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Subject: Re: [geda-user] Thermals: size problem, SMD
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From: "Richard Rasker (rasker AT linetec DOT nl) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
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Date: Sun, 15 Jul 2018 00:14:50 +0200
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Op 13-07-18 om 13:09 schreef Chad Parker (parker DOT charles AT gmail DOT com) [via 
geda-user AT delorie DOT com]:
> It can be a problem when installing the parts too, not just removing 
> them. I've had technicians complain to me about this before... "I had 
> to use TWO soldering irons just to solder that one pin..."

True enough, but that usually pertains to through-hole components(*), as 
I routinely use reflow for any SMD stuff.

My main question is how often things like 'tombstoning' occur when not 
using thermals for SMD components.
I've only seen it happen when trying to use the wrong size components 
(e.g. 0805 or smaller on a 1206 footprint), and the first-to-flow side 
dragged the component away from the other pad.
In all other cases, I never actually had any problems with pads fully 
enclosed in a copper plane; I was merely wondering if other people have 
other experiences.


*: In the rare cases that I encounter these things -- SMA RF connectors 
are notorious in this respect -- I load up my trusty 1982 Weller WECP-20 
with a special 'brute force' tip (a wide, sawn-off stump of an old tip), 
crank it up to 450°C, and hey, presto: no problem. Sure, the soldering 
tips last only minutes this way, but they were discarded for normal use 
already anyway due to wear.

And if I don't have an old soldering tip, hot-air preheating the PCB to 
some 150°C and using the widest available tip usually does the trick 
quite neatly; it's just a bit more precarious if there are electrolytic 
capacitors and nylon connector housings on the PCB already.


Best regards,

Richard Rasker