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I am by no means a beginner but at time have such a hard time desoldering something. I was working on a TIPM last night to replace a relay. My process was add a little leaded solder to the unleaded, wick it up with my hakko iron, then use hot air to get the through hole solder melted. my hot air is just one of those cheap ones but I had it set on 500 and max air but still seems like it took forever to release. The board is pretty thick and looks like the via's had quite a bit of solder in them. Is it time to give up the cheap hot air or any other tricks to remove these relays. Put pressure on the relay to remove it scares me that a trace will tear. Thanks Michael

There is the low melting point "solder" alloy intended to ease rework.
It melts around half the temperature of a lead free solder, lower than leaded solder even.  It stays liquid a long time
and when it mixes with lead free or leaded solder it forms a lower melting point alloy of that solder, too.

You melt a big blob of it over the tops of the pads for the component to be removed which is easy due to the low melting point.
Then it mixes with the existing solder, melting it , too.  Leaving a big liquid puddle of solder that will stay liquid while you remove
the part or work on the next pin / pad going around to each with the hot air / iron until they're all liquid.  Then just pull it out.

Then you clean up all residue of this solder since it isn't suitable to be left on with the new component, so after you remove the
contaminated solder you add fresh flux / solder to install the replacement.

Other than that...

1: Good suction solder removal tool with lots of flux?  May or may not help.
2: Get a board pre-heater so you can heat up the whole board or an area of it so when you go to remove the part with hot air or an iron tip you only have to add another 20C or whatever to the part temperature to get it to reflow easily.
3: Use a fixture like some people use for rework that positions the hot air wand hands free over the component leads to be removed... then you can use either a soldering tip or suction tool or second hot air wand to work on the already hot leads to add more heat to reflow them.  Basically acting as a localized pre-heater for the component area and allowing focused rework with a second tool.

Chip-quick (spelling?) is one company / brand of the rework alloy.
Others exist, SRA solder in the US, has another brand, et. al.
They're indium based just for rework / removal.

Yeah I tried the low melt on the first relay, while I had the iron set lower at 350. When I pulled that one out it still had quite a bit of solder left on the legs through the holes. When i bumped up the heat on both iron and hot air it work better but still took some work to get it out of hole, wicked as much as I could and the hot air. I do have my hakko air solder sucker but it is stopped up right now and needed to unclog it.


--- Quote from: evb149 on June 23, 2021, 07:38:05 pm ---Chip-quick (spelling?) is one company / brand of the rework alloy.
Others exist, SRA solder in the US, has another brand, et. al.
They're indium based just for rework / removal.

--- End quote ---

Chip-quik.  The alloys vary (there's ROHS and leaded) and contain indium and bismuth, as well as silver, tin, lead and copper in varying amounts.  You can get ever more expensive alloys that melt below 100C, but that's not necessary.

Just be careful with alternatives--there is an Indium brand of solder that is just regular solder. 


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