Sarah and Ian Posted May 15, 2013 Report Share Posted May 15, 2013 Hello All How long does this product take to go off. Or does it cure or go off when their is a moderate fire lit. My old experience of fire cement was that it went if very quickly. Thanks in advance. Link to comment Share on other sites More sharing options...
Ex- Member Posted May 15, 2013 Report Share Posted May 15, 2013 (edited) Hello All How long does this product take to go off. Or does it cure or go off when their is a moderate fire lit. My old experience of fire cement was that it went if very quickly. Thanks in advance. If you require this for a boat stove chimney, personally I wouldn't use a cement that sets rock hard as the Victus products seem to do. Boats vibrate and have a lot structural of movement, Our stove collar was supplied with Intumescent putty which is a non setting and far superior product. It's called FJC Putty here http://www.canalshoponline.co.uk/contents/en-uk/d25.html 9th product down. Edited May 15, 2013 by Julynian Link to comment Share on other sites More sharing options...
Guest Posted May 15, 2013 Report Share Posted May 15, 2013 Hello All How long does this product take to go off. Or does it cure or go off when their is a moderate fire lit. My old experience of fire cement was that it went if very quickly. Thanks in advance. We have given up on hard setting cement - you are forever having to re-apply it as it cracks and falls out after only a month or so. Far better to use a high temp silicone or something else that doesn't completely set hard. Link to comment Share on other sites More sharing options...
Mac of Cygnet Posted May 15, 2013 Report Share Posted May 15, 2013 (edited) It's called FJC Putty here http://www.canalshoponline.co.uk/contents/en-uk/d25.html 9th product down. From the spec: "Must not be used either where the pipe will be hotter than 250 °C (482 °F), or directly onto heating appliances." So how have you found it then? I've used something called Envirograf http://www.envirograf.com which is supposed to withstand 1200deg C. It has worked but be warned that even when cured as per instructions, the first time a hot stove is lit it produces the most awful noxious fumes for about half an hour. I had to evacuate the the boat. In Wigan. In the rain. Edited to say that it was the silicone sealant I used, sold to me by a stove shop in Hebden Bridge, but looking again at the link, they seem to have more suitable products for the job. As a matter of fact I've had the stove out this morning to remove a top damper and this time I've packed the gap between the flue and stove collar really tightly with stove rope bedded in with stove rope adhesive. I'm not adding anything else until I see how this performs. Edited May 15, 2013 by Mac of Cygnet Link to comment Share on other sites More sharing options...
Boaty Jo Posted May 15, 2013 Report Share Posted May 15, 2013 Yes, that Canalshop putty looks inappropriate. Just come across Fortafix here: http://www.fortafix.com/high-temperature-fire-resistant.html There seem to be a couple of alternatives but I don't think they're flexible when cured (datasheet indicates rigid on one of them). Hereto I've not seen anything that is 300 degrees plus that is flexible. Link to comment Share on other sites More sharing options...
Ex- Member Posted May 15, 2013 Report Share Posted May 15, 2013 Yes, that Canalshop putty looks inappropriate. Just come across Fortafix here: http://www.fortafix.com/high-temperature-fire-resistant.html There seem to be a couple of alternatives but I don't think they're flexible when cured (datasheet indicates rigid on one of them). Hereto I've not seen anything that is 300 degrees plus that is flexible. Well it's been on our chimney for 8 years, the chimney was changed 4 years ago and I reused the same putty again. Also Bubble stoves supply the same stuff when you buy one of their chimney fitting kits. Ive never had and fumes leaks using it. Intumessent putty is also used in ships engine room bulkheads to prevent fire ingress through bulkheads where cables & pipes run. If it's good enough for them it's good enough for me. Also any boiler stove chimney should never reach 250 degrees. Link to comment Share on other sites More sharing options...
onionbargee Posted May 15, 2013 Report Share Posted May 15, 2013 If you require this for a boat stove chimney, personally I wouldn't use a cement that sets rock hard as the Victus products seem to do. Boats vibrate and have a lot structural of movement, Our stove collar was supplied with Intumescent putty which is a non setting and far superior product. It's called FJC Putty here http://www.canalshoponline.co.uk/contents/en-uk/d25.html 9th product down. intumecent is a materiel that expands to seal off air supply to a fire, used in buildings, doors windows ect, i'm not sure this putty is intumscent ? Any how, high temp silicone is used to seal flues. Link to comment Share on other sites More sharing options...
Mac of Cygnet Posted May 15, 2013 Report Share Posted May 15, 2013 Well it's been on our chimney for 8 years, the chimney was changed 4 years ago and I reused the same putty again. Also Bubble stoves supply the same stuff when you buy one of their chimney fitting kits. Ive never had and fumes leaks using it. Intumessent putty is also used in ships engine room bulkheads to prevent fire ingress through bulkheads where cables & pipes run. If it's good enough for them it's good enough for me. Also any boiler stove chimney should never reach 250 degrees. I'm afraid you are mistaken, although I don't quite know what you mean by 'boiler stove chimney'. I think we are talking about the stove/flue seal, not the chimney. From a stove manufacturer's website: A traditional steel or cast iron stove can reach temperatures of 400 to 500 degrees Celsius, creating a small radius of intense heat. I certainly would be alarmed if my stove reached 500 deg C, but it can happen. Link to comment Share on other sites More sharing options...
Ex- Member Posted May 16, 2013 Report Share Posted May 16, 2013 I'm afraid you are mistaken, although I don't quite know what you mean by 'boiler stove chimney'. I think we are talking about the stove/flue seal, not the chimney. From a stove manufacturer's website: I certainly would be alarmed if my stove reached 500 deg C, but it can happen. Any stove that heats water ie a stove with a back boiler will not heat up to over boiling point otherwise you would be superheating water. I'm only talking of the flu and chimney cowl where cement has been used to seal the flu inside the collar. I don't quite understand where fire cement would be required anywhere else other than the collar and where the flu pipe joins the stove. Link to comment Share on other sites More sharing options...
smileypete Posted May 16, 2013 Report Share Posted May 16, 2013 Would help if the OP came back and told us where they want to use the fire cement, might be ideal or completely unsuitable.... cheers, Pete. ~smpt~ Link to comment Share on other sites More sharing options...
Boaty Jo Posted May 17, 2013 Report Share Posted May 17, 2013 Any stove that heats water ie a stove with a back boiler will not heat up to over boiling point otherwise you would be superheating water. ??????????????????? Link to comment Share on other sites More sharing options...
Paul C Posted May 17, 2013 Report Share Posted May 17, 2013 So there's 2 kinds of fire sealant: Fire cement - which dries hard, and is prone to cracking High temperature silicone sealant - flexible, but only good to approx. 250°C Is this a reasonable summary or is there some kind of magic product out there which can be used on the top of a stove, yet is still flexible? Link to comment Share on other sites More sharing options...
matty40s Posted May 17, 2013 Report Share Posted May 17, 2013 Any stove that heats water ie a stove with a back boiler will not heat up to over boiling point otherwise you would be superheating water. ??????????????????? Boaty Jo- keeping your logs and smokeless nuggets simmering at 95 deg C is an art you have not yet mastered??? Link to comment Share on other sites More sharing options...
Sarah and Ian Posted May 17, 2013 Author Report Share Posted May 17, 2013 The cement is for where the chimeny meats the stove. I was advised for not getting the silicone as its not rated hire enough tempreture wise for the being that close to the stove. Link to comment Share on other sites More sharing options...
Ex- Member Posted May 17, 2013 Report Share Posted May 17, 2013 Well my stove has a back boiler which obviously contains water, the flue outlet is no more that 3 inches away from that boiler section. If the boiling point of water is 99.98c then explain how a flue joint just 3 inches away it will reach 250c It might get slightly hotter being slightly higher, but no where near 250c Also we sit a kettle on top of the stove directly next to the same the flue outlet, the kettle has never boiled,or boiled over, the stove would need to burn hotter than 100c to do that. Of course you could also go to 300c http://www.sealantsandtoolsdirect.co.uk/fireplace_and_heat_resistant_products/everbuild_purimachos_fire_heat_resistant_silicone_P24019.html Appreciated non boiler wood burning stoves would get hotter, but who would want all the hassle of one of those Link to comment Share on other sites More sharing options...
Mac of Cygnet Posted May 17, 2013 Report Share Posted May 17, 2013 (edited) Well my stove has a back boiler which obviously contains water, the flue outlet is no more that 3 inches away from that boiler section. If the boiling point of water is 99.98c then explain how a flue joint just 3 inches away it will reach 250c It might get slightly hotter being slightly higher, but no where near 250c Also we sit a kettle on top of the stove directly next to the same the flue outlet, the kettle has never boiled,or boiled over, the stove would need to burn hotter than 100c to do that. Of course you could also go to 300c http://www.sealantsandtoolsdirect.co.uk/fireplace_and_heat_resistant_products/everbuild_purimachos_fire_heat_resistant_silicone_P24019.html Appreciated non boiler wood burning stoves would get hotter, but who would want all the hassle of one of those Where do I start? Your back boiler only works because your stove (including the part where the flue exits) is waaaayyyyy above 100deg C. a lot of the time. The boiler itself will rarely reach 100 deg C (but it can - we sometimes hear the water boiling in our back boiler in the woodburner at home). Many stoves will exceeed 250 deg C where the flue joins the stove. I'll assume you're just being a bit naughty in your last comment. If you look at my post #4 you'll see a link to products with a much higher spec than 300deg C Edited May 17, 2013 by Mac of Cygnet Link to comment Share on other sites More sharing options...
Guest Posted May 17, 2013 Report Share Posted May 17, 2013 Good post Mac, I'd lost the link to a suitable product, Now sorted. Link to comment Share on other sites More sharing options...
Ex- Member Posted May 17, 2013 Report Share Posted May 17, 2013 Where do I start? Your back boiler only works because your stove (including the part where the flue exits) is waaaayyyyy above 100deg C. a lot of the time. The boiler itself will rarely reach 100 deg C (but it can - we sometimes hear the water boiling in our back boiler in the woodburner at home). Many stoves will exceeed 250 deg C where the flue joins the stove. I'll assume you're just being a bit naughty in your last comment. If you look at my post #4 you'll see a link to products with a much higher spec than 300deg C Blimy that's amazing. My flue outlet which I've just measured is actually only 2 inches away from the top inlet water pipe. Again how can and area limited to 100 degrees then produce 250c just 2 inches away. Also a diesel stove will automatically cut off if water point exceeds max. Again the kettle sits directly against this outlet and never boils, I would suggest temps of 250 degrees would boil that water, even is slightly to the side. The intumescent putty I used was supplied by Harworth heating, It's worked fine for 7 years + It's also really good spanning the wide gap between the chimney cowl and flu pipe. The other high temp cauking products are probably based on intumescent putty anyway. Link to comment Share on other sites More sharing options...
Paul C Posted May 17, 2013 Report Share Posted May 17, 2013 2 inches is plenty of room for a boundary layer of a fluid to exist, and produce a large temperature differential across. Diesel burns cooler than solid fuels - when we replaced our diesel stove with a solid fuel one, we had to rip out the old fireplace and suitably upgrade it. Link to comment Share on other sites More sharing options...
Ex- Member Posted May 17, 2013 Report Share Posted May 17, 2013 (edited) 2 inches is plenty of room for a boundary layer of a fluid to exist, and produce a large temperature differential across. Diesel burns cooler than solid fuels - when we replaced our diesel stove with a solid fuel one, we had to rip out the old fireplace and suitably upgrade it. That's incorrecet, if your talking boiling temperature, the temperature one side of this water boundry is 100c and the other over100c then the 100c + side would boil the water on the hot side of the boundry. As soon as that would happen the stove would shut off anyway. However in this case it's not a boundry the water inlet it's adjasent to the backboiler behind it. Any heat difference would be minimal and no where near 250c. Edited May 17, 2013 by Julynian Link to comment Share on other sites More sharing options...
Paul C Posted May 17, 2013 Report Share Posted May 17, 2013 Its not incorrect. You don't seem to appreciate/know what a boundary layer in fluid dynamics is. I have a degree in the subject, was trying to keep things on an understandable basis though by not using too technical terms.... Link to comment Share on other sites More sharing options...
Ex- Member Posted May 17, 2013 Report Share Posted May 17, 2013 (edited) Its not incorrect. You don't seem to appreciate/know what a boundary layer in fluid dynamics is. I have a degree in the subject, was trying to keep things on an understandable basis though by not using too technical terms.... Well there's no boundry other than the steel thickness of the stove. Any water in a confined space which was heated at 98 degrees on one side, and if the temperature the other side was 120 degrees Then the water would not boil. I would love to know how and why that wouldn't happen. I can accept a small difference in temperature from a part of the stove with water in a boiler will be say 98 degrees. How is then could be as much as 250c just 2 inches away traversing just steel plate would also be most interesting. Edited May 17, 2013 by Julynian Link to comment Share on other sites More sharing options...
Boaty Jo Posted May 18, 2013 Report Share Posted May 18, 2013 Hang on, hang on. Either I'm being daft, this is a wind-up or someone's mistaken. Water flows through the back-boiler either via convection or by use of a pump. It's an independent circuit. The water does not just 'sit' in a back-boiler. Water comes in cool, gets heated up and sets off to radiators (and perhaps calorifier) to disperse the heat and returns to the back-boiler again to be re-heated. You need to have enough 'heat dump' (radiators for example) to enable you to disperse the heat in the water circuit otherwise the water will boil. Do not count the calorifier in this calculation because once that's hot it will not disperse any more heat because it's insulated. Stews / kettles / veggy steamer boil away happily on top of our stove. If I've missed the point here please ignore this post. Link to comment Share on other sites More sharing options...
nicknorman Posted May 18, 2013 Report Share Posted May 18, 2013 (edited) Well there's no boundry other than the steel thickness of the stove. Any water in a confined space which was heated at 98 degrees on one side, and if the temperature the other side was 120 degrees Then the water would not boil. I would love to know how and why that wouldn't happen. I can accept a small difference in temperature from a part of the stove with water in a boiler will be say 98 degrees. How is then could be as much as 250c just 2 inches away traversing just steel plate would also be most interesting. You are forgetting that air / flue gasses is a fluid. A fluid is not necessarily a liquid. Light a blow torch. Hold your finger 2 inches to the side of the flame. It will be cool. Now move your finger 2 inches into the flame. It will disappear in smoke and steam. So in a fluid such as air, you can have very large temperature gradients. By the way, don't try the above unless you still have plenty of spare fingers. Oh, and you can get silicone sealant rated up to 1200 deg. I replaced our crumbling fire cement with this stuff and its been perfect ever since. Something like this: http://www.hotline-chimneys.co.uk/fire-cement-smoke/high-temperature-silicone-black.html Edited May 18, 2013 by nicknorman Link to comment Share on other sites More sharing options...
Ex- Member Posted May 18, 2013 Report Share Posted May 18, 2013 You are forgetting that air / flue gasses is a fluid. A fluid is not necessarily a liquid. Light a blow torch. Hold your finger 2 inches to the side of the flame. It will be cool. Now move your finger 2 inches into the flame. It will disappear in smoke and steam. So in a fluid such as air, you can have very large temperature gradients. By the way, don't try the above unless you still have plenty of spare fingers. Oh, and you can get silicone sealant rated up to 1200 deg. I replaced our crumbling fire cement with this stuff and its been perfect ever since. Something like this: http://www.hotline-chimneys.co.uk/fire-cement-smoke/high-temperature-silicone-black.htm But steel plate is also convecting heat and it's the steel where the sealant is applied. The internal stove gasses I agree are much hotter, but at the end of the day the collar where the flue goes into the stove being just 2 inches away from the water top outlet would not reach 250 degrees. I'm aware of the silicone, the point about the putty is it's good for spanning large gaps, it's consistency is of stiff plasticine and can span and cope with a much larger gap that silicone, so ideal for roof collars. Water flows through the back-boiler either via convection or by use of a pump. It's an independent circuit. The water does not just 'sit' in a back-boiler. Well it's not independent of the stove is it. It has to be in contact with it for it to heat. Stews / kettles / veggy steamer boil away happily on top of our stove. Well sounds like a woodburner, I hardly think it's boiling at 250c though. Your central heating fluid must be boiling too I would suggest. Water flows through the back-boiler either via convection or by use of a pump. It's an independent circuit. The water does not just 'sit' in a back-boiler. Water comes in cool, gets heated up and sets off to radiators (and perhaps calorifier) to disperse the heat and returns to the back-boiler again to be re-heated. The water re enters the stove cooler, so in affect cooling it. Water left in the boiler would superheat causing steal pressure. Link to comment Share on other sites More sharing options...
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