I thought one of the more home practical things a guy did was 3d print lug molds out of plastic, it think he made a thread here. He then molded carbon lugs in the plastic molds. I forget whether this actually helped in any particularly useful way compared to just tying stuff together with tow. If you read up on the bamboo bikes, but substituted carbon tubes and Al elements, and knit it together with carbon tow, you could make a high end bike with little of the nonsense involved in steel. Steel is great, but the heat distortion is a major nightmare relative to the gear you need to have, like taps. There are Chinese carbon tube suppliers on ebay that compare well on cost, but it may not be bike grade stuff.