# Forum Home Renovation Heating & Cooling  What glass for woodheater?

## montiee

As you can see from the above pic the woodheater I've nearly finished restoring (at least from the rear end) has a broken glass pane. As part of the restoration I was thinking of replacing the entire door anyway and going with glass that is one piece. 
Anyone know the spec I should be asking for when I ring the glaziers wrt the glass that can be used in fireplaces (woodheater). 
Any idea how much it'll set me back? Dimensions are 340mmx250mm 
Any recommendations for places in Sydney. Prefer non fireplace vendors as I'd rather not get ripped off due to the limited nature of these vendors. 
Many Thanks
Montiee.

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## Smurf

I'm not certain on this, but I've heard the glass used in these referred to as being ceramic so that's what I assume it is. It sure does withstand a lot of heat which would crack or even melt ordinary glass. 
I must say though that I've never seen a wood heater that looks quite like that one before. What make is it? I assume it's pretty old?

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## montiee

> I must say though that I've never seen a wood heater that looks quite like that one before. What make is it? I assume it's pretty old?

  Yeh it would have to be at least 40-50 years old. Made by A.E Goodwin in Sydney and called the "Wonder heater" according to the badge.. 
I was going to dump it on the scrap heap until I saw new heater go from $1.5k for a super cheapo. I wanted to get into welding and a bit of metal work and this was the project. Didn't care if I stuffed it up but it worked out pretty well (see http://www.woodworkforums.com/showthread.php?t=92572 for the start of it all and a basic work diary if you are interested). 
Ignoring the price of the welder it's been a relatively inexpensive (albeit basic) restoration process (~$100 for materials and that included mig gasless wire, metal sheet, metal rod and High heat(1000F) spray paint). Yet to use the spray paint but that's going on in the next few days weather permitting. 
Now looking at redoing the door and glass panel and that'll be it. Door will cost me under $10 but got a feeling the glass is going to cost a bit.. 
At the end i'm left with a unique looking woodheater (actually it looks alot better than that pic would have you believe) and a discussion topic as well as having learnt how to weld. Win all around..

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## Bloss

Most fireplace  shops have fireplace glass or can get it as can glass suppliers. Not all that expensive. Take care when removing the surround to replace - almost certainly will be asbestos fibre rope and or putty used to seal the glass. Just use a mask and clean up well afterwards. You'll need a suitable fibreglass rope and fireproof sealing putty to use instead.  :2thumbsup:

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## montiee

> Most fireplace  shops have fireplace glass or can get it as can glass suppliers. Not all that expensive. Take care when removing the surround to replace - almost certainly will be asbestos fibre rope and or putty used to seal the glass. Just use a mask and clean up well afterwards. You'll need a suitable fibreglass rope and fireproof sealing putty to use instead.

  Thanks. I figured the rope in there might be asbestos based... I'm not all that keen on touching the door to repair what's there. If I do replace it it'll be a complete throw away item as it's not in the best of shape. I'll just cut one hinge off and pull it out and knock up a brand new door from scratch.

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## montiee

Seems my options are tempered glass or ceramic glass. Ceramic is better as it allows more heat to transfer, is clearer as well as being more shock resistent to heat changes. Tempered glass I guess is what they used to use in the old days. 
I rang up one place close by and was quoted ~$90 for the ceramic glass for the size I wanted. Don't know how competitive this is but I'll seriously start ringing around early next week. 
As for the firerpoof rope I couldn't find any signs of it's usage on the unit with the exception of the door where it's used to hold the glass firmly against the steel frame and it wasn't exactly replaceable since the cover was welded into place. Perhaps the rope was flat and adhered to the frame surround with some cement but over the years it fell off and wasn't replaced by the original owner. I assume modern heaters use rope around the door surround as a sealing mechanism. Might rock up into a BBQ galore and see what's on display to get an idea of how modern designs do it.

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## Smurf

> I assume modern heaters use rope around the door surround as a sealing mechanism. Might rock up into a BBQ galore and see what's on display to get an idea of how modern designs do it.

  I'm not certain how old mine is, but the house was built in 1995 so I assume the heater would be no older than that. It has two uses of fibreglass rope: 
Thin rope between the glass and the door as a seal.  
Thick rope right around the door where it seals against the body of the heater when the door is closed. 
When I moved into the house, I had the heater checked by a professional as I was a bit worried about how close it is to the wall (they said it's fine). They cleaned the flue and also replaced the thick rope, saying they only last a few years and it seemed to never have been replaced. I don't remember the exact cost but it was less than $100 for the inspection, flue clean and rope so I was quite happy with that.  
Another thing they made me aware of is to make sure there are no unintended air leaks anywhere. Excess air getting in will cause the fire to burn hotter which will eventually burn out the heater. Even a fairly small gap in a door seal or a burnt-out air inlet pipe (I don't think most heaters have these, but mine does) will be enough to raise the temperature of the fire too much so it's worth keeping a check on these.

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## montiee

> I'm not certain how old mine is, but the house was built in 1995 so I assume the heater would be no older than that. It has two uses of fibreglass rope: 
> Thin rope between the glass and the door as a seal.  
> Thick rope right around the door where it seals against the body of the heater when the door is closed.

  Yeh I saw that when I went into BBQ's galore today. Mine definitely does not and never had any rope around the door surround. It does have it on the glass panel against the door frame. There isn't any U channel in the door frame for a rope. When I rebuild the door I might change that.   

> When I moved into the house, I had the heater checked by a professional as I was a bit worried about how close it is to the wall (they said it's fine).

  Well mine sits inside a bricked chimney so no problem there. 
I was stunned how crap the new woodheaters are from a design point of view. It's the way I would of designed it without thinking to hard about it and if I wanted to cut major corners :lol:. Its essentially just a steel box surrounded by another steel box and they want 3k-5k for that?.. Looking at mine it's excellently engineered to get the maximum heat out into the room by increasing surface area not only on the outside of the firebox but inside (have a look at the two large "beams that run through the firebox interior. It isn't just a simple box. To be honest once this thing burns out I will be more than happy to build a woodheater from scratch following the existing design except out of thicker steel and materials will probably set me back no more than $500. If I was to replicate the modern woodheater it's probably be $300. We've definitely moved away from superior design to cheap quick and nasty but forgot to lessen the price it seems here in Australia. I guess that's what happens when competition is so low due to the low demand of wood heaters here over gas/electric. 
I explained my design to the sales guy and he had a feeling it was borrowed from a canadian design. You know you are onto a good thing when the design comes from a decently cold country where high btu's are a must rather than what we get here. 
I love how the sales guy went on about 10 year firebox warranty and then I pressed him on how much for the outside box to which he replied 1 year :lol:. From my experience it's the outside box that died on mine with the interior holding up relatively well all things considering it's age poor upkeep. Once the outside goes it's not that great if it's sitting in a bricked chimney venting heat up it rather than into the room. Different story I guess you have one of those units sitting in the middle of the room. 
Apologies for rambling on. I really enjoyed doing this project and learnt quite a bit and really glad I got into welding...It's going to save me a fortune in alot of projects I have in mind.

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## Smurf

The one I have was designed and manufactured locally (Tas) by a company that's no longer in business. 
It has a fairly thick firebox, two air inlets adjustable plus another two non- adjustable and the top panel inside is easily replaceable (and that's the part most likely to wear out). It's a freestanding unit (not in a fireplace) and easily heats the whole 3 bed house.  
The person who checked it told me it's rated at 11kW maximum output in normal operation (top air fully open, bottom air inlet closed). The bottom air is opened only to get the fire going, then closed for normal running with heat output adjusted by the top one. 
Only hassle with it is there's a bar through the top and that has almost worn out now (though I've patched it up for now). It could be replaced with a bit of work - a job for next Summer.

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## montiee

> It has a fairly thick firebox, two air inlets adjustable plus another two non- adjustable and the top panel inside is easily replaceable (and that's the part most likely to wear out). It's a *freestanding* unit (not in a fireplace) and easily heats the whole 3 bed house.

  I think this is the important bit (bolded). The simplistic design will work for a free standing unit because funnelling air to the front of the unit is not all that important. It's all going into the room surrounding it. It'll be alot worse if it's used in a brick chimney. In my unit alot of stuff is directing air towards to front vents. Something the free standing models don't even attempt to do, at least not the ones I've seen.. I have a feeling the majority of heaters these days would be free standing but instead of redesigning it properly for a chimney version they re-use the free standing design which imho is ill suited for an enclosed chimney.

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## stats2001

Montiee, Sorry for the bumping of this post, but I have a very similar heater here at a building that we have just purchased. I have a question for you.....Did you manage to get the door off in one piece, or did you cut it off? I need to replace the glass too, and think it would be much easier with the door removed. 
Looking forward to hearing from you !!! 
Mark.

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