31–40 of 60 posts
I knew I was bad at soldering, I didn't know I was THAT bad. I need to take a course.
Yeah. Damn. I hope nobody at NASA looks at some of the repairs I've had to make on my riding mower. I blame the work angles of some of those jobs...
No harm, no foul is what I mean to say, haha.
Earlier quoted context omitted.
I've been told that in areas where lots of prototyping isgoing on, there is lots of scope for manual rework. (a pcb design only 95% correct needs modifications to figure out the right design)
We had a board where somehow the footprint of an 8 pin SOIC got flipped in the layout. One engineer was able to desolder it, flip it, and solder it on using wires so that it floated about 1-2 cm above the board upside down. I was impressed ;-)
Was curious what their treatment was going to be regarding tin whiskers. Not much there (of course this is point in time inspection so it kind of makes sense), but a quick google revealed quite a bit of study: https://nepp.nasa.gov/whisker/ I thought they were just one of those low probability items until a Sunday morning when I was running live audio for a church service. Singer was mid verse and BOOOOM! Huge boomin…
Did you read their specs?
There's a small part about whiskers that already convey enough meaning:
> UNACCEPTABLE WHISKER
> A whisker is a slender needle-shaped metallic growth between a conductor and a land. Typically the result of mechanical stresses in high tin compounds, it is a reliability concern."
Was curious what their treatment was going to be regarding tin whiskers. Not much there (of course this is point in time inspection so it kind of makes sense), but a quick google revealed quite a bit of study: https://nepp.nasa.gov/whisker/ I thought they were just one of those low probability items until a Sunday morning when I was running live audio for a church service. Singer was mid verse and BOOOOM! Huge boomin…
Conformal coat really is the saving grace for tin whiskers. It's not perfect, a whisker can push through sometimes but then the whisker has to push back through the conformal coat again which is much harder.
Was curious what their treatment was going to be regarding tin whiskers. Not much there (of course this is point in time inspection so it kind of makes sense), but a quick google revealed quite a bit of study: https://nepp.nasa.gov/whisker/ I thought they were just one of those low probability items until a Sunday morning when I was running live audio for a church service. Singer was mid verse and BOOOOM! Huge boomin…
> Was curious what their treatment was going to be regarding tin whiskers. Not much there (of course this is point in time inspection so it kind of makes sense) Did you read their specs? There's a small part about whiskers that already convey enough meaning: > UNACCEPTABLE WHISKER > A whisker is a slender needle-shaped metallic growth between a conductor and a land. Typically the result of mechanical stresses in high…
'Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that."'
It doesn't add anything to the discussion. And in this case it was very clear that the OP read the article and just missed that part.
Your comment would have been just as informative and less snarky if it was simply:
There's a small part about whiskers that already convey enough meaning:
> UNACCEPTABLE WHISKER
> A whisker is a slender needle-shaped metallic growth between a conductor and a land. Typically the result of mechanical stresses in high tin compounds, it is a reliability concern."
Earlier quoted context omitted.
> Was curious what their treatment was going to be regarding tin whiskers. Not much there (of course this is point in time inspection so it kind of makes sense) Did you read their specs? There's a small part about whiskers that already convey enough meaning: > UNACCEPTABLE WHISKER > A whisker is a slender needle-shaped metallic growth between a conductor and a land. Typically the result of mechanical stresses in high…
From the HN guidelines: 'Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that."' It doesn't add anything to the discussion. And in this case it was very clear that the OP read the article and just missed that part. Your comment would have been just as informative and less snarky if it was simply: There's a small part…
> 'Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that."'
Not an article, but specs. You read specs carefully, you don't skim, especially to write long paragraphs about your personal experience
> And in this case it was very clear that the OP read the article
I disagree. Not read, skimmed at best.
> and just missed that part.
I agree: the most important part was indeed skipped.
Was curious what their treatment was going to be regarding tin whiskers. Not much there (of course this is point in time inspection so it kind of makes sense), but a quick google revealed quite a bit of study: https://nepp.nasa.gov/whisker/ I thought they were just one of those low probability items until a Sunday morning when I was running live audio for a church service. Singer was mid verse and BOOOOM! Huge boomin…
NASA and aviation in general are later adopters of lead-free. It definitely wouldn't have been reflected in older standards.
I want to share some of my thought on soldering: The best way to understand soldering is to think primarily in terms of surface tension or capillary action and intermetallic compounds. You set it up correctly and apply heat so that fluid dynamics can finish the job. The atoms get to where they are supposed to be. There is no technique or dexterity required with the soldering iron itself. I would also recommend that you think of solder wire as a 2in1. The flux core in the solder wire is helpful, but not the endgame. Use extra flux from a flux pen or flux bottle that is compatible with the flux core in the solder wire. For example: You can put a glob of solder on the tip of your soldering iron and just bring it in to the surface or joint. If you have pre-applied flux on a clean surface or joint, the liquid solder will wick off the soldering iron and onto the surface by itself. Perfect every time. (Surface tension, capillary action.)
For manual hand soldering, the flux management is the only complicated part. What flux to use? Do you have to clean it? How to clean it? Saponifiers, or IPA good enough? Compatible with the flux in the solder wire? You must be sure to reach the activation temperature of all the flux on the board or it can corrode metals over time. "No Clean" fluxes are really hard to clean without special saponifiers, I would avoid these fluxes. Is the flux residue on the board still inert after it gets wet by accident or at high humidity? There are also problems with high frequency circuits and No Cleans. Water soluble fluxes require excellent process control. Even tiny defects in the PCB can cause failures if you use water soluble flux. Read the datasheets and recommendations from the flux manufacturer.
Some fluxes are more easy going: For you Americans I would recommend Kester 186 Flux-Pen and Kester 285 Sn63Pb37 RMA Flux-Cored Wire. Do not use more flux than necessary, do not make a mess. Use eye protection for this flux from Kester!
Soldering gets even more interesting with gold embrittlement (gold plating thickness and migration to the center of the IMC), tin whiskers, silver whiskers, etc. There is much more to all of this if you want really high reliability. I went deep down this rabbit hole once. Not a professional soldering guy. Just obsessive compulsive about high reliability design. This is enough text for a post on HN :)
I knew I was bad at soldering, I didn't know I was THAT bad. I need to take a course.
>course I used to work with a developer whose second job was with HP back in the 70s. He was hired as a technician building lab equipment and had to be prequalified from an educational and trades/skill perspective to be hired. Then they taught him to solder again. Their standards were apparently incredibly high.