> durafix to hold it together (presumably less warping issues than welding steel as the temps are lower)

I've had some success and some failures with durafix type rods.

I did try and "weld" some 3mm sheets together to make up a model tank hull, but the time it took to get the area up to the right temperature meant I ended up with some warping.

I was using a MAPP torch, as that was the hottest heat source I had available. In future I'm going to stick to getting things professionally MIG/TIG welded for taht sort of thing.

Adrian.