computerguy08 wrote on 2020-03-29, 17:03:

aha2940 wrote on 2020-03-29, 15:19:

Just to be clear here: where are you getting these numbers from? I ask because 3000°C is extremely high temperature, it's almost twice the melting point of titanium and platinum, and near the melting point of tungsten (3422°C), which is the highest melting-point metal on Earth, so that can't be correct. Either that, or the C after your 3000 has a different meaning.

I think he meant 300 °C

Now that makes much more sense 😁

_UV_ wrote on 2020-03-29, 10:53:

You need to control temperature to avoid possible damage to weak PCB or component. I have no issues with desoldering ROHS components with old copper iron without regulation, just need proper flux and wet tip.

These two statements are contradictory.

Using a temperature controlled iron for both soldering and desoldering is easier, safer, and usually faster. Most (not all) temperature controlled irons are in the form of a soldering station. Most (not all) irons not in the form of a soldering station are not temperature controlled.

gdjacobs wrote on 2020-03-30, 14:33:

These two statements are contradictory.

They related to different statements. People complain that they can't desolder ROHS era components without temperature control and soldering station. Most of the time this ends by raising temperature to 300+ degrees, so it doesn't matter what to use if you don't understand what you doing.

About temperature control for old (or pretty modern cheap made) weak PCBs that is mandatory if you want to not destroy further. First time soldering in a facility very rarely lead to bad consequences, so even most cheap "goods" can survive it.

_UV_ wrote on 2020-03-30, 17:05:

About temperature control for old (or pretty modern cheap made) weak PCBs that is mandatory if you want to not destroy further. First time soldering in a facility very rarely lead to bad consequences, so even most cheap "goods" can survive it.

Smaller pads and traces with less thermal mass are much less forgiving when raw heat is applied from your line voltage buzz wand. Maybe more expensive board vendors do a better job with bonding of their copper layers and plating to the FR4, but I've never noticed a significant difference in how resilient they are. I'm not the be all in terms of experience, but I've worked the full range from random yumcha boards to expensive on shore custom stuff. IMO, quality is usually evident in other ways like mask details, feature alignment, defect size and rate, etc.

Can you do soldering with a buzz wand? Yes, absolutely. Should you? No, not unless you have no other choice, not if you're dealing with parts that have low thermal tolerances (like pretty well any computer component). An unregulated iron will introduce additional thermal stress compared to a regulated iron, needlessly damaging the piece you're working on. Even the cheap Hakko 936 clones are a good investment in comparison.

My 40W iron is good for burning my hands and random substances, not solder. Ugh.

_UV_ wrote on 2020-03-30, 17:05:

They related to different statements. People complain that they can't desolder ROHS era components without temperature control and soldering station. Most of the time this ends by raising temperature to 300+ degrees, so it doesn't matter what to use if you don't understand what you doing.

About temperature control for old (or pretty modern cheap made) weak PCBs that is mandatory if you want to not destroy further. First time soldering in a facility very rarely lead to bad consequences, so even most cheap "goods" can survive it.

It does matter what you use, and you should know what you're doing (at least the basics).

You can't really desolder/solder anything properly with a cheap iron because it's crap (like in the author's case). It will do the job, but it's risky. No heat regulation means that it will always dump more heat in traces (it runs at maximum power) than a station, it's not beneficial for thin traces, which computer parts have plenty of.

You will lift traces if you aren't moving fast enough. When adding fresh solder, you won't need very high temperatures to desolder. The overall melting point of the solder will get lower and you will be able to desolder/remove parts safely and easily at moderate temps (with a s. station), thus not having to worry if the board will survive the process.