Hi,
We wish to hand solder the SIM800 RF module...(seen here on pages 15 and 16)

https://www.simcom.com/service-844.html

There is a 0.4mm gap between the pads, though due to the castellated side pads, the solder splurges out and shorts between the pads when you are soldering it. You cannot use a fine tip iron as it doesnt heap up the pad and connection enough.

This is the soldering station we have..
https://kurtzersa.com/products/elec...ols/soldering-desolderingstations/i-con-1-mk2

This was the soldering tip we used, but it was giving shorts between pins....
https://ersashop.com/weco(====)/app...ail&m_ca_bd_GV_ITMGUID=051MciB67joYcIpE1UvH20

 

Use a better iron with lots of tacky flux, small solder and magnification. Those modules are easy with good equipment. Preheat the PCB with a hot air gun to reduce the bulk heat adsorption during soldering.

https://forum.allaboutcircuits.com/threads/tmt-9000s-soldering-station.206528/