Sodder is the common American pronunciation, most of the rest of the world says solder.
Nah some of the rest of us say sodder too, solder sounds too close to soldier when you've got an accent haha.
I did say _most_ for a reason :) Neither pronunciation is universal, but Commonwealth English speakers (except Canada which uses both) normally pronounce the l, American English speakers don’t. Other English varieties vary.
Interesting. My experience is the opposite. Sodder, soddering is the norm. Every lab, every tech at every company has said it that way. I'm from the west coast USA if thats relevant. If I ever heard someone say "sold-er" I probably dismissed it as someone who only ever read the word, and was sounding it out phonetically.