Peak Loupe cleaning and re-ink of engraved glass scale

I purchased a used Peak inspection loupe at a local pawn shop. This loupe appeared of decent quality when originally made in Japan. It was in good condition except for greasy finger prints. The loupe came with five reticles, each with a separate protective plastic sleeve, and had intricate markings showing circle diameters, angles, length, grids, etc, in both inch and metric measuring systems. I was successful in cleaning everything except for the engraved reticles. I carefully exhaled on the first reticle, creating a fog on the reticle, and used a new / clean cotton swab with a gentle rubbing motion to clean it. A bunch of little black things appeared on the reticle and swab. It turns out these are the (?) dried ink markings which were in the engravings and which I had expertly rubbed off. The reticle appears to be made of glass on the basis of resistance to a knife blade applied to the edge and the ringing sound when gently dropped from half an inch onto a hard surface. In the portions where there is missing ink, I can see an engraving depression suggestive of some kind of precision engraving process, which further suggests to me the blackness was not merely stamped on. This de-inking occurred to the first of the five reticles I attempted to clean, so I left the other four reticles alone. The de-inked engraving markings are sort of visible when the loupe is used in good light, but not nearly as clearly seen as the ones with ink in them. Please see the pictures.

Questions: How should I have cleaned this? How can I re-ink the graduations to restore them, or how can I re-ink them to make them at least usable? Bonus question: What is the best way to mark engraved graduations / markings for best visibility on things like metal or plastic dials?

I chose this forum as opposed to the antique, metrology or general forums because it seemed the best fit to me, but if I judged wrong, please feel free to move it to a better forum.

Close up of the damaged reticle:

I would *guess* those are made by a kind of printing process (like how watch faces are printed, etc.)

I would *bet* that you get new ones to fit that loupe here: Reticle Scales : Peak Optics, Magnifiers, Comparators, Loupes, For Inspection & Measuring, 2x to 3x
(and probably other places on the web)

I've no experience filling tiny grooves like those on the reticle so this may or may not be useful. I do a fair number of machine dials with graduations and numbers but they're much wider and deeper than the perhaps diamond engraved ones on the glass. There are lacquer sticks intended exactly for filling markings like dials and might work with the reticle. It's about crayon consistency or slightly softer once you scrape off the hardened skin. Rub it on and wipe off the excess.

bryan_machine suggested a website which sells replacement reticles of many types/styles to fit my loupe and other loupes. They also have a bunch of other optical inspection devices which look very useful. They also make custom reticles for their instruments as well as others. I'll have to explore their site further and maybe buy a thing or two.

TGTool do you have any further information on lacquer sticks such as brand name, who sells them, or ? I like that idea for refurbishing the reticles I have. I bet all five will have the black markings rub off when I go to clean them, and prefer not to have to replace all five at $15 a piece when a probably cheaper fix is available.

No doubt other suppliers, but you can review at McMaster Carr here McMaster-Carr

Phone call to Peak.

Given the black paper leatherette case in which I bought the loupe, it looked decades old; and given that I had never heard of Peak optics previously, I assumed there was no longer a Peak optics business. I was very happy to see I was incorrect because of the website linked by bryan_machine. A phone number was listed so I decided to call it, and see what advice they could offer regarding the reticle issue I have.

The male voice at GWJ, parent company of Peak had two pieces of advice. Buy a new reticle. And if they must be cleaned, use soap and water (warm was probably okay). He said there is NO method by which the reticle can be repaired. He refused to discuss the lacquer sticks mentioned by TGTool, because he said the reticles were NOT repairable. He had never heard of a problem such as mine, nor heard of someone who wanted to repair them. He did mention that the reticle is printed by a photographic process. I questioned this in the case of mine, which appears to be engraved. I tried to explore the possibility that maybe the reticle is something which is engraved by a photographic process, so maybe the two methods are not mutually contradictory, and all he said was the reticle was engraved at the factory (which I found confusing, but since it was not a topic to discuss I remain confused). Not his exact words, but since I bought it used, I had to suffer the consequences of buying used. I would say the phone call was a difficult phone call.

/rant deleted (to the likely relief of all readers.)

I spent $20 on this loupe and reticle set, and a new set of five reticles costs a mere $75, which I view as not an option. I don't understand how these reticles are made. I want to make what I have better. If anyone can explain how these reticles are made, I would find that useful in deciding on a repair method and prevention of the same problem with the other four reticles. TGTool's suggestion sounds like the way to go, but more knowledge is always a good thing before making a commitment.

I have that same loupe but with the Folwler name.
The lines are not etched with depth that can be filled. They appear to be screen printed, the lines look like mirror reflective metal. The link byron' gave you says "photo printed".
I buy these comparators, leave the reticles in the box and use it as a normal loupe. A comparator must have distortion free lenses all the way to the edges so they make great general purpouse loupes.

I'd offer my unused reticles if I can find them. I only have one so far.
BTW, I have a 70 year old Leitz that has reticles sandwhiched in a glass and probably bonded in the same way as complex lenses. That might be something you could do.

I would be really surprised if the engraving in your reticles are even 0.001" deep. I'm very skeptical that you would be able to fill the grooves properly with any of the above-mentioned sticks.
Perhaps, the best bet would be to use India ink: after cleaning and degreasing thoroughly the reticle, pour some ink on the whole reticle, and let it dry. After it's dry, you can try scraping the excess away with a safety blade, or by some sort of light buffing.
An alternative could be to try removing the excess with a squeegee when it is still wet.
If you verify that the material is indeed glass, as last resort, I would use a Sharpie marker and buff off all the excess, once it's dry.

Paolo

I figured, the reticle is toast as is, so there is not much to lose in a repair attempt. Well, for something that is NOT repairable, it turned out pretty good with the repair I accomplished.

What I did: I washed it gently under cold water with mild hand soap. All of the remaining black marks disappeared. NOTE: Soap and water is not safe to use on a reticle you like of this age from this company and only want to clean dust, grease and finger prints off of, which is contrary to the advice provided by the manufacturers representative. I experimented with a sharpy type marker on a piece of glass that did not matter and confirmed it wiped off with acetone. I experimented a bit. What worked: Blacken the reticle with the sharpy. I used a relatively thick coating. Let it dry for a few minutes till most of the odor is gone. I used a fresh from the package razor blade of the box cutter type to scrape off most of the ink. I used the blade at a low angle rather than a right angle to do the scraping, and used a large amount of blade in contact with the reticle rather than just the tip. I did not see any scratches in the glass when finished. When I had most of the ink scraped off, I switched to a dry cotton tip swab to rub most of the remaining extraneous ink off. I then got the last bits of unwanted ink off with a slightly moist cotton tipped swab.

With all the original black lines washed off, the engraved lines were plainly visible against some backgrounds, but it was hard to do any measuring on most test surfaces. As you can see from the attached photograph, > 95% of the lines are blackened, and nothing else is blackened. When I installed the reticle in the loupe, I had no trouble visualizing the newly blackened lines against several test surfaces. I could not see the black lines well against a black test surface, but I sort of expected that. My main complaint with the function of the loupe is the dust on the reticle is irritating if it happens to be right over whatever I am inspecting, which I view as life in the real world and not a deficiency of the loupe or the repair other than I should have used some canned air when reassembling. If anyone else out there is going to attempt this, be careful not to drop the reticle. I think that was the main risk of doing this.



Regarding Paolo_MD 's comment about the lines being very shallow, I agree. If you look at the picture in this post, you can see a line marked for 0.001" width. It is the same width of all the other lines on the reticle. I didn't measure their depth, but they are barely discernible with a fingernail gently passed over the surface. I would guess they are +/- 0.0005 deep. One of the attempted methods of marking the lines I used was to use a bit of acetone on a paper towel to remove the unwanted blackness. After multiple attempts, even with minimal acetone on the towel, barely wet as it were, all the black came off, even the ink in the engravings. Yes they are very shallow. I count myself lucky that I got such good results with the method I outlined.

Nice job with the Sharpie. And you can always do a 2nd pass if you want to clean up the remaining 5%.

Happy to hear of your successful rescue. I hope I never have to do that particular repair but if I do I'm glad to know someone who's been there before.

Nice save. Those optical measuring tools are great to have, and I used one of mine last week. This is the head of a 0-80 screw I wanted to measure the slot width of, and at 30x magnification it was easy. Mine isn't a loop, but it's similar and has its own tripod stand.

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