light firebricks

Dear all,

I have been looking to make fire bricks a few times.
I am now in the Netherlands, materials are easy to get, however I would like to see if I can make a mix myself, also to use in different countries.

I have been looking at a good few recipies s here and elsewhere.
Sawdust and clay mix is one of the best insulative materials if baked of at 1050 C

Mortars with portland and lime would be an idea too. Where the Portland starts to disintegrate the lime takes over,
but I don't see ti being used with sawdust.

Now as I don't have a pottery oven, I can't bake off clay.

So I was thinking, could one make a mix with clay, portland, lime and sawdust?
Where the portland starts to disintegrate, the lime takes over, and where the lime starts to disintegrate the silicates in the clay are already baked off.
Would this be an idea?

Cheers Bart

Bart : Can you get your hands on Ciment Fundue ? non Portland type cement ?

Here is a good source from learning to make your own, this site is specific for Pottery and bread/pizzaovens

But very useful ! Check out the other articles and links !


http://www.traditionaloven.com/tutorials/concrete.html

For the Good of the Crafts ! Big AL

Hi Bart Meijer

I am not sure what research you have done, but it isn’t cost effective outside of a lab, or advanced ceramic studio to really make your own “firebrick” or “kiln brick”....lightweight or otherwise. Remember, that much of the “DIY” and “new inventor” stuff on the internet is not accurate information...I can't tell you how many times a week someone tells me…”well I saw it on YouTube…” or I read it in a chat room…

Your suggested recipes are not robust enough either I am afraid to withstand the temperatures to vitrify the interstitial silicates and other materials properly, as firebrick starts at 1450°C (2642°F) and range up to 1650°C (3002°F)

If I have missed your point some how please let me know…

Regards,

j

Here is a link to an interesting conversation about Making your own fire brick.

Hi Big Al, J

I have been looking at that site indeed, and was looking at the fireclay and mortar mix
where to find fireclay

At the other hand I have been looking at the insulative proportions of several mixies amongst others the one with sawdust and clay.
insulative ceramics

Why am I looking into this and not simple and available fireproof concrete, well as Peter v. d. Berg states and did research aht if a rocket burner is light and highly insulative, it works a lot better.
The better the insulation rate, the higher the temp in the burn tunnel,

Cheers Bart

...Why am I looking into this and not simple and available fireproof concrete, well as Peter v. d. Berg states and did research aht if a rocket burner is light and highly insulative, it works a lot better. The better the insulation rate, the higher the temp in the burn tunnel...

Yes, it is true that any combustion chamber...be it a RMH's or a ceramic kilns is going to function better in complete utilization of fuel burn whenever there is better insulation. Nevertheless, there is a balance point of "functionality vs other factors"...such as longevity, etc.

None of the listed materials in the articles and thus fare will meet the "durability" side of this equations as they cannot endure the temperatures reached within the burn chamber...or at least not for a reasonable time frame before a "rebuild" would be required. I must also point out (that sounds snarky...apologies for that, but my brain is moving back into the blunt language of the science lab) that homeostasis in design of anything is also a vital focal point.

There is much "wheel inventing" on the internet these days, and folks coming here to Permies to examine and debate ad nauseam points that are already well put to rest. These "fruitless" experiments that so many conduct on the web...often distract from actual good design.

With that said...I do love creativity, and experimentation...as new (or often old) discovers are made (or remade.) So what I try to do is "boil down" posters question/comments into simple components.

Yes you can create and insulative brick...

The ones suggested will not support the temps of the combustion chamber for a reasonable duration or endurance...

Do you have others ideas that may withstand these high temps?

Will your final goal actually exceed current designs standards for efficiency by just using simple firebrick and mineral wool insulation and light cobb mixes as so many excellent designs already achieve?

Regards,

j

So I was thinking, could one make a mix with clay, portland, lime and sawdust?

No...not able to withstand temps.

Hi Jay,

It more or less sounds like; Stay within the borders of that what has already been used and proven safe to use, and durable.
Don't look any further, for most will be worthless to look at anyway.

Portland/lime combination has been used for ages, sometimes only with lime. This also is mentioned on the traditional oven site.
So, why would this not be good enough for rocketstove cores?

In this combination, gravel normally is used, crushed firebrick or perlite.
Why not sawdust? It would create a honeycomb structure.

Fireclay, the same.
I have seen bread ovens in Limburg, 150 years old, made with a clay straw mixture.
So again, why not with with sawdust.
The HEDON site states that the durability and insulative characters of the clay/sawdust mixture is rather good.Or is this faulty information?

Cheers Bart

Hey Bart,

It more or less sounds like; Stay within the borders of that what has already been used and proven safe to use, and durable.
Don't look any further, for most will be worthless to look at anyway.

Gosh...sorry...I don't mean for that at all...

Like I stated above...I love experimentation and re-examination of historical, as well as, contemporary concepts. However...apples and oranges...so very often the internet takes folks down the path of not creating something new and unique...but...reinventing the wheel...with means, methods and materials that are NOT as efficient or as durable than what is already working quite well.

I will own that I am very old fashioned in many was and tend not to fix to many things that aren't broken and working well as they are...

Portland/lime combination has been used for ages, sometimes only with lime. This also is mentioned on the traditional oven site.
So, why would this not be good enough for rocket stove cores?

I would have to read the exact application...especially about portlands, as these just can't stand up to heat at all...as I feel this may well be taken far out of context. Yes, lime, and just simple clay slip is often used in many different types of traditional wood burn devices...as mortar. They are not used as the elements that makes up the "working body" of firebrick or soapstone building blocks that take the brunt of the thermal forces...

If there is a good working example, I would love studying it and learning more about it.

In this combination, gravel normally is used, crushed firebrick or perlite.
Why not sawdust? It would create a honeycomb structure.

As stated...there are no examples (that I know of?) that can make a viable working clay (or clay like) body to form a durable and functional firebrick with these materials. Gravel (usually a steatite form, crushed firebrick (aka "grog"), perlite, etc. etc. .... may sometimes be a limited additive to some clay bodies...they do not constitute a major element in firebricks and typically are in the interstitial zones as a mortar or perhaps a sacrificial element of the "firing device."

Fireclay, the same. I have seen bread ovens in Limburg, 150 years old, made with a clay straw mixture. So again, why not with with sawdust. The HEDON site states that the durability and insulative characters of the clay/sawdust mixture is rather good.Or is this faulty information?

So here we go...comparing apples and oranges...

A bread oven , of which many I have restored the vernacular and historic forms of , and made contemporary replications, are not, nor ever will see, the temperatures of a combustion chamber in a kiln or similar wood burning device like a RMH. Maximum temps a bread oven may see (and not for very long duration) is perhaps 400 °C to 500 °C.

I would further point out that many of the historic vernacular design have in them sacrificial layers and elements that are meant to be routinely replaced and restored...Even some types of traditional kilns such as the Japanese Anagama 穴窯 Step or Mountain side kilns may have designed into them "sacrificial components" and layers that are in places that can be easily serviced and/removed. These very well may (as I have seen and used these methods) sawdust, oyster shell hot lime, natural cements and other pozilonics in there building...all of which is sacrificial and replaced...often with each firing as they just can not endure the thermal cyclic shock of continued use...

Tearing down a RMH once to several times a year is not a goal worth attaining just to achieve a more insulative layer...Especially when better designs and material applications already exist.