Cleaning old Valuable Clocks / Timepieces etc

[Tmuir]

I was at my local watch and clock makers association meeting on the weekend and during a discussion after the meeting was finished one member raised a point that old (250 years or older) and valuable clocks or timepieces should not be cleaned with modern cleaning solutions because it could ruin them. He was taking it to mean it could damage the material the item was made from.

I have a slightly different take on this, yes the alloy of brass and quality of steel (iron) will be different to modern items, but I don't think it would so much damage it as maybe remove some of its history. Such as marking out lines from when it was made, also I would feel returning a 300 year old clock to 'as new' condition would be wrong and it should preserve its patina. There is obviously exceptions to this where an item is so far gone where restoration is the only option, but I would say in general a more conservative cleaning would be in order.

Just thought this might be an interesting topic to discuss.

I will add that I have not touched nor do I see myself working on a rare and valuable clock / timepiece in the near future.

Edited August 28, 2017 by Tmuir
correct spelling mistakes

[wls1971]

There is a train of thought amongst some clock repairers that ammonia based cleaners should not be used on older movements because it can cause stress fractures to form in brass plates  due to the process used to make them on older clocks by hammering brass plate to the correct thickness rather than rolling on more modern movements thus putting the brass under stress, but I think most are happy to use them as long as the parts cleaned are rinsed well after cleaning and exposure to them is limited.

[Ishima]

Not a clock repairer but I would lean on whatever was best and most safe and effective to clean the hidden functional parts for that particular clock (so yes by all means consider changing cleaning method if you're worried about causing cracks or such) should be prioritised over any sentiment historical or otherwise, for visible parts such as the face and hands obviously a different mindset is necessary and I would say virtually no cleaning is the ideal (to preserve the patina) unless it's gotten to an extreme where no one would want to look at it and then you're looking at restoring. But I'm not really familiar with clock making practices, it's possible minor feats of re enameling and painting and chemical cleaning are used on the face is standard practice. 

Where's Clockboy 

Edited August 28, 2017 by Ishima

[rogart63]

Could be hard finding 250 year old cleaning solutions But i think if you are a watchmaker that work on this old clocks you should now how to work on them and now which tools and cleaners that would be right. 

[vinn3]

old brass   does tend to fall apart.    copper, bronze and brass -  ill look  it up.

[oldhippy]

This is a bit of a minefield. Some say it does some say it does not.

There is a big difference in a repair and a restore. You should never restore something that does not need restoring.

Very old brass is extremely hard and can be a sod just too even ream out, it can and will take the edge of a reamer/broach it also has tiny pockets of air which some say clock cleaning solutions can get into the pockets and the brass becomes inferior over time. I have yet to see such a thing, just how much time do they expect?  A lot depends on the type of clock, how it looked when it was new. A restore should never be different in any way from when it was new. If parts were not polished then they should never be polished now. Any marks in the plates never should be removed or polished out, this is why you should never use any type of electric machine when it comes to polishing and everything should be undertaken by hand.

Brasso is what I used to clean the plates and if parts were to be polished then a cloth would be used. All parts washed out in petrol and dried in sawdust, brushed clean to remove sawdust and French chalked, applied with a very clean brush, the chalk is taken to the brush. I had a hand soft bristle brush just for this work. French chalk stopes tarnish. If a dial is in a bad way and the customer agrees to a restore, the dial is restored to its original appearance, the same applies to the case.

This is a very basic run through.  

[Tmuir]

Thanks for that oldhippy.

I recently purchased a watch makers handbook published in 1882 when I get a moment I will scan the pages on cleaning as it makes for some interesting reading, it talks about french chalk and brushing, but also using bread and charred bone, which neither of the last two are in my cleaning kit.