A method to restore permanently etched fireplace insert glass

Hello Everyone. Here’s a process I have used to restore fireplace insert glass that has become permanently etched and cloudy over time. Not a problem for everyone, etching of ceramic glass does (or does not) occur depending on how and what you burn. Etching is different from the usual ash or soot layer that can be wiped away. In this demonstration I knew that the glass was etched, so I started with some strong acid to remove any alkali and organic deposits before following up with a cerium oxide polish to restore a smooth, optically-clear surface so I can enjoy the view again. Perhaps this will be helpful to some. The video link is below:

Great article, Mark! Before I retired Neoceram was about $10/sq inch. I'm sure it's much higher now. I like your idea better. Keep us posted on the life of your glass...how much longer it lasted. Also, using only the video as my information, it looks like you may have removed the firebrick baffle from inside your insert. Am I wrong on that? If you did, why not replace them? Firebrick splits are only one or two dollars each, and as I recall, Lopi's bricks across the top of the firebox are all standard sizes. They should provide a noticeable increase in efficiency from your unit.

Thanks. All the firebricks are actually in place. You might be noticing the large space above the forward recombustion tube and the ceiling of the firebox. After years of use, the forward tube became thin and then started to sag dramatically over the last season. Since making the video, I have replaced the tube. I had to cut the old tube out with a sawzall and, although the tube looked like it was about to fall down, it had a surprizing amount of strength left. Of course, it was cool at time I cut it. Because those tubes get red hot, it is not surprizing they would sag if the metal gets thin.

In the spirit of sharing information for the benifit of others (no flames please), I'll tell you that burning a single piece of CPVC scrap pipe produces corrosive hydrogen choride gas for several hours. That gas, coupled with the high temperatures, can put the equivalent of a few years of corrosion on the inside of your stove in just a few hours. Flakes of corroded metal may spall off the internals making "pinging" sounds as they pop off. Incomplete combustion of chorinated products also produces dioxins (which are carcinogenic). Welding and fabrication skills are helpful in the rebuilding of the internals. On the plus side, it makes very pretty blue flames... so there's that...

Is this video available to view?  When I click on it I get this message:  "null
If the owner of this video has granted you access, please sign in."  Please advise.

Sorry about that.  The new link is:

I shortened up the video.  Took out 20% of the long-winded blah blah.

I have watched hundreds of videos on cleaning glass but the ONLY one that got it RIGHT was Mark White's video. It took me hours of grinding away with cerium oxide but my ceramic glass is COMPLETELY restored - you've saved me some big bucks!  Many thanks!!

Hi folks.  Coming up on burning season here (I think).  Over time, my glass gets etched.  It's not just covered in soot; it's surface damaged - so no kind of "wiping" or wet newspaper trick is going to fix it.  I made a video of what I did to polish the glass perfectly clear.  It takes about an hour of work, but if you want to save some money (not buy new glass) then here you go.
https://youtu.be/9HnfIlqqaJk

Happy and safe burning!

I embedded it for you.

I did this polishing technique as directed and it worked. It was messy and took a bit. Thank you so much for the video.

My glass has very light scratches that I believe is from using an incorrect scrubbing pad in the past. Will this solution work for that or is it only for damage caused by heat from the fire like in the video?

My damage isn’t a cloudy haze like in the video, but more like micro scratches. Here’s the best photo I could take of it (very hard to focus the phone camera on the scratches rather than the fire, so I’ve circled it): https://ibb.co/pLjnZcC

I have found if you play with the air supply, the flame changes and very often self cleans the glass.
How clean and unblemished do you want?

Nice video…does this work on etching from propane?

The source of etching is irrelevant here - polishing with cerium oxide will restore a mirror surface to the glass. If scratched more deeply, it will not remove the texture without a lot more polishing, but will make it shiny while still micro-bumpy.

Altering the flame may clean deposits, but will not affect an etched surface if that is what has happened.