Stove Glass Crazing and Cracking, Why Does it Happen?


This article will cover the following

  • What is stove glass crazing/cracking?

  • What the professionals are saying about Stove Glass crazing/cracking

  • Hetas, the media and other Katie Sweep updates


Earlier in the month (August) I merrily set out sweeping on an early Saturday Crazy Crazing Myths and Mystery’s!morning, feeling all content and at one with the world.

I was booked in to sweep some of my long term regular customers chimneys who had wisely got booked in early for their annual sweep before the mad autumn rush commences… although we seem to be having a bit of a mad August rush actually! Not that we are complaining, but anyhow; I arrived at my first job of the day and was warmly greeted by the nice customer lady, offered a lovely cup of tea and shown into the familiar sitting room, as usual with absolutely everything unnecessarily sheeted over and news papered up, just old habits for some people I suppose.

What is stove glass crazing/cracking?

I was a little surprised to see what I  would  usually sweep  had vanished, and in its place stood a new new stove. The customer informed me they had changed it last year and were exceedingly pleased with it. So all good stuff, but I immediately noticed behind the sooted up door glass that it was severely crazed. After carrying out a thorough sweep & smoke evacuation check, I gave the glass a good clean with my super stove glass cleaning sponge to reveal the full extent of the Crazing…not so pretty!

I discussed the crazing of the glass with my customer, as well as the fuel used (seasoned logs along with Smokeless fuel) and how they operate the stove. I advised on best practice. Mrs Customer has asked if I will look in to the pricing for replacement glass for her, which I am in the process of doing. This all provoked my curiosity!

Us sweeps see this alllll the time, with different customers taking different approaches to the problem, some having no interest and no intentions what so ever of replacing their glass and are quite happy to live with it, whilst other customers are extremely concerned and rather miffed that the crazing is still happening after installing their 3rd piece of replacement glass.
So my search for others experiences and thoughts began. First I posted some of the pictures of the previously mentioned Stove glass on my Katie Sweep Facebook page, appealing to my fellow sweeps and customers to see if they had any more anecdotal experiences of crazing Stove Glass. I received a great response.

Crazy Crazing Myths and Mystery’s! 2What the professionals are saying about Stove Glass crazing/cracking

It seems a lot of people are equally baffled (excuse the pun) as to why this actually happens and why it is so common?
Thank you to Craig Forster, who is also an experienced NACS approved Sweep, Craig commented on my Facebook appeal and crazed stove glass photos with what I think is some really interesting ideas: -
 ‘’a quality stove with a powerful air-wash would not usually suffer this fate, when you refuel open the vents fully, if when you close it and if the glass goes misty your fuel is way too wet” ‘it could be wet wood simply mixing with the wood ash that makes it go milky? From what I’ve seen it  looks like smokeless fuel slumbered, worse if its mixed with the wood doesn’t help? I can only suggest  because of the extra water evaporating from the wood this might condenses along with the Sulphur from the smokeless onto the glass .

And thanks to Tom Helsby a HETAS Installer from down the road from me in York who commented with-
’’I think it can happen if the stove is regularly slumbered down too soon after adding new logs?  Perhaps the gases don’t get burnt off and they can etch the glass?’’

There was also then mentioning of...

’’Sulphuric acid is corrosive. If left for any length of time it will start to etch into the surface of the ceramic glass.  As the stove heats up the moisture boils away leaving a mixture of sulphur dioxide and sulphur trioxide which is a white powder.  it cannot be cleaned off, resulting in the cloudiness. When the glass is wiped with a wet cloth, it will first look as though the cloudiness has gone. But, as soon as the glass has dried, the white powder  appears again’’- unknown internet source.

All really interesting stuff.  If anyone else has any ideas plese let me or Phil know. Lets see if we can unravel this  mystery. The Facebook conversations also led on to the hot topic of Smokeless fuels and flexible flue liners...but that’s another long story for another day. Thanks to all for the brilliant anecdotes and thinking.

I have made enquiries with both HETAS & about the issue, rather than making assumptions. So there we have it!

Hetas, the media and other Katie Sweep updates

In other goings on this month as well as being ridiculously busy sweeping, I was delighted (and equally petrified) to receive a phone call asking (as HETAS approved experienced Chimney Sweep) if I would be interested in some possible PR appearances speaking to local and even nationwide media in connection to the upcoming Chimney Fire Awareness Week (5th – 11th of September 2016) talking to various media outlets about the importance of having your chimney swept regularly, and highlighting the upcoming awareness campaign being promoted by HETAS and Fire Kills. I will let you know all about how that goes in next month’s diary! Quite nerve-racking but far too good an opportunity to turn down… and I do like an adventure.

Speaking of adventures, I have just returned from a delightful yet brief road trip to Coventry …or Cotton Tree as my 3-year-old daughter calls it. We combined a business trip for husband Tom of Biomass Sweeping Solutions, with a family outing. The purpose of Toms business trip being to attend the grand opening at ‘GroFuel’ and meet Pete Turner and the team and spend the afternoon talking all things Biomass! Myself and the children popped in at the end to say a quick hello, but spent our time enjoying the sights and sounds of sunny Cotton Tree.Crazy Crazing Myths and Mystery’s! 3

To briefly mention some other exciting plans…We are in the process of adding a ‘Sweep Shop’ to my Katie Sweep website (which receives a heck of a lot of traffic at this time of year) selling all sorts of useful chimney and fire side accessory related products for our customers, available to buy online or direct from our sweep vans on our visit.  I have been busy as ever organising and chatting with all the nice people at Valiant, Grenadier, Chimney Sheep, Chimney balloon and a few others getting trade accounts in place and making plans.

My new  fire spares catalog has just arrived too, I best get looking the replacement glass section. I know our customers are going to love being able to simply and easily get the correct beneficial product for all their fireplace needs directly from us. All exciting stuff.

On a closing note, earlier this month I spotted a video clip of a prototype flueless wood burning stove design. Wow, what will they think of next! As someone who’s profession depends on appliances actually having flues this is not quite the technical advance I was hoping for, but never the less all very interesting, but let’s hope it does not take off!

(Check out previous Katie Sweep diary entries here)


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