I do what someone else suggested in the forum. I find an ore rich area, make an outpost there with a forge and a smelter. Don't need a kiln since coal transports thru portals. Then with the forge I just make and upgrade the weapons I need at site. No portal restrictions on the weapons. This is easier than above guide really. Your only out the 6 copper from building the forge that won't go thru the portal.

Of course you have to bring the copper with you by boat to mining area (if its on a different continent which I figure is what we are talking about.