Conformal coating

[Kelpie]

As any self respecting sailor should, I carry a digital stage piano aboard. Obviously not a patch on the baby grand I had to leave behind but we all have to make sacrifices.

Anyway, it's inevitably beginning to suffer from being at sea. I'm going to replace the PCB underneath the keys, because it's showing signs of corrosion, and the piano is starting to behave a bit erratically.

Question- would it be wise to spray the new board (and probably everything else while I'm at it) with some sort of conformal coating stuff? I've heard of this magic substance but never used it. I guess I'd need to make sure none of it got on the keybed sensors themselves, which sit under little rubber caps. If the spray is the kind of stuff that creep through little gaps then it could cause more problems than it solves.

 

[jdc]

In my experience it's almost always the contacts which corrode first in the sea air, so coating will probably not do much.

As for 'magic stuff', if you've ever used 2-part epoxy paint it's much the same. In fact I used Hempel High Protect as conformal coating this very afternoon (on some temperature probes which have to go from -40 to +100°C in a damp environment where water will frequently be spilt on them). The 1-part spray-on conformal coat is just acrylic spray paint, but unless your PCB has virtually no connections, and none which are high impedance, it wont be that useful imho.

 

[Kelpie]

In my experience it's almost always the contacts which corrode first in the sea air, so coating will probably not do much.

As for 'magic stuff', if you've ever used 2-part epoxy paint it's much the same. In fact I used Hempel High Protect as conformal coating this very afternoon (on some temperature probes which have to go from -40 to +100°C in a damp environment where water will frequently be spilt on them). The 1-part spray-on conformal coat is just acrylic spray paint, but unless your PCB has virtually no connections, and none which are high impedance, it wont be that useful imho.

The main damage I've spotted was where some solder had corroded and appeared to have created a short. I would have guessed that the corrosion products of solder wouldn't be conductive but all I can say is that I cleaned it up and that key is working again.

 

[William_H]

Back in WW2 radios were sprayed with varnish to deter moisture corrosion and that may help your problem. But as said real problems will come with contact corrosion of keys. Dismantle and clean if possible. On my TV remote controller buttons are in the form of a rubber knob in a sheet of rubber witha conductive coating on end of the knob. The printed circuit board has pattern of bare copper lands that are connected together when button is pressed. Mine need frequnt cleaning. I use alcahol. ol'will

 

[Poey50]

As any self respecting sailor should, I carry a digital stage piano aboard. Obviously not a patch on the baby grand I had to leave behind but we all have to make sacrifices.

Anyway, it's inevitably beginning to suffer from being at sea. I'm going to replace the PCB underneath the keys, because it's showing signs of corrosion, and the piano is starting to behave a bit erratically.

Question- would it be wise to spray the new board (and probably everything else while I'm at it) with some sort of conformal coating stuff? I've heard of this magic substance but never used it. I guess I'd need to make sure none of it got on the keybed sensors themselves, which sit under little rubber caps. If the spray is the kind of stuff that creep through little gaps then it could cause more problems than it solves.

I use Plastik70 on the BMS boards for my LFP pack and any other electronics that aren't sealed. Good stuff but you definitely want to have a good supply of fresh air and / or a suitable mask to use it.

 

[ash2020]

Interesting having musical instruments at sea. I used to restore concertinas and, although we might have a quaint picture of fisherman sitting on the side deck playing a concertina, it never happened! It's the very last place you would want one. Wouldn't last a month!

 

[Kelpie]

Interesting having musical instruments at sea. I used to restore concertinas and, although we might have a quaint picture of fisherman sitting on the side deck playing a concertina, it never happened! It's the very last place you would want one. Wouldn't last a month!

Some fare better than others.
My guitar is carbon fibre and has lived on the boat permanently for over three years. The strings get rusty though.

 

[penberth3]

Interesting having musical instruments at sea. I used to restore concertinas and, although we might have a quaint picture of fisherman sitting on the side deck playing a concertina, it never happened! It's the very last place you would want one. Wouldn't last a month!

You're absolutely right. A tin whistle or other metal pipes I can believe, certainly nothing delicate.

 

[ylop]

I think you are looking at this problem the wrong way! Clearly you wouldn’t have this problem with an “acoustic” piano - so what you need is a bigger boat to fit a proper piano in rather than this electrical stuff ;-) a bigger boat may also have space for a resident piano tuner which you will need of course!

I wonder if it might be better to think about how you store the piano - can you get/make a dry bag (or vacuum bag?) big enough? With some desiccant in there the problem probably goes away.

 

[saxonpirate]

Some fare better than others.
My guitar is carbon fibre and has lived on the boat permanently for over three years. The strings get rusty though.

I spend a lot of time living on my boat and always have a couple of guitars with me, an acoustic and an electric. I must say I've never suffered from rusty strings. I always wipe them down with a clean rag after playing, but I think sometimes its the acidity in peoples hands that contributes to the problem. Just my twopence worth anyway..

 

[KevinV]

I think you are looking at this problem the wrong way! Clearly you wouldn’t have this problem with an “acoustic” piano - so what you need is a bigger boat to fit a proper piano in rather than this electrical stuff ;-) a bigger boat may also have space for a resident piano tuner which you will need of course!

I wonder if it might be better to think about how you store the piano - can you get/make a dry bag (or vacuum bag?) big enough? With some desiccant in there the problem probably goes away.

Nah, acoustic pianos have a great lump of cast iron in them. A proper organ, with rubberised bellows pumped by the cabin boy is surely a more sensible option?

 

[The Q]

As a retired electronics technician who worked on military conformally coated equipment, I'd recommend you use genuine conformal coating.
An acrylic version would be suitable for your use, which can be brushed on, without the problems of aerosol versions which can get everywhere including into switches aka keysboards..
You won't need a huge amount and it's easily available from Amazon or the like..

 

[MikeBz]

I think this topic has opened up an opportunity for a business in the marine industry to produced a "marinised digital electric piano", at 10 times the cost of the same item available elsewhere

 

[Graham_Wright]

In my experience it's almost always the contacts which corrode first in the sea air, so coating will probably not do much.

As for 'magic stuff', if you've ever used 2-part epoxy paint it's much the same. In fact I used Hempel High Protect as conformal coating this very afternoon (on some temperature probes which have to go from -40 to +100°C in a damp environment where water will frequently be spilt on them). The 1-part spray-on conformal coat is just acrylic spray paint, but unless your PCB has virtually no connections, and none which are high impedance, it wont be that useful imho.

If the keys are touch sensitive, like wot mine are, there may not be contacts. I believe they work on proximity (but I may be wrong).

 

[Kelpie]

If the keys are touch sensitive, like wot mine are, there may not be contacts. I believe they work on proximity (but I may be wrong).

Each key has two sensors. The difference in timing between them is used to determine how soft or loud each note is. So it's actually related to speed rather than pressure. But somehow it still works.
The sensors are in two parts- a grid on the face of the PCB, with a rubber boot which sits on top. Inside the boot is a little foot with a conductive tip.

Obviously if any conformal coating got under the rubber it would coat the inside of the sensor and stop that key from working.

 

[ProDave]

Re design the piano to use hall effect sensors and the problem will go away

I'll get my coat.

 

[The Q]

Re design the piano to use hall effect sensors and the problem will go away

I'll get my coat.

Is that a conformal coat? I'd recommend one!

 

[geem]

You're absolutely right. A tin whistle or other metal pipes I can believe, certainly nothing delicate.

You would be surprised how many guitars, fiddles and banjos we see on cruisers boats. The music nights onboard are great fun

 

[Kelpie]

I was aboard a boat the other night that had a digital piano, two accordions, a banjo, a guitar, and possibly a fiddle. And several different mouth organs.
Made my collection look quite reasonable.

 

[zulloboy]

Some fare better than others.
My guitar is carbon fibre and has lived on the boat permanently for over three years. The strings get rusty though.

You could try coated strings (Elixir etc). I have no maritime experience with them, but they lasted really well for me on my electric and accoustic guitars when I was gigging regularly. They are a bit dearer, but it might be worth trying one set just to see.

Cheers, Graeme