So I bought a Chinese pneumatic solder paste dispenser ( a bit like this one - http://www.ebay.co.uk/itm/SMT-Solder-Pa … 336de411b4 ), but I’m having a hard time trying to get the solder to dispense out the nozzle at a fine enough width …I work down to SOT-23-6 footprints, but the dispenser nozzle dispenses a blob, rather than a precise but of solder paste.
So, to my questions…
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What viscosity should the solder paste be (presently I’m using some solder paste sold by Deal Extreme - but it doesn’t come in a syringe…so I manually put it into one of the syringes supplied with the dispenser …but it strikes me that it’s a bit thick…& sure enough if I put my finest nozzle on there…nothing comes out (though this could be my compressor being a bit weak)
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Can anyone recommend a (cheap) solder paste already in a syringe with a nozzle fine enough to do sot23-6?
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Failing that, what nozzle size should I be using (to help you visualize…SOT23-6 is about one step down from SOIC pitch …not ludicrously small like MSOP etc, but still ‘tight’)
The other problem I have is that when the solder paste does come out of the nozzle…it doesn’t ‘grab’/adhere to the copper pad very well, when I lift the nozzle away, the solder comes away with it…meaning I have to then go back & try & wipe/drag it off the nozzle onto the copper pad - I’m sure this isn’t how it’s meant to be.
Basically, I’m not getting along with this method very well …so any related top tips would be most welcome!