Hot metal smell - Roxul?

[SculptureOfSound]

Hi all

Recently installed the used vc Montpelier I picked up and am getting a hot metal smell on each fire once it gets up to about 500 degrees or more.

I did repaint the unit with stove bright, but only really painted what is visible from the flush install, the top was in ok shape. Just a bit of paint up top in the vents.

I also put Roxul up as a block off plate (will complete the metal block off soon) and have Roxul against the sides and back of the firebox. This Roxul on back and sides is touching the insert, however in my test burns in the driveway the back and sides didn't get too hot due to the unit being insulated by design (it uses a ceramic insulation behind the refractory bricks and also on the sides and back of the cast body, which is then covered in a sheet metal shell).

Could this smell be the Roxul off gassing??? Do you think it's still the paint? I've only had 3 or 4 fires taking it over 500.

I also used some meeco stove cement on the liner where it connected to the collar, and within the liner itself (a thick bead to seal the gap between the inner and outer flange...not sure if im wording that right). The liner is mostly duravent rigid oval duraliner with 3 feet of flex at the bottom.

Could it be this stove cement that smells?

I'm at a loss but am quite worried to keep burning as I've got a one year old and don't want to put him in any danger.

 

[SculptureOfSound]

I'm not even sure it's a hot metal smell. It smells kind of like when the furnace kicks on the first time in the year, that burning dust smell but quite a bit stronger. Somewhere between that smell and hot metal.

Curious if anyone who has had Roxul up against the sides or back of the insert has had any weird smells when they burn or maybe only for the first few burns (burning off Roxul binding agents maybe??)

 

[webby3650]

Was the insert used?

 

[SculptureOfSound]

Yes it was used and definitely burned in prior

 

[webby3650]

I bring in used stoves all the time, usually a few different ones each season. They all have a smell, and they will keep smelling for a while. It’s often just a recent used furnace smell you described, along with whatever smells were in its previous home. It’s weird, but i can smell the previous home in a used stove for a pretty long time, even after a full repaint. It goes away in time.

 

[NateH]

So the Roxul is safe where it’s at?

 

[webby3650]

So the Roxul is safe where it’s at?

I wouldn’t recommend burying the stove in it, but touching it sure isn’t going to be a problem. Hitting it with a propane torch doesn’t even alter the stuff, a jacketed stove sure won’t.

 

[NateH]

I wouldn’t recommend burying the stove in it, but touching it sure isn’t going to be a problem. Hitting it with a propane torch doesn’t even alter the stuff, a jacketed stove sure won’t.

Hmm. I’m installing my stove and stove pipe right now. I was going to put it right behind my Durock backer board so very close to the masonry adapter passing through my chimney. I think this should be okay right?

 

[SculptureOfSound]

Anyone have issues with their Roxul that touches the liner smelling when things get hot?

If so, how long until it went away?

 

[Bushels20]

I actually was going to start a thread on this same topic; I searched first and found this. I just added a block off plate this week and had our first fire tonight.

I too notice a smell. Your description of somewhere between firing up the furnace for the first time and hot metal is a good one.

I too sealed my block off plate with sealant. It is rated for up to 1385 degrees Fahrenheit. I then insulated above the block off plate and then around the insert with Roxul/mineral wool rated for up to 2000 degrees Fahrenheit. There are no concerns of anything burning/igniting or even being a fire risk. But i too am wondering if the newly installed block off plate and insulation may be off gassing/going through a “seasoning” or “break in” period similar to the way a new stove does with odd smells.

Anyone have any input? Like the OP, I have young ones too. More worried about them than anything else. Could care less about the smell as long as it’s not dangerous and will go away with time.

 

[SculptureOfSound]

Bushels, did you burn your insert prior to the block off and have no smell?

 

[SculptureOfSound]

Btw you didn't you galvanized steel for your block off did you? Galvanized will off gas at around 500

 

[Bushels20]

Bushels, did you burn your insert prior to the block off and have no smell?

Correct.

 

[Bushels20]

Btw you didn't you galvanized steel for your block off did you? Galvanized will off gas at around 500

Yes i used galvanized. It is pretty widely accepted on here that galvanized is an acceptable type of steel to use however. Is the off gassing a one time thing?

 

[SculptureOfSound]

Well with galvanized it's the zinc coming off and it can be pretty wicked from what I've read. Look up metal fume fever, something welders can get from the fumes of galvanized steel.

 

[webby3650]

I actually was going to start a thread on this same topic; I searched first and found this. I just added a block off plate this week and had our first fire tonight.

I too notice a smell. Your description of somewhere between firing up the furnace for the first time and hot metal is a good one.

I too sealed my block off plate with sealant. It is rated for up to 1385 degrees Fahrenheit. I then insulated above the block off plate and then around the insert with Roxul/mineral wool rated for up to 2000 degrees Fahrenheit. There are no concerns of anything burning/igniting or even being a fire risk. But i too am wondering if the newly installed block off plate and insulation may be off gassing/going through a “seasoning” or “break in” period similar to the way a new stove does with odd smells.

Anyone have any input? Like the OP, I have young ones too. More worried about them than anything else. Could care less about the smell as long as it’s not dangerous and will go away with time.

Is yours also a used insert?

 

[webby3650]

Well with galvanized it's the zinc coming off and it can be pretty wicked from what I've read. Look up metal fume fever, something welders can get from the fumes of galvanized steel.

Galvanized is a commonly used metal for a blockoff plate. It’s not an issue.

 

[SculptureOfSound]

I'm no expert on galvanized. Maybe it is safe to use I just heard that the zinc can start to vaporize around 500 degrees and got worried it might get that hot right next to the liner. I'll defer to the experts on that.

Anyhow, back to the Roxul smell. Surely others have experienced this if it is indeed the Roxul. Lots of people have Roxul right against their liners

 

[Bushels20]

Well with galvanized it's the zinc coming off and it can be pretty wicked from what I've read. Look up metal fume fever, something welders can get from the fumes of galvanized steel.

I’m not sure that’s what is actually happening. I ran my install plans and materials past some of the more experienced guys on here before buying anything or starting to install anything. Galvanized steel was perfectly acceptable for this application.

My guess is if we give it enough time, we will get some good info here soon on this thread.

I’m guessing this is a pretty normal thing after a new block off plate install. Or at least I’m hoping...

The smell isn’t terrible. Just something “different”.

 

[Bushels20]

Is yours also a used insert?

Used In that it has been in my home for 6 years heating our home (without) the block off plate up until, tonight. I bought the unit new 6 seasons ago. This will be year 7 and year 1 with a block off plate and Roxul around the insert.

 

[SculptureOfSound]

Bushels, did you let your Roxul off gas at all prior to install or was it fresh out of the bag? I had some Roxul in the open fireplace last year (just as insulation as we weren't using it last year) and no issues there. The Roxul I used in the install though about a week ago was fresh out of a new bag and had no time to off gas before the install.


What worries me is that formaldehyde is used as a binder in the production of Roxul, along with who knows what else.

 

[Bushels20]

Bushels, did you let your Roxul off gas at all prior to install or was it fresh out of the bag? I had some Roxul in the open fireplace last year (just as insulation as we weren't using it last year) and no issues there. The Roxul I used in the install though about a week ago was fresh out of a new bag and had no time to off gas before the install.


What worries me is that formaldehyde is used as a binder in the production of Roxul, along with who knows what else.

Mine is fresh out of the bag.

Roxul too is a very widely accepted application. I don’t think there are any health concerns. I’m more worried about whether the smell will go away with time.

 

[begreen]

It should go away soon. Perhaps you are smelling dust that got knocked down on the insert and is getting heated up? Or dust on the inside of the convection chamber of the insert that settled on top of the firebox as the block-off plate was installed?

 

[SculptureOfSound]

Roxul is used in another domain that is atypical - it is used by studio folk recording music as sound/bass traps.

I've been reading threads on that and some people do have issues with fresh Roxul off gassing. It seems like some Roxul is much stinkier out of tht bag, too, while some is effectively odorless. Probably due to some variation in the final "cook" process it goes through.

Anyhow, not trying to stir up fear but I think it is good to consider all possibilities.

The smell really built up in our house as the fire burned, even with windows open.however as I've got Roxul on the sides and back of the insert I've got a lot more of it heating up. It dissipated pretty quick though once the fire cooled down

 

[begreen]

"Roxul has argued that virtually all of the formaldehyde in the binder it used was driven off by heat during the manufacturing process. “The result is no measurable free-form formaldehyde in the final product and no volatile organic compounds that can off-gas,” the company said in an email forwarded to GBA in 2014. Three types of Roxul mineral wool are already listed by GreenGuard, a certification program designed to help builders choose products with low chemical emissions."
https://www.greenbuildingadvisor.com/article/mineral-wool-makers-dropping-formaldehyde-binders