2:29 this was extremely helpful, the systematic representation was provided there with an explanation of effect of temperature on pendulum, thanks for putting it in this manner.

I had a nasty boo boo today I was standing up a liquid mercury clock a smaller one and as I was bringing it up I found a patch of oil I didnt know was there and it slipped and fell forward thankfully I was able to repair what went wrong and the mercury stayed contained in that moment I really realized how careful you have to be with these things

That's a monster of a pinwheel. I enjoy looking at the mercury pendulums but they are rare and would require more attention during setup. Very nice clock, thanks for the video.

@MinnesotaClocksandWatches

3 жыл бұрын

Thank you. It is an interesting movement and somewhat different than my other pinwheels. Yes, mercury is very cool, but definitely has its downsides, and requires care to not cause big problems.

Thanks for the video. I think it would be a good idea to also wear gloves when working with mercury. I don't have any mercury clocks, if I did I'd put a plastic tray at the bottom of the clock - just in case. Not very pretty but extra insurance. Usually if I want accuracy in a pendulum I build John Harrison's grid, I even installed one on the three story E. Howard tower clock I maintain but I know mercury pendulums are popular with collectors though.

@MinnesotaClocksandWatches

2 жыл бұрын

I would argue that as metallic mercury isn't especially well absorbed by skin, you would want to weight loss of dexterity and risk of spill due to wearing gloves. There are definitely other ways to achieve temperature compensation, but for historic pieces where originality trumps precision timekeeping, my preference would be to replace something that looks like mercury if that is a concern rather than remaking a pendulum. For a project clock - absolutely - Invar and other mechanisms are likely the equal or better to mercury.

I bought an antique mercury clock and the vile is leaking and glass is broken in the clock, is it possible to buy new glass and seal the mercury in the clock? Or would it still be possible to cause harm, thank u!

@MinnesotaClocksandWatches

Жыл бұрын

Uncontained mercury is a concern. If mercury has spilled, you should follow the EPA spill directions to clean it up or have someone help you clean it up. Commercially made mercury spill kits are available. I don't know of any suppliers of new mercury vials as they come in many sizes, but you may find an artisan glass guild where someone might be able to blow you a vial that is the right size and shape.

Does mercury have a substitute as unable to source in uk Thank you

@MinnesotaClocksandWatches

Жыл бұрын

I don't know of any complete equivalent to mercury that would perform the same compensation function, however the clock will run fine with any kind of heavy weight in the pendulum - steel shot, lead, etc.

Mercury wasn’t so hazardous back in high school science class we used it all the time in the 70s and before. And I’m still here.😁

@MinnesotaClocksandWatches

2 жыл бұрын

In the modern era, any recommendation to take on any kind of risk is perilous. I agree with you that metallic mercury that is contained is not a high risk, however that risk increases significantly if mercury is spilled. Will it kill you? Probably not. Will cleaning it up be an expensive pain in the butt? Yes. Keep it in your clock and it's all good.

@willf5768

2 жыл бұрын

@@MinnesotaClocksandWatches well it’s a good thing you didn’t see what we used to do with it in high school in in science class the safety Sally’s of today would have had a hemorrhage.😁

Why not wear gloves when transferring the mercury from the jar to the vial?

@MinnesotaClocksandWatches

2 жыл бұрын

The danger of metallic mercury isn't skin absorption, it's vapor inhalation. A simple hand washing is adequate to remove any mercury contamination from skin. The practical concern is mercury droplets from a spill that get tracked around over a large surface area and then evaporate and cause a long-term vapor exposure risk.

So why did they use mercury and not just plain o'l tap water?

@MinnesotaClocksandWatches

Жыл бұрын

The volumetric temperature expansion coefficient of water (.00021/ºC) and mercury (.00018/ºC) are reasonably similar so in theory water would have some compensating effect. The challenges are keeping the water from evaporating as it has a much higher vapor pressure than mercury, which would require a lot better seal - we're trying to have a seal good for decades rather than days - and more than that, mercury's density (weight) made it more practical to move the center of mass up and down with a reasonable sized pendulum. It would take considerably more water than mercury to compensate for a typical heavy, large regulator pendulum. Those are my educated guesses, anyway. It would be an interesting experiment to see how much water you would need to have effective compensation.

@Zane-It

Жыл бұрын

@@MinnesotaClocksandWatches that's a cool video Idea. I also have to ask though doesn't mercury vaporize?

@MinnesotaClocksandWatches

Жыл бұрын

Mercury does evaporate, but it does so far more slowly than water. A drop of water will be gone in minutes or hours depending on the temperature and humidity. Mercury takes far, far longer. Also, mercury oxidizes and forms a skin that further reduces evaporation.

@Zane-It

Жыл бұрын

@@MinnesotaClocksandWatches plus water will damage the wood as it evaporates. If the lid is sealed tight enough it could theoretically contain the mercury fumes long enough for them to condense back into liquid form.