DIY wave solder. Is it possible?

Hello


Recently, i have been reading about wave soldering. The principle behind the machine to me is to first pre-heat the pcb then flux it and finally solde the components by dipping the pcb into a molten solder. Having understand how the machine work, am thinking may be it is possible to make a diy wave soldering machine by manually passing the pcb through the three stages involved. I need your opinion on this. Thanks

actually the "wave" is molten solder pumped through a strip nozzle. not really possible to do on your own, not to mention the cost of the solder itself to fill the thing!

Doing reflow soldering using flux and bits of solder or solder paste in a temperature controlled toaster oven is far more practical at home. Some people have even used hot plates for whole board reflow soldering, I think the toaster oven method is more practical.

Hot plate or fry pan works well. Sparkfun used it for some time prior to going to a real reflow oven. See their tutorials.

The down side is that you can only put parts on one side.

The heat comes up through the PCB so it is possible that less heat gets to the parts.

Use it, like it.

Thanks 4 your replies,

but i still thing flow soldering is possible in a diy version, Since all i need to do is clear off the oxidised solder before each pcb bath and dip then find a way to control the temperature.

I assume that you know that this is a mass production technique so you are going to have to start with the idea of about 6 to 10 feet of space for the whole thing.

Second, you need to get a couple of bicycle chains you can splice together to make a conveyor belt. One of its critical features is adjustable speed so the board passes over the solder wave slow enough to get a good bond and fast enough to prevent excessive heat transfer to the components. Expect to ruin 5 or 6 boards on each production run getting this right since the thermal characteristics of each board type, copper pattern number of layers and size will change the optimal speed for each run.

Third, you need to build a solder pump. That means including some way to keep it at the temperature of the molten solder. You also need a reservoir of molten metal and a way to lower an ingot into the reservoir as you use it so the level is maintained for the entire production run.

Last is the design of the preheat and flux coating. Since you have massive amounts of heat available to melt all of the solder, the first is just a matter of spacing between the heat source and the board track and conveyer speed. The second can be handled by dissolving rosin in ethanol and spraying it on. Again, the spacing and conveyer speed has to be adjusted so the ethanol all evaporates before it hits the wave. That is why the process has to be run over a distance of 6 feet or more. Also, you need to plan on a run-out area after the actual wave solder so you can control the cool down of the board before anybody touches it. If you want to get fancy, you can spray the board with pure ethanol in this area to clean off any remaining flux.

It is strongly suggested that you plan on including a fume hood in the design over both the fluxing and defluxing stations for worker safety. Also, pay particular attention to fire safety in the design. You are going to be spraying volatile solvents in the vicinity of a heat source so make sure nothing can drip into something dangerous. Indeed, the liquid is not as big of a problem as the vapors. With the right mix of evaporating liquid flux, air and heat you could get a really spectacular explosion if you don’t plan on how to control every aspect of this.

At this point, I have to say, “Good luck” you’ll need it.

Most wave solder machines have the entire thing filled with nitrogen to stop the solder oxidising. Otherwise, it just wouldn't stick to the board.

Andrew

cowana said:

Most wave solder machines have the entire thing filled with nitrogen to stop the solder oxidising. Otherwise, it just wouldn't stick to the board.

Andrew

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thats funny. of the 3 we have here, one of which is LF and only a few years old, non have a nitrogen atmosphere.

Gary B said:

I assume that you know that this is a mass production technique so you are going to have to start with the idea of about 6 to 10 feet of space for the whole thing.

Click to expand...

Your post is really helpful , its a pointer because hardly will you find a web page that breaks down the stages involved in the wave machine just like you've done.Thanks


Actually, i want to change over from hand soldering to wave soldering my electronics projects. So, designing a standard w.s. Machine might not be economical.
So, i still want to know if fluxing the pcb and then dip it into the molten solder with manual equipments will work. Thanks in advance for your responses.

You do not want to literally take a PCB and dip/submerse it in a molten solder bath.

Think of wave soldering as sorta like a water bubbler/fountain except its molten solder, not water that comes out… the PCB is just passed over it, never “dipped”

holax, what's the point of trying to do this? Hotplate or IR reflow is significantly easier, cheaper, and generally practical for a hobbyist.

It seems like you have heard mostly from naysayers. I have heard from many who have used a simple "solder pot" and just skimmed boards across the top of the molten solder, with excellent results. Yes, there are major limitations. But if you are doing very small production runs and just want something to solder 50 to 100 single-sided pcbs in an evening instead of hand soldering only 10, it could be wonderful for you. Do some searches at Google Groups because I seem to remember that there were some important hints and tips that were posted.

If you only run the wave and preheat, flux, cool down and deflux manually you might be able to get it down to 3 feet. Before you dive off the deep end, calculate the volume of solder needed to initially charge your design. Convert that to weight and add the estimated weight of the structure needed to support it to get an estimate of floor loading and material startup cost. Assuming that you are only going to do narrow boards, you should be able to get the cost of the first board down to something in the $1,000 range. You are probably better off buying a used one on the secondhand market from somebody going out of business. Even if you just strip it for parts and only use the hot box and pump.