DIY Firearms - galvanized and B-pipe barrels

Hello everyone. I'm new hear and hoping this is a cool community w/o too many trolls. XD

This will be a long post and an ongoing and evolving project

Here's the situation. I'm a Red blooded American, my beautiful wife, however, is a foreigner and due to some family circumstances we won't be Stateside for awhile. Firearms are a bit of a gray area where we are and are difficult/costly to come by. I give that context so that any readers/responders understand that anything discussed in this thread has no interest in US laws.

Secondly, I'm a skilled craftsman and have done my due diligence learning about this topic and what does and doesn't work. I want to keep this thread on topic. So for example, if I'm asking about plumbing pipe. it's because I understand the thresholds. Don't make irrelevant comments or don't suggest another material that you know to be stronger.

The questions I ask are specific to my location, tools, and available materials

With that out of the way I found a store that sells .38 special and 22lr. I can only get one box of .38 though and from what I understood as much .22 as I want.

To start with I'm going to make a derringer in both calibers and let things evolve from there

My questions for today are:
Is there a difference in strength between galvanized vs back iron pipe?
How thick is the galvanized coating? Asking this one because I think it will wear away quickly with each shot but correct me if that might not be the case


I haven't found black iron pipe anywhere and according to the locals they only use galvanized when necessary and for everything else they use pvc or some plastic form of piping.

For anyone with extra interest or just want to see plumbing pipe being used in this context this is a good video and he has another video where he reems the same barrel out to 40 S&W.

Thanks if you stuck around to read all that