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I purchased a Weller WSD161V soldering station (similar to this one, at least with regards to the pneumatic system I'm about to describe -- sorry, I was unable to find a manual for my specific model on the internet) with a DSX80 desoldering iron.

This desoldering iron works like an automatic desoldering pump -- when pressing a button on the iron, it suctions the molten solder.

To work, it needs (as described on the link above) a 35 l/min supply of dry, oil-free, 58-87 psi (4-6 bar) compressed air. I recall reading somewhere that there is a venturi inside the soldering station which generates the vacuum for the pump.

Due to space and noise constraints, I decided to purchase a tankless air compressor -- specifically, the Einhell BT-AC-180. It is able to supply compressed air at a pressure of 8 bar, with a flow rate of 77 l/min at 4 bar and 63 l/min at 7 bar, so it should be plenty to supply my desoldering iron.

However, I have a couple of questions -- keep in mind my expertise is in electronics, and I have very little knowledge of pneumatic equipment:

  1. The compressor doesn't appear to have any kind of pressure regulator. Since my desoldering system only consumes 35 l/min of air, which is well above what the compressor can supply even at a pressure of 8 bar, I understand the compressor should well be capable of supplying the full 8 bar to the desoldering system. This would be out of spec for the system, and I'm afraid it might blow some kind of safety valve inside it. Does there exist some kind of pressure regulator I can couple to the output of the compressor, which will drop pressure to the safe 4-6 bar range for the desoldering system?

  2. In looking for such a system, I was told by a salesman at a compressor shop that if a tankless compressor's flow is impeded, their internal safety valve will blow, so there needs to be a path for the compressed air to get out at all times. I've learned not to take salesmen at their word, and in this particular case I'm inclined to believe this is wrong, because the compressor in question comes with some kind of pistol which can cut out the flow of air -- I guess the manufacturer wouldn't include such an accessory if it would cause the compressor's safety valve to blow out. Still, since I recently purchased this compressor, there's still time to return it to the dealer if it is unfit for my purpose. Is this compressor compatible with the desoldering system, or should I return it and go for a compressor with a tank?

  3. The desoldering system calls for dry air, and I was told by a salesman that condensation is an issue with compressors -- at first I found it weird since compressing air should increase (not decrease) its temperature, but now I believe I understand the effect, which should be similar to a capillary tube in refrigeration systems: when the flow of air is restricted, its pressure drops and so does the temperature, which may then form condensation. The salesman said the solution to this is adding a filter to the compressor output. Is my understanding of the phenomenon correct? Will a filter solve the problem? What kind of filter should I look for?

Taking into account my complete lack of experience with pneumatic systems, any other tips on how to connect the system, what extra equipment to purchase, etc. are welcome.

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  • $\begingroup$ A conventional air regulator probably will not work for you if there is a pressure relief valve in the system. Without anywhere to store the energy, the compressor either has to be running or you will have no pressure. From what the salesperson said, if it is running and the flow is restricted, the pressure will grow too high and the PRV will activate and dump the air to atmospheric pressure. Systems with a tank just turn off the compressor at a certain pressure until the tank pressure goes down. I would look for a compressor with a small tank, or plan to add your own if you're in a DIY mood. $\endgroup$
    – Ethan48
    Feb 7, 2015 at 14:41
  • $\begingroup$ Still, as seen on the compressor's web site, it comes with a blow-out pistol, which I guess it wouldn't if it caused a valve to blow when not triggered. I should mention the salesman in question had no idea which specific compressor model I owned, and just made a general remark on tankless compressors. $\endgroup$
    – swineone
    Feb 7, 2015 at 14:45
  • $\begingroup$ The manual makes it sound like there is a built in adjustable regulator. It describes using that to set the tire inflation pressure you want. So it sounds like the salesperson might not have understood. If that is the case, use the internal regulator to set the pressure you need and all you need on the outside is an air dryer. $\endgroup$
    – Ethan48
    Feb 7, 2015 at 14:55
  • $\begingroup$ Actually, I don't think this is an automatic regulator but merely a pressure gauge. You are responsible for determining whether you should push the trigger (to increase tire pressure) or press the button that lets air out (to decrease tire pressure). I'm looking for a piece of equipment that allows me to dial in a pressure, and makes sure it's never exceeded. Would something like this be compatible with my setup? $\endgroup$
    – swineone
    Feb 7, 2015 at 15:14
  • $\begingroup$ Potentially, yes. It really depends on how the output stage of the compressor is designed. Does the manufacturer have any kind of schematic or design recommendations? Is it easy to open so you could take a picture of the components? This clearly isn't what this compressor was designed for, but there is probably some way to make it work. $\endgroup$
    – Ethan48
    Feb 7, 2015 at 15:28

1 Answer 1

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For 1. and 2., you can solve the problem by having an adjustable valve from the output line to free air. This way you let some of the compressors output flow escape, leaving enough of flow and pressure for the soldering station.

To operate:

  1. Fully open the "release valve" before starting the compressor.
  2. Monitor air pressure with a gauge, ideally next to the soldering station but if the compressor has one on output it'll probably work also.
  3. Slowly close the "release valve" until the pressure is at the level you want.

As for 3., there are various kinds of filters for removing condensation water from compressed air, but I'm not able to recommend any specific kind.

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