System won't hold 10 psi pressure even for 15 minutes. All valves are open with appliance stubs capped closed. Test gauge held pressure ok on small section of pipe to prove test procedure works on a good system. Clean black pipe and fittings assembled with RectorSeal pipe thread sealant.
A wood burning fireplace needs a much wider flue than an ordinary coal fire flue, the modern conversion is to fit a stainless steel liner. Wood produces much more tar and can soon block a normal flue. I'm not sure from your description what this black pipe is, it could be a remnant of a balanced flue system, /balanced_flue_ If so it should also appear on the outside of the wall.
Put on your safety goggles and try it. Peroxide is an oxidizer and it would convert the acetone to an acid. Vinegar is around 5% acetic acid. The two acids may react with the sugar to form a black carbon snake. Calcium chloride absorbs moisture and it may act to keep the snake dry enough to hold it's shape. The more I think about this the more I want to try just to satisfy my curiosity.
