Easier, more efficient way to solder large batches of boards?

[skiraly017]

Obviously a PCB assembly house is an option but a costly one. I found this on Ebay.



Has anyone used something like this? Thoughts, pros, cons? Any suggestions would be greatly appreciated, thanks!

[Hides-His-Eyes]

If you think PCB fab is costly, you're looking in the wrong places, for too many layers, or we have very different ideas of 'costly'...

You could buy a lot of boards for $200!

[R.G.]

If you think PCB fab is costly, you're looking in the wrong places, for too many layers, or we have very different ideas of 'costly'...

PCB **assembly** not fab. Put parts in holes, solder, trim leads, test.

Different animal. And expensive.

[Hides-His-Eyes]

Right you are, sorry.

How about SMD? Solder paste, place the component, stick it in a mini oven thing...

[skiraly017]

Right you are, sorry.

How about SMD? Solder paste, place the component, stick it in a mini oven thing...

And lose the mojo of through hole components?!    

RG...any thoughts on the solder pot shown above? Thanks.

[Barcode80]

I don't get it. How does the thing work?

[Taylor]

I don't get it. How does the thing work?

Pretty sure it's just like a pot for yer spaghetti (conceptually). Put in some big hunks of solder bar, some flux, and it heats it up into molten solder, like T-1000. You then place your PCB, with all the parts in place, so that the bottom of the board is dipped into the molten solder, then remove the board, and all of your parts are soldered in.

[R.G.]

RG...any thoughts on the solder pot shown above? Thanks.

I haven't seen that particular one, but I've seen solder pots of several kinds, from industrial setups to electric frying pans with the temp regulator disabled or modded.

They all work if they'll get the solder to the right temp and hold it there.

They're as dangerous as pet cobras.

Most people have no idea how destructive large masses of molten metals are. You simply have to put them where you can't knock them over or knock the table over, or let cats, dogs (or other pets, including cobras  ), children, spouses, etc. get to them, and where they simply can't be touched accidentally or start fires. These are all real, valid dangers.

I worked in a primitive print shop back in my teens and had to run the type metal melter, which was about half a cubic foot of type metal, same stuff almost. Incredibly dangerous.

That being said, a solder pot is a dandy way to solder a whole board at once. You get the boards stuffed, flux the bottoms, then pick up the board with tongs, skim the dross/oxides off the solder surface, and dip the board bottom onto the solder surface gently ensuring coverage, count one-thousand-one-one-thousand-two and lift the completely soldered board off the surface. If you drop it, the whole board floats because liquid solder is heavier than the board with parts. Doing that probably heat-damages everything, so it's still a manual skill.

You need to wear a full face shield, gloves, preferably a heavy apron and shoes that flying droplets can't get into, for obvious reasons. The fumes are irritating or toxic.

It's a real virtue to have the solder be thin and wide, but it's harder to keep it molten that way. Temp control is always an issue, so is keeping skimmers and fluxes.

Just random thoughts.

[MetalUpYerEye]

I had considered an option like that for speeding up the soldering process, but i'm far too clumsy to be around something that can destroy like that if I knock it over.

Also it has become apparent to me over my past 2 builds that cold solder joints are my arch-enemy so i'm going to stick with soldering 1 pad at a time.

[defaced]

If you decide to go this route, your local welding supply store will have everything you need in terms of safety gear. This sort of risk is something welding guys deal with every time they strike an arc.

[Earthscum]

From experience (not related to electronics, I grew up as a metal fabricator), don't go etching a board and think you can stuff it right away and dip it. You will find out how quickly the "cobra" can bite you. I've noticed wet pockets just under the edges of traces on boards that I soldered right away, and they pop and the traces get popped off the board. I now use a heat gun or stick them in the oven for bit and warm just the board for about 10 minutes if I'm gonna populate it right away.

Even the smallest amounts of moisture will cause some serious damage... if you have one 'pop' in a pot, it can shoot everything around the pot with little bits of molten projectiles. Pretty gnarly to see molten metal do that... watched a kid drop something into a crucible of aluminum and watched it nearly start the welding class on fire. His leather apron did not survive well enough to be used again, but it saved him from not getting hurt too bad. Looked like someone put an M-80 in the thing  with how violent it was. Solder isn't as bad (~350 degrees F compared to about 1700 deg melting point of aluminum), but it's still the same thing... molten metal.

Found this:

Also, there's an episode of "How It's Made" that had a production house making something on electronic boards. They had a nice setup, of course, but it was very illustrative on how things get done quickly. They flowed the board, then used a belt sander to take off all the leads hanging underneath. I notice since I watched that episode that I catch myself checking to see how they clean the leads when I crack open an assembly. Most look sanded, and most of THOSE look like they were at least reflowed afterwards, or sharp edges buffed or something... some kind of care.

[PRR]

> This sort of risk is something welding guys deal with every time they strike an arc.

Steel arc welding gets MUCH hotter, true.

The puddle under a large arc, if it runs off, will melt a hole through your foot.

R.G. has a point. A gallon, even a pint, of molten solder does "less" damage over a MUCH larger AREA. Hole through your foot, you gimp to the hospital to get the dead tissue cut away before it rots and poisons you. A solder-pot will give 2nd (blister) maybe 3rd (black) degree burns over most of the front of your body.

Take a steak off the grill rare. It's oozing precious juice. Wait a day, it smells bad. Another day and it is grossly rotten. A finger blister heals, but a large-area blister sucks the life-juice out of your body and becomes a playground for germs.

Traditionally, such extensive burns are slowly fatal.

Modern Burn Centers are saving larger-burn victims more often. You really don't want to go there.

> a primitive print shop back in my teens and had to run the type metal melter

That had to be a newspaper? Linotype?

Small print shops were cold-type, and newer shops (without legacy Linotypes) were all offset. I've worked in both, and feel lucky to still have all (99.44%) of my fingers and much of my hearing.

[tech9_79]

I swear PRR,  I love reading your posts. It doesnt matter what the topic is. 

If you ever wrote a book.. i would buy it.

[Gurner]

SMD - the solder is in paste form (unless you put it on your toothbrush, it won't cause you any harm)...the flow takes place in the sfe confines of an oven.

Solder bath - the solder is in molten form - I'd rather have my kneecaps drilled with a blunt bit, than be messing around with such methods.

if you want an easier, more efficient way of soldering large batches of boards, go SMD (it's apparently caught on in the electronics industry in general)

[cloudscapes]

Don't try and use this on boards without a solder mask (the green stuff on professionally made boards). Without the mask, you'll get solder EVERYWHERE.

[DiscoVlad]

Solder pots like these are more meant for bulk tinning of wire, or removing complex through-hole components (like bridge inverter modules) from the PCB.

Like everyone else has said, using them for assembly is a terrible idea.

[skiraly017]

Okay, so general consensus is nix the solder pot so the question still remains...what's an easier, more efficient way to solder large batches of boards (aside from going SMD)? thanks.

[R.G.]

Let me be clear: Solder pots are a GREAT way to solder moderate numbers of boards. You just have to know the process, know the risks and work accordingly. Solder pots are how wave soldering got started.

Being a responsible adult means that you think about what you're doing, evaluate the benefits, costs and risks, and act accordingly.

A solder pot is fast, and efficient, especially if you have PCBs that either have solder mask, or are designed with spacing proper for dipping. A solder pot is dangerous up to the point of death and destruction if used improperly; so are automobiles, as a measure of relative merit.

Know the risks, make a decision.

An alternative is solder paste and IR reflow, but that has its set of risks, too. TI used to use solder ringlets on component leads and dip the stuffed boards in boiling peanut oil. Boiling peanut oil is only marginally less dangerous than molten solder, and for the same reasons. Pretty much any technique that accumulates enough energy in one spot to bring the solder and leads on the bottom of a board to solder flow temps will have the issues that any misuse or failures will let that energy out into the operators, bystanders, and surroundings.

Simply using high energy levels of anything - heat, movement, air or water flow, nuclear radiation, light, whatever, means that the waste energy and possible "spillages" will be painful or deadly.

[John Lyons]

Makes me think of the person (people) who drank too much water.
Who would have though it was dangerous?

http://chemistry.about.com/cs/5/f/blwaterintox.htm

[R.G.]

Makes me think of the person (people) who drank too much water.
Who would have though it was dangerous?

Then there are our political heroes. Apparently some group got UN reps to the climate conference in Mexico to sign a petition supporting outlawing the use of dihydrogen monoxide, which, as the petition said "DHMO contributes to the greenhouse effect, it's a major substance in acid rain, it's fatal if inhaled, it contributes to the erosion of natural landscapes ... Basically, they want to use it in nuclear power plants, the production of Styrofoam, fire retardants, pesticides, and cruel animal research.".

At least one rep signed while being video recorded drinking a glass of DHMO then signing.

Deadly DHMO is also know as Dihydrogen Oxide, Hydrogen Hydroxide, Hydronium Hydroxide, or simply Hydric acid. Its basis is the highly reactive hydroxyl radical, a species shown to mutate DNA, denature proteins, disrupt cell membranes, and chemically alter critical neurotransmitters. The atomic components of DHMO are found in a number of caustic, explosive and poisonous compounds such as Sulfuric Acid, Nitroglycerine and Ethyl Alcohol.


Yep - to those who think about it and have a inkling what chemistry is, DHMO is ... water.