Metallic coating flaking off my Stuv wood stove door glass

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Pedro61

New Member
Oct 21, 2021
1
Nelson, BC
My relatively new Stuv stove (used one season) is flaking off tiny pieces of shiny metal flakes in one irregular shaped section. I have only ever cleaned the glass with a damp paper towel and fine ashes, almost every morning before firing it up. Any ideas on what's going on here? Defective IR coating? Thanks in advance!
 

stoveliker

Minister of Fire
Nov 17, 2019
2,923
Long Island NY
There should be no metal coating on the glass. Could it be (shiny) creosote?
A picture would help.
 

begreen

Mooderator
Staff member
Nov 18, 2005
91,355
South Puget Sound, WA
Some stove glass, like Neoceram, has an option for a heat-reflective coating. This is to reflect infrared heat back into the firebox. If that is the case with this Stuv, the bond may have broken down.

Screen Shot 2021-10-27 at 5.46.06 PM.png
 
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stoveliker

Minister of Fire
Nov 17, 2019
2,923
Long Island NY
I find that rather strange. Metallic coatings don't do well (expand when the glass does less so, especially high temp glass). Also, I like the radiative heat from the window.

Anyway, I learned something. Thanks.
 

begreen

Mooderator
Staff member
Nov 18, 2005
91,355
South Puget Sound, WA
Check out the warranty and see if this is covered.
 

Corey

Minister of Fire
Nov 19, 2005
2,626
Midwest
Neoceram/pyroceram 'glass' has essentially zero thermal expansion - that is why they use it for stove glass. So expansion/contraction issues are non existent. Plus, the IR coating is typically an atomically thin metalized layer... you can see through it,, after all... so not like bending a plate of steel.

You mention flaking off and cleaning the glass - is this on the inside of the stove? As shown in the pic, the metal layer should be on the outside. Though again, it's a few atoms thick, so not like there is much to 'flake off'.

Pics would help a lot. I have noted creosote to build up and flake off - sometimes in interesting patterns.
 

stoveliker

Minister of Fire
Nov 17, 2019
2,923
Long Island NY
Neoceram/pyroceram 'glass' has essentially zero thermal expansion - that is why they use it for stove glass. So expansion/contraction issues are non existent. Plus, the IR coating is typically an atomically thin metalized layer... you can see through it,, after all... so not like bending a plate of steel.

You mention flaking off and cleaning the glass - is this on the inside of the stove? As shown in the pic, the metal layer should be on the outside. Though again, it's a few atoms thick, so not like there is much to 'flake off'.

Pics would help a lot. I have noted creosote to build up and flake off - sometimes in interesting patterns.

IR coatings are on the order of a micrometer thick, not by far atomically thick. IR wavelength is ~1-20 um. And metallic coatings expand whereas the glass does not - the mismatch between this expansion and non-expansion is one of the main reasons coating delamination in all fields. (that's what I meant to say)
 

EbS-P

Minister of Fire
Jan 19, 2019
1,725
SE North Carolina
Is it possible that the glass was put in the wrong side out?
 

begreen

Mooderator
Staff member
Nov 18, 2005
91,355
South Puget Sound, WA
It would help to have a picture of the issue. The neoceram image shows the coating on the outside. Other coatings are available on this glass. One is half-mirror. I don't know what Stuv uses and we have not seen the problem, so I am just guessing this may be the issue. The best place to start is with the dealer or Stuv tech support.