update on radio fun, this morning i drove some of the steel chassis innards to the sandblasting / plating shops up in Oakland
started some cleanup work on the tuner unit used Meguiar's ultimate polish to clean the dial face, i think it turned out very well some parts had received a good layer of blue paint, i'm going to reuse the plastic part of the escutcheon because the aftermarket replacements don't allow an original dial face to fit. (i find that in general reproduction plastic escutcheons won't fit most of the parts that need to go into them)
after carefully scraping off the paint and sun damaged parts, i was able to use boiling water to carefully straighten and restore the form of the original plastic i'll repaint it with a wine/maroon color, it's not original to have paint, but it's in too rough of shape and color anyway anyone wanting a more precise restoration would either have to work with the aftermarket plastics or use a better matched paint on this one repainting this part would not require much effort -s
i don't have any cleaning apparatus, so far i have been using evapo-rust, soap, rubbing alcohol and manual labor. i have though about getting some sort of small bench top device, would ultrasonic baths clean off surface rust? is it like a fancy rock tumbler? i will go google this, i've thought about it before and i do have a couple dozen screws that need cleaning or replacement
I did some googling, and watched some YouTube about these ultrasonic cleaners, some folks swear they can remove rust with reasonable results with the correct cleaning solution Based on what I saw on YouTube it should be a useful tool for cleaning dirt and grease at the very least, so I ordered one from amazon for under 100 It will arrive in a few days and I’ll post how well this China machine does. -s
progress... refurbishing the power/volume/tone switch took it apart, cleaned all the bits, put a bit of fresh zinc onto some of the parts, re-assembled
the brass is stained because the oxidization reduced the alloy to just copper at the surface in some places not sure the best way to make it look brass again, if i had a very fine wire brush i could probably polish until i'm at brass again but it's in the bottom of the threads suggestions? -s
Maybe try Flitz polish on the brass? Will take some work to get down into the threads, but it works well to polish brass (among other things). I first used it when I was working as an electronics tech in grad school, to polish the internals (brass tubing) of an electron beam column in what would now be considered an antique scanning electron beam microscope. It was the only thing that allowed us to keep the internal structure clean enough to keep the beam focused, FWIW. Basically removes oxidation and leaves no significant residue if wiped off thoroughly. We used isopropyl alcohol for that. Nothing very exotic...
i found some compounding paste and used a fine steel wire brush, the brass got reasonably better
also i got an ultrasonic cleaner on amazon, gonna test it out soon on some intricate tuner unit parts in the mean while, please enjoy the tuner coil before and after photos
the center double coil halves had broken free from each they should be glued together so they can't move i ended up rewinding the coil after all the brittle gyptal flaked off and the windings came loose -s
the ultrasonic cleaner... it works okay, but it won't remove everything it did a reasonable job of this complicated part in the tuner unit, photos attached i used only water and a bit of shampoo in the cleaning bath
i have two of this particular assembly, the other one is brighter and better looking, probably will go with the other one
maybe i should try baking soda or some stronger chemicals in the bath, i heard folks use evapo-rust directly in the cleaning bath -s
By my experience, ultrasonic cleaners work great with weak solvents (isopropyl alcohol, methanol, that type of thing) for degreasing. Detergent solutions are fine, but with anything that is more aggressive, be cautious. They start etching pretty fast with mild to stronger acids, like evapo-rust. If you try those, go with short cleaning times initially, until you see how a particular solvent behaves with the parts that are being cleaned.