How to fix sticky plastic?

Question

I have a music keyboard (Korg PA-3x) and it’s been at the corner of my living room for a year or so without touching it. One day I realised the plastic parts around the screen and the area where the joystick is located is very sticky. The plastic used to be a bit soft and now it’s sticky as if it’s covered with oil residue. At first I thought it’s really oil fron the cooking landed on it but when I try to wipe it, I can collect a layer of oily stuff but underneath is still sticky. Because I’m not using the keyboard I want to sell it but with this issue people are hesitant to buy it or they bid a very low price. I tried to wash it with a mixture of vinegar and baking soda but no luck. The layer seems to be very thick and because if the shape of the plastic it’s hard to wash it.

Does anyone know what happened to the plastic and how to clean it?

Answer 1

This is a problem that has been discussed on Korg forums:

Where to get replacement joystick bezel and LCD bezel?

As many have noted, the joystick bezel and the bezel around the LCD on the PA3x have a tendency to oxidize, become sticky, and degrade in humid environments. I would like to replace these (as I suspect others would also). Can anyone direct me to where these parts can be purchased? Thank you!

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Solution 1: buy another panel

I have located the part names and numbers as follows: Joystick panel: KEYBOARD SIDE PANEL PA3X SILKSCREEN PLAL001024

Here is a video showing how to make the replacement
KORG Pa3X - wymiana panelu joysticka (side panel)

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Solution 2: clean off the sticky mess

I can confirm that rubbing with a methylated spirits soaked cloth (might be called denatured alcohol in US) worked well for me and the problem is gone. You should weigh up the risk of doing this (rub too hard and you could remove some printing) vs the risk of damaging the unit in removing the bezels.

As noted, don't overdo it

Sadly the previous owner overdid the job and destroyed the lettering.

Answer 2

Korg is a major worldwide brand.

It is most probable that they have heard of similar situations among the millions of units they produced over the years.

Contact them korg.com for their input on what happened to your equipment and for a repair (replacement) or instructions for refurbishment.

Of course, you kept and still have your sales receipt to establish the age of the part.

Good luck.

Answer 3

As one of the comments states, it appears the plastic has started to degrade/deteriorate. One thing I use to remove sticky substances is eucalyptus oil. Put some on a clean dry cloth or paper towel and then remove the sticky residue.

Answer 4

I think Stan's answer is the best approach but if you don't get anywhere with that there are some things you could try. If it really is oil then I'd try a detergent and water, obviously you have to be very careful to keep these on the outside of the keyboard and not damage the electronics.

If that doesn't work then my usual approach is to try methylated spirits (denatured alcohol) on a small swab, somewhere out of sight to limit any visible damage that might occur. If you're still not having any success there's always acetone, but I've found that can damage or remove the surface finish, varnish, lacquer etc.

From the photo, it looks like there's a sticky deposit but it may be that the surface is actually degrading and any treatment may make things worse. Whatever you do, test it first and do it in a small, discrete section. Any chemicals you use should be treated with respect and caution and follow the manufacturer's warnings.