Alum on broken screw in Arbour?

[Waggy]

Greetings,

I was working on the Accurist below an AS1977-2 and all of the screws were put in by an Olympic power lifter, I managed to get all of them out except the ratchet wheel screw (left hand) which sheared off leaving a a stub inside the arbour.

Here are some pictures:

Here is the movement:

And here is the screw sheared off, you can see the grey shear surface of the screw remnants inside the arbour:

Fortunately I managed to wiggle it out after 10 mins in the ultrasonic freed it up enough, and I have a donor screw I can steal. My question is, if I wasn't so lucky next time could I have used alum to dissolve the remains of the screw inside the arbour the same way you would with a winding stem inside a crown, or would the arbour also dissolve in the alum? This is good information for me to have for future escapades and maybe other forum members.

[nevenbekriev]

No, You can use alum only if the screw is in brass plate. All the steel parts have to be removed from the plate, othervise they will dissolve too. Arbour will be damaged for sure.

[Jon]

3 hours ago, Waggy said:

Greetings,

I was working on the Accurist below an AS1977-2 and all of the screws were put in by an Olympic power lifter, I managed to get all of them out except the ratchet wheel screw (left hand) which sheared off leaving a a stub inside the arbour.

Here are some pictures:

Here is the movement:

And here is the screw sheared off, you can see the grey shear surface of the screw remnants inside the arbour:

Fortunately I managed to wiggle it out after 10 mins in the ultrasonic freed it up enough, and I have a donor screw I can steal. My question is, if I wasn't so lucky next time could I have used alum to dissolve the remains of the screw inside the arbour the same way you would with a winding stem inside a crown, or would the arbour also dissolve in the alum? This is good information for me to have for future escapades and maybe other forum members.

I know I may be stating the obvious, but you do know that both screws are a left-handed thread?

Also, alum is a bit crap, unless you have lots of time on your hands. the best thing to use if you do need to dissolve screws in Bergeon Visson which takes less than ten minutes when whatever you need dissolving is put in a crucible and heated with a spirit lamp. make sure there is nothing like a minute wheel post in the crucible which is usually made of steel. Also Incbloc setting will dissolve, so be very wary what you are doing

https://www.hswalsh.com/product/screw-loosening-extractor-fluid-vissin-bergeon-4503-0050-hv40

[Waggy]

@Jon thanks for the advice on the Bergeon Vissin I'll look it up. Fortunately I did spot that the screw was left handed before I went at it, unfortunately I think maybe the previous the previous person didn't and really cranked down on it, so much so that it was weakened and broke when I tried to remove it. All of the screws in the watch were very tight and when you look at them the reflected light wasn't even, indicating that the screw head was deformed on all but the heaviest screws.

Good news is that it is all disassembled now and I have a replacement screw - I put it all through the cleaner last night and will start putting it together tonight (unless I have a rough day at work), so hopefully no more calamities.

10 hours ago, nevenbekriev said:

No, You can use alum only if the screw is in brass plate. All the steel parts have to be removed from the plate, othervise they will dissolve too. Arbour will be damaged for sure.

@nevenbekriev Thanks for the confirmation, I assumed as much, but was holding on to the slim hope that maybe they used some special steel alloy for the arbour to maintain its hardness which would protect it from the alum (in a similar way to the way the chrome does in stainless steel).

9 hours ago, Jon said:

if you do need to dissolve screws in Bergeon Visson which takes less than ten minutes when whatever you need dissolving is put in a crucible and heated with a spirit lamp.

I was looking up the Bergeon Vissin to see how hard it would be to import it to where I live, turns out it is only 96% sulphuric acid with a Bergeon stamp on the bottle:

Edited November 15, 2023 by Waggy

[AlexeiJ1]

Yep you could get an old battery and use it. Although may have some lead contamination so if you boil it I'd avoid inhaling.  But I'd avoid inhaling corrosives anyway haha. 

I also wonder how hydrochloric acid would go. 

[Waggy]

One of the strange things about where I live is that they are very strict on what you can import, so all solvents and chemicals are a no-no, and anything with a battery (they automatically assume its a lithium battery) is also not allowed - so you can order a new cell phone with a battery, but not the battery by itself?!?! However, the lab chemical suppliers in country will supply virtually anything to an individual, which has been a life saver as it means that I can make my own 'home-brew' versions of watch cleaning fluids, as I cannot import the pre-prepared commercial versions here (eg 111, rinse 3 etc..) and there are no local suppliers.

[JohnR725]

On 11/14/2023 at 10:43 AM, Jon said:

alum is a bit crap, unless you have lots of time on your hands. the best thing to use if you do need to dissolve screws in Bergeon Visson which takes less than ten minutes when whatever you need dissolving is put in a crucible and heated with a spirit lamp.

probably won't work in 30 seconds but did you know you can heat up the alum? Plus it's really available versus the other stuff which has to be ordered.

 

2 hours ago, AlexeiJ1 said:

old battery

2 hours ago, Waggy said:

anything with a battery (they automatically assume its a lithium battery) is also not allowed

interesting that's not technically correct because otherwise how do the automobile start in your country? The electric automobiles all have lithium batteries but everything else running on petrol or diesel typically would have a lead acid battery. You want to take a guess at what the acid is in a lead acid battery?

https://en.wikipedia.org/wiki/Lead–acid_battery

 

 

[Waggy]

28 minutes ago, JohnR725 said:

interesting that's not technically correct because otherwise how do the automobile start in your country?

Fair enough, I should have been more specific, I should have said "as a private individual" you can't import batteries, as you point out car dealerships and businesses can import them under license as a business. As for the Lithium/lead-acid types that is more a case of knowledge and expediency. It's quicker for the official to just to assume that all batteries are lithium and block the import rather than take the time to read the documentation or learn the difference.

I have had many mechanical watches blocked because on the x-ray the spring barrel 'looks like' a battery, therefore it's lithium and therefore not allowed and returned back to the sender (at my expense). Their decisions are final, like the Terminator: "It can't be bargained with, it can't be reasoned with. It doesn't feel pity! Or remorse or fear and it absolutely will not stop!... ever... until you are dead!"

Edited December 15, 2023 by Waggy

[JohnR725]

I do find it odd that you cannot import just about anything yet?

2 hours ago, Waggy said:

However, the lab chemical suppliers in country will supply virtually anything to an individual,

I do find this interesting that you can go to the chemical supplier and conceivably get just about anything which means you could probably make just about anything if you are really creative individual totally getting around whatever the original ban was?

so in the case of a lead acid battery you don't need the entire battery you just need some of the acid out of the battery.

and yes the video looks promising but he mentions Home Depot and you couldn't possibly have a Home Depot in your country it's filled with stuff that you're not allowed to have at all. Then because the video is so long I'm not going go to the end but I assume he actually does make the sulfuric acid. Which of course you could just go to your chemical supplier and just buy it in the first place and avoid all of this.

 

 

[Waggy]

1 minute ago, JohnR725 said:

you just need some of the acid out of the battery.

I just called a chemical lab supplier and they are happy to deliver to my door in under an hour 4 litres of 96% lab grade sulphuric acid for less than $30 US. But I think I'll stick with the alum

[JohnR725]

49 minutes ago, Waggy said:

I just called a chemical lab supplier and they are happy to deliver to my door in under an hour 4 litres of 96% lab grade sulphuric acid for less than $30 US. But I think I'll stick with the alum

yes the alum has always been my choice for dissolving screws out of things. I would usually make kind of like a double boiler where I have a glass like Pyrex in a pot with some water and heat up the water on the stove. if it's heated up and super concentrated it does seem to work quite fast maybe not fast enough for some people but still it works fast and it's harmless to anything except a course steel.

Versus the acid where not good for things like clothing for instance. Then I like the sound of your lab supply I wonder if you could get nitric acid it's an interesting substance may be some glycerin and make something really fun which I find amusing that you can just order this and it shows up. I wonder what it is they're trying to prevent you from importing but you could go ahead and make it anyway?  then yes if you look at YouTube does all sorts of videos on making interesting things that you probably really don't want to be making at all for a variety of reasons.