Discussion in 'Amateur Radio News' started by KB7TBT, Aug 10, 2019.
Electronics - Tapping and repairing PCB traces.
PLEASE --DO NOT-- blow dust made from FR4!!!!
The 'green PCB' stuff is of FR4 composition.
Inhaling FR4 dust exposes your lungs to many dangerous compounds: fiberglass; resins, etc. Go look up the typical composition of 'fire retardant 4'. Having the microparticles around like dander is an invitation to irritation at best, cancer at worst!
Solder mask is also a sealant for FR4. It was not meant to be scrapped off.
IF you MUST remove the coatings to get at the copper, then use a moist paper towel to remove the dust. Also, if the board is multi layer, well, good luck! The substrate is part of the circuit as an embedded (in) dielectric. Insulating to DC is loading to RF.
"The production and handling of fiberglass can produce fibrous glass dust that is considered by the National Toxicology Program to be “reasonably anticipated as a human carcinogen” if it is inadvertently inhaled, although it has not been directly linked with mesothelioma..."
Usually soldering to a trace is a last resort. Much easier to run another wire between the closest pins or parts and route over the trace. Unless of course there is an overiding factor like too much cross talk, or inductance if the trace is actually half of a controlled impedance transmission line.
Mask and safety glasses.
would be way better and cleaner if you use soldering paste this way you don't get spikes on the solder, simply use alcohol to clean the paste after you're done
Soldering paste yields an even flow of heat, but residual flux can enhance growth of dendritic shorts, that destroy PCB's. Tough to get it all off.
For those who are interested, the 'PCB shorting' problem has a design-based solution. To wit:
It helps to have some to drink also.
I use Everclear multi purpose alcohol.
LOL, share the love my friend
fyi i used to work at a pcb manufacturing company, i should know what's best, i'll say it again, use alcohol to clean the residue
and no it does not cause any shorts, solder paste is not conductive people, pun totally intended
Please read carefully:
No one said solder flux was CONDUCTIVE.
It DOES enhance dendritic growth. Solder flux , if not properly removed, will PROPAGATE DENDRITES and these SHORT OUT TRACES.
The dendrites are CONDUCTIVE. The solder paste IS NOT. OK?
If you WORKED at a PCB company--as opposed to SOLVED the problems of such companies--then why don't you know that?
Iron too big, solder too big, shaky hands...