[Project] Find the best solution for removing pad printed ink

[Blaise170]

Introduction

Hello DT! I have several keysets where the ink is starting to fade and I have had a hard time finding any good information myself. The company Ink Cups currently produces a product which they claim is safe on ABS and removes pad print, however they have ignored every email I've sent to them asking to purchase the product. So I'm going to make my own! The issue for me is finding a chemical that will remove the ink without also melting the ABS. So as many of you may know, you cannot use chemicals like Acetone since it will completely destroy the keys.

The Goal: To find a way to remove pad-printed ink without using abrasives like sandpaper and without melting the ABS.
The Task: Try out different chemicals and chemical concentrations to see if anything works without damaging ABS.

The Process

The current plan is to try out several different chemicals in varying concentrations. These chemicals need two properties to be useful for this experiment: Accessibility and relative safety with ABS plastic.

[*] Ethyl alcohol (40%) [Vodka]
[*] Isopropyl alcohol (91%)
[*] Sulfuric acid (2%) [Drain Cleaner]
[*] Citric + Maleic + Abscorbic [Lemon Juice]
[*] Glycol ether (100%) [DOT 3 Brake Fluid]
[*] Glycol ether (50%) [DOT 3 + Water]

Chemicals were researched via published documents and have all been found to have little or no reaction with ABS except for DOT 3 brake fluid, which may have a moderate reaction with ABS. In the case of brake fluid, we will test for a period of 24 hours submersed and see if there is significant chemical change as there are many different glycols present in DOT 3. You can see the table below, where ABSir is the kind most commonly used in electronics since it does not need high or medium impact resistance.



The information on glycol ethers comes from and is copyright of DOW Corporation.

For the samples, I plan on having two sets of pad printed keys, those which come stock with the KBP V60MTS. A poor rubberdome with pad printed keys may be sacrificed instead if one can be found. One set of keys will be the control, which will be placed in water only. A hammer will be used to lightly tap the keys to test for structural integrity.

Hypothesis

I believe that we will see best results with drain cleaner in very low concentrations, however I am not a chemist so this is mostly conjecture. On the other hand, we may see very good results with the DOT 3 in exchange for a breakdown of the plastic and a loss of structural integrity.

Conclusion

To be determined!

* * *

WARNING: SOME OF THE PRODUCTS USED IN THIS EXPERIMENT ARE EXTREMELY DANGEROUS. DO NOT PERFORM ANY OF THESE EXPERIMENTS WITHOUT PROPER SAFETY EQUIPMENT, INCLUDING GOGGLES, A FACEMASK, AND ANY OTHER POTENTIAL CLOTHING REQUIRED SUCH AS A COAT. YOU HAVE BEEN WARNED!

[scottc]

Vodka, eh? You should try Spirytus! I doubt you can buy it easily outside of Poland though...

[XMIT]

> pad printed keys, those which come stock with the KBP V60MTS

To avoid confusion: on my V60MTS the top legends were lasered and the front pad printed. YMMV.

I think what you want is a strong organic solvent that won't dissolve ABS.

A quick Google search for "abs solvent resistance" turned up:
http://www.gilsoneng.com/reference/ChemRes.pdf

[Blaise170]

Yeah, that's roughly the same chart I was using. Didn't completely look that one over though.

[snuci]

You don't need very long with Dot 3 Brake Fluid. I would say 10 - 30 minutes at the most. Make sure you clean the key caps in soapy water afterwards. I use this all the time to remove marker and spray painted labels. I have actually removed paint off of a painted metal case before too.

NOTE: Your mileage may vary. Try it on one item until you get the timing right. I try to take off the brake fluid as soon as possible just in case.

PC40-III - with painted identification

PC40-III - with painted identification.jpg (341.06 KiB) Viewed 7036 times

PC40-III - paint partially removed

PC40-III - paint partially removed.jpg (352.8 KiB) Viewed 7036 times

PC40-III - paint removed

PC40-III - paint removed.jpg (300.09 KiB) Viewed 7036 times

[Blaise170]

Vodka, eh? You should try Spirytus! I doubt you can buy it easily outside of Poland though...

Also known as Everclear in the US.

You don't need very long with Dot 3 Brake Fluid. I would say 10 - 30 minutes at the most. Make sure you clean the key caps in soapy water afterwards. I use this all the time to remove marker and spray painted labels. I have actually removed paint off of a painted metal case before too.

Good to know, I'll see how well it works with 20 minutes or so of soaking. Have you ever tried this on keys before? I'm afraid that the interactions between glycol ethers and ABS will pose a problem.

[snuci]

I have done this with monitors and keyboards but not specifically with keys. Marker almost vanishes. Paint needs to be rubbed off depending on how long you wait. You can do it multiple times (as shown above) to be safer. If I left it sitting for 24 hours, the original case paint would have come off.

[Chyros]

I think I know a few that almost certainly won't work xD . If you've got any that you think might be interesting, I've got a whole lab full of super nasty crap that I can test out for you if you want to :p . I very much doubt alcohols, light petroleum ethers, (dilute) acids or glycols will work, to be honest, as pad printing appears to be completely sealed and covered in plastics. Paint and marker leftovers shouldn't be similar to pad printed legends at all.

I know a few that will work without a doubt, but they will also dissolve the keycaps. The problem is that the pad material is probably not all that different from the keycap material. Of course, I might be wrong though. Also, rimless pad printing appears to be very different in composition, matter and makeup than the usual rimmed pad printing and may be much more prone to dissolution.

[Engicoder]

I wonder if Wodan's adventures in sandblasting might hold an answer. Perhaps there is a blast media that will remove the printing without removing much of the base cap material. Walnut and soda blasting is used to remove paint on cars without damaging the metal, granted key caps aren't made of steel.

[Blaise170]

I think I know a few that almost certainly won't work xD . If you've got any that you think might be interesting, I've got a whole lab full of super nasty crap that I can test out for you if you want to :p . I very much doubt alcohols, light petroleum ethers, (dilute) acids or glycols will work, to be honest, as pad printing appears to be completely sealed and covered in plastics. Paint and marker leftovers shouldn't be similar to pad printed legends at all.

I know a few that will work without a doubt, but they will also dissolve the keycaps. The problem is that the pad material is probably not all that different from the keycap material. Of course, I might be wrong though. Also, rimless pad printing appears to be very different in composition, matter and makeup than the usual rimmed pad printing and may be much more prone to dissolution.

Yeah probably won't work for most of these, but they are readily available so why not? I probably won't do all of them anyways, only one I know for sure of is the DOT 3.

[Blaise170]

Day 1 - 29 February 2016

The Test Subjects



Test 1

I performed the first test today, using the moderately strong 100% DOT 3. Four different keycaps from different brands were tested. The test was performed for 90 minutes at 50°F (10°C). A small glass vase was used and the keycaps were fully submerged. After 90 minutes, nothing interesting happened. The pad print ink is still stuck on and there is no noticeable change in the ABS. Hammering on the keys did not cause them to break. The test is now being rerun.

Test 2

Right after finishing, I am now running a new test with 100% DOT 3. The current plan is to keep the keys submerged for 24 hours and then redo the above tests to see if there are any noticeable changes. If this still fails, 48 hours will be tried, and then a stronger chemical if all else fails. The weaker acids I was thinking of testing such as citric acid will likely no longer be considered due to the lack of any reaction of the ABS with the glycol ethers.