Corrosion on Soviet Industar Lens Barrel

I bought a Zenit-4 camera with a Industar 50mm f/3.5 lens a decade or so ago in Union of Soviet. Everything

worked smoothly and it has been stored on a closet shelf since then in my central air conditioned home. I

just took it down for maybe the first time in three or four years and found a lot of corrosion on the top of the

lens barrel. <P>.<BR>

 

<center><img src="http://jdainis.com/zenit_4lens.jpg"></center><P>.<BR>

 

The bottom of the lens still is shiny chrome. I never got the lens wet so I don't know why that happened. I can

barely turn the focusing ring using two hands. What can I do to free it up to make it turn freely? Could I try

adding some oil and working the lens to free it up or would I be in danger of getting oil or crud on the lens

glass or in the internals of the lens?

<p>Just atmospheric, and I'm sure there isn't much you can do about it. The soft alloys that were used back then are very prone to this. Agfa cameras from that period are very prone as well, which is a shame as it spoils the look.<br>

Others may chime in, but I have never had much luck with restoring these finishes. Good news is that the actual lensis not affected and new Industars are nice and cheap.</p>

 

<p>DON'T OIL IT.</p>

<p>for the stiffness, try a little, tiny, really, really small amount of naphtha (aka, Ronsonol™, but costs more) into the threads and work it back and forth, repeat as necessary. For a severe problem, it may require dis-assembly and cleaning.</p>

<p>Never <strong>flood</strong> the lens with any solvent or lubricant.</p>

<p>The corrosion on the exterior is just what happens to aluminum under the right pH.</p>

<blockquote>

<p>Generally, aluminum corrosion rates are the lowest when the solution pH is somewhere between four and seven. However, aluminum also corrodes rapidly when the solution pH is below approximately four, and aluminum dissolves in very high pH solutions (e.g., a pH of 12). <a href="http://www.spraytm.com/is-aluminum-really-more-corrosion-resistant-than-steel.html">link</a></p>

</blockquote>

<p>I've tried jewelers' rouge to buff it off, but not very successfully. Perhaps someone will have a 'solution' for the problem.</p>

<p>Non-anodized aluminum is not a good material for lens barrels, as demonstrated by this problem. Anodizing makes the surface hard and non-reactive.</p>

<p>The good news is that it (the corrosion) keeps the lens cheap without altering its optical quality. ;)</p>

<p>Look on the bright side of life....</p>

<p>If you think the lens is too ugly, a replacement would be very cheap:<br>

http://www.ebay.co.uk/sch/i.html?_trksid=p2050601.m570.l2632.R2.TR2.TRC1.A0.H0.Xindustar+61+&_nkw=industar+61&_sacat=78997&_from=R40</p>

at a marine supplier buy brass wool, it does a great job on metals without scratching. Avoid any solvents and cover

optics at both ends while polishing the barrel. This hint is given at your risk.

I really don' t care about the finish. It is just that I can barely turn the lens to focus. I guess the corrosion has welded the moving parts together.

<p>Jim -</p>

<p>One industry standard for de-uglying aluminum is to abrade it with a 3D abrasive, e.g. <strong>3M Scotchbrite</strong> or <strong>Norton Beartex</strong>. The green scouring pads available for frying pans are about 400 grit aluminum oxide. Many auto parts stores will carry a more industrial product, 3M 7448 ultra-fine silicon carbide or 3M 7447 very-fine aluminum oxide.</p>

<p>The idea is that they produce a brushed look and blend in the surface issues. In fact, the material is referred to as 'blending pads' and is principally used to buff things like stainless steel sinks to give that 'brushed metal' look. It won't be a yummy, pearly, sandblasted-looking matte finish, but it would look more even.</p>

<p>Is it worth the trouble? It may or may not ... it's cosmetic once you get the ring freed up again. If the surface is baddly pitted, then a quick fix is less likely.</p>

<p>(I'd try it on a piece of aluminum first to see if you like the look and if it looks OK next to the rest of the camera finish.)</p>

<p>Jim</p>

<p> </p>

<blockquote>

<p><em>The bottom of the lens still is shiny chrome</em></p>

</blockquote>

<p>Hi James! this lens has no chrome at all. It is all Aluminum. You can polish it off to shining goodness with a little Rubbing Compound or Brasso. Please do it carefully so the particles do not get in between the cylinders.<br>

The best way to do it is to disassemble the lens and clean and lube. That way you will have a shining new lens. Please remember not to remove the rear ring near the mount. it can be removed; but then you may slip the mount from the Helical. Then getting it back will take a lot of trial and error.<br>

There are some 6 positions in which the helical is mounted; only one of them will make the lens focus to infinity and the full range. it is possible to loosen three small screws on the bigger cylinder at the rear and slide it forward. Then you will see the Helical grooves. If the grease in the helical is solidified you can add some Naphtha, as JDM says, or petrol [gas] to loosen. If it is too old then you can clean it and add new grease All Purpose Grade 2 [ ie., Front-nd bearing grease].<br>

I have renewed any number of these lenses. They are easy to work with. If you need more detailed instructions with pictures please let me know. I can send details in a few days. Best, sp</p>

It must be corrosion between the cylinders that makes the lens so stiff to focus. I had hoped that a little oil and working the lens would free it up but that is not a good idea to try. It looks like I will have to take the lens apart. That is not my favorite thing to do. The last lens I tried to work on was a Minolta Rokkor MC 58mm f/1.2. It was only after I ruined the lens that I learned that I should have taped the aperture ring at f/16 before I opened it up. Well, this Industar lens is useless as it is unless I only want to take photos of things that are 10 meters away.

<p>Hi! I am providing the pictures that show step by step dismantling, cleaning and lubricating on the Industar 50 F/3.5 lens. I could not get the text into the picture due to some problems with my software. I am providing the comments below each picture.<br>

Before starting to dismantle you will need a mini screw driver set including 0.4mm. If your blade is broader then you can hone it on a emery stone or file and make it narrow to fit the Russian screws. Have some Naphtha or petrol ready; a couple of ounces will suffice. You will need some AP2 or AP3 grease [or front end bearing grease. You will also need some clean cloth without lint or fluff to clean the helical. You could use an old tooth brush too.<br>

Now the pictures.</p><div></div>

<p>Please note the two knurled rings, one in front of the lens and one in the middle. They have screws visible. There are 3 such set screws on each of these rings. Just loosen them craefully, like only 2 or 3 turns each. I try not to remove them from the rings, as they are very small and likely to get lost. As you loosen the screws on one ring at a time [the front of the lens first] try to push the ring forward. When the screws are equally loosened the ring will slide off easily to the front. You may do the same to the second ring too.</p><div></div>

<p>The picture above shows the front and middle rings removed. The screws wil be loose on them you secure them with paper tape or by tightening a turn or two so they do not fall off. In the picture above you can see the front of the helical. Also, please, note that there is a black rod perpendicular to the front flange/ring near the notch. This rod is one of the stoppers [end point to stop the helical from being turned beyond limits]. There will be two more rods on the other side of the barrel. Some Industars come with only two stopper rods. Others come with three. Now wait for the next step.</p><div></div>

<p>In this picture Step 3 above, I have turned the rear barrel by about 180 degrees. You will see another black rod attached to the rear barrel that stops against the one in the front barrel. The notch is aligned to enable the screw driver to reach the rod on the rear barrel. It is easy to unscrew the rod as shown from the rear barrel. I use a magnetic screw driver so the rod stays on the screw driver when removed. It would be easier to put it back.<br>

If you do not have a magnetic screw driver try dipping the screw driver head in thicker grease before applying it to the screw head. Most screws will stick to the greasy screw driver. Of course, there is no guarantee that they will!</p><div></div>

<p>This picture shows the black rod in the rear barrel removed. It is held at the head of the screw driver. I have also unthreaded the rear barrel to expose the helical for cleaning. Please do this carefully just enough to expose a major part of the helical threads.<br>

If you do it fast, you are likely to jerk the rear barrel out of the helical thread. Then it would be a problem getting it back in the correct position. As I mentioned earlier only one of the six thread entry positions will allow the lens to focus fully from close up to infinity. So take care.<br>

Now the helical thread is ready for cleaning. Please do not douse it with a lot of Naphtha or petrol. Just a couple of drops at a time will allow your brush to clean the threads. You may use kerosene to clean the grease too. I prefer petrol because it dries fast and leaves no residue. Use unleaded [or dry cleaning petrol if you can get it].</p><div></div>

<p>After cleaning the threads apply a thin layer of grease with a plastic spatula or even an ice cream spoon! turn the helicals over a few times.<br>

While the front and middle rings are out you may polish them with a brass wire brush, Rubbing Compund and/or Brasso. They will shine like new. You may also polish the rear barrel after protecting helical threads with cloth. After polishing make sure to clean all the surfaces while protecting the grooves.<br>

Now, thread the rear barrel in and fit the black rod to the original stopping position. This is the position in which it will focus to infinity, to cite a bench mark.<br>

Your work is almost done.</p><div></div>

That is great and it looks easy enough. I'll have to give it a try. Thank you.

<p>Finally, you may slide the middle ring and the front ring in that order. Do them one by one and make sure you fix the set screws in the same position as before. You can see the old screw marks on the inner rings. That would ensure your focusing scale and aperture scale to synchronize. This step is also an opportunity to correct any mistake in the positioning of the scales.<br>

That is all folks! i hope this helps anyone who is not familiar with the Industar 50. Regards, sp.</p>

 

If the shelves are plain wood, unsealed, say oak, they may be offgassing organic acids like acetic acid, which attack

corrosion prone metals. The chrome camera top plate looks like it has been under attack.

Because you see the corrosion coming from above; alternatively, there may be a rusty nail high up in the cupboard

above the camera spraying iron corrosion over the camera & lens, although I suppose I would expect colour.

It was a metal wire shelf such as one would buy to install one's own shelves in a closet. The shelf was half way up and shirts were hung above the shelf. With a smaller house that I now live in I don't have much room to dedicated to photo equipment. One hall closet takes my large and medium format cameras and cases and various strobes, larger lenses, tripods and miscellania.

 

So the problem with the stiffness of the lens was hardened grease and not corrosion build up as I had thought. I'll give it a go taking the lens apart. Hopefully the little bitty screws aren't corrosion welded in place.

 

Subbarayan, Thank you again. I really appreciate the time you took to explain and show how to dis-assemble the lens, clean and lubricate.

<p>We <strong><em>all</em></strong> appreciate SP taking the trouble to post this.<br>

Thanks.</p>

Done!. It took less than 1/2 hour and the focusing ring moves smooth as silk. I will pick up some polishing compound and try to clean the corrosion off sometime later. Right now I have a working camera. Thank you once again.

When you manage to clean the barrel (and top of the camera) up, you might consider giving it a thin coat of clear lacquer.

<p><strong>SP</strong>, that's one of the most lucid explanatory demonstrations I've seen on this forum, and I've created a Word document for my files. Congratulations, and many thanks.</p>