But that seem to be point.. both you and your fellow country man are vehemently insisting their way of pronounciation are right and the others are wrong..
The evidence is all on my side that the pronunciation "sodder" is "right" (see below for an explanation of that term).
But there is no evidence to suggest that sodder is the correct pronunciation and the same is also true for soLd er. It's just what happens when a language spreads from one region to another; it develops two distinct dialects.
There's a load of nonsense about received pronunciation being the correct way, which is not the case. It was just a form of snobbery and few people in Great Britain every spoke with that accent. Then there's the idea of original pronunciation, which was supposed to be closer to modern American-English and is also a nonsensical idea. Original pronunciation didn't exist because English, like any language with a large number of speakers is always changing and were are a larger number of dialects of British English hundreds of years ago compared to today. We do know that one feature of American English, rhoticity was more prevalent in British English a couple of centuries ago but other than a few words such as gotten (this didn't die out so much in Scotland and Ireland) and fall, that's it. Other Americanisms such as yod dropping did exist in some British dialects but were nowhere as widespread as is the case in modern American English.
We don't know for sure which pronunciation of solder was more common 250 years ago. I suspect it's most likely there were a mixture of the current American and British pronunciations in circulation, yet purely by chance one variant became dominant in Great Britain and another in North America. Either way, we don't know for sure, because there was no sound recording back then.
I do find this interesting, but it doesn't upset me. The only reason why Americans are teased about this is because it sounds a little rude to us, like sod her, but with the H-dropped. I certainly don't mean to be nasty about it.