Bismuth, too; lowers melting point. Antimony raises it. Indium is for compatibility with gold plated contacts. Rohs was a big deal starting in the 90s and even us software engineers got the training.
Anyone have any random nerdy facts?
- Thread starter ljwilley
- Start date
Help Support The Rocketry Forum:
- Joined
- Jan 19, 2009
- Messages
- 3,796
- Reaction score
- 1,860
Speaking of Heavy Metal bans, due to the antics of the Tin Whiskers, avionic equipment is exempt from the various regulation, such as CE that you will see on most commercial electronic equipment, We still get to savor the aroma of melted lead solder.
Bunny suites, shoe covers, and caps to keep the clean room clean. No protective equipment for the people. It's not hazardous work.
Fe, because "FeFe pumps iron".
If you solder with tin-lead solder onto gold, the gold is actually soluble in the solder matrix and will move into the solder leaving a gap in the joint. This happens in the solid phase!
For this reason high-reliability soldering requires the gold plating to be removed before soldering.
For this reason high-reliability soldering requires the gold plating to be removed before soldering.
Yes but I’ve seen pictures of the electrical labs, fume hoods and everything.
Backward, I'm afraid. Plumb comes originally from a root that means writing or marking. Lead can do that, so was called plumbum. Pipes were made from it, so the pipes were called the plumbing (well, the Latin equivalent) just as call we call the wiree in the house wiring, applying paint is painting, etc. That's also why the graphite in pencils (graphite clay blend, really) is called a lead, and why graphite used to called plumbago.
Where lots of soldering goes on, there are hoods to get rid of the fumes from the flux, and maybe some solvent fumes. But when the stuff has been soldered and the enclosures complete and the item is ready to go onto the spacecraft, it goes to a whole different place. The satellites I worked on ranged is size from a small car to a half length school bus.
Also, in the lab you're talking about, the people might be waring face protection in case of liquid solder splashing or something, but that's all the PPE you're likely to see, to the best of my knowledge. (When I was a preteen, I unsoldered a wire I didn't know, and failed to check, was under tension beom bending down. The solder melted, the wire sprung, I blinked fast enough and got a blob wrapped around an eyelash.)
A few years ago, I had formal training in soldering for electronics that would go onto military aircraft. There was no PPE, and no more than normal ventilation in the classroom. (There was a strike looming, and engineers were being trained to take strikers place's. If the strike had happened, which it never did, I would not have gone to work, but I went along with all the training anyway. It was fun.)
I would have to, it’d be like building a bunch of egg timers.
No PPE except for safety glasses needed for soldering with SnPb solder. Wash hands after using it, and before eating, which you should be doing anyway. Don't breathe the fumes from the flux. I have done hundreds of thousands of joints over more than 50 years without any impact to my health from lead or flux fumes.
- Joined
- Dec 27, 2014
- Messages
- 9,312
- Reaction score
- 11,105
Some Shakespeare nerdy facts:
Love's Labour's Lost is the only comedy that doesn't end in marriage. In a remarkable (for the rest of the comedies) outbreak of good sense, the women tell the men to wait a year and not rush into anything.
"Nothing" in Shakespeare's era was slang for a woman's nether regions. So "Much Ado About Nothing" is roughly as lewd as the average late-90's rap album.
Love's Labour's Lost is the only comedy that doesn't end in marriage. In a remarkable (for the rest of the comedies) outbreak of good sense, the women tell the men to wait a year and not rush into anything.
"Nothing" in Shakespeare's era was slang for a woman's nether regions. So "Much Ado About Nothing" is roughly as lewd as the average late-90's rap album.
ljwilley
I’m pretty sure it will work…
Shakespeare also invented a lot of words that we use today, and no one realizes it.
Just a few include Alligator, Eyeball, Lonely, Manager, Critic, Addiction, Generous, Majestic, and Gloomy. If the English language didn't have a word for what he wanted to say, he made one up.
some day I like to imagine that Conway West will be considered high and fancy.
what did the conquistadors call Alligators? he could have just stole that?
ljwilley
I’m pretty sure it will work…
I don't know, I just copied some of the words that google said he invented. I only really knew that there was a whole bunch and I knew about lonely and eyeball.
looks like google made that up, or he modified it from Spanish.
Origin
late 16th century: from Spanish el lagarto ‘the lizard’, probably based on Latin lacerta .
I was trying to work out a way to explain how big Avogadro's constant (or number, or whatever it's called nowadays) is to a friend's HS daughter. It's a really, really huge number. It's almost 64,000,000 times larger than the number of meters in a light year (which most people would consider a pretty big number)
Since you can, in principle, have have a mole of anything (it's used for photons with high-power LEDs), I thought, how big would a mole of ping-pong balls be, if they were hexagonal-close-packed into a sphere? (I chose ping-pong balls because they are a standard size and mass, easily visualized, available, and a convenient size for demonstrations)
Answer: Slightly larger than the Moon, at ~3734km diameter (wow!)
I found this amazing and things got a bit out of hand after that.
If you put a mole of ping-pong balls end-to-end, they would stretch more than 2.5 million light years, all the way to the Andromeda galaxy (this blew me away even more than the first result)
That got me thinking the other way around... is there any element in the periodic table such that 1 mole would make a sphere the size of a ping-pong ball?
Why yes, there is: strontium! It's the only one even close, at 39.872mm vs. 40mm for the ball.
(the punch line to this story is that my pal's daughter did not end up taking chemistry as an elective...)
And now a return to our scheduled programming: there the same number of firkins in a butt as there are blobs in a slug (12)
Since you can, in principle, have have a mole of anything (it's used for photons with high-power LEDs), I thought, how big would a mole of ping-pong balls be, if they were hexagonal-close-packed into a sphere? (I chose ping-pong balls because they are a standard size and mass, easily visualized, available, and a convenient size for demonstrations)
Answer: Slightly larger than the Moon, at ~3734km diameter (wow!)
I found this amazing and things got a bit out of hand after that.
If you put a mole of ping-pong balls end-to-end, they would stretch more than 2.5 million light years, all the way to the Andromeda galaxy (this blew me away even more than the first result)
That got me thinking the other way around... is there any element in the periodic table such that 1 mole would make a sphere the size of a ping-pong ball?
Why yes, there is: strontium! It's the only one even close, at 39.872mm vs. 40mm for the ball.
(the punch line to this story is that my pal's daughter did not end up taking chemistry as an elective...)
And now a return to our scheduled programming: there the same number of firkins in a butt as there are blobs in a slug (12)
And the XKCD classic a mole of moles….
It's a big number, and it's used because atoms and molecules are so incredibly tiny.
A colleague told me what he told students who asked "How much (in terms of what can be seen) is a mole?" Answer: for many/most compounds or elements, it's very roughly...a handful. Not a bucketful, not a thimbleful, but a handful.
Ok for 3 dimensions, mathematicians think 24 dimension sphere packing may be most dense.
And now for some extreme nerdliness:
There are 56 hemispherical bumps on the lower section of a Dalek casing (including the mechanized chair used by Davros)
(mentally preparing for guffaws of derisive laughter or a stunned, pitying, silence...)
There are 56 hemispherical bumps on the lower section of a Dalek casing (including the mechanized chair used by Davros)
(mentally preparing for guffaws of derisive laughter or a stunned, pitying, silence...)
Now I'm going to have to count them. I guess I should have suspected that it was a fixed number and was used consistently but I never really thought about that before....
- Joined
- Aug 25, 2019
- Messages
- 6,780
- Reaction score
- 5,196
Old-fashioned swear words and their sources:
Gadzooks! = God's hooks!
Zounds! = God's wounds!
Bejabbers! = By Jesus!
Strewth! = God's Truth (I've heard Australians use this one in the present day)
Ods bodkins (or Odds Bodkins) = God's little body
Snails! = God's nails!
Gadzooks! = God's hooks!
Zounds! = God's wounds!
Bejabbers! = By Jesus!
Strewth! = God's Truth (I've heard Australians use this one in the present day)
Ods bodkins (or Odds Bodkins) = God's little body
Snails! = God's nails!
God is apparently the main character of old timey swearing.
- Joined
- Aug 25, 2019
- Messages
- 6,780
- Reaction score
- 5,196
Gosh, I always thought that one was a contraction from "[it] is truth".
Similar threads
