[R-390] Synthetic Grease For R-390A Geartrain

[Bob Camp]

Hi

One thing to be very careful about when picking lubricants is to be 
sure that they are compatible with each other.  Lubricant's don't 
always play well together.

In general you will be using something like a grease, a light oil, and 
a couple of cleaners (including contact cleaner ...). Some people also 
add a heavy oil to the process. The more things you use the more odd 
combinations you can wind up with, but the more you can optimize the 
lubricant to each part of the radio.

In some cases you can get a wonderful gummy goo when you mix cleaner X 
with heavy oil Y. In other cases it's light oil A and grease B that 
creates an amazingly rugged varnish. On the other end of the process 
you can find a light oil that does a great job of acting as a cleaner 
for the grease. You may even find that none of your cleaners have any 
affect at all on your grease. A light oil that instantly washes the 
grease away may not be a real good choice ....

The solution isn't terribly complex, just try mixing a little of each 
of the things you plan to use. Some people add a little water to each 
of the mixtures just to throw in another variable. Leave them out in 
the air for a while and see what happens. If all is going well then 
apply some heat for a couple of days. Something around 120 to 150 F is 
a pretty good starting point. If nothing odd happens you might go up to 
200 F for a few weeks. Ideally you would like nothing at all to happen 
to any of the chemicals or the mixes after a couple of weeks in the 
heat.  A light bulb in a box type heater works fine for this sort of 
thing or a surplus lab oven.

There are actually more combinations that you might think. A little 
grease in a lot of light oil is a different combination than a lot of 
grease and a little oil. In one case you are checking the grease and in 
the other you are checking the oil.

Generally you find that some of the light oil evaporates and the 
cleaners are gone before you ever get to the heat stage. In both cases 
you want to be sure that there is no residue when they evaporate. If 
you do the test on a piece of glass this can be easy to check out.

The heavy oil and grease should hold up very well to the heat process. 
The thing here is to be sure that the mixes behave the same way as the 
unmixed combinations. If the light oil combined with the grease turns 
into bubble gum after a couple of weeks then it's not a good 
combination.

I have never found a problem using stuff that all came from the same 
manufacturer and product line. I wouldn't worry a whole lot about 
mixing a light oil and heavy oil from the same product line with each 
other.  Unfortunately I have yet to find a cleaner and all the other 
stuff from one guy that I actually like. That's where the combination 
can get you.

Combinations of synthetic products with "natural" compounds seem to be 
the most likely to have trouble. You can also find light oils that 
don't seem to be very well made or are actually being sold as a 
varnish.

The wild card in the whole process is that you may or may not be 
starting from scratch on your radio.I have yet to see two radios with 
the same set of lubricants on them. If you don't know what the previous 
owner used then you are more or less playing a random combination game. 
There is no way to know what the outcome will be. Another strong 
argument for tearing the whole thing down, cleaning it all and then 
lubricating it from scratch.

Even if you don't go with all the weeks of heat stuff simply doing the 
combinations and letting them sit for a couple weeks will give you a 
pretty good idea if there's a major problem. I would at least do this 
part of the process before using any combination of lubricants and 
cleaners. I would always check any multi manufacturer / multi product 
line combinations.

Sorry for the long post on a fairly simple topic ....

	Take Care
		
		Bob Camp
		KB8TQ




On Jun 26, 2004, at 12:38 AM, ToddRoberts2001 at aol.com wrote:

> I have had trouble finding a local source for synthetic grease to use 
> in the
> R-390A geartrain after cleaning. I found a good online source -
> www.oil4kids.com          They have a nice selection of synthetic oils 
> and greases under
> the name AMSOIL that you can order online. Their Series 2000 synthetic 
> grease
> is rated even better than RedLine grease, but RedLine would be my 
> second
> choice. I wouldn't consider using anything other than synthetic oil 
> and grease when
> rebuilding an R-390A geartrain. 73 Todd Roberts WD4NGG.
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