used and seems to do the job just fine.

However, don't get it on neoprene if you want to glue it afterwards!!!

If you just want to lubricate rubber or neoprene to make it slip onto
something, KY or Vet-Lube is easier to handle and washes off.

Vet-Lube is avalable from country stores, etc. and is generally the same
price for a litre tub as a small tube of KY is in boots...

It makes getting into those tight rubber suits so much easier...

Gordon

"Tony Bryer" wrote in message
...
In article , Newshound wrote:
You make silicone greases from a mixture of shorter and
longer chain silicone molecules.They are biologically inert
so are good for lubricating plastic fittings (such as
drinking water joints, taps).

Just what I need - is there a trade name. Until I read your post I
sort of assumed that grease was grease.


If you only want a small amount pop into your local Plumb Centre. They have
clear Silicone Grease to WRC standard on display behind the counters in
toothpaste sized tubes. They are Green/White livery but I can't offhand
recall the brand D.......??

On Thu, 17 Feb 2005 13:31:11 GMT, (RickyC)
wrote:

Very informative - thank you! I undestand that mineral oils (and
gease) rots rubber.

Rots _natural_ rubber. Almost every modern synthetic rubber is OK. If
you want a deliberate grease for rubber though, use either silicone or
a water-based. Silicone if you want it to last more than 5 minutes.

What about silicone grease? Is that safe to use on
rubber?

It's the usual polish for rubberwear.

Very informative - thank you! I undestand that mineral oils (and
gease) rots rubber.

Not quite true. Oil (also petrol, diesel, white spirit) will cause natural
rubber and synthetic butadiene rubber (which are chemically much the same)
to swell and become softer and weaker, but it is a reversible effect as long
as they don't get damaged while softened. Tyres and the like are made from
NR and SBR.

But Nitrile rubber, which is what most common O rings (and car oil seals)
are made from will be fine. Neoprene (or chloroprene) will also cope with
oil.

What about silicone grease? Is that safe to use on
rubber? And then there is neoprene (as often used nowadays in place of
rubber for seals and o-rings. Which greases are safe to use on that? I
think you might know the answer.

Silicone oils are benign on most sorts of rubber, but I suspect they might
dissolve into, and thus soften, silicone rubbers. I will try that one on my
tame experts.