Soldering tip of the day

[puretube]

After R.G.`s coming out,
I blushingly have to admit, that I`ve been guilty of doing the "Rorschach"-solderblot-method for decades, too... 

[tranceracer]

Great thread!  I just scored the guts of an old RCA CRT TV and being a soldering braid person myself, needed a good fast technique to get the components off the board! 

Anyone have any good suggestions for a flyback?   

[aron]

The whacking tip is an old standby I have seen people use. I do it if I don't have all of my tools around me.

[gez]

Call me slow, but is this tip for soldering (neatening up the joint) or desoldering (removing the whole lot)??  Isn't very clear from all the replies...

[Lurco]

de-

[R.G.]

Great thread!  I just scored the guts of an old RCA CRT TV and being a soldering braid person myself, needed a good fast technique to get the components off the board! 

There's a much better way if you just want to remove them. Chuck one edge of the board in a vise so you have access to both solder side and component side. Take a propane torch ( ) and put the widest spreader tip on it you have. Get it burning and gently, from a distance, wave the torch's hot-gasses plume on the back of the board, pulling gently on the components from the parts side. When the solder lets go, the part will pop right out.

This used to be even easier. Before clinching part leads on the board, you could just suspend the board over a bucket of water and wave the torch over the board. Components would drop out the bottom side into the cooling water. Clinched leads mean that you have to pull hard enough to un-bend the leads.

The solder-whack trick is for empty holes, not full ones. When the lead is still in the hole, it will retain a fair amount of the solder. Get the lead out first.

Note that In removing parts from boards, you have to decide up front whether you have to end up with a good part, a good board, or if you really have to end up with both part and board salvaged. It is much, much easier if you can trash the board to get the part out or to trash the part to save the board.

[trixdropd]

very cool info R.G..

Thank you very much!!

Jeremy

[Paul Marossy]

I've used the melt and shake method for years, yes it can be dangerous but when you get used to it it's very easy and any splashes that do solidify usually just come off with a finger nail.

I always watch for it (the solder) solidifying. You can actually see it doing this on bigger solder connections, like on a wire on the lug of a 1/4" jack. If I don't watch it and blow on it gently until its solidified, that wire wants to pull right out of there and then I have to do it again. Sometimes it can be a few seconds before it solidifies.

I was under the impression you should not blow on solder to solidify it quickly as this can cause dry joints or brittle joints.

Neither of those things have ever happened to me in the 7 years I have been building DIY effects and/or tube amps. I blow on it lightly, I don't try to blow on it like I'm an air compressor or something. 

[BDuguay]

I discovered this technique myself here at work. We have a bunch of Video test cables with the small SMA connectors on each end. The center pin can either be solder or crimped on. I swear some of my colleagues use these things as skipping ropes because they're constantly bringing them to me, in peices, needing to be fixed.
Often what happens is the dialectric breaks off clean where it enters the center pin. When they're crimped, they're usually chucked however I've gone so far as to drill them out and re-use them. I'm hopelessly addicted to trying to save the planet single handedly.
One time though, I was handed a soldered pin that had broken off and thought to myself 'how am I going to empty the remains from the hole in this pin?' 'I must save the planet!'
I grabbed the pin with my tiny forceps, heated the pin with my soldering iron, then slammed it down on my bench and whoosh!, the hole was clear and the pin was ready to re-use and continue it's service as a test cable/double dutch mechanism.
B.

[Michael Weidenauer]

I've always done the "melt'n'drop" procedure RG pointed out... also for excesses of solder or joined traces... everytime thinking "good electro-gurus wouldn't apporve..." but now I know they do!!! supercool!!

It's the same way with me - I'm using this method for years for quick desoldering. Works great with bad flowing lead-free solder, too.
Never had problems with solder getting into my eyes (just bang the thing down, away from you), though I have burned my knees with hot solder sometimes (only a problem in the summer season, ordinary jeans are protection eough).

Michael

[soggybag]

If you are holding a PCB about two inches above your work table and melt the solder in the hole, then -*whack*- the board down sharply on the table surface, the liquid solder's momentum keeps it moving when the PCB stops and the ...solder...drops...out...of...the...hole... into a little splat on the table. Clean hole. It's hard to believe how easy it is until you've done it.

This really works, great tip. Nothing better when you accidentally get some solder in a plated hole. 

[kristoffereide]

I love tips and tricks! The bucket-trick worked perfectly for my old boards!!!

I saw a program on the discovery channel a couple of months ago, where they used something called flow-soldering to solder a guitar amp. I got me thinking;
solder only sticks to metal and not the pcb itself? If this is so, would it be possible to just gently dip the solderside of the circuitboard in molten solder??? With all the parts mounted.

I know it would require a lot of solder, and a lot of heat, but would it work or am I overly ambitious, hahha?

[jefe]

I love tips and tricks! The bucket-trick worked perfectly for my old boards!!!

I saw a program on the discovery channel a couple of months ago, where they used something called flow-soldering to solder a guitar amp. I got me thinking;
solder only sticks to metal and not the pcb itself? If this is so, would it be possible to just gently dip the solderside of the circuitboard in molten solder??? With all the parts mounted.

I know it would require a lot of solder, and a lot of heat, but would it work or am I overly ambitious, hahha?

Aka "wave soldering" in the commercial world (I think). Yeah, that would require a lot of solder... lol...

[R.G.]

Solder pots were the way soldering was done before wave soldering.

DANGER! DANGER! DANGER!
Solder pots are incredibly dangerous to work with! You are literally taking your vision and health in your own hands.

A solder pot is a heated vessel of molten solder. Boards used to be stuffed with parts, painted with liquid flux on the copper/leads side, and then laid gently on the freshly-skimmed surface of the solder pot. The solder made joints where the PCB and leads were.

THE DANGER OF A WHOLE POT OF MOLTEN METAL SPILLING OR EXPLODING IF YOU PUT ANYTHING EVEN SLIGHTLY DAMP INTO IT IS HUGE!

Wave soldering was the next step, where liquid molten solder was actually pumped up through a slot so there was a slight wave of solder above the level of the other molten solder. It's modestly safer in that it's in a bolted-down machine with guards.

I've seen solder pots that were just electric cooking skillets with the thermostats broken. Incredibly stupid and dangerous.

[ayayay!]

Anyone have any good suggestions for a flyback?   

Yeah, a welding mask and rubber gloves! 

Dude, DON'T mess with those things.  I think you're funny comment above states that you already know better, but I still shudder to think... 

[kristoffereide]

hahaha, I never meant to try it out bigscale! I don't have either the wish to make a tin-Midas of myself nor lose my hands and arms  Cause I'm so clumsy I'd either fall in, or tip the pot over myself. But technically it'd work right? Would it work in small-scale? A 2" diameter pot and dip f.ex a 1x1" perf in there? I'd rather solder it the old fashion way, I'm just curious

[trixdropd]

hahaha, I never meant to try it out bigscale! I don't have either the wish to make a tin-Midas of myself nor lose my hands and arms  Cause I'm so clumsy I'd either fall in, or tip the pot over myself. But technically it'd work right? Would it work in small-scale? A 2" diameter pot and dip f.ex a 1x1" perf in there? I'd rather solder it the old fashion way, I'm just curious

I'd expect a ton of solder bridges, at least on perfboard.

[frank_p]

DANGER! DANGER! DANGER!
Solder pots are incredibly dangerous to work with! You are literally taking your vision and health in your own hands.

An other idea that was mentioned (instead of wave solder):

I came up with my own tinning process. It's common in the industry - or used to be, before solder mask was common - to roller-tin PCBs.

Did you ever spend any time in the back of a snow-ski rental shop? They have a machine there for waxing skis. It's a pot of molten wax with a large diameter metal wheel which spins slowly above it, dipping the wheel into the wax and rotating above the wax. The wheel gets coated in molten wax - and you just pass the wax-ready ski over the top of the wheel as it rotates. A nice thin coat of wax is deposited onto the ski.

So it is with roller tinning. A metal roller is rotated into and out of a pan of molten solder. The wheel is tinned steel, and carries a thin layer of molten solder on it as it rotates out of the pan. To tin a PCB, you take the freshly etched PCB, paint it with flux, pre-heat, and then just pass the copper side over the top surface of the wheel as it rotates. A thin layer of solder is deposited only on the copper.

The hot vat of solder is dangerous, but I came up with a simpler, smaller process. You go to a plumbing store and get a 6-8" length of heavy brass pipe. At home, you arrange a long handle on the pipe from the middle so the pipe looks like the cross of a "T". You heat the pipe by blowing the flame of a propane torch through the middle. For first prep, sandpaper the outside of the pipe, paint on flux, then heat and tin the pipe with solder.

To use it, you lay your PCB down, copper side up, and paint with flux. Then you heat the brass pipe and load it up with solder, maybe laying a few niblets of solder onto the PCB to replenish. When the pipe is good and hot, well above solder melting, you squeegee the pipe across the PCB copper side. The pipe is coated in melted solder and transfers a thin layer to the PCB. With practice, it's easy and fast, and you don't have to run a solder pot.

I first posted this about eight years ago.

[Ice-9]

Lol, you would also need a small mortgage to buy the solder to fill the tank

[Jargo]

I remember being taught to flow the solder and then hold the board with your hand and tap your hand against your bench (or leg, or head)...virtually no stress on the PCB itself...plus it gets the holes cleared pretty much every time!!  Also, to clear the holes, flow the solder and introduce a toothpick. I use this Dental Probe that I bought at CVS pharmacy (like $4) - it's dual-pointed and both tips have LED's - also comes with a dental-style mirror.