4 inches is not always 4 inches

[CoogeeBoy]

This is my vent.
I now have some 4 inch copper pipe and am slowly buying parts to build a flute.
Apart from the fact that it is cheaper to buy sight glass kits than build your own sight glass (2" brass fittings are bloody expensive as are the brass connector unions) it is also easier to source!

Finally, my 4 inch copper is pretty well 100mm internal and 102 external diameter, so lets go looking for ferrules (to make my life a little more simple, don't worry, I was thinking about making one and then getting it cast but I suspect that too would now be even more expensive).

Problem is of course, all the different standards.....4 inch ferrules can be anywhere from 98mm OD to 102OD!

Anyway, enough of my vent, at least I have found some but they are not cheap at AUD25 a pop. Making this proposed build look a lot more expensive than I was hoping but still cheaper than buying a...still (pun intended)