Science desk
< May 16	<< Apr \| May \| Jun >>	May 18 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

May 17[edit]

WW2 bomb disposal[edit]

Resolved

A WW2 bomb was dealt with in Birmingham this week. Any idea what the device is that they've attached to bomb in this picture? http://i2.birminghammail.co.uk/incoming/article13042590.ece/ALTERNATES/s615b/bomb.jpg

Thanks! --TrogWoolley (talk) 09:54, 17 May 2017 (UTC)[reply]

An article says it is a clockstopper. The idea is to create a magnetic field that makes the gears of a detonation timer tilt and twist so the clock stops ticking. Search the web for "magnetic clockstopper", "bomb disposal clockstopper" and such. 91.155.195.247 (talk) 10:47, 17 May 2017 (UTC)[reply]

Thanks! I might not have read that article - there have been quite a few and keeping up with them has been difficult. --TrogWoolley (talk) 12:48, 17 May 2017 (UTC)[reply]

Hmm. Anyone want to add something about this device to the bomb disposal article? --76.71.6.254 (talk) 21:51, 17 May 2017 (UTC)[reply]

Absolutely, when we find a volunteer to hunt down a reliable source. Tag, you are it, haha! 91.155.195.247 (talk) 15:52, 19 May 2017 (UTC)[reply]

Lathe coolant[edit]

What is the composition of lathe coolant? If it gets on clothes, do they have to be dry-cleaned, or will ordinary washing get it out? 2601:646:8E01:7E0B:81C2:C457:D19E:177C (talk) 11:49, 17 May 2017 (UTC)[reply]

They're oil emulsions, in water. So they're fairly easy to launder.

The HSE guidance is always good, but they are thinking mostly of industrial scales. http://www.hse.gov.uk/pubns/indg365.pdf Andy Dingley (talk) 12:21, 17 May 2017 (UTC)[reply]

Here is an MSDS for "machine coolant". It lists ingredients and known hazards. --Jayron 32 12:29, 17 May 2017 (UTC)[reply]

The MSDS doesn't really tell the story with machining coolants. There are several hazards, mostly chronic. It's a classic case study for occupational health workers.

Apart from the hazards listed on their linked page [1], of *amines and (very rare) cobalt, the worst hazard used to be mineral oils, and nowadays the worst acute hazard is bacterial. That MSDS doesn't mention either.

Mineral oils are a problem for skin absorption. They can cause skin dermatitis, they also manifest as bladder or scrotal cancer. Classic chronic exposure symptoms, these are due to long exposure and where the toxins remain concentrated for longest. This is largely avoided by regular laundry and provision of clean overalls (a requirement in factories), also plentiful drinking water and easy access to toilet breaks. Bladder cancers have been noted as worse in some sites, simply because toilets were a long way from the production floor, thus discouraging either their use or adequate drinking. Also mineral oils are mostly gone from today's cutting fluids.

Mineral oil in cutting fluid these days is mostly a contaminant, leaked in from lubricating oil.

The worst hazard, and the acute one, is bacterial contamination of the cutting fluid tank. This can show symptoms in a couple of days, if bad, especially for new workers who aren't inured to it. Keep the tanks clean and covered, use a bactericide (or UV light), check for contamination (oil too) and clean thoroughly if found. Andy Dingley (talk) 12:42, 17 May 2017 (UTC)[reply]

Do you have some references for that so we can all read about it? --Jayron 32 13:03, 17 May 2017 (UTC)[reply]

There's tons of this stuff out there - just search on whatever your particular specialisation might be. It's also enshrined (the provision of laundered overalls) in most industrial Occup Health legislation for developed countries. Here's one of the classic papers that established legislation in the UK, just because I happened to have this one handy. As well as machine tool operators, some textile trades had a similar problem with mineral oil aerosols.

Carcinoma of the Skin in Machine Tool Setters J. G. Fife British Journal of Industrial Medicine Vol. 19, No. 2 (Apr., 1962), pp. 123-125 http://www.jstor.org/stable/27721729

Andy Dingley (talk) 13:13, 17 May 2017 (UTC)[reply]

The toilet stuff is from some of the British shadow factories during WWII. These were new factories, built with the latest modern conveniences and efficiencies (even though some were hidden underground). Workers, often newly recruited youngsters, worked on identical machines doing identical tasks, but in different factories. When investigated decades later (and the bladder cancer link was recognised), it was found that the only differences could be as small as better toilet facilities. Andy Dingley (talk) 13:20, 17 May 2017 (UTC)[reply]

Thanks, all! So, the bottom line is, I won't need to have my Levis dry-cleaned after all? 2601:646:8E01:7E0B:FCD4:1102:5887:1AF8 (talk) 09:17, 18 May 2017 (UTC)[reply]

Ordinary washing will solve this like any other dirt. 95% will be washed out and the remaining 5% will be evenly spread over all textiles in the washingmachine. To add the illusion of tidy cleanness some chemicals for bleaching and for perfume are evenly spread over all textiles aswell. --Kharon (talk) 15:38, 18 May 2017 (UTC)[reply]

You should get far more than 95% removed. Andy Dingley (talk) 17:30, 18 May 2017 (UTC)[reply]

OK, lets say 97-98%. And if you wash hot enough it even kills most microbes. --Kharon (talk) 12:11, 21 May 2017 (UTC)[reply]