I went down to building bloqs in north London the other day buildingbloqs.com to build the 6 into 1 exhaust manifold. I cracked on hard for about 11 hours but didn’t manage to finish it one day as I had hoped. It’s all tacked together though and about 30% finish welded. I'm quite happy with how it went. There are some gaps up to about 1mm wide which can be filled with weld but will increase the chances of the whole thing warping. I spent about £30 on the tube and bends from DC iron www.dciron.co.uk. Super cheap which is goal on this project. I treated myself to an air die grinder (£20 from screwfix, part number 5458H) and a decent carbide burr (a tenner from ebay). That definitely saved me a few hours. Cuts through steel like butter. Dont forget you can click to enlarge photos.