Hi,
I honestly don't remember the last time I restored a gauge, but I do believe you can accomplish a lot yourself. Just based on somewhat similar work I've done recently, here is what I'd try:
These are mostly products and methods I've used to make cameras and lenses from the 1950s and 1960s look close to new and get them working perfectly. Reconditioning gauges is not all that different. The ages of the paint and types of finishes are in many cases quite similar.
If at all possible, test any and all cleaners on a hidden area first, to see if it's going to lift or soften paint, and to get feel for how it works.
It's impossible to be 100% certain any single product will work in each and every case, even if the parts all came off the same assembly line originally. This is because the paint has likely been "modified" to some extent by years of environmental. These effects will likely be different from one car to the next, since they have been exposed to differing environments. For example, "yellowing" in one case may be from a previous owners cigars, or from "gassing off" of a vinyl interior in another, or maybe even "kitchen grease" in another. Who knows! The upshot is that cleaner might work perfectly in one case, but less effectively or even detrimentally in another. Again, test on a hidden area to be sure!
First look for and try a product called
Endust for Electronics. (You probably won't need to buy a carton of 12, this link is for the photo only.) I'd avoid spraying it directly onto (and into) the gauge. Instead spray onto a soft cloth and use that to clean the face of the gauge. This stuff also comes on pre-moistened wipes and in pump sprays.
This will usually do a great job brightening old paint and removing years of grime and yellowing, but needs to be done cautiously because sometimes it will soften paint to the point it can be smeared or even completely wiped off. Again, test a small, hidden area first!
Many glass/surface cleaners work well too, but I'd avoid using anything with ammonia. Many non-ammonia cleaners might be used first, but will still need to be followed up with a product like Endust or some isopropyl (rubbing) alcohol.
You might try cotton swabs (Q-tips), but be a little careful, perhaps only on the exterior and not inside the mechanism. I was taught to avoid using Q-Tips inside cameras and lenses because they will always leave fine cotton hairs behind that can jam things up. The same might be true of gauges, although generally they are less complex and nowhere near as delicate as the insides of most cameras!
Gauges can get pretty nasty inside, too. There is probably old oil or grease that's dried out, gathered dirt over the years and might foul the mechanism. Several products that can be used as degreasers inside camera equipment might be very helpful with gauges, too.
Try to find
Asahikalin AK225. This is an excellent light duty degreaser spray that works about the best of any inside delicate mechanisms and evaporates very quickly.
Another thing that works really well as a degreaser is Ronsonol Lighter Fluid, which is basically the same as dry cleaning fluid, but for some reason seems to be a purer quality (even though it's much cheaper). A tip that sometimes helps jammed or sticky camera shutter and aperture mechanisms, I've used lighter fluid as a degreaser and stirred in a bit of powdered graphite (aka lock lubricant, in tubes, in hardware stores) This will re-lubricate things at the same time the old grease is being "flooded" out.
Of course, be extra careful using lighter fluid! It's highly flammable... After all it's lighter fluid! Asahikalin is not flammable.
Other re-lubrication will likely be needed. Gauges are generally much coarser mechanisms than cameras and lenses (where "dampening" grease with varoius wieghts and properties might actually be used to "adjust" clearances and "tune" the feel of, say, a focusing ring or shutter advance mechanism) so in many cases simply a good, non-oiling grease and one or two weights of clear oil (sewing machine or watch oil are particularly light types) will probably be all that's needed. Use needle oilers (some are actually hypodermics with different sizes of blunt "needles"), toothpicks, etc. to put just a little oil or grease right where it's needed, not all over the place.
Dielectric grease might be used in rheostats to both lubricate the mechanism and prevent or delay more oxidization in the future. It's available as "Spark Plug Boot" grease in auto parts stores, in little packets, or in squeeze tubes as "Bulb Grease" (for light bulbs) in hardware stores.
Some gauges (and cameras) have white or black nylon gears in them. These call for special grease, or the nylon might be damaged. Often what is safe to use are non-mineral synthetics such as
this stuff. Hopefully you can find something cheaper, though!
Never, EVER spray WD40 in this sort of work. The stuff works fine anywhere it can be re-applied easily and often. But sprayed inside a mechanism that's normally well sealed and inaccessible, it will too quickly dry out and probably cause things to start sticking. Best avoided.
For mechanical/electrical mechanisms, there are two other products that can be very helpful, available at Radio Shack or similar stores. "Color TV Tuner Cleaner and Lubricant" is a spray that can restore a lot of contact type mechanisms to full function. I've used this stuff to get many switches and rheostats working again, even around the home and in the car.
There are also "electrical contact cleaners" that might help, but many of these really aren't much more than isopropyl alcohol. A couple true deoxidizers that I know really work and can be very useful revujenating old electrical contacts are
Stabilant 22 and
DeOxit . Unfortunately, both are quite expensive. Still, they often quickly solve problems that nothing else will.
There are many sources of paint. Try Testor model paints, available in many toy and hobby stores, for quick drying paint in small quantites and a wide variety of colors.
If a needle needs touch-up, I think I'd usually paint the entire needle, rather than try to precisely match a color for a partial touch-up.
Red paints are more prone to fading than other colors, so an area on the tach where the redline is marked might look particularly old and dingy. Clean the face well first, perhaps with alcohol to remove any and all grease so new paint will stick. Then slightly thin the right color/gloss of some model paint and brush it on carefully with a very fine, high quality brush. The reason for thinning the paint a little is so that brush strokes will level out.
In terms of a black dial face, with it's imprinted lettering, that's more of a problem if you need to preserve the existing letters. I have about 30 different bottles of "black" paint for use on cameras. There are limitless shades and glosses of black, plus age tends to fade or color-shift much of it, making it difficult to match for small touchups.
Still, sometimes it's possible to get very close with a custom mixed color/gloss. Just be very patient, mix and let completely dry many experimental formulas before actually applying any directly to the gauge face (where YOU will ALWAYS notice any error, even if it's so small that no one else ever does).
Something else to NEVER use around painted surfaces is "disk brake degreaser". It will remove grease and oil wonderfully, and some types leave little if any residue once they quickly evaporate.... HOWEVER, it will aggressively remove most paints, too! Makes a good "stripper" in fact, for engine paints and more.
Almost any kitchen glass/surface cleaner can be used as a first step cleaning the lens of the gauge, of course. One tip: follow up the glass cleaner with isopropyl (rubbing) alcohol to really get it sparkling. I always do this when framing photographs, for example, where the goal is an archivally sealed picture and the glass must be absolutely clean and spotless.
While the gauge front is disassembled is a great time to really, properly clean up the chrome bezel, too. Simichrome is a good product, and so is Mother's Chrome Polish. I'm sure the Mother's leaves a protective coating that lasts a long time (chrome is actually porous, needs to be sealed), probably the Simichrome does too. Polishing "wadding" is another type of product that might help clean up somewhat crusty, corroded bezels. This is sort of a tear-off cotton that has polish already in it. Just wipe off the residue when it dries. Another good product for both chrome and other metals is "Mr. Metal". A bit hard to find but cleans things up really well.
Hope this helps!
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