Having neither of us having ever built a boiler. I started asking the chaps at PADMEC a few questions. Given the cost of the materials, if we get it wrong, the boiler is effectively scrap metal. Therefore it makes sense to find a professional to build one. That also has the added bonus of a guarantee. I found that Maxitrack were selling a fully TIG welded copper boiler but it was very expensive. Although after much digging around I discovered the chap that Maxitrack subcontract the boiler making to. My father spoke to him and the cost is much less.