SMDs and stripboard - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Bazz4CQJ · 28th Nov 2017, 11:44 pm

Quote:

Originally Posted by paulsherwin

Has anybody tried attaching a bit of ring main copper wire to a standard iron to create a miniature tip?

Tried it but was not impressed. I think the limited area of contact is a problem. I'm now using an iron with interchangeable bits; a 1.6mm chisel seems to work well on the smaller stuff I deal with.

I have really poor vision in one eye, effectively monocular, and I haven't yet tried working with SMD's and suspect it will prove quite difficult!

B

MrBungle · 29th Nov 2017, 9:03 am

Quote:

Originally Posted by paulsherwin

The problem I've found with proper solder wick is that it tends to go off within a month or two of opening, presumably as it oxidises. I'll experiment a bit with coax braid.

I do have some very thin leaded solder which should be suitable.

Chemtronics stuff has a very long shelf life (years). Some of the cheap stuff is hygroscopic so keep it in a zip lock bag and it’ll last longer. To be honest I’m getting through a roll a month at the moment (thanks Tektronix!

) so it doesn’t hang around.

Nickthedentist · 29th Nov 2017, 10:41 am

I find the Servisol braid is still OK after several months too.

As for the copper wire wrapped round the iron, it's great for melting wax into woodworm holes but not much else in my experience.

Nick.

lesmw0sec · 29th Nov 2017, 10:52 am

Being a 19" rack man, I long ago decided that SMD's were only suitable for watchmakers!

paulsherwin · 29th Nov 2017, 11:14 am

I must admit to being surprised at how tiny they were, despite having read the specs and seen lots of SOT23 devices in commercial products. They look bigger fitted to PCBs, presumably because of the pads and solder.

Diabolical Artificer · 29th Nov 2017, 12:58 pm

Liquid flux makes soldering these tiny packages a lot easier. A fine bent 45 degree tip also helps. If the device is glued down, the pins flooded as described, a sharp tap on the bench gets rid of excess solder. This is how they do it on the assembly lines for individually installed IC's like FPGA's etc.

Andy.

MrBungle · 29th Nov 2017, 2:45 pm

I wouldn't tap it on the bench to get rid of solder. That solder doesn't always end up where you expect and turns up between the pins on a TSSOP package for example. This, when it is a switching converter, is followed by a miniature firework display. I speak from experience

If that is being done on assembly lines, they should be shot. Glue, then drag solder, then use wick to get rid of the excess, then clean, then inspect.

29th Nov 2017, 10:41 am	#23
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,845	Re: SMDs and stripboard I find the Servisol braid is still OK after several months too. As for the copper wire wrapped round the iron, it's great for melting wax into woodworm holes but not much else in my experience. Nick.

29th Nov 2017, 10:52 am	#24
lesmw0sec Octode Join Date: Jul 2009 Location: Carmel, Llannerchymedd, Anglesey, UK. Posts: 1,507	Re: SMDs and stripboard Being a 19" rack man, I long ago decided that SMD's were only suitable for watchmakers!

29th Nov 2017, 11:14 am	#25
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,943	Re: SMDs and stripboard I must admit to being surprised at how tiny they were, despite having read the specs and seen lots of SOT23 devices in commercial products. They look bigger fitted to PCBs, presumably because of the pads and solder.

29th Nov 2017, 12:58 pm	#26
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,658	Re: SMDs and stripboard Liquid flux makes soldering these tiny packages a lot easier. A fine bent 45 degree tip also helps. If the device is glued down, the pins flooded as described, a sharp tap on the bench gets rid of excess solder. This is how they do it on the assembly lines for individually installed IC's like FPGA's etc. Andy. __________________ Curiosity hasn't killed this cat...so far.

29th Nov 2017, 2:45 pm	#27
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: SMDs and stripboard I wouldn't tap it on the bench to get rid of solder. That solder doesn't always end up where you expect and turns up between the pins on a TSSOP package for example. This, when it is a switching converter, is followed by a miniature firework display. I speak from experience If that is being done on assembly lines, they should be shot. Glue, then drag solder, then use wick to get rid of the excess, then clean, then inspect.