Hi Brino,
I used mig to tack the flue up with a 1/2" tack every six inches or so, makes it very strong, and minimises the zinc poisoning! I use a large 200 amp three phase mig, which I find to be much more stable at low amperage settings, and much less tendency to burn through. I also have a Clarke single phase 160 amp mig, but the arc is not as smooth at lower settings (there is a BIG choke on the three phase one), and the more you turn it up, the better it works, maybe I have just got to be a better welder with all the practice I have been getting! I don't try to seam weld it, to much heat, and always burns through! I really need insulated flue, but it is so expensive, I will try for some second hand stuff. Ppl are lazy, put in a woodburner for all the right reasons, then can't be bothered with the upkeep, and more often try to burn wood that is unsuitable, or wet, or both, and give up, claiming that "woodburners dont get hot enougn". Thats where I move in and buy them up for peanuts!! With the internal ducting, I cover the joints with aluminium duct tape to make them airtight.
Insurance is similar here, VERY hard to get insurance for any form of workshop that uses any sort of naked flame, like a forge, or O/A, most of the garages now use induction heaters for rusted bolts etc, because of the insurance. The blacksmiths shop end of the workshop is not dry lined and the ceilings are plasterboard, with bare concrete block walls, so it is pretty fireproof, and all the sources of ignition are kept and used in there, including the woodburner. I think the traditional stovepipe heaters are more of a danger fron CO poisoning than fire, and in the UK the number of housefires we have today is vanishingly smal, but insurers will use any excuse to hike policies!
The girls used to be interested in what I was doing when they were younger, and still enjoy trips to see the workshop, but the eldest has just turned 18 and is doing A levels at college , wants to study biochemistry at uni, she has Aspergers, and is a bit of a worksholic when it comes to revision, and my youngest, now 15, also doing well at school, and wants to go into medicine, and eventually pathology! They are also good artists, and do enjoy making things, but they are so busy at the moment, that they get little time for practical work.
I am back at work Monday, for the continuing saga on the shower pump, I have new pump hoses to fit, and suspect (hope!) that our lack of gravity flow may have been caused by the valves not opening fully, We will see!
Thanks for your interest, and thanks for watching!
Phil
East Yorkshire.