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Anyone skilled in rheology?
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PostPosted: Mon Oct 01, 2012 6:04 pm    Post subject: Anyone skilled in rheology? Reply with quote
Hi all,
I have taken my first quivering steps in the
art or re-lubing a lens. I managed to obtain
a set of 5 damping grease samples, ranging from
"very heavy" (5) to "very light" (1).

I began experimenting with an Industar 50-2.
The manufacturer recommended "very heavy" (5)
for focusing mechanisms. I started with (4).
Far too stiff. Cleaned the helix and re-lubed using (2).
Still too stiff.

A local technician recommended Vaseline.
Much too light /even if it had a very positive effect
on focusing/!

Another technician told me that he made his own compound
consisting of ball-bearing grease + graphite
(presumably to break down the long molecule chains
of the ball-bearing grease).

Another old camera shop suggested Ocular grease,
which in present day terms can be translated into
either "Dow Corning High vacuum grease" or
"111 Molykote compound".

To put it simple: I am sort of lost...
All suggestions and advice are welcome. Luckily, the
Industar 50-2 is easy to handle.


PostPosted: Mon Oct 01, 2012 8:43 pm    Post subject: Reply with quote
Bicycle silicone grease.
Works for me, but I am not very sensitive to these things.


PostPosted: Tue Oct 02, 2012 2:15 am    Post subject: Reply with quote
Too much grease also makes difficult to turn. Wink


PostPosted: Tue Oct 02, 2012 5:48 pm    Post subject: Reply with quote
visualopsins wrote:
Too much grease also makes difficult to turn. Wink

Sigh. Too true. I guess there is no other way than using the
trial-and-error method. In Swedish we have a word lagom,
which can be translated into not too much, not too less.
The problem is to know when...


PostPosted: Wed Oct 03, 2012 9:15 pm    Post subject: Reply with quote
When I started fixing lenses I wanted to use a synthetic grease with low or zero volatile compound content because I didn't want any "nasty chemicals" drifting onto the sensor. I tried various vacuum greases but found they were all far too sticky. I then read someone recommend a synthetic PTFE based bicycle grease and bought some of that. Generally, I found that too thick as well (though useful in some circumstances). So, in the end, I gave up and now I just Castrol LM lithium based grease. It's a high temperature grease so shouldn't go runny if the lens gets hot. It is also about the right viscosity for my tastes. And its cheap and widely available.

Mark


PostPosted: Wed Oct 03, 2012 10:05 pm    Post subject: Reply with quote
I also use lithium grease from the auto parts store. First one I did was a Suntar 135mm f2.8, something I wouldn't be upset if I ruined. Then I did a Mamiya Sekor 60mm f2.8 Macro, then a Jupiter-9.

If it doesn't go all runny when I push my old drum brakes to the point of fading, there is no way it is going anywhere in these lenses.


PostPosted: Thu Oct 04, 2012 1:23 pm    Post subject: Reply with quote
Did you clean the helicoids carefully with solvents (naphta, petrol ether, benzine etc.) before regreasing? That's important!

I'm using a ball bearing lubricant ("Hanseline Kugellager Abschmierfett") which works imho pretty good (usable viscosity, not volatile, long durability, not temperature sensitive, very cheap). According to description from the producer it's made to work well from -30°C to +60°C, which is perfect for lenses. I have it from a local store but you could buy it also from Ebay etc.

But be careful, not every ball bearing lubricant will have the same viscosity (I guess there are much more viscous ones)


Before I found that lubricant I also tried "white vaseline" (from a hardware store for technical purposes) several times which is a bit more temperature sensitive (slightly stiff when it's cold, a little soft when it's warm), but overall it worked ok anyway. Viscosity from different vaseline-brands can differ from ultra-slippery to nearly wax-like.

Last edited by ForenSeil on Thu Oct 04, 2012 8:04 pm; edited 2 times in total


PostPosted: Thu Oct 04, 2012 5:57 pm    Post subject: Reply with quote
Interesting. I am grateful for all advice! Thank you.
One of the problems with an international forum is
that what is common in one country, is totally
unknown in another.

Castrol in Sweden has never heard of "Castrol LM".
Neither is "Hanseline Kugellager Abschmierfett" known
north of Kiel.

Sigh. I'll keep on experimenting...


PostPosted: Thu Oct 04, 2012 5:58 pm    Post subject: Reply with quote
ForenSeil wrote:
Did you clean the helicoids carefully with solvents (naphta, petrol ether, benzine etc.) before regreasing? That's important!

Yes. I did.


PostPosted: Thu Oct 04, 2012 6:48 pm    Post subject: Reply with quote
http://viewitem.eim.ebay.se/KUGELLAGERFETT--50-ml--von-Hanseline-Abschmierfett/280973265789/item
Smile Maybe that's interesting for you

Hope the viscosity is working well for your lenses. It has consitency class 2, nearly 3. I only made good experience with it so far. But every Helicoid is different.

Last edited by ForenSeil on Thu Oct 04, 2012 7:51 pm; edited 2 times in total


PostPosted: Thu Oct 04, 2012 7:09 pm    Post subject: Reply with quote
Affengeil! Danke vielmals!
I just bought one. Tube = 2.80. Postage to Sweden = 3.75.
But it is well worth it if you consider it good for
the intended use. Thank you.

With "consistency class 2", do you mean NLGI 2?


PostPosted: Thu Oct 04, 2012 7:13 pm    Post subject: Reply with quote
twinquartz wrote:
Affengeil! Danke vielmals!
I just bought one. Tube = 2.80. Postage to Sweden = 3.75.
But it is well worth it if you consider it good for
the intended use. Thank you.

With "consistency class 2", do you mean NLGI 2?

No problem Smile And yes exactly, I mean NLGI! In German it's generally called "Konsistenzklasse" and it was a straight tanslation Embarassed

Please report if viscosity is working for you lenses!
If it's not stiff enough, you might try to mix it with graphite, a little molten artificial wax from cheap white candles, or similar.

Bye the way for anyone else NLGI/consistency class "stiffness" can be easily explained with eatables:
000 cooking oil
00 apple sauce
0 brown mustard
1 tomato paste
2 peanut butter
3 white vegetable shortening
4 frozen yogurt
5 pate
6 cheddar cheese

I wonder if already anyone tried to grease his lens with peanut butter Laughing


PostPosted: Sat Nov 24, 2012 11:28 pm    Post subject: Reply with quote
ForenSeil wrote:


I wonder if already anyone tried to grease his lens with peanut butter Laughing


or cheddar cheese

Interesting to see candlewax isn't on this list


PostPosted: Sun Nov 25, 2012 12:18 am    Post subject: Reply with quote
Why would it be on the list of "eatables"?
Dou you eat candlewax on a regular basis Wink


PostPosted: Mon Nov 26, 2012 12:13 am    Post subject: Reply with quote
kds315* wrote:
Why would it be on the list of "eatables"?
Dou you eat candlewax on a regular basis Wink


Not regular, about once a year. My birthday cake is so full of them I always miss one or two Laughing

I was so engrossed in the other answers I forgot it was eatables. oops!

I've used candlewax as an aperture ring lubricant on modified lenses where the ring comes up against the mount. I works quite well and the first one I did about a year ago is still turning smoothly.


PostPosted: Mon Nov 26, 2012 1:09 am    Post subject: Reply with quote
kds315* wrote:
Why would it be on the list of "eatables"?
Dou you eat candlewax on a regular basis Wink


Tallow candles are edible, but only if you're stuck at the North Pole, I would think.
http://en.wikipedia.org/wiki/Tallow#Candles

I occasionally use a wax candle for rubbing along desk drawer runners or curtain rails, to leave a film of dry lubricant on them.


PostPosted: Sat Dec 15, 2012 12:01 pm    Post subject: Reply with quote
I too have got the pack of 5 Nyogel damping greases and all are far too think for manual foucus Helicoids.

I've tried the P.T.F.E bicycle grease and the white lithium suggested here on a CZJ Triotar and Flektogon. Both have quite long helicoids (large surface areas) and worked better with the lithium grease. But I recently relubed the Flektogon with some Aeroshell 7 grease (very stable) I acquired from a helicopter engineer. I also got some Aeroshell 21 from him too and will try that on the Triotar as it is still way too stiff (with the lithium grease) for my liking.

The result of using Aeroshell 7 on the flektogon was very good. MUCH better than any other grease i have tried. Aeroshell 7 uses clay as a thickener. I am concerened whether this may wear the aluminium. I do not know where they come on the hardness scale? The feel of the Flektogon is now much lighter but slightly rough. Not silky /oily smooth like my Pancolar or takumar lenses.

I do have some Makita grease for use on the chuck of a 24v SDS hammer drill. It is much less viscous than the ptfe or lithium grease and closely resembles the original grease i've found in lenses in both feel and colour! The trouble is, i have not yet been able to find any of specifications for it so I'm unsure of it's temperature stability. If i do, I will post results.
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