Hairline cracks on piano keys

[the boxman]

I have an accordion that has what looks to be hairline cracks along the length of the white keys. The keys are still solid and working, they are all level and straight the way they should be it's just more of a cosmetic issue. Does anyone know what causes this and what can I do to improve the apperance of the keys without replacing the key tops.

 

[Soulsaver]

Ageing in some plastics... along maybe temperature changes and/or UV light. I've seen it on both Hohners and Sopranis and others, mainly 1950s - ones that don't yellow much - so it's not the make, it's the material. You could try 'sanding' them out but in my experience it will only remove the very lightest ones.

 

[JIM D.]

In the late 60's accordion makers began equipping their accordion models with key tops of plexiglass (perspex) and these types of key tops have weathered well over the past half century. Before this period it was typical to use key tops of cellulose and or styrene plastic. In the case of cellulose, the key tops will yellow with exposure to sunlight and this yellowing will permeate the whole key top and cannot be sanded off. In the case of styrene plastic key tops, the plastic will dry with age and hairline cracks and shrinkage occurs and the tops become brittle with age. Aged cellulose and styrene key tops will require replacement.

 

[the boxman]

Yes I was thinking it was the material. Do you suggest a very fine wet and dry paper. Was thinking of using T cut a long with the wet and dry.

 

[Soulsaver]

Yes wet & dry. Discussed in more detail here (thnx JimD) before for key gouges, http://www.accordionists.co.uk/viewtopic.php?f=4&t=2772
..but as I say, unless the majority are very light it prob isnt worth the effort.T cut wont touch it in my experience.. unless you mean for a near final polish.

 

[the boxman]

Hi I was going to use the T cut a long with the wet and dry then once dry give it a polish up. I wonder if rubbing white nail varnish in would help disguise them.

 

[JIM D.]

In the case of plexiglass (perspex) keys, sanding and polishing will remove scratches and gouges. In the case of an older plastic key top that has hairline cracks appearing, I'm afraid to say the only recourse you have is to replace the key top. The appearance of hairline cracks is the sign of the plastic material shrinking and becoming brittle. This condition will only increase in time.
And whatever you do, DO NOT APPLY NAIL VARNISH TO THE KEY TOP !! Nail varnish contains acetone that will eat into the plastic and ruin the finish forever.

 

[the boxman]

I don't know what material they are made from. The accordion dates from early 90''s. The keys are sold so would be reluctant to start taking them off. Was just hoping to do some cosmetic work to take the bad look away if posible

 

[JIM D.]

If it is a solid key top, it's a low grade styrene plastic.

 

[Soulsaver]

If you think rubbing anything in it will help, then they are worse than I imagined. When I've seen them you can't feel them with your finger nail unless they're really bad!

 

[the boxman]

Your right I wouldn't be able to rub anything in. As you say you can see them but not feel them.

 

[fjsys]

I have an elkavox that has similar cracks, but they are not on the surface so sanding would not help.
Mine looks like the lower layer of the key (not the key top) has shrunk and cracked due to the dry climate. (at least that is what I was told once)
The only option was to replace and honestly they are just hairlines and not visible from more than 5 ft away.
My personal opinion if they are the same type of cracks is to live with them and realize they give the accordion some character.
Ben

 

[the boxman]

Think your spot on with your assessment the cracks are in line with the wooden key block.

 

[the boxman]

Jim

What would you use to fill a gouge if nail varnish isn't a good idea. Is there some sort of compound you could recommend