putting small window on wood furnace help

I have a Fire Chief wood furnace and would like to put a small window on the door or somewhere so I could see how it is burning without opening the door. Has anybody done this? If so where did you get the heat resistent glass? thanks :greenchainsaw:

I never put a window in a door that didn't have a window already. But, I did break the glass in my Harman Mark II stove last year. I just measured it and went to the local glass store. They are in any phone book. I told them what I needed it for and they had it right there no problem...

I have an old homemade stove in my workshop that was here when I bought the place that I put a window in. I just got a little glass square from Mcmaster. I don't remember exactly what it was, but it was rated to super high temp and it's lasted a year now with now issues.

Your are looking for pyrex glass that you can get at a local glass store. Put a gasket around the glass and build some stops to hold in the glass and your all set. Go to a fireplace shop and look at a woodstove with glass in it and copy that.


Rob

028 user said:

I have a Fire Chief wood furnace and would like to put a small window on the door or somewhere so I could see how it is burning without opening the door. Has anybody done this? If so where did you get the heat resistent glass? thanks :greenchainsaw:

Click to expand...

You will want an air wash for the window to keep it clean. Otherwise it will gunk up and the fire wont be visible.

The airwash lets in just a little bit of air and directs it across the fireside of the window. It keeps a thin layer of cllean air between the smoke on the inside of the stove and the glass. The air keeps the smoke from geting to the glass and staining it.

It shouldn't be hard to do the glass is available. taxidermist gave a good idea, look at how it was done before and follow their example. Just make sure the glass doesnt fit snugly or it might crack from expansion of the frame in the heat.

I built a new door for mine with a 10" x 10" window.
I'll post up some pics and more details tonight for you.
It really is nice to be able to see the fire and tune your air.

window

I really would like those pictures. Where did you get the glass? Does it get black? Do you have a Fire CHIEF? thanks

I got too busy last night installing my compressor for my helper bags.

Plus, it was too warm for a fire!

I'll try to get some pics again tonight.

I got my glass online, EDIT: here>>http://www.onedayglass.com/neoceram.php

It can get dirty, depending on how I have the air adjusted.
usually just some ashy stuff that wipe away easily though.
I am working on an air wash setup.

see sig for furnace.

Check your local glass shop for transparent ceramic glass. It's sold by the square inch.
http://www.robaxglass.com/prop.htm

nice glass.. but it's .47 to .60 cent per sq inch

definitely for smaller high temp windows...

my glass is 400 sq inches.... or $200 for a piece of glass... :censored:
good thing mine works fine with tempered glass.

ray benson said:

Check your local glass shop for transparent ceramic glass. It's sold by the square inch.
http://www.robaxglass.com/prop.htm

Click to expand...

window in furnace (air wash?)

How do I go about the air wash setup if I cut in a window in the door of my wood furnace? thanks

KsWoodsMan said:

It shouldn't be hard to do the glass is available. taxidermist gave a good idea, look at how it was done before and follow their example. Just make sure the glass doesnt fit snugly or it might crack from expansion of the frame in the heat.

Click to expand...

Actually, glass(ceramic) has a much lower coeffecient of expansion compared to metal. When it heats up, metal expands far more than glass will.

028 user said:

How do I go about the air wash setup if I cut in a window in the door of my wood furnace? thanks

Click to expand...

Make your bracket/frame for the glass large enough for a gasket to go around the glass and fit snugly, holding it in.
Make the gasket only long enough to go around 3 sides of the glass and a small portion of the remaing 4th side at the corners.
The air that gets around the gap, at the top, will be directed down across the glass giving you an airwash. The upper corners may end up with some soot but it cleans easily with ashes and warm water once it has cooled.

YMMV

OK so it is quick and dirty. We have some great minds in play here. There are sure to be some better or more attractive ways of doing this.

WetBehindtheEar, In my mind the lower density of the glass allows it to heat quicker. Expanding faster than the steel door. If it is too snug it make create uneven pressure on the glass causing it to break. If the door warps that cant be good on the glass either. Good point to bring up, Thanks.

If the glass is wrapped by a fiber gasket this should take care of tight spots and allow for the door to warp some.

here are a few pics.
The door is made of 3/8 plate steel.
the "glass" is neoceram. cost about $60 I think.
the glass retainers were made from 1/2" steel, and have some gasket material between the glass and retainers, so the metal and glass never touch.





Getting the firebox warmed up...

And here are a few pics of the fire and secondaries after it's up to temp.

I modified the firebox last year. I piped in some air for a secondary burn, and added 2 widths of firebrick to the top shelf. So the fire has to travel a lot further forward across the top before it heads to the back again and out the flue.
Please dismiss the random chunks of brick in the back. I haven't cut any nice pieces yet.

KsWoodsMan said:

In my mind the lower density of the glass allows it to heat quicker. Expanding faster than the steel door. If it is too snug it make create uneven pressure on the glass causing it to break. If the door warps that cant be good on the glass either. Good point to bring up, Thanks.

If the glass is wrapped by a fiber gasket this should take care of tight spots and allow for the door to warp some.

Click to expand...

Glass has a lower density but its thermal characteristics are different than metals. Glass and ceramics, by nature are insulators and have a lower coefficient of thermal conductivity than metals.

From my Engineering materials books and this website:
http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

glass(es) have a range from 0.04 (fiberglass insulation, duh) to 1.05. Steel is listed as having a coefficient of 46 W/m K (Watts per meter-Kelvin)

Lower numbers equal lower transmission of thermal energy (heat).

Glass doesn't heat as quickly as metal, it doesn't expand as much as metal given the same thermal environment.

I'll try to include a scan from my textbook (haven't cracked this thing in 10 years). :monkey:

I'm not trying to be all high and mighty about this - knowlege is power and we can use this knowlege in future applications for our wood burning adventures!

My .02
I researched the "glass" for many hours.
neoceram seemed so expensive...

Bottom line, this stuff is tough as nails. You can spray it with a hose when it's 1000 degrees+. It doesn't scratch with ash and grit.

There really is no other choice in a furnace application.
Your glass breaks, and you have a serious problem. whether you are home or not.

Give everything some room to move, and you'll be alright.

If it's worth doing, it's worth doing right.