Has anyone with success used potter's clay in mortaring their combustion unit? If so what ratio and for what kind of brick? I only have Ianto's book and it doesn't specify consistency or ratios. Please do share your recommendations for consistency. I would rather not have to buy brick mortar and sand and fire clay if I don't have to. I have a 5gal bucket of light gray pottery clay.
Also, my combustion unit except for the last 6 courses (~33") of riser are salvaged fire brick from a demolition of a chimney. The last 6 courses of riser are red brick also salvaged from another chimney.
Remy O. : Please believe me, inspire of your high opinion of us no one here Knows what you mean when you say you have a bucket of Potters Clay!
It is probably the close equivalent of saying you have a Car Automobile. It will have zero silt in it so it is better than most of what you can get out of
the ground ! It may or may not have Grog or sand in it, if it did it probably would have been called stoneware ! Does the bucket say anything, as you
say it is light grey is it at least a dry powder?
What fire clay is: Fireclay gets its name not from any magical special ability to take high heats, rather this clay does not swell much when formed wet
or shrink much when it dries, also when 'fired' it does not expand much or shrink much when it cools !Therefore it has little tendency to crack. This is
what makes fire clay fire clay ! Lincohn 60 is 'good' fire clay ! It is sold under other names ! here is a good site to check out !
www.traditionaloven.com/articles/101/what-is-fire-clay-and-where-to-get-it hint Highlight the BOLD part and Right Click
This should open in the address window, or as a Google Search. While there read the articles on fire brick and 100 yr old dead soft house brick!
Speaking of searching, at the right top of the page below the Permies banner and above the Permies Video is the Permies Toolbox. Locate the
[Search} tab and click on it. at the new page you can enter a term like making test bricks with cob, do a search within Rocket Stoves, and set
your search for within Permies, once you have tested Cob that you have made yourself, you are well on your way to figuring what makes good Cob with every batch of Clay you find !
mortar, good mortar for brick laying is a combination of Clay and Builders sand, damn the man who uses a cement mortar to lay bricks, and you
cant use a Cement based mortar on Your Firebricks any way ! Big AL!
late note : sorry, in order for me to make sure that I am giving out a good address i must use the http to test it, it is corrected now
Success has a Thousand Fathers , Failure is an Orphan
I know exactly what is meant by "light grey potters clay," or at least about 98% sure. This is a mid ranged bodied clay used for general purpose ceramics, fired up to about cone 6 (7 tops for most types.)
It is not remotely close to saying you have a "...Car Automobile..." as this is just one form of clay body and can be augmented with others for various application and effects in a ceramic piece. Typically (but not always) these are lower firing clay when described this way, yet could be (this is my 2% from above) a grey porcelain clay body. which of course is much finer and can be fired at very high temperatures.
I would suggest that Renny make sure this is actually a ceramists clay and not something else....Such as your suggested bucket of "silt."...
The adding of a "grog" would not necessarily make it a stoneware, but would render a stronger body and perhaps a cone or so of more heat tolerance.
Sorry to sound so..."Proffessory"...on this subject but saying the word "fire clay" is actually the part that is like saying "car automobile."
"Fire clay" is an exceedingly generic term when used outside of specific context. As "red terracotta clay" is also a "fire clay." All "fire clay" suggests, when just said generically in a sentence without context, is a clay that is capable of forming a clay body that can be fired to a bisque and/or other level of vitrification...Nothing more or less, generically than that.
Expansion rates, and other physical, thermal and chemical characteristics are all augmented by the "type of clay body," added ingredients like paper pulp as just one example, and other chemicals and minerals additives do not stop any from being "fire clay."
Now...back to Renny's question. (Please forgive me Allen for being so silly above... )
Yes, with perhaps a little sand added and some experimentation, with some more research/reading on Kiln Mortars you can use your "bucket of grey clay." I would disregard any that suggest using OPC in the blend as Allen has so wisely warned against...Cement/protland is just not required at all for the making of "kiln mortars" or building of ovens and kilns of any type.
Michael R. : Thanks for catching that, good information is good information only when its available, (re-)corrected now!
Jay C. Well who-da thunkit? For some reason unknown to me, Permies own collection of potters and ceramists all seem to be in hiding
For a long time I have suggested that by honoring the potters and ceramists among us with their own Forum / Thread we might be able
to get them to share some of their vast knowledge, not only amongst themselves but also here and in the COB Forum / Threads,
especially when it comes to finishes and final coat s/ings
So far no one else has come forward to help create a stepping stone to that simple goal, I expect to get a I second that idea from you! For the GOOD OF THE CRAFTS Big AL
Success has a Thousand Fathers , Failure is an Orphan
One mountain, but with many paths to the top. As with personal computing, there's more than one way to do almost everything. Thus all methods can be considered proper. As to which is easier, ask ten people and you may very well get ten different answers.
When designing web sites I keep in mind that there are always Internet newbies out there (my mom for one!) that won't recognize common written text that has a dual personality of having been turned into a hypertext link. But they (and she;) will understand when directed to, i.e. as Al suggests, to click on the following link:
As presented above in its full complete form, browsers running on all platforms (Linux in my case) will recognize the text as being a web link. When posting on Permies the forum software will also recognize the text as being a link and automatically make it active, allowing readers to simply left click (normal click) on it to open the link. And they have the option of executing a right click instead, with more options such as opening the link in a new tab or window.
Getting that "remains a ball when dropped from hip height" recommendation I had in my notes from God knows where wasn't easy using wet clay, and near impossible to trowel with so I ended up using my hands to slap and spread the mix. I had a handy friend who had mortared houses with Portland before have a look and said of the consistency, "yeah that looks kinda right!" Good enough I hope!
This is SO MUCH FUN!!!
Next question: the drum over the feed tube I found a water heater tank for this. What are ideal dimensions or ratios? Ianto isn't super clear on this in his dimentia & proportia section.
Also, my tunnel is 8.25x7.25, riser can be up to 8.5x7.75 and flues will be 8" diameter round stove pipe. With the large fire bricks I have this is the best I could do to manage a tight tunnel and slightly larger riser. The mockup worked (tunnel was slightly smaller sans mortar) but I wonder if the slight increase due to mortar will be negative?
Also as I understand optimal ratio the riser height at 2x the tunnel length is ideal but then I wondered is this from the bottom of the tunnel or the top of the tunnel that riser height is measured? My tunnel will be 18" with mortar and riser height can max at 32" to accommodate 2" of headspace before drum top.
I'll assume, that by "C", you're referring to "the book" (RMH, 3rd edition, Evans & Jackson).
In that case, check out page 48, lower RH corner of the page, where it shows 7"x7" throughout the "J".
Ideally, the feed, burn tunnel and riser should be all have the same CSA, which should match the thermal bench pipe. Small variations can be tolerated in most circumstances. I.e. the burn tunnel could be made slightly "tighter", and the feed tightened up to match, where the riser remains slightly larger in CSA.
The largest dimensions I've seen on a well working 8" system had the brickwork set at 7.0" x 7.5" throughout the "J".
best regards, Byron
Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''