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What Is This White Powder?


Guest Cynic
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[Calm down, I'm not talking about Cocaine!!]

 

I'm anxious to tap some of the expert knowledge held by various readers of this forum. Thankyou in advance for any help that readers can give.

 

Problem

I have discovered quite an amount of a white powdery substance around and in the feet of some relatively new, ?80% or so pure tin pipes. They are in contact with modern plywood upperboards, (I hasten to add, not MDF, which I am aware gives off a chemical if not properly sealed). This is in an imported organ, made in Germany under twenty years ago. I am not aware that it has suffered from anything untoward - a little damp, maybe, and some cold....nothing new in churches I'd have thought.

 

I realise that this white substance must be something akin to oxidisation, but am anxious to give the affected pipes some sort of treatment. For a start, the smaller pipes are now getting rather less than their intended wind supply due to the powder forming in the pipe tip-hole.

 

Help!

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[Calm down, I'm not talking about Cocaine!!]

 

I'm anxious to tap some of the expert knowledge held by various readers of this forum. Thankyou in advance for any help that readers can give.

 

Problem

I have discovered quite an amount of a white powdery substance around and in the feet of some relatively new, ?80% or so pure tin pipes. They are in contact with modern plywood upperboards, (I hasten to add, not MDF, which I am aware gives off a chemical if not properly sealed). This is in an imported organ, made in Germany under twenty years ago. I am not aware that it has suffered from anything untoward - a little damp, maybe, and some cold....nothing new in churches I'd have thought.

 

I realise that this white substance must be something akin to oxidisation, but am anxious to give the affected pipes some sort of treatment. For a start, the smaller pipes are now getting rather less than their intended wind supply due to the powder forming in the pipe tip-hole.

 

Help!

 

 

===========================

 

 

Big brother = clever metallurgist.

 

Contact me privately Paul.

 

MM

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[Calm down, I'm not talking about Cocaine!!]

 

I'm anxious to tap some of the expert knowledge held by various readers of this forum. Thankyou in advance for any help that readers can give.

 

Problem

I have discovered quite an amount of a white powdery substance around and in the feet of some relatively new, ?80% or so pure tin pipes. They are in contact with modern plywood upperboards, (I hasten to add, not MDF, which I am aware gives off a chemical if not properly sealed). This is in an imported organ, made in Germany under twenty years ago. I am not aware that it has suffered from anything untoward - a little damp, maybe, and some cold....nothing new in churches I'd have thought.

 

I realise that this white substance must be something akin to oxidisation, but am anxious to give the affected pipes some sort of treatment. For a start, the smaller pipes are now getting rather less than their intended wind supply due to the powder forming in the pipe tip-hole.

 

Help!

 

Tin (the element) exists in two forms or allomorphs: one the shiny metal; the other a greyish powder. This may be the explanation of your problem, which has been reported frequently in organs and electronic equipment. At low temperatures the transition to the grey form is favoured, so you could be right in speculating that cold is to blame. It's nothing to do with oxidation. If you google 'grey tin' you will find all sorts of information. An expert metallugist may be able to explain why some organ pipes of tin seem to have survived unscathed many years of occasional exposure to temperatures below the transition point. It may be that impurities inhibit the transition. 18 degrees Celsius is usually quoted as being 'safe'. I seem to recall polar explorers having trouble with tin cans.

 

The alternative, of course, if the tin is only 80% pure, is that other constituents are corroding. There's another thread somewhere where this problem (e.g. lead becoming converted into complex carbonates and acetates) is discussed at length. In that case, moisture is essential and could well come from the metal getting cold and then coming into contact with warmer moist air. There have been several days recently when my car engine and the electrics have been dripping wet, when a cold spell has been followed by a much milder one. I am certain exactly the same will happen to an organ, either if the church heating is turned on or if the blower to the organ warms the air. In this case, the antidote is clearer. Even WD40 should be enough.

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Tin (the element) exists in two forms or allomorphs: one the shiny metal; the other a greyish powder. This may be the explanation of your problem, which has been reported frequently in organs and electronic equipment. At low temperatures the transition to the grey form is favoured, so you could be right in speculating that cold is to blame. It's nothing to do with oxidation. If you google 'grey tin' you will find all sorts of information. An expert metallugist may be able to explain why some organ pipes of tin seem to have survived unscathed many years of occasional exposure to temperatures below the transition point. It may be that impurities inhibit the transition. 18 degrees Celsius is usually quoted as being 'safe'. I seem to recall polar explorers having trouble with tin cans.

 

The alternative, of course, if the tin is only 80% pure, is that other constituents are corroding. There's another thread somewhere where this problem (e.g. lead becoming converted into complex carbonates and acetates) is discussed at length. In that case, moisture is essential and could well come from the metal getting cold and then coming into contact with warmer moist air. There have been several days recently when my car engine and the electrics have been dripping wet, when a cold spell has been followed by a much milder one. I am certain exactly the same will happen to an organ, either if the church heating is turned on or if the blower to the organ warms the air. In this case, the antidote is clearer. Even WD40 should be enough.

 

 

==============================

 

 

I would suggest going back to the previous thread, because it is quite complex, and probably has nothing to do with "tin pest" at all.

 

I've replied to Paul privately, but the alarming thing is probably more to do with the lead rather than the tin, which once it starts to corrode, will set up almost a chain-reaction of self-destruction, which even normal coatings such as phosphates will superficially remove, but not prevent. Apparently, once lead starts to corrode, it does so very, very rapidly.

 

This is one of the reasons why they put "sacrificial metal" in car body seams, which allows the electrolytic process to continue, but which feeds off the sacrificial "jam" in the middle of a sheet-steel sandwich; if that makes sense.

 

Anyway, I have an expert metallurgist at the end of the phone if needed.

 

WD40 would be absolutely lethal to leather and possibly seals; being an oil-based compound totally unsuited to the inside workings of an organ. The same would be true of wax-based inhibitors also.

 

MM

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A small addendum about "tin pest" and allotropic conversion in tin.

 

Lead actually acts as an inhibitor to the process, and my brother seems to think that the addition of lead (as in solder) would push the allotropic conversion down to around -30 centigrade.

 

Another inhibitor is antimony, which has been has been/is used in organ pipes.

 

Historically, the best and purest natural tin came from Cornwall, and it is interesting that the tin front at St.Bavo is made of Cornish tin. Nowadays, tin now seems to come largely from Bolivia, but is nevertheless quite refined.

 

Once "old" lead enters the smelt, as is likely the case with organ-pipes, there may be all sorts of impurities, which can include arsenic and traces of silver among other things. The less pure the lead, the more prone it is to "boundary layer corrosion," and apparently, some of the worst old lead comes from central europe.

 

Of course, expecting great answers to great questions, I was looking for some great miracle cure, but with characteristic economy of words, my brother simply said, "Use ACF50....it's what they use to fighter-jets on aircraft carriers."

 

He uses it to protect his very powerful Suzuki......59 years of age, and he never grew up.

 

He hates it when I call him "Doc Rocker." :rolleyes:

 

 

 

MM

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  • 2 weeks later...

I write to acknowledge kind help received from MM and Dr.David Wylde (Henry Willis & Co.) on this subject.

I have carried out the treatment suggested and am most grateful for their response to my problem.

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I write to acknowledge kind help received from MM and Dr.David Wylde (Henry Willis & Co.) on this subject.

I have carried out the treatment suggested and am most grateful for their response to my problem.

 

 

======================

 

If Paul has used the ACF-50 treatment, I would be grateful to know if little green monsters start crawling out of the organ-pipes, or not, as the case may be.

 

Possibly at the cutting-edge of organ-pipe preservation technology, this could be the definitive starting point for the preservation of old european organ-pipes, which currently appear to be crumbling away at an alarming rate.

 

MM

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