TOOLS & MATERIALS
In Part One of this series, we examined useful reference books for repair students because you can never have too much information about your subject. This week we’ll cover some requisite items you’ll want to source, places to find these, followed by a look at optical bonding products.
Micro-Tools are probably the best known specialist supplier of tools, materials and lubricants to the repair trade. They stock the miniature screwdrivers, tweezers and other implements for fine mechanical work available from numerous other sources. But they also list those items tailored specially to the repair of cameras and optics—Eg. Lens spanners, collet wrenches, rubber tools, lubricants, and other materials which are helpful or, in some cases, essential for certain tasks. Their range of stock is huge.
Edmund Optics supply specialised optical bonding agents or solvents from makers like Norland, not easily found elsewhere. Products such as Milbond adhesive are designed for cementing optical pieces—not a process for novice repairers, but it’s wise to know the materials available and why they’re used. It’s part of the big picture of repairing old cameras (which includes knowing what is out there, what you know, and, what you don’t know). One day, you may want to use them.
The big auction site has no shortage of interesting items repairers. Screwdrivers, lens spanners, hobbyist dental picks, files and many other small tools are listed, both by general tool sellers or some specialist suppliers to jewellers or horologists. It’s also the best place to find Canada Balsam at affordable, prices. Brass and steel shim stock of various thicknesses for making washers and shims with which to adjust clearances etc. may be readily obtained, too.
Broach the topic of solvents to a group of camera repairers and you’ll get a range of suggestions. In truth, most types have advantages and disadvantages, however the most universally recommended fluid for general cleaning of mechanisms is lighter fluid. It’s certainly the one I look to in the first instance, unless there is a specific need for alternatives, such as lens cleaning, where I’d usually avoid lighter fluid (unless for instance a lens is particularly dirty and needs surface grease or other contaminants removed before “normal” cleaning).
I prefer lighter fluid for most tasks because, whilst its petroleum fractions are light, highly refined ones which flash off easily. They’re also harmless to nearly all the materials used in film cameras over the last sixty or so years. Alcohol is often mentioned, but it may potentially react badly with certain soft plastics (such as SLR focus screens). Screen manufacturers such as Katz, Maxell and Beattie do not recommend it (briefly, don’t use fluids on these at all if possible, otherwise when unavoidable distilled water will not itself harm them, though the same may or may not be said for any contact you make with them).
Acetone, whilst undoubtedly useful for certain specific applications, has a voracious appetite for painted surfaces and must be used with great discretion. Lighter fluid is a reasonably effective cleaning solvent and is very unlikely to harm anything it contacts (advertently or otherwise), when used in reasonable amounts. This is not, however a licence to drizzle it into shutters or other mechanisms—it’s of great assistance to the repairer, but is rarely ever a repair, in its own right! Invariably, less is best.
Prior to the development of synthetic lens bonding compounds, lens pieces comprising two or more pieces of ground glass were traditionally bonded with Canada Balsam—literally, resin extracted from the Balsam fir pine found in parts of Canada.
Historically used also for mounting microscope specimens onto glass slides (still sometimes the case today) Canada Balsam is very close to optical glass in its transmission of light. It also possesses a tendency to yellow or go brown decades after application which can severely affect items assembled with it. Therefore its use in the commercial manufacture of photographic optics has diminished greatly from the 1950s.
Carl Zeiss were one of the first companies, if not the first, to adopt synthetic bonding alternatives to Balsam. It’s interesting to note that, decades later, certain older Zeiss lenses assembled with early synthetics (including some Planars and Sonnars used in Rolleiflex TLRs and Contaflex SLR lenses) manifest a tendency for cemented doublets to separate because the cement may slowly relinquish its hold on the glass. Hence, the move from Canada Balsam was not without its initial problems, even if these problems didn’t always appear until decades later.
Most modern synthetic lens cements tend to be of the “UV cured” type—the cement will remain pliable to permit the precise alignment of the glass pieces to be joined, at which point the work is exposed to ultra violet light for a specified period, which rapidly cures the cement. This clearly offers time and efficiency benefits to a modern production facility. It’s easy to see why manufacturers began to implement synthetic adhesives when they became available.
Modern lens cements are now very stable when correctly applied, but they do have two potential disadvantages for the DIY repairer. Firstly, once opened, they have a relatively short shelf life which can result in wastage and additional expense. Secondly, when cured, their grip is tenacious, which can be problematic if the job needs to be re-done for any reason, which, in a home workshop without all the facilities of an optical manufacturing, it possibly might.
Canada Balsam, on the other hand, may have (very) long term stability issues, and it takes longer to cure but this last point is one I see as more of a benefit than a liability—it makes the bonding process more forgiving even if some more care may be dictated initially, in order to stabilise the optics satisfactorily until curing is complete.
I have not yet had to do any optical bonding (I’d be prepared to do so, if a particular lens that presented itself was valuable enough to warrant the effort). If so, I personally would incline towards Canada Balsam, rather than modern synthetics, because the former is easier to re-work if a piece needs to be adjusted. And with many Balsam cemented lenses from the 1930s or earlier still surviving in good, usable condition today, any long term complications arising from it over the next forty or fifty plus years are unlikely to be my concern at my age...
Canada Balsam is usually expensive, and difficult to procure in smaller quantities for home users. It’s traditionally sourced through specialist medical and lab suppliers in large volumes at high unit prices—totally impractical for DIY purposes. Fortunately, there are now some sellers who now sell it online in smaller sizes, so anyone who needs to do a little optical assembly (or mount a few microscope slides) can easily acquire it affordably. Here is link to one such listing at the time of writing.
I'm a photographer who images on 35mm or medium format film. I enjoy using older, all manual cameras from my collection, and I'm also a self taught camera repairer who can never resist just one more German classic (according to my long-suffering wife). We live on a few acres of forest and pasture near Hobart, with our two children, four Border Collies, three cats, alpacas, goats, geese, ducks, peafowl, turkeys and chickens, and Tasmanian native fauna species like echidnas, wallabies, kookaburras, bandicoots, (and many others). You can see more of my work here or via my Facebook page. I have also recently started a blog about my adventures in film and collecting and repairing old cameras.