Karl Posted December 18, 2020 Report Share Posted December 18, 2020 Hi All. I had a problem recently were i was getting condensation like oil or tar running down the outside of the flue pipe in the boat and dripping onto the top of the stove and making a horrible burning smell. I thought id fixed it by re sealing in from the top but it started again last night. Now I've gone a step further and dug out the seal between the flue and the collar on the roof. What a messy job ! Anyway I Have taken the flue pipe out and cleaned it all ready to put back but there is a quarter inch gap all round the top of the flue pipe to join the Collar on the roof. Some people have said use an exhaust bandage, some say a fire rope seal and some say both with a fire sealant top and bottom. As i don't know what size thickness rope to use anyway is an exhaust bandage better. I want to get this done right and not to lek again. Advice please ! Link to comment Share on other sites More sharing options...
GUMPY Posted December 18, 2020 Report Share Posted December 18, 2020 (edited) I used exhaust bandage as it's what I had to hand. Had to roll it to make it thick enough as mine is 4" flue in a 5" collar. Filled top and bottom with Envirograf High Temperature Silicone. Seems to do the job. Edited December 18, 2020 by Loddon Link to comment Share on other sites More sharing options...
nb Innisfree Posted December 18, 2020 Report Share Posted December 18, 2020 29 minutes ago, Karl said: Hi All. I had a problem recently were i was getting condensation like oil or tar running down the outside of the flue pipe in the boat and dripping onto the top of the stove and making a horrible burning smell. I thought id fixed it by re sealing in from the top but it started again last night. Now I've gone a step further and dug out the seal between the flue and the collar on the roof. What a messy job ! Anyway I Have taken the flue pipe out and cleaned it all ready to put back but there is a quarter inch gap all round the top of the flue pipe to join the Collar on the roof. Some people have said use an exhaust bandage, some say a fire rope seal and some say both with a fire sealant top and bottom. As i don't know what size thickness rope to use anyway is an exhaust bandage better. I want to get this done right and not to lek again. Advice please ! Stuff fire rope/bandage tightly into gap and seal with high temp silicone (I prefer bandage) then fit a double skin chimney, when it's placed on flue outlet it will allow outer skin to fit over the outside of chimney collar and inner skin to fit inside flue pipe, then stuff will drain either onto roof or back down into the fire. Link to comment Share on other sites More sharing options...
Tony Brooks Posted December 18, 2020 Report Share Posted December 18, 2020 Personally I would force some 8mm fire door rope down into the gap from top and bottom and then leave enough of a gap to fill with heat resistant silicon. then ft a double skin to the chimney so the inner skin fits inside the flue and insulae the gap between both skins. Link to comment Share on other sites More sharing options...
bizzard Posted December 18, 2020 Report Share Posted December 18, 2020 Just use cheap silicone, its all fire resistant. Link to comment Share on other sites More sharing options...
Jen-in-Wellies Posted December 18, 2020 Report Share Posted December 18, 2020 I'm with Bizzard on this. If the silicone at the roof collar gets too hot for normal silicone sealant to cope with, then the entire boat is probably ablaze and the flue seal is the least of your problems! I've sealed flues to roof collars with fibreglass rope, plus silicone, but have also used just silicone on its own, as the bead will bridge a reasonable sized gap on its own without falling through. Only did it because I didn't have any spare rope, but it worked. Jen Link to comment Share on other sites More sharing options...
bizzard Posted December 18, 2020 Report Share Posted December 18, 2020 I think I've mentioned it before. I did an experiment with the stuff. I put a blob of £10 so called fire resistant silicone and a blob of cheap £1.50p silicone on my shovel. Stuck it onto the red hot coals in my stove and watched what happened. After a while both types just crumbled away at exactly the same moment, neither caught alight. Link to comment Share on other sites More sharing options...
Jen-in-Wellies Posted December 18, 2020 Report Share Posted December 18, 2020 11 minutes ago, bizzard said: I think I've mentioned it before. I did an experiment with the stuff. I put a blob of £10 so called fire resistant silicone and a blob of cheap £1.50p silicone on my shovel. Stuck it onto the red hot coals in my stove and watched what happened. After a while both types just crumbled away at exactly the same moment, neither caught alight. The only difference may be that one has actually been through the official fire safety tests and the other has not. Link to comment Share on other sites More sharing options...
Guest Posted December 23, 2020 Report Share Posted December 23, 2020 I had the exact same problem - used Geocel flue silicone (no rope): https://www.geocel.co.uk/products/trade-mate-plumber-flue/ No leaks in four months. I had the chimney off last week and it looks as I did when I first sealed it. I know that's not a particularly long test, but it's all I have. Link to comment Share on other sites More sharing options...
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