Ultrasonic Cleaning Science

[pizza_is_a_lie]

Yesterday, I pulled the trigger and bought a GT Sonic 2L ultrasonic cleaner, 50W with a 100W heater.

The aim of this post is to highlight the successes and failures I've exhibited when using the cleaner.

Some key points:

• Ultrasonic cleaners are noisy, please consider your neighbours

• Metal baskets can damage items; I created a kevlar basket liner after test 3
  Spoiler:

  

• ABS shouldn't be heated too high; 40degC is ample

• Exercise caution if ultrasonically cleaning old (particularly coloured) items; see test 3

• Ultrasonic cleaning will restore texture where possible but cannot reverse shine

• After cleaning using an ultrasonic cleaner, ensure that you wash your items down with plain water (some advise de-isonised or reverse osmosis water though I use tap water) and dry them thoroughly

Test One - AT102W Caps

Article(s): AT102W pad printed ABS Alps keycap set
Conditions: One bath at 8 minutes, 40degC, 1 part Dentural denture cleaning solution to 10-12 parts ordinary water
Result: Caution!

Spoiler:

Pad printed legends may be damaged by prolonged ultrasonic cleaning. Hand washing is advised else keep the time spent in the ultrasonic cleaner to a minimum.

Evidence:

Spoiler:

Test Two - IBM 5140 Caps

Article(s): IBM 5140 dye-sub PBT Alps keycap set
Conditions: One bath at 8 minutes, 40degC, 1 part Dentural denture cleaning solution to 10-12 parts ordinary water
Result: Success!
Evidence:

Spoiler:

No before and afters. Sorry!

Test Three - Old PBT, Engraved Caps

Article(s): Various 25 year-old PBT, engraved keycaps
Conditions: One bath at 8 minutes, 40degC, 1 part Dentural denture cleaning solution to 10-12 parts ordinary water
Result: Failed!

Spoiler:

There were white artefacts on the red keycaps within this set. Other users have reported issues with ultrasonically cleaning much older caps (such as typewriter keycaps). It won't rub off, leading me to believe it's bleached like an old, red car in the sun. The engraving has faded on some caps and the off-white caps were bleached white too.

This test was repeated without the Dentural denture cleaning solution and the same results were exhibited.

Damage (chips and scratches) to the keycaps was also observed from contact with the metal basket.

I would consider hand cleaning considerably old keycap sets.

Evidence:

Spoiler:

Test Four - HEU292 Keycaps

Article(s): HEU292 doubleshot ABS Alps keycap set
Conditions: Two 5-minute baths at 20degC with a stir in between, 1 part Dentural denture cleaning solution to 10-12 parts ordinary water
Result: Success!
Evidence:

Spoiler:

Test Five - Orange Alps Switches (Partial)

Article(s): 5 worn orange Alps top housings and sliders
Conditions: One bath at 6 minutes, 20degC, 1 part Dentural denture cleaning solution to 10-12 parts ordinary water
Result: Success!

Spoiler:

After cleaning the top housings and sliders, the slider was lubed using a small amount of Super Lube multi-purpose synthetic oil with PTFE all the way around. The switches were reassembled and a 1u M0116 cap was placed on both a cleaned switch and uncleaned switch.

The cleaned switches are much less grainy on the downstroke and the upstroke is very fluid. On the uncleaned switches, the upstroke is almost in 3 separate parts, making it feel awfully jagged.

As the evidence shows, some of the sliders are permanently marked and will struggle to achieve the performance of 'NOS' switches although this ultrasonic cleaning process has definitely helped.

Evidence:

Spoiler:

Test Six - Orange Alps Switches (Complete)

Article(s): 26 worn orange Alps, all components
Conditions: One bath at 6 minutes, 20degC, 1 part Dentural denture cleaning solution to 10-12 parts ordinary water
Result: Success!

Spoiler:

After cleaning the switches which had been split in to loose components, the slider was lubed using a small amount of Super Lube multi-purpose synthetic oil with PTFE all the way around. The switches were reassembled and a 1u M0116 cap was placed on both a fully cleaned switch and switch with a cleaned bottom housing and slider.

The difference between the two switches truly is negligible however, with the switches apart anywho, it's perhaps worth cleaning all of the components.

Evidence:

Spoiler:

As above, really!

Test Seven - Apple M0116 Keycap Set

Article(s): Apple M0116 PBT Dye-Sub Keycaps (Japanese Sublegends)
Conditions: One bath at 7 minutes, 30degC, 1 part Dentural denture cleaning solution to 10-12 parts ordinary water
Result: Partial Success!

Spoiler:

Much like the other keycaps I've cleaned, I just dropped them in the ultrasonic cleaner and gave them the occasional stir. While some of the more notable surface grime was removed, some more stubborn grime deep in the 30 year-old caps was merely brought to the surface. The keycaps required a firm, manual wipe-down with a microfibre cloth to remove this grime. However, they cleaned up exceptionally well.

After this, I then rinsed them with ordinary water and dried as usual.

Evidence:

Spoiler:

[OldIsNew]

This is interesting - I don't have an US cleaner but I always supposed this was a safe way to clean things (short of putting bleach, etc. in the solution). I'm at somewhat of a loss to understand, unless somehow the red was a very superficial dye - and it doesn't sound like that is the case.

Has anyone else observed something like this ?

[Sangdrax]

Yep, another ultrasonic cleaning post!
it's a similar symptom to that of old, red cars.

The only issue with my old red car is the clearcoat giving out after 20 years.

But seriously, I've found anything aggressive on old colored caps is a complete crapshoot. Warm water and Dawn dish soap is as far as I'll go with anything like that anymore. A couple hour soak then a toothbrush scrub gets them squeaky clean anyhow.

[vvp]

I used ultrasonic cleaner with a bit of dish soap in hot water on black, blue and green keycaps. All keycaps were ABS. No problems.

[pizza_is_a_lie]

Yep, another ultrasonic cleaning post!
it's a similar symptom to that of old, red cars.

The only issue with my old red car is the clearcoat giving out after 20 years.

But seriously, I've found anything aggressive on old colored caps is a complete crapshoot. Warm water and Dawn dish soap is as far as I'll go with anything like that anymore. A couple hour soak then a toothbrush scrub gets them squeaky clean anyhow.

I totally agree. Old, red caps are not served well in an ultrasonic cleaner. That said, the off-white caps in this same set are now bleached white. It may be the manufacturing or dyeing technique used, I wouldn't be sure.

However, what I need to make perfectly clear is that anything else I've thrown in the ultrasonic cleaner has been absolutely fine.

Yesterday, the PBT 5140 caps and ABS AT102W caps were fine and cleaned up wonderfully.

Today, I'm in the process of ultrasonically cleaning some HEU292 doubleshot ABS Alps keycaps.

I've updated the OP to illustrate my tests

[pizza_is_a_lie]

I used ultrasonic cleaner with a bit of dish soap in hot water on black, blue and green keycaps. All keycaps were ABS. No problems.

Worth mentioning that the green, blue and yellow keycaps were not bleached or damaged, just the red and off-white.

[snufflecat]

Thanks for posting! I'd be curious to see whether or not the older keycaps still got the same results if you hadn't used the denture cleaning solution. Were the other colored caps also just dyed, or was the plastic colored all the way through?

[pizza_is_a_lie]

Thanks for posting! I'd be curious to see whether or not the older keycaps still got the same results if you hadn't used the denture cleaning solution. Were the other colored caps also just dyed, or was the plastic colored all the way through?

Hey Snuffle,

Yep - same results without the cleaning solution. I assumed that it may have been the 1.5% of sodium hypochlorite but clearly not. This was in a clean bath, too.

I've just cut the keycaps open. I don't see anything notable about why it would be bleaching but reds throughout time have always suffered AFAIK.

Spoiler:

[snufflecat]

Interesting. And honestly I'm a bit shocked that you went to the extreme of cutting up several of your keycaps! Oh well, I guess we can add it to the list of sacrifices made for science.

Edit:
I finally caved and bought my own US cleaner today. The results are so far sub-par, but this could be because some of my caps have some dirt on them that is really hard to get off. Most of the dirt on the surface disappeared after two rounds with lukewarm water and soap, but the tougher dirt on the sides of the keycaps stuck regardless of how many times I tried. I even tried a mixture of isopropyl alcohol and water but with the same results.

[pizza_is_a_lie]

Interesting. And honestly I'm a bit shocked that you went to the extreme of cutting up several of your keycaps! Oh well, I guess we can add it to the list of sacrifices made for science.

Edit:
I finally caved and bought my own US cleaner today. The results are so far sub-par, but this could be because some of my caps have some dirt on them that is really hard to get off. Most of the dirt on the surface disappeared after two rounds with lukewarm water and soap, but the tougher dirt on the sides of the keycaps stuck regardless of how many times I tried. I even tried a mixture of isopropyl alcohol and water but with the same results.

I have a couple dozen sets of these keycaps straight from my Gridboard project; https://ppkr.co.uk/classifieds/gridboard-keycaps/

A sacrifice worth making!

What are the stats, wattage etc for your US cleaner? I'm absolutely in love with mine, besides the Gridboard caps, of course!

[pizza_is_a_lie]

Interesting. And honestly I'm a bit shocked that you went to the extreme of cutting up several of your keycaps! Oh well, I guess we can add it to the list of sacrifices made for science.

Edit:
I finally caved and bought my own US cleaner today. The results are so far sub-par, but this could be because some of my caps have some dirt on them that is really hard to get off. Most of the dirt on the surface disappeared after two rounds with lukewarm water and soap, but the tougher dirt on the sides of the keycaps stuck regardless of how many times I tried. I even tried a mixture of isopropyl alcohol and water but with the same results.

Hey!

So, since we last caught up, I tried ultrasonically cleaning some M0116 (Apple dyesub) keycaps. These 30 year-old caps fared really well in the ultrasonic cleaner. However, like you say, there was a stubborn 'sludge' after cleaning, regardless of how long they were in the cleaner for.

After ultrasonically cleaning these caps, I removed them, cleaning and drying them manually with a microfibre cloth. The 'sludge' was removed with ease. I then rinsed and dried them again as normal.

There's no doubt that these caps are cleaner than they would have been if I had only hand cleaned them and the effort required was much less than if I had only manually tended to them. The process of ultrasonic cleaning definitely lifted the 'sludge'.

[vvp]

There's no doubt that these caps are cleaner than they would have been if I had only hand cleaned them and the effort required was much less than if I had only manually tended to them. The process of ultrasonic cleaning definitely lifted the 'sludge'.

+1
I have the same experience though not with keycaps.
Sometimes an ultrasonic cleaner cannot remove all the dirt but it helps a lot for manual removal.

[pizza_is_a_lie]

There's no doubt that these caps are cleaner than they would have been if I had only hand cleaned them and the effort required was much less than if I had only manually tended to them. The process of ultrasonic cleaning definitely lifted the 'sludge'.

+1
I have the same experience though not with keycaps.
Sometimes an ultrasonic cleaner cannot remove all the dirt but it helps a lot for manual removal.

Yep. I can see why some people would be disappointed however I'm very happy knowing that the ultrasonic process is helping to clean them to a degree I couldn't do easily manually!

Updated the OP with findings.