What’s an economical way to get into metallurgical microscopy?

[josmann]

A user on reddit asked a question related to something I’ve been wondering about. Is there an economical way to get into metallurgical microscopy? I mostly look at Olympus stuff on eBay and I’ve noticed the metallurgical BH scopes seem to generally carry a much higher price tag than comparable biological scopes. Anybody know why that is? Were they always more expensive than biological scopes?

And moreover, are there any metallurgical scopes out there that can be had for a more beginner-friendly price? A, frankly, pretty shoddy looking metallurgical amscope comes in at around 900 bucks! It feels like these things are more expensive than they ought to be…

[Scarodactyl]

Off the top of my dome, unitron examets are sometimes cheap (they were made by Union optical in Japan). Nikon optiphots can be surprisingly affordable sometimes. Every nw and then a bausch and lomb microzoom can be had cheap. It kind of depends on ehat you mean by cheap and what features you want. Generally they should be cheaper than a biological scope since there is less hobby demand.

[Greg Howald]

Metallurgy needs episcopic polarization. That usually means that polarized light goes down through the objective and is reflected back up through the objective and through an analyzer before getting to the eyepiece. Putting those elements together in a single package is why it tends to be expensive, needed a housing to hold the centerable lamp, field and iris diaphragms, and adjustable polarization filters So..... cheat!
Using a gooseneck led lamp with a polarizing sheet and an analyzer in the head of the scope, aim the polarized light at the specimen on the stage, adjust the led polarization to extinction, and you can kind of try it out.

Metallurgical scopes can be costly because of the epi lighting system and long distance objectives used. My metallurgical scope came in at $1500.00.
Greg

[zzffnn]

If a microscopist already has a Nikon Optiphot, (s)he can add metallurgical attachment to it cheaply, by buying parts from unknowing sellers on eBay.

Unknowing sellers need help to make sure parts are complete though; or at least buy from "used" (not "parts") in eBay's "Scientific and Industrial " category, so that you can return and get refund.

Optiphot accepts both 210 metallurgical objectives and infinity ones, depending on the attachment (I don't have knowledge on the infinity attachment). Some Nikon objectives are favored by macro photographers, so those can get expensive.

Cheaper option may be using Unitron or Bausch & Lomb metallurgical objectives of the correct tube length on a DIY-assembled Nikon Optiphot.

I don't know Olympus enough to say if BH series can do the same.

Through-the-objective illumination is usually more expensive, but not necessarily better, depending on what the microscopists want.

[BramHuntingNematodes]

Cheaper option may be using Unitron or Bausch & Lomb metallurgical objectives of the correct tube length on a DIY-assembled Nikon Optiphot.

You can occasionally find very nice B&L apo metallurgical objectives for cheap even. Two notes of caution: avoid the "flat field" marked ones unless you know what you're doing and watch out for the especially squat-looking ones as I believe they belong to a series that used a non-RMS thread size.

[zzffnn]

Correct, the easiest way is, if such an objective doesn't say the exact tube length you want on its shell, don't buy. A "semi objective" would be difficult to impossible to use on non-B&L scopes.

[Alexander]

Once I found an episcopic Leitz SM-Lux HL with polarizer, lambda-compensator, analyzer and darkfield objectives in like new condition for little more than 400 bucks.

The bargains are out there but one must be patient. It may take time to find something nice at an attractive price level. Buying a complete microscope will be cheaper than building from parts in most cases.

[MicroBob]

The most economic way of all is probably to start reading on this topic, on archive.org there will most likely be a book available on free loan.

My impression is that metallurgical microscopes are sometimes offered for a lot of money but are rarely bought at this price as amateurs usually are not interested in them, and institutes and companies buy new. In auctions with a lot starting bid they only reach modest prices. I think that quite a few amateur microscopists have such microscope or the needed components in the cupboard and don't really use them. So it might be successful to ask for offers, e.g. in this forum.

Bob

[Chas]

" are there any metallurgical scopes out there that can be had for a more beginner-friendly price?"
Radical seem to sell some... albeit this one has only two objectives:

Radical metallic.jpg (63.01 KiB) Viewed 5324 times

(I am tempted to buy a set of their metallic objectives to go on an old (pre coatings era) metallic as the back-reflection from uncoated objectives can pretty much drown out the image of a biological subject).

[josmann]

" are there any metallurgical scopes out there that can be had for a more beginner-friendly price?"
Radical seem to sell some... albeit this one has only two objectives:

To add into the weird off brand stuff, I found these economically priced metallurgical scopes: https://www.ebay.com/itm/165201232119?h ... Sw68hhAkot

I’d never heard of Miko before. They have a facebook page which used to be updated quite frequently showing them installing microscopes around India and SE Asia. Their website seems to be down since 2020 and there hasn’t been much posting in the last year or so which makes me wonder if the company is in trouble and they’re liquidating inventory. I’m not sure I’m brave enough to take the plunge on a strange Indian brand I’ve never heard of but it’s real tempting! They have a lot of biological scopes too.

[PeteM]

Microscopes meant for wafer fab inspection are often quite cheap (compared to brightfield equivalents) and will have episcopic illumination, polarization, BF/DF, and sometimes DIC. That satisfies most of the requirements for a metallurgical scope. In addition to the dedicated Optiphot scopes, "Scientific Instruments" would take Olympus etc. epi components and create scopes with deep stages with Pol and BF/DF. So maybe searching beyond "metalllurgical" would find some bargains? Meiji also made decent epi scopes that show up affordably now and then. Ditto Leitz, AO, and of course the Olympus BHM scopes. I'd be inclined to skip the Indian ones (that Ebay listing). The examples I've seen weren't nearly as nice as, say, an ancient Olympus Neo era epi scope.

The expensive part in my own experience is the equipment to cut and polish metallurgical samples. Not sure why, but anything marked "Buehler" seems to be considered a lottery ticket by sellers.

[Scarodactyl]

"Metallurgical" is indeed a poor keyword. It often comes alkng with a higher price point, possibly because the sellers know too much. So many of these were surplused over the years that you can find many being sold by people who know nothing about them, often at very appealing prices--but to find them you have to sometimes cast a wide net and look for poorly labeled items.

[woyjwjl]

Used BH2 metallographic microscope

Salted fish (second-hand platforms) are usually sold for less than 5,000 yuan, it is not clear whether it is considered economically reasonable?

BH2 金相.jpg (67.17 KiB) Viewed 5231 times

[zzffnn]

^ He meant on a Chinese version of eBay (Xianyu) such a BH2 scope would cost about 5000 RMB, which is about 786 USD.

Whether or not it is a good deal depends on what objectives are included in that price, I guess.

[josmann]

^ He meant on a Chinese version of eBay (Xianyu) such a BH2 scope would cost about 5000 RMB, which is about 786 USD.

Whether or not it is a good deal depends on what objectives are included in that price, I guess.

I guess I generally consider economical to be 500 or below. Basically prices that a younger amateur just getting into the hobby could imagine paying. Pretty sweetly outfitted biological BH2s are regularly available at or below that price but almost every metallurgical microscope I've seen is higher.

The issue with Chinese located scopes, of course, is the shipping costs, potential for long shipping times, and of course not knowing whether the hardware will be packed securely enough to survive an international voyage. That said, 786 USD for that scope would probably be a pretty reasonable deal

[Chas]

Many of the old metallic epi illuminators seem to have been fitted to the bottom of the microscope directly above the objective holder.
Thanks to Greg Howald (Thanks!) mentioning that you need polarised light going INTO the illuminator, I now have one working happily:
This one has lost all its illuminator diapragms etc ...it now has just a hole:

RMS epi2.jpg (83.86 KiB) Viewed 5180 times

Inside is a small coverslip mounted on a ring that can be twizzled with the silver knob.


Long and short ..I shone the mobile phone-light into it through some polarising film, and using a Watson 40x:

(This is the top of the brass lid, with an engraving groove to the right of the image.. you can just about see that the engraving was done with a rotary tool like milling cutter)

Watson40x pot lid2.jpg (69.53 KiB) Viewed 5180 times

The illuminator is about an inch wide ( and has an RMS thread at the top and at the bottom).

I have a later (Grey period) version of it and this one has the the angle of the glass fixed (maybe there was no need to twizzle the coverslip once lenses became coated?)

So perhaps a small gasman type of construction could be knocked up with a coverslip inside, to go in the same postion as these, at not too much expense?
viewtopic.php?f=12&t=14717

[zzffnn]

If there is at least 3mm of working distance and objective tip is reasonably tapered, oftentimes there is no need to use true metallurgical illuminator and through-the-objective illumination.

Oftentimes, if not used well, through-the-objective will result in poor contrast. That was what experienced macrophotographers at photomacrography.net told me.

Unless you have use for epi DIC.

We can diffuse light with tracing paper, wax paper or even (worst) office printing paper. Make a cone around the objective using trace paper and shine in oblique light. Or use a ping pong ball (see Charles Krebs' work using ping pong ball diffusion). Up to 40x NA 0.55 LWD, that work well for me. Over that, as working distance runs out, through-the-objective illumination helps.

Just use the correct D= 0 / NCG (no cover glass) objective of the correct tube length.

[apochronaut]

Don't begin by looking at gold or platinum!

[woyjwjl]

My solution

[woyjwjl]

Don't look at gold

[microcosmos]

My strategy was to add a vertical illuminator to an existing transmitted light microscope so it can do both metallurgy and biology (and others). This might not be cheaper than getting a purely metallurgical microscope, but it could be "economical" in the sense that you have an instrument that is much more versatile. However, you will probably have to make do with objectives that can perform well with both transmitted and reflected light, which means that they cannot be perfect in either of those illumination modes (unless you use a different set of objectives for each, which isn't economical any more!). But they can still give you very good images in both - that's what my microscope is doing.

Another consideration that you might want to take into account early on is that a lot of the more interesting type of metallurgical microscopy (in my opinion) involves examining polished metal sections (i.e. metallography). Only with polished sections is it possible to analyze the microscopic crystal structure and deduce the chemical composition of the metal or alloy. To make polished sections requires wet lab equipment and often dangerous controlled chemicals to etch the surface to reveal the microscopic grain structure. Episcopic polarization and episcopic DIC/darkfield complement this.

The point I'm trying to highlight is that the most economical way to start out might depend on how deep you plan to go into metallurgical microscopy in the future. If this topic is fascinating enough that you think you will need all the sophisticated attachments later, you might want to find a microscope that isn't the cheapest but is modular and upgradeable with those future add-ons. So you spend more money now, but the savings come later.