the iron dwarf Posted January 19, 2017 Share Posted January 19, 2017 made a new hood and will be testing it soon, in my new shop we could not o through the roof and the forge is not against an outside wall so had to go horizontal, will see if it works and if not will try a venturi with excess air from the blower to help it it is about 60cm ( 24 inches square ) will do it made up or as a kit I think with a choice of outlet sizes pipe is galv but we are going to check the temp it gets to when we try it Quote Link to comment Share on other sites More sharing options...
the iron dwarf Posted January 20, 2017 Author Share Posted January 20, 2017 fitted the hood and horizontal pipe and tried it out today, only had a bend on the end of it as it will be a few days before I can fit the stack but even as it is it draws ok. checked temp of galvanized duct to see if it was safe and after 3 hours the hottest it got was 25.5 degrees c ( 77.9 degree Fahrenheit ) next need to look up the melting / boiling point of zinc but I think it is way hotter duct is 150mm ( 6" ) bore and from the middle of the hood to the end of the horizontal is about 2m ( 78" ) at a guess if it works ok like this it will be much better with the flue straight up through the roof so we are testing it in the worst conditions we can Quote Link to comment Share on other sites More sharing options...
Daswulf Posted January 20, 2017 Share Posted January 20, 2017 I'm surprised it's working that high up from the forge. Looks like a nice hood. I'd double check but I think you are atleast good up to 4-500degrees F before the galvy is at risk. Keep up the testing. Quote Link to comment Share on other sites More sharing options...
the iron dwarf Posted January 20, 2017 Author Share Posted January 20, 2017 am planning on some removable extensions for the bottom of the hood, each will be about 60cm ( 24" ) long and 15cm ( 6" ) tall to fit on 3 sides as required and it will be possible to add more than 1 row at a guess it is 27" from the top of the forge to the bottom of the hood, can measure it tomorrow Quote Link to comment Share on other sites More sharing options...
Glenn Posted January 20, 2017 Share Posted January 20, 2017 Suggest that you lower the hood so it has a better chance to collect the smoke, instead of room air. Quote Link to comment Share on other sites More sharing options...
the iron dwarf Posted January 20, 2017 Author Share Posted January 20, 2017 the hood will soon have removable extensions to the lower edge so we can have good access and a lower hood if needed Quote Link to comment Share on other sites More sharing options...
the iron dwarf Posted January 25, 2017 Author Share Posted January 25, 2017 added some steel to the sides and front of the hood, it is getting better but still awaiting parts for the stack, hope that will be tomorrow and it can be tested properly then. checked melting point of zinc 420 degrees c max measured temp on bend is 36.5 degrees c, will keep checking it and monitoring the CO levels Quote Link to comment Share on other sites More sharing options...
Alan Evans Posted January 26, 2017 Share Posted January 26, 2017 Why have you mounted it so high above the hearth? I think mine is around 500mm above with 200mm hinged flaps which can hang down or flip up and lie back on the hood. Alan Quote Link to comment Share on other sites More sharing options...
the iron dwarf Posted January 26, 2017 Author Share Posted January 26, 2017 here are some pix of the added sides and front, after getting the rest of the bits we needed it was to cold to want to do much outside today so adding the stack will have to wait till next week. it draws as it is and will prob get better with the stack fitted, will suggest to others to start at 500mm above the forge and see if extra flaps are needed ours is much higher Quote Link to comment Share on other sites More sharing options...
the iron dwarf Posted February 12, 2017 Author Share Posted February 12, 2017 ok I think I can now make these, 500mm from top of forge to bottom of hood with added side plates and hinged / removable front plate will be the recommendations ( much lower than ours ). fix on wall or a frame can be supplied to bolt onto back of forge Quote Link to comment Share on other sites More sharing options...
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