Heavy Duty Soldering

[R Adsett]

I have an assembly that uses Cu bus bars 1.55 mm thick connected to a 3
oz Cu plane on PCB via through hole pins 1.5mm wide. So that gives pins
about 1.5 mm sq.

The problem I have is that with the iron I'm using at the moment the
combined heat sinking of the Cu plane and the Cu bus bar is too much for
the iron to overcome. I'm looking for something that would be
appropriate. I've used American Beauty heavy duty Irons in the past for
similar purposes but I'm wondering if any one has other (perhaps better)
suggestions.

Robert

 

[Jerry G.]

For heavy soldering, I use a 60 Watt, and a 100 Watt iron. For general
circuit board use, I have a proper soldering station.

If the soldering job is demanding more than what I can accomplish with an
iron, I then use a soldering gas torch.

--

Jerry G.
======


I have an assembly that uses Cu bus bars 1.55 mm thick connected to a 3
oz Cu plane on PCB via through hole pins 1.5mm wide. So that gives pins
about 1.5 mm sq.

The problem I have is that with the iron I'm using at the moment the
combined heat sinking of the Cu plane and the Cu bus bar is too much for
the iron to overcome. I'm looking for something that would be
appropriate. I've used American Beauty heavy duty Irons in the past for
similar purposes but I'm wondering if any one has other (perhaps better)
suggestions.

Robert

 

[Chris]

I have an assembly that uses Cu bus bars 1.55 mm thick connected to a 3
oz Cu plane on PCB via through hole pins 1.5mm wide. So that gives pins
about 1.5 mm sq.

The problem I have is that with the iron I'm using at the moment the
combined heat sinking of the Cu plane and the Cu bus bar is too much for
the iron to overcome. I'm looking for something that would be
appropriate. I've used American Beauty heavy duty Irons in the past for
similar purposes but I'm wondering if any one has other (perhaps better)
suggestions.

Robert

Hi, Robert. You have to pump heat into the solder joint faster than it
can be drawn away. That means wattage.

For things like this, I'll usually use a Weller 8200 dual temp pistol
grip solder gun (100/140W). Try to put most of the heat into the
copper bar -- delamination of the PCB is your biggest problem here.
The solder joint will remain hot a lot longer than a standard solder
joint.

If you need one quickly, they're available at nearly all hardware
stores as well as standard electronics equipment outlets.

Good luck
Chris

 

[Spehro Pefhany]

I have an assembly that uses Cu bus bars 1.55 mm thick connected to a 3
oz Cu plane on PCB via through hole pins 1.5mm wide. So that gives pins
about 1.5 mm sq.

The problem I have is that with the iron I'm using at the moment the
combined heat sinking of the Cu plane and the Cu bus bar is too much for
the iron to overcome. I'm looking for something that would be
appropriate. I've used American Beauty heavy duty Irons in the past for
similar purposes but I'm wondering if any one has other (perhaps better)
suggestions.

Robert

Maybe a solder pot (or a wave if you can pick one up for a reasonable
price). The latter have almost infinite ability to transfer heat to
the material. I picked up a small wave (without conveyor, preheater or
fluxer) for a couple of hundred dollars including a thermocouple
temperature controller. Well, I didn't actually pick it up, it weighs
about 80kg/175 lbs.


Best regards,
Spehro Pefhany

 

[Tim Shoppa]

Cu bus bars 1.55 mm thick

[...] I've used American Beauty heavy duty Irons in the past

Those will work, but I prefer the pistol-trigger Weller soldering guns
for heavy-duty stuff. The gotcha with these is that it's real easy to
overheat a PCB and cause the foil to pull off. That's also a problem
with underheating too, if you've got skinny traces in particular.

1.55mm thick really isn't that big. Maybe you've got a really tiny
soldering station or something. A Weller WTCPS with a wider tip will
probably do the job, and you get temperature control.

Tim.

 

[Dave VanHorn]

I've done similar with a broad tip on my metcal.

 

[John Popelish]

I have an assembly that uses Cu bus bars 1.55 mm thick connected to a 3
oz Cu plane on PCB via through hole pins 1.5mm wide. So that gives pins
about 1.5 mm sq.

The problem I have is that with the iron I'm using at the moment the
combined heat sinking of the Cu plane and the Cu bus bar is too much for
the iron to overcome. I'm looking for something that would be
appropriate. I've used American Beauty heavy duty Irons in the past for
similar purposes but I'm wondering if any one has other (perhaps better)
suggestions.

Robert

If you are not talking about production, but just one or two, you
might try using an oven to preheat the whole thing before soldering.
I think I would flux the joints before preheating to prevent
oxidation. Even working on an insulated (wooden) surface under an
infrared heat lamp may help a bit. Let the assembly sit there under
the lamp until it is too warm to touch and then try soldering.
Just using a bigger iron is more likely to damage the board with hot
spots.

 

[Tim Shoppa]

I've done similar with a broad tip on my metcal.

Everbody tells me that the skinny metcal tips can pump out that much
heat, but I never believe them .

 

[R Adsett]

Hi, Robert. You have to pump heat into the solder joint faster than it
can be drawn away. That means wattage.

And fast enough not to heat up the rest of the board too much.

For things like this, I'll usually use a Weller 8200 dual temp pistol
grip solder gun (100/140W). Try to put most of the heat into the
copper bar -- delamination of the PCB is your biggest problem here.
The solder joint will remain hot a lot longer than a standard solder
joint.

I actually tried that, I've an old tip and it needs replacing but even
with a new tip I think it would be marginal at best. It can heat up
solder to the melting point at the tip but not enough to flow it around
the pin. The bus bar and the Cu plane appear to be enough to draw the
heat away on the larger bus bars. The smaller bars I can just do.

The bigger Bus bars have more pins and an larger associated area for both
the Cu bar and the Cu Plane they connect to.

Robert

 

[R Adsett]

Maybe a solder pot (or a wave if you can pick one up for a reasonable
price). The latter have almost infinite ability to transfer heat to
the material. I picked up a small wave (without conveyor, preheater or
fluxer) for a couple of hundred dollars including a thermocouple
temperature controller. Well, I didn't actually pick it up, it weighs
about 80kg/175 lbs.

That's an interesting thought. The production units will probably be
wave soldered in any case. Anyone have any pointers as to where I might
find one (either commercially or local to Ontario, CA)?

I'll probably keep my eyes open for one even if I don't use it for this
project.

Thanks Spehro

Robert

 

[R Adsett]

Cu bus bars 1.55 mm thick
[...] I've used American Beauty heavy duty Irons in the past

Those will work, but I prefer the pistol-trigger Weller soldering guns
for heavy-duty stuff. The gotcha with these is that it's real easy to
overheat a PCB and cause the foil to pull off. That's also a problem
with underheating too, if you've got skinny traces in particular.

1.55mm thick really isn't that big. Maybe you've got a really tiny
soldering station or something. A Weller WTCPS with a wider tip will
probably do the job, and you get temperature control.

Well remember it's more than just the pins (they just run from the bus
bar to the PCB), there is a fairly extensive Cu plane to connect to and
the Cu bus bar itself has a fair amount of thermal mass and radiant area.

I can almost do it with either a Weller Pistol type or my smaller pencil
soldering iron. In fact I can solder power pole connectors on the Cu
bars, but once I add the extra load of the Cu plane on the PCB...

Thanks Tim.

Robert

 

[Guy Macon]

Well remember it's more than just the pins (they just run from the bus
bar to the PCB), there is a fairly extensive Cu plane to connect to and
the Cu bus bar itself has a fair amount of thermal mass and radiant area.

Did you design in thermal relief on the connections to the Cu plane?

 

[CWatters]

I have an assembly that uses Cu bus bars 1.55 mm thick connected to a 3
oz Cu plane on PCB via through hole pins 1.5mm wide. So that gives pins
about 1.5 mm sq.

The problem I have is that with the iron I'm using at the moment the
combined heat sinking of the Cu plane and the Cu bus bar is too much for
the iron to overcome. I'm looking for something that would be
appropriate. I've used American Beauty heavy duty Irons in the past for
similar purposes but I'm wondering if any one has other (perhaps better)
suggestions.

Robert

If you aren't likely to do a lot of this in the future you could try what
they used years ago... eg a block of copper heated in a gas ring. You might
find that some scrap bus bar folded up has sufficient thermal mass.

 

[[email protected]]

Robert,
I've used a soldering gun with 2 electrodes made out of solid wire.
Flatten the business ends into sort of a squared off chisel, ~1/4" gap.
Then make an electric contact in the area you need to solder, sparks a
lot but heats the area you need nicely. I've used this for rechargeable
battery pack reconstruction. Faster and you don't have to wait for
those large irons to heat up.
Richard

 

[mike]

I have an assembly that uses Cu bus bars 1.55 mm thick connected to a 3
oz Cu plane on PCB via through hole pins 1.5mm wide. So that gives pins
about 1.5 mm sq.

The problem I have is that with the iron I'm using at the moment the
combined heat sinking of the Cu plane and the Cu bus bar is too much for
the iron to overcome. I'm looking for something that would be
appropriate. I've used American Beauty heavy duty Irons in the past for
similar purposes but I'm wondering if any one has other (perhaps better)
suggestions.

Robert

I use an Ungar 45W 1050F pencil with 3/8" tip. Lots of theremal mass.
If that don't do it, I preheat the opposite side with a heat gun.
I've had poor luck with soldering "guns" on items with lots of thermal mass.
mike

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[qrk]

I have an assembly that uses Cu bus bars 1.55 mm thick connected to a 3
oz Cu plane on PCB via through hole pins 1.5mm wide. So that gives pins
about 1.5 mm sq.

The problem I have is that with the iron I'm using at the moment the
combined heat sinking of the Cu plane and the Cu bus bar is too much for
the iron to overcome. I'm looking for something that would be
appropriate. I've used American Beauty heavy duty Irons in the past for
similar purposes but I'm wondering if any one has other (perhaps better)
suggestions.

Robert

I use a hot air gun to preheat the assembly. You can also place the
assembly on a hot plate (commercial unit for surface mount rework or a
portable single burner stove with an aluminum plate to act as a heat
spreader). If you get the parts up to 150 to 180 deg C, that will help
alot. A pair of irons is always helpful in stubborn cases.

Mark

 

[[email protected]]

I've used an "open circuit" solder gun for stuff like this. I replace
the normal tip with two solid copper #10? flattened to two chisel
points with about a 1/4" gap. When contact is made, sparks and the area
contacted heats up nicely. I've used this to repair NiCad packs. Does
that "cold" soldering thing on TV work like this? Of course you
wouldn't want to use it around sensitive components.
Richard

 

[[email protected]]

I use an soldering gun with 2 solid copper #10? flattened chisel points
and a 1/4" gap. I discovered this trying to make a mini spot welder.
Works well on reattaching NiCad tabs. Not good around sensitive
electronics.
Richard

 

[James T. White]

I actually tried that, I've an old tip and it needs replacing but even
with a new tip I think it would be marginal at best. It can heat up
solder to the melting point at the tip but not enough to flow it around
the pin. The bus bar and the Cu plane appear to be enough to draw the
heat away on the larger bus bars. The smaller bars I can just do.

Robert,

Did you try preheating the assembly with a board preheater or a hot air gun?
The larger Weller D650 (300W/200W) might also do the trick.

 

[Sergey Kubushin]

Robert,

Did you try preheating the assembly with a board preheater or a hot air gun?
The larger Weller D650 (300W/200W) might also do the trick.

I wonder why wouldn't you guys just use a bigger iron? Not a soldering gun,
their Watts are of that Chinese variety that they manage to squeeze 2x1000W
into a tiny boombox...

Just use a normal 100 Watt soldering pencil. Works miracles on big jobs...

I personally use MCM Electronics 100 Watt iron, their item # 21-4350. Works
like a charm, no problems soldering even a box made of 1/16" thick copper...