I have a pic of what I'm trying to do:

http://i.imgur.com/zwFgcyt.jpg

I don't know if it's possible, this is just an experiment. I installed the conveyor modpack, and one of the blocks is a non-mergeable conveyor. I'm trying to use that to create a ship that can swap out grinder/welder modules so I don't have to transfer building materials. I imagine an even better design would use rotors or pistons, but that's for later versions.

The problem is that the welders won't weld. I can transfer building materials to them through the conveyor system from my cargo containers but when I click to weld they just light up red.

Am I doing something wrong or does this just not work?