Materials used to line fireboxes - a test

[precaud]

Thanks for the support, guys.

It seems to me he’s providing reassurance to those who may have stoves with cast iron liners that might see your findings and think that they have purchased the wrong stove.

karri0n, apparently it's a moderator's job to protect the feelings of those folks. Seems like nonsense to me. I don't think such a user will ever even read a thread like this. If they're so upset, perhaps Hearth.com can start a new forum/support group for them. Iron Liners Anonymous, maybe.

kksalm, keep us posted on what you do and how it turns out.

Dexter, I'm not familiar with the Firelight. Is this a liner under the top plate? Or is it the baffle? Can you post a pic of this?

What thoughts might you entertain on how to modify, the thinner “Fire Brick” (space and economics may leave many in this scenario)?

ml, what's their thickness? The ones used in most modern stoves are 1.25" thick, called "splits' in the industry. I only looked briefly, and don't know of a good source for them yet. Am hoping someone will discover and post one. There's a guy on eBay selling some but they're the old heavy type.

And yes, the sunrises/sunsets are wonderful...

 

[Dexter]

PreCaud:

Re: your last. Mine is an early version of what is now the 600 cb. I use 1.25 split firebrick (whitish/grey). It is held over the secondary burn tubes 3/16" using cold-rolled steel dowls. I used a hand-held dremmel-type cutting tool and a borrowed diamond blade to cut them into an approximately 14 3/4" square of bricks. I still use the insulating blanket over the top of them. 'Third season burning this way. 'Seems to work well. Chimney cleaning is about the same. Got firebricks at a hardware store in Boulder. Their motto is: "If we don't have it, you don't need it."

Regards,

Dexter

 

[karri0n]

Precaud, The only source I've managed to find is firebricks.com, and it seems they only supply to furnace manufacturers and the like. What was the source that you used for the pieces that you fabricated?

 

[kksalm]

I usually check here first
http://shop.ebay.com/?_from=R40&_trksid=m38&_nkw=ceramic+firebrick&_sacat=See-All-Categories
Cheers, kksalm

 

[precaud]

Glad to hear it's working well, Dexter. The store in Boulder, does it happen to be McGucken Hardware?

karri0n, I've looked at firebricks.com before but the problem is the very sketchy info they provide about each item. No K factor at any temperature, no compressive strength, nothing about color, no hardness, and most have no density spec. Some of these are needed to see if it will stand up to use in a woodstove environment. It would be a crap shoot ordering from them.

 

[begreen]

precaud, what have you found as the closest second to the Zircar material? Would zirconia bricks be similar?

http://www.zircoa.com/assets.common/pdfs/insulating.structures.pdf

also found this company offering various refractory brick compositions
http://www.mcgillswarehouse.com/Itemslist.aspx?GroupID=12211&GN=INSULATINGBRICKS

I'm also wondering about refractory bricks for glass kilns and the like. They come in standardized sized similar to wood stove sizes, but no idea about their durability.

 

[kenny chaos]

If we're brain storming here then any silly idea is okay to throw on the table?
How about making some good old fashion vermiculite panels?

 

[precaud]

Give it a try. I bought some but haven't used them. My thinking says anything in the flame path is better if it's white. Or at least starts out that way

I pulled out the bottom liner of the F602 today, two cast iron pieces weighing 8 lbs each, with a 1/4" sheet of ceramic wool underneath. The dimensions of the stove floor are 9-1/8" x 16-1/4". Standard 9" IFB's will fit nicely down there and should hold up fine on the floor - this will raise interior temps another notch. I'll be looking around the 'net to find some this weekend. Something in the 1-1/4" to 2" thick range.

Added: Vermiculite does have some nice properties for use in a wood stove:
http://www.opie-woodstoves.co.uk/skamol.htm

My Nestor Martin has Skamol panels on the sides and had a Skamol baffle too. I replaced the baffle with Kaowool M Board, resulting in the firebox heats up much quicker, and the 2ndary burn is hotter and more intense. I'm tempted to replace the side panels too.

"Vermiculite is the geological name given to a group of hydrated laminar minerals, which are aluminium-iron magnesium silicates."

My experience is that it is not as insulative as it's decent K values suggest. Certainly better than an iron/ceramic sandwich but not as good as the ceramics.

 

[precaud]

precaud, what have you found as the closest second to the Zircar material? Would zirconia bricks be similar?
http://www.zircoa.com/assets.common/pdfs/insulating.structures.pdf

Corrected: Zircoa is a different company than Zircar. They appear to be using the same Zirconium-based materials as the basis for their sheet, brick, and custom-shaped products. I talked at length with one of the Zircar apps people, he agreed RS-1200 was overkill pricewise for a wood stove, but might be the only thing they had rugged enough to hold up to abuse. He said their ZIRCAL-95 material has similar properties at half the price of RS-1200 but has less abrasion resistance so I think we'd have to check it out before recommending it. But at $32 per sq ft., even that stuff is pricey.

also found this company offering various refractory brick compositions
http://www.mcgillswarehouse.com/Itemslist.aspx?GroupID=12211&GN=INSULATINGBRICKS

Yes, I saw their stuff and wrote to them, the prices are good but no real specs. They have nothing in 1-1/4" thickness.

I'm also wondering about refractory bricks for glass kilns and the like. They come in standardized sized similar to wood stove sizes, but no idea about their durability.

You're on the right track, as that's the main appplication area for all of these materials, and the durability vs. low K factor is the issue for us. That's exactly what I'm looking into. And also some possible surface treatments to make the bricks more durable. like ITC 100 HT and ITC 296:
http://www.axner.com/axner/equipment/itc-ceramic-coatings.php
Again, pricey stuff...

 

[begreen]

Were you able to locate a retailer for zircoa bricks - 9 x 4.5 x 1.25"? If so, do you know what are they running per brick?

 

[precaud]

The apps guy said McMaster-Carr sells their stuff. But I look on their site and they don't identify the manufacturer, so we don't know who makes what. MC doesn't sell any 1.25" brick... only 2.5".

This co. has some 3/4" brick that looks interesting, halfway down the page:
http://www.zoellerforge.com/flare.html

And this 2" thick stuff looks promising:
http://cgi.ebay.com/Firebrick-kiln-ceramic-oven-15-pr-bx-Morgan-K-28-silica_W0QQitemZ290263097610

 

[jebatty]

Finished reading the entire thread and very interesting. My old SeeFire (bot 1990) has a fully lined firebox with, I assume, the dense yellow firebrick. It is, except for backup heat when we're gone, our only heat source - 19 heating seasons now. I replaced about 1/2 of the firebrick 8 years ago due to deterioration. We live in a very cold area (saw -36F twice this winter), windy, etc. We burn 4-5 cords of aspen each heating season.

I didn't notice cost info on the various materials, except the RS-1200 at $63 sq ft. That's about the cost, if I bought it, of 1 full cord of aspen where I live.

What is the bank for the buck of the various materials? What is the gain in btuh output from the increase in efficiency? What is the durability relating to pushing/throwing in fresh logs which hit the back of the firebox? What is the longevity of each material and payback as to useful life under normal home stove usage and increased btuh output? How easily is each type of material formed, cut or broken to fit a stove (the firebrick lay right in my stove as the firebox is designed to hold full bricks)?

Although the fire in the firebox may be hotter with some materials, unless the stove is designed for that material, will the extra heat be usable? ...will it just go up the chimney because it no longer can be radiated through the sides and can only radiate from the top and the flue? Is it possible that the air intake design for a particular stove (with dense yellow firebrick, for example) produces a very efficient burn with good heat radiation, and that burn no longer will be correct for a different "firebrick" lining?

I am reaching the point when more firebrick will need to be replaced in my stove and some real world economics and performance would be useful in deciding which material to use. Thanks.

 

[precaud]

jebatty, I just wrote a thorough response and apparently didn't click on submit... so here we go again.
You ask good questions. Some of them cannot be answered by me, as I only have so much time and resources to give to this experiment.
Some will find answers as the process unfolds, and as other users experiment with their stoves and post the results.
It's unlikely that hard figures of btu increases or efficiency percentage gains will come out of this experiment.
Workability: Most refractories can be cut using normal woodworking tools. Some may require special masonry blades.

Although the fire in the firebox may be hotter with some materials, unless the stove is designed for that material, will the extra heat be usable? ...will it just go up the chimney because it no longer can be radiated through the sides and can only radiate from the top and the flue?

Huh? Perhaps you should read again... the only experiment thus far resulted in higher temps inside and out.

Is it possible that the air intake design for a particular stove (with dense yellow firebrick, for example) produces a very efficient burn with good heat radiation, and that burn no longer will be correct for a different “firebrick” lining?

Unlikely. A good air system design will be able to take advantage of a better environment for combustion to occur. But a change in lining material will not correct for a bad air design. The F602 is a good example of this.

 

[precaud]

duplicate post, sorry

 

[precaud]

Here's a photo of the original F602 cast iron liners for the bottom of the firebox, weight 16 lbs, alongside one I just made from 1" vermiculite slab, weight 4.5 lbs. The vermiculite cuts like butter on a tablesaw.

The side runners were necessary to get the Zircar side panels at the proper height. Jotul had 1/4" ceramic wool under the iron liners, so I'll leave that in place under the vermiculite and reinstall the stove tonight for burn tests tomorrow and Tuesday. Fortunately I cut the stovepipes so that it only takes about a half hour or so to swap the stoves...

 

[kenny chaos]

I saw this and pictured precaud piecing together high tech insulation to blanket the globe, hence, global warming.
http://photoblog.msnbc.msn.com/archive/2009/02/12/1792539.aspx?GT1=43001

 

[begreen]

Note, this is for an F602CB and not for the original F602. The bottom liner (one piece) is different on the F602.

 

[68 Couper]

Today I was at TSC in the area and they had a pallet of fire bricks for sale at 2.50 each on clearance. They had a light orange color and were not as heavy as the bricks at Menards. Could these be the better variety?

Thanks,
Couper

 

[precaud]

Note, this is for an F602CB and not for the original F602. The bottom liner (one piece) is different on the F602.

Huh? I've never heard of an F602 that was not a CB.

 

[precaud]

Today I was at TSC in the area and they had a pallet of fire bricks for sale at 2.50 each on clearance. They had a light orange color and were not as heavy as the bricks at Menards. Could these be the better variety?

Lighter weight is a good thing. Ask them for more data. For lining the side walls I'd want something with less color, i.e. as close to white as possible.

 

[begreen]

Note, this is for an F602CB and not for the original F602. The bottom liner (one piece) is different on the F602.

Huh? I've never heard of an F602 that was not a CB.

The 602 had a long life before they added the secondary air assembly for EPA qualification and the CB designation. IIRC it first showed up in the 1940s. We have the pre-EPA version. Great little stove. It has a record of being one of the most popular stoves sold. Here's a picture of the 602 in the back row. It's the red model, one from the right, next to the green unit on the right. Our's is the identical unit, same color and even has the same trivet top. There's a black one in the upper back corner too.
https://www.hearth.com/visit/woodsmans/source/1505jotuls.html

 

[precaud]

That's 602, not an F602. You and I have extolled the virtues of the old 602 many times on this site.

 

[begreen]

My bad, the numbers got blurred in my fuzzy mind. I just looked at the old parts diagram that I 'thought' had it listed as an F602 and no, it's a simple Nr. 602.

 

[precaud]

Does your 602 diagram show an internal bottom liner? I don't remember mine having one.

 

[begreen]

There is an iron bottom liner and insulation of some sort underneath. I'll scan the copy and will post it in the Jotul stove wiki area.