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I understand thermals are used to prevent tombstoning during oven soldering by allowing all pads to heat up more evenly, but are they necessary when the PCB is going to be soldered by hand?

Consider that I have experience soldering SMDs and that I have a good soldering station(as in one that has no problem soldering heavy packages and heavy wire).

Also, the PCB will have solder mask so solder won't just run around, etc..

I ask this because I'm designing a 2 layer PCB which is quite dense in some places and disabling thermals allows me to leave more copper on the power pours in dense areas..

Below image without(left) and with thermals(right).

enter image description here

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  • \$\begingroup\$ If you're hand-soldering then it's extremely likely that you'll be able to hold the package down with the other hand (or with a tool held in it, rather). \$\endgroup\$ – Ignacio Vazquez-Abrams Feb 16 '15 at 6:55
  • \$\begingroup\$ Yes, I'll be using tweezers. I ask this because I'd like to know if there is any other reason to use thermals besides preventing tombstoning. \$\endgroup\$ – Wesley Lee Feb 16 '15 at 6:56
  • \$\begingroup\$ Thermals are not just there to stop tombstones. They're to stop all the heat from being conducted away from the pad. They make hand soldering easier as well as machine soldering. The size of the pour and the thickness of the copper will be factors. It's a good idea to have thermals if you can. If it's a prototype you need to take into account the fact thermals make de soldering easier too \$\endgroup\$ – Will Feb 16 '15 at 8:37
  • \$\begingroup\$ I think it will come to wether I prefer easier to solder PCBs or more solid planes. Honestly I believe I'll have no problem if I abandon the thermals for this project. Thanks for the input though. \$\endgroup\$ – Wesley Lee Feb 16 '15 at 8:40
  • \$\begingroup\$ Soldering the 0603 smd pads on a plane without thermals is tough, specially with sharp conical tip. I always use thermals. \$\endgroup\$ – Flanker Nov 22 '16 at 15:13
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In my opinion, if you are hand-soldering the board and have a decent soldering iron, you don't need thermals.

I regularly hand-solder on ground planes with stitched vias (RF boards) with no problems. Because these are RF ground planes, they don't have thermal relief for the vias.

FWIW - my old Weller soldering station isn't happy soldering large ground plane areas. On the other hand, my Metcal MX-500 with a sttc-113 tip works well. I was doing a bunch of soldering of RG-58 shield braid on ground plane earlier today with absolutely no problems.

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