Wikipedia:Reference desk/Archives/Science/2019 October 30

= October 30 =

Cadmium fumes from molten solder
When heated above 321 °C cadmium melts and cadmium oxide fumes present a hazard to health. My question is, if cadmium is part of a solder alloy which is heated to, say, 220 °C and has a melting temperature far below this, would it also be expected to produce significant cadmium oxide fumes? --88.106.182.98 (talk) 08:50, 30 October 2019 (UTC)
 * "significant" is a tricky word to interpret... For professional use, there will be norms, fume hood would be compulsory, etc. For unprofessional use, really dangerous device would be forbidden in developed countries, and if some caution is required it would be mentioned. You may find this of help. In any case, if you are worried just use a fan blowing fumes away (this will work for any fume) Gem fr (talk) 11:21, 30 October 2019 (UTC)


 * What sort of solder involves both cadmium and a melting point so low? That's the lead-tin soft solder range and they just don't include cadmium – and for a long time now, almost nothing includes cadmium.
 * Now, silver solder used to contain significant cadmium, but that has been removed for a couple of decades now. My own workshop is full of the old stuff, snapped up cheaply when it changed over! But the temperature there is much higher. The only commonplace solders nowadays which contain cadmium are those sold for DIY or home repair of aluminium (or zinc) alloys.
 * There are a couple of hazards from silver solder. Fumes from cadmium metal in molten solder aren't really a big one. Firstly, silver soldering is done with a gas torch, which is much hotter itself than the melting point of the solder. If the flame is somewhat oxidising (rather than neutral), then cadmium may be oxidised on the surface (it will do so preferentially to the less reactive silver). This is now cadmium oxide, and (as always for metals, especially beryllium) that's a much less mechanically stable material than the metal. The oxide may be brushed off as a powder (not fumes) and the oxide can be absorbed by the body quite easily.  Secondly, fluxes for hard soldering and brazing often include sodium fluoride and the fumes from heating that can include oxygen difluorides, which are pretty nasty in themselves. Andy Dingley (talk) 11:47, 30 October 2019 (UTC)
 * Solder alloys include a sortable table, some of them with Cd are indeed very low MP Gem fr (talk) 14:49, 30 October 2019 (UTC)
 * Those are alloys like Woods metal, which are barely solders but are instead specifically-formulated low-melting point materials for other uses. Nor are they particularly common. Another group are the cryogenic solders, which aren't seen outside a physics lab. Nor does anyone use Cerrobend as a cryo solder since the 1950s!  We have proper equipment now, even in my day, we're not sealing glassware with sealing wax either.
 * The only one which might turn up in a "household" context would be the easy-flux solders for aluminium or zinc, like Lumiweld. Andy Dingley (talk) 17:42, 30 October 2019 (UTC)
 * Low temperature solders like LowMelt and Chip Quik are used for desoldering sensitive electronics components and there are alloys to do this which contains cadmium (and others which don't). The soldering iron temperature for these operations would be set to about 210 C. 88.106.182.98 (talk) 00:29, 31 October 2019 (UTC)
 * Looks like the Solder alloys article need some fixing, then. I lack expertise to do that, if you have, please proceed. Gem fr (talk) 04:42, 31 October 2019 (UTC)

When eggs go bad
A hard-boiled chicken egg occasionally has a small area of brown liquid inside, usually in the white of the egg. What is this ? SinisterLefty (talk) 19:01, 30 October 2019 (UTC)
 * Incubating the egg might reveal it to be fertile, in which case you can serve it as Balut (food). DroneB (talk) 19:23, 30 October 2019 (UTC)
 * Does that still work once the egg is cracked open? ←Baseball Bugs What's up, Doc? carrots→ 01:26, 31 October 2019 (UTC)
 * Yes, just duck tape over the quack. DroneB (talk) 14:04, 31 October 2019 (UTC)
 * : Did you know this would actually work? There was a video of someone incubating a chick all the way to ""hatching"" in a wine glass without the shell. Forget where tho. Also nice pun --MoonyTheDwarf (Braden N.) (talk) 21:08, 31 October 2019 (UTC)


 * A company also took advantage of this frequent misspelling: . SinisterLefty (talk) 22:17, 31 October 2019 (UTC)


 * Some say duck tape is the original (made from duck canvas) and duct tape a product of folk etymology. —Tamfang (talk) 05:47, 2 November 2019 (UTC)


 * Does anyone have good sources for this process of taping a crack? I am trying to develop Draft:Egg repair. Graeme Bartlett (talk) 21:13, 31 October 2019 (UTC)
 * Video is described here: DMacks (talk) 21:25, 31 October 2019 (UTC)
 * Growing chick embryos in vitro. A few survive up to 15 days, see pictures. DroneB (talk) 22:18, 31 October 2019 (UTC)
 * This is unlikely if it's a typical commercial egg. Egg-laying hens are not kept around males; the eggs are unfertilized. The chance is slightly higher if the egg is from a free-range farm where a rooster could possibly get to the hens, but still not very high. Egg farmers don't want non-castrated roosters around layer hens because they can be aggressive, and multiple roosters will fight over the hens. --47.146.63.87 (talk) 23:40, 31 October 2019 (UTC)


 * These are just basic eggs, not free-range or anything fancy. SinisterLefty (talk) 02:31, 1 November 2019 (UTC)

One other bit of info, the last bad egg did not float in water before it was hard-boiled. (I do the float test to find rotten eggs and discard them, prior to cooking.) SinisterLefty (talk) 07:36, 31 October 2019 (UTC)


 * How often do you get eggs that are actually bad? I don't recall ever getting one that was actually smelly or poor eating. Even leaving them sitting for a couple of weeks (this is in North America, so they're in the fridge) doesn't result in problems. I only bring is up because you may be throwing out eggs that are perfectly edible. Matt Deres (talk) 15:29, 4 November 2019 (UTC)


 * I'd guess it's about 1% of the time. But always the same area of brown liquid (even after hard boiling), in the white of the egg, on one side. I'd have to guess that those eggs were fertilized, but never developed very far. I would have expected the yolk to be affected, though. SinisterLefty (talk) 08:11, 6 November 2019 (UTC)
 * Have you asked your grocer about this? ←Baseball Bugs What's up, Doc? carrots→ 08:22, 6 November 2019 (UTC)


 * No. I shop at places like Walmart. I consider myself lucky if the people working there know that eggs come from chickens. SinisterLefty (talk) 08:27, 6 November 2019 (UTC)