gdocktor3
Well-known member
The heatilator in my fireplace has a crack in the back from tossing a big log in. Is there some type of JB Weld or similar material I can patch it with that will bond cast iron and withstand high heat?
Crack In Cast Iron Heatilator
- Thread starter gdocktor3
- Start date
nadogail
Well-known member
Not to my knowledge, welding cast iron is very tricky.
rlitman
Well-known member
Doesn’t that risk blowing exhaust into the room?
Cast iron can be brazed, but I’m not sure that’s a good idea in a fireplace.
Cast iron can be brazed, but I’m not sure that’s a good idea in a fireplace.
Jim greengo
Well-known member
Can it be removed and taken to to a welding shop?
rsanter
Well-known member
They make epoxy for use in exhaust ports (for porting race engines)
Really tough stuff and never comes loose, but I don’t know about the alternate application.
Cast iron can be brased, but it can also be Mig welded with pre and post heating
Really tough stuff and never comes loose, but I don’t know about the alternate application.
Cast iron can be brased, but it can also be Mig welded with pre and post heating
Jim greengo
Well-known member
Well that's what I was wondering,if it could be taken out reasonably easy or not.
Epoxy in a fireplace? Nope.
Generally, some 'better' epoxies might be able to withstand about 500-600F, while the 'regular' epoxies are usually only able to with stand 150-300F.
Hmm, took a quick look with some google-fu on "high temp epoxy" and JB-Weld has a product that is 'rated' to withstand 2400F.
JB Weld ExtremeHeat paste. I've never used it, so YMMV.
https://www.jbweld.com/product/j-b-extremeheat
Home Depot lists it on their web page, $24 for a 3 oz jar. Ouch. Although less expensive than a 'competent' weld or braze repair.
Cast iron can be (sometimes) brazed or (sometimes) welded to repair a crack.
There are several approaches to either type of repair, both usually involve rather large amounts of heat input for preheat and then a VERY slow cool down (usually in a temperature controlled oven/furnace or in a very well insulated cover/container/whatnot). Slow as in cool down from 'hot' down to room temp in 12 hours or so.
Heatilator as in some pipes with a manifold all inside the fireplace that pull room air through the pipes, the air then gets heated inside the hot pipes, and then the now hot air gets circulated back into the room?
If so, the situation is not just an esthetic crack, but a structural/functional problem.
Because you do NOT ever-ever-ever want any crack in a 'furnace' air heat exchanger because of the carbon monoxide danger.
Even without the air circulator fan running (if you have one) and just with passive air circulation, the CO danger is still present big time.
No matter what, you NEED to fix it ASAP.
And until it IS fixed, the fireplace is red-tagged and OUT-OF-SERVICE completely.
Generally, some 'better' epoxies might be able to withstand about 500-600F, while the 'regular' epoxies are usually only able to with stand 150-300F.
Hmm, took a quick look with some google-fu on "high temp epoxy" and JB-Weld has a product that is 'rated' to withstand 2400F.
JB Weld ExtremeHeat paste. I've never used it, so YMMV.
https://www.jbweld.com/product/j-b-extremeheat
Home Depot lists it on their web page, $24 for a 3 oz jar. Ouch. Although less expensive than a 'competent' weld or braze repair.
Cast iron can be (sometimes) brazed or (sometimes) welded to repair a crack.
There are several approaches to either type of repair, both usually involve rather large amounts of heat input for preheat and then a VERY slow cool down (usually in a temperature controlled oven/furnace or in a very well insulated cover/container/whatnot). Slow as in cool down from 'hot' down to room temp in 12 hours or so.
Heatilator as in some pipes with a manifold all inside the fireplace that pull room air through the pipes, the air then gets heated inside the hot pipes, and then the now hot air gets circulated back into the room?
If so, the situation is not just an esthetic crack, but a structural/functional problem.
Because you do NOT ever-ever-ever want any crack in a 'furnace' air heat exchanger because of the carbon monoxide danger.
Even without the air circulator fan running (if you have one) and just with passive air circulation, the CO danger is still present big time.
No matter what, you NEED to fix it ASAP.
And until it IS fixed, the fireplace is red-tagged and OUT-OF-SERVICE completely.
I have worked in the hearth appliance field in the past for over 10 years. I would recommend not using that fireplace anymore. In cases like this, we would likely have recommended installing a wood burning insert to keep the fireplace functional. This involves cutting out some of the heatilator tubes in order to insert a liner into the existing chimney. Not a cheap option, but it does give you a more efficient appliance in the end.
metlmunchr
Well-known member
- Joined
- Sep 10, 2011
- Messages
- 1,281
How long is the crack? Just cracked, or did the log knock a chunk out of the casting?
Personally, I'd stick weld it with 99% nickel rod using the cold welding technique where you make short welds with peening and allowing time between the welds for cooling such that the area around the crack doesn't get very hot. The downside to this is, if you can't do it yourself, you could easily spend upward of $1000 to hire someone with a portable welding service to come in and do the job turnkey. Even so, that would only be a fraction of the cost of replacing the unit.
Depending on the extent of the crack and it's separation and location, you might be able to seal it with sodium silicate (water glass) and a heat gun for curing. There's a lot of information out there on sealing with water glass. The material itself is cheap, and once it's cured, it remains in solid form at temperatures well in excess of 1200*F. Repair cost would be near nothing, but you'd have to invest the sweat equity in figuring out how to attack your specific situation. I've used water glass to successfully repair a crack in the combustion chamber of a diesel cylinder head, but that wouldn't be applicable in your case.
Personally, I'd stick weld it with 99% nickel rod using the cold welding technique where you make short welds with peening and allowing time between the welds for cooling such that the area around the crack doesn't get very hot. The downside to this is, if you can't do it yourself, you could easily spend upward of $1000 to hire someone with a portable welding service to come in and do the job turnkey. Even so, that would only be a fraction of the cost of replacing the unit.
Depending on the extent of the crack and it's separation and location, you might be able to seal it with sodium silicate (water glass) and a heat gun for curing. There's a lot of information out there on sealing with water glass. The material itself is cheap, and once it's cured, it remains in solid form at temperatures well in excess of 1200*F. Repair cost would be near nothing, but you'd have to invest the sweat equity in figuring out how to attack your specific situation. I've used water glass to successfully repair a crack in the combustion chamber of a diesel cylinder head, but that wouldn't be applicable in your case.
Well no matter what it can't be used because the smoke enters the living room via the vents in the side. I was considering an insert, but I have a wood stove in the basement for heat. This is basically a twice a year, cuddle with my girl around the fire type thing. That's why I asked about a cheap epoxy fix. I'll likely never use the damn thing, but nice to have that option...
rlitman
Well-known member
That’s what I suspected. Knowing that for sure, I would say it is not repairable. What you effectively have is a furnace with a cracked heat exchanger. There is no safe fix for this, and it is not worth risking your like on epoxy.
BD1
Well-known member
Can you get to it to and see it ? A Nickle stick rod doesn't need much room but you need to get arm in there to weld.
Calling a boilermaker shop or heating contractors would be best.
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Calling a boilermaker shop or heating contractors would be best.
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Can it be repaired? Maybe. It will be costly and with old, dirty heat cycled cast I would want to be able to get on it to do the repair. Meaning clear clean access and I doubt you have that. Perhaps we should re-direct and talk about other ways to create ambiance those couple times a year with your girlfriend