What Causes Crazed Stove Glass?

After using your wood burner for a while, you may find that your stove glass develops a cloudy, milky or crazed pattern on the surface. In this post, we will explain what causes this and how it can be fixed and prevented.

What Causes Crazed Stove Glass?

It is highly unlikely that this has been caused by a faulty piece of glass. Cloudy, milky or crazed stove glass is caused by a combination of:

  • Burning low quality coal/smokeless fuel.
  • Burning fuel that has a high sulphur content. Examples include bituminous coal or manufactured coal that contains petroleum coke.
  • Burning a combination of wood and coal/smokeless fuel at the same time.
  • Slumbering the stove, or providing your fuel with an inadequate air supply.
  • Not cleaning the glass regularly enough.

Salamander Stoves Crazed Stove Glass

Image from coalpail.com

Cloudy, milky or crazed stove glass is caused by unburnt build-ups of acidic compounds. The incomplete combustion of fuel can lead to sulphur dioxide mixing with any condensation, or moisture that’s released from wood. This forms sulphuric acid, which is corrosive. This will etch a crazed pattern into the surface of the glass if it is not regularly cleaned.

Reducing the amount of air that enters the firebox will reduce the effectiveness of the Airwash system. This control helps to ‘wash’ these compounds away. Shutting the stove down will lead to incomplete combustion, which will result in acidic condensates settling on the stove glass.

Wood has a much lower sulphur content compared to coal or smokeless fuel, but it can still cause cloudy, milky or crazed stove glass if it is not burnt completely. Burning wet wood will also add to the problem, but tighter restrictions were placed on the sale of fuel back in May 2021.

How Can I Fix This?

Any cloudiness or crazing is purely cosmetic and it does not impact the performance of the glass. Unfortunately, it is very difficult to remove this without using a proprietary brand of grinding paste.

If it bothers you, then it is best to order a piece of replacement stove glass. We also have a video on how to change the stove glass for your Hobbit stove or Little Range.

If you go to the effort of removing the glass, then you might as well keep your small stove up-to-date with any other form of spares and maintenance. Ensure the baffle is not warped and check the rope seals. You can order a fire rope and glue kit if the gaskets are worn.

How Can I Prevent Crazed Stove Glass?

You can prevent cloudy, milky or crazed stove glass from developing by:

  • Burning dry, seasoned wood or high quality coal.
  • Ensuring there is always a sufficient amount of air entering the firebox. Keep the fire burning fairly vigorously and keep the Airwash control open.
  • Avoiding the incomplete combustion of fuel. Try not to slumber the stove overnight. Burn the stove hard for 20-30 minutes after periods of slow burning.
  • Regularly cleaning the glass to remove any possible build-ups. Clean the glass even if it does not look very dirty. Remove any build-ups of soot at the bottom of the glass and any soot that’s behind or between the front bars.
  • Do not mix wood with coal/smokeless fuel products. If you would like to mix the two, then ensure one fuel type is almost completely burnt before adding the other type of fuel.


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Our Hobbit Stove Has Been Fitted!

"We had a Hobbit stove fitted this week by Alex Reay from Flues and Fires, and I just wanted to get in touch to say it is AMAZING and we love it! We have a lovely cast iron tiled fireplace which I was desperate not to lose when we installed a small wood burning stove, but until I found the Hobbit on Google, everyone told me it would be impossible to keep the fire surround. The Hobbit is perfect - not only does it fit very snugly, but it looks fantastic and the blue door complements the tiles very nicely. We are sitting enjoying a fire now and absolutely loving it! Thanks for creating such an amazing product."

Nicola Williams

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The Best Stove Ever!

"It’s the best stove ever! It’s easy to light, very efficient, burns anthracite and stays in overnight (ours has been in for three weeks now). It even keeps a kettle of water at the ready for a cuppa! What more can I say, we love it! Just the thing to make our Yorkshire home cosy, and the cat loves it too!"

Lynn and Andrew, West Yorkshire

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First Small Stove Installation

Was looking for a small stove for my first self-install. Found Mark very helpful. Knowledgeable, friendly service. Stove burns well and generates lots more heat than the previous open fire. What is not to like?


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A Huge Thank You!

"Dear Mark and Gill, a huge thank you for designing and making the Hobbit stove! We had two different London-based fireplace companies tell us that we simply had to knock out the old cast iron and tile fireplace to fit in a woodburning stove, and that there was no other option! Then we found you online. We are delighted with our little Hobbit, which swallows up logs and kicks out a good amount of heat. Perfect for the winter! I will also be writing to the London-based fireplace companies to put the Hobbit on their radar. Best wishes."


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"Mark, Gill, thank you for your assistance, we are delighted with our Hobbit! I fired it up this evening after taking all afternoon making a register plate to fit the opening."


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It's Brilliant!

"Hi Mark, here's a photo of the Hobbit installed in my Yorkist grate. It’s brilliant! It also throws out a lot more heat than the grate did."

Roger T

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Just to Say Thank You!

"I just had a chat with Gill saying how delighted we are with our little Hobbit stove, and to also thank you both for your attention to detail and excellent customer service!"


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The Little Hobbit Has Stepped Up To The Challenge!

"We just wanted to say how impressed and how much of a life saver our little Hobbit has been! It was fitted a few months ago in our holiday home in Rhu, Scotland, which is a large open plan conversion in a Victorian house. This weekend our boiler decided it was not going to play ball. The little Hobbit has stepped up to the challenge, providing heat to a very large area, about twenty eight foot by twenty four foot with a high ceiling of about eighteen foot, keeping the room reasonably warm, warm enough for us not to use cardigans!”

Alan W

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"We are very pleased with the stove and think it looks great! We restored our fireplace (it was hidden under plaster!) and the whole look is better than we hoped!"


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"What a fantastic fireplace with the beautiful Hobbit stove. It fits perfectly into the small space and throws out a lot of heat. Here's a photo of our little stove, now our pride and joy and much admired by all who see and feel the warmth."

Chris and C

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"Just to bid you all a Happy New Year and to say how much we’re enjoying having our Hobbit stove! It was easy to fit with the help of your excellent ‘how to’ videos and we’re just awaiting our inspection by building control for the certification. The Hobbit has fitted neatly into the hearth vacated by the old gas back boiler (with a little cosmetic rendering) and never ceases to surprise us how much heat it can deliver to the point that the new condenser boiler is having an easy life, thereby saving us on gas bills too! Everyone loves having a ‘real fire’ in the living room."

Philip Baird

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A Brilliant Little Wood Burner!

"The stove we bought from you is really starting to come into its own as the weather cools down. Here is a photo showing how much one of our dogs is enjoying it!"

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Brilliant Product!

"Just wanted to share a picture of our newly installed Hobbit. Absolutely delighted with it, and so pleased we were able to retain our existing fireplace as well. Brilliant product, thank you!"



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