wiping the great wheel dry

Clock Repair 101: Cleaning (or Something Approaching It)

In my previous post, I disassembled my Goodwill, practice clock. In this post, I begin to clean it. The pro’s use an ultrasonic cleaner, but I’m on a budget, so I’m doing it by hand.

Update: I’ve learned a lot since I wrote this blog. See Update at the end of this post.

The unattributed VHS video I mentioned earlier shows how to repair a clock on a budget. Instead of using an ultrasonic cleaner, that person does it Old School: he uses an SOS pad (soaped steel wool) and a toothbrush to do the cleaning, then rinses the parts in water, then does a final rinse in alcohol and dries the parts. The steel wool helps remove rust and grit; the soap cuts the grease and oil; the water rinse removes the soap; the alcohol rinse drives the remaining water out; the final dry removes any remaining soap scum or alcohol.

Digging old oil and gunk out with a toothpick
Digging old oil and gunk out with a toothpick

In the picture above you can get an idea of how dirty this clock was: all the holes were gummed up with old oil and dirt. The wheels were also very greasy, and there was a huge amount of dirty oil on the mainsprings. All that dirt can keep the clock from running like it should, and can cause the parts to wear prematurely.

As a first step – unlike in the budget cleaning video – I used toothpicks (cocktail picks) to scrape out old oil, dust, and who knows what else from the pivot holes and the oil sinks: the little indentation around the pivot hole. Then I wiped as much old oil off as I could, using paper towels. Then I was ready for the real cleaning.

Cleaning by hand, using an SOS pad, toothbrush, and water
Cleaning by hand, using an SOS pad, toothbrush, and water

Like the video suggested, I used an SOS pad (soapy steel wool), a toothbrush, and water to break down the old oil and rust.

After the rinsing in water, the alcohol rinse, and the drying, I was pretty disappointed in the results. As you can see below, there isn’t much visible difference between the clean and dirty parts.

The front plate (left) after cleaning, compared to the uncleaned back plate
The front plate (left) after cleaning, compared to the uncleaned back plate

You can also see a lot of remaining oil and gunk (dust, ground brass, and old oil) in the photo below. The steel wool also scraped up the brass quite a bit, which you wouldn’t want to do to a good clock.

Lots of dirt remains after “cleaning”
Lots of dirt remains after “cleaning”

So now my plan is to “clean” this clock with the SOS pad, etc., and to buy an ultrasonic cleaner for the next clock. I see I can get a good, “mini” ultrasonic cleaner for just over $100, that should be big enough for the mantel style of clocks I’m interested in repairing (update: it isn’t. See below).

I mentioned above that a dirty clock can wear parts prematurely. Another part of a clock overhaul – which I won’t be doing anytime soon – is “bushing” worn pivot holes. As you can see in the photo below, the circled hole is nowhere near round; over the years, the pivot in this hole pressed against one side of the hole, causing the hole to wear in that direction. Out-of-round holes like this keep the clock’s parts from meshing correctly, which can make the clock stop before it should, or even not run at all.

Bushing a pivot hole involves drilling the hole out so it’s round and centered where it should be again, then pressing in a brass fitting that has a hole the right size for the pivot (the end of the wheel that fits in the hole).

Unfortunately, a decent bushing tool – which is a precision machine – can run $1,000, which is well beyond my Hobby Exploration budget.

A pivot hole that needs bushing
A pivot hole that needs bushing

In my next post, I finish cleaning the clock and have a look at the remaining dirt.

Update May 2021

I clean clocks very differently now:

  1. Don’t use SOS pads (steel wool). As I mentioned above, steel wool scratches up the brass. It also catches on small parts, and leaves a fine grid of steel in the wash water – you don’t want to pour that down the drain. Instead I use mild dishwashing liquid and a brass brush.
  2. The ultrasonic cleaner I bought works great for cuckoo clocks, but is too small for most clocks. I’m considering buying this Rosun cleaner, but I haven’t decided on the size yet. One plus for a small ultrasonic cleaner is that you won’t use as much cleaning fluid for smaller clocks such as cuckoo clocks.
  3. I’ve seen and read a lot about bushing by hand, and am now convinced I don’t need a $1000 bushing machine. I still need to learn how to do bushing.
  4. My cleaning process is now:
    1. Wash parts by hand in dishwashing liquid and water, using a brass brush and gentle toothbrush.
    2. Transfer the parts into the ultrasonic cleaner as I wash each one, to avoid exposing the wet parts to air.
    3. Rinse each part in water, to get the cleaning fluids out.
    4. Wipe each part in paper towels soaked in isopropyl alcohol, to drive out the water (to avoid rust).
    5. Wipe each part with dry paper towels, to remove the alcohol.
    6. Peg the pivot holes, etc. with toothpicks (cocktail picks) to remove remaining gunk. I should probably do this step before rinsing the parts.