When we build a viking era bloomery our mix is: 3 shovelfuls of the local silty sandy dirt, 2 "head sized" bundles of chopped straw and 1 shovelful of the cattle feed clay.  This was mixed by hand with as little water as possible---real pain to mix!  Comes out looking like dirty muddy straw and we can build a 4' tall bloomery and smelt wrought iron from ore in it.

Yea, about right!

Let's say a person procrastinated enough to let the ground freeze and can't get to the ample reserves of clay and dirt right under their feet. Only things readily available are water, ash and kitty litter. What sort of percentage(by volume) of components would be ideal to mix? 4/10 clay, 6/10 ash, gentle spritz of water? If only the weather would be above freezing...

2 hours ago, Meadowgrove said:

Let's say a person procrastinated enough to let the ground freeze and can't get to the ample reserves of clay and dirt right under their feet.

That person can simply build a fire on the ground and thaw out enough of it to get to said ample reserves.

30% clay and 50-70% sand is the classic ratio for adobe brick or cob. The use of cattle or horse manure or pulped paper or chopped straw might be nesisary to control cracking. Cheep clay cat litter or dry sweep ( pure bentonite clay) or fire clay from a masonry supply. Mix fire clay dry and ad water and let it case in a plastic bucket or tub with a lid. Some folks grind cat litter to a powder, but if one makes a slip ( thin past) one can mix in the sand and then let it set in an open container till it dries to your working consistency.(casing also improves the effectiveness of straw and paper reinforcement) once you like it, put a lid on it and case overnight. This will eliminate the crusties and even out the moisture.

If your forge will stay dry you can just dump the dry clay in your pan ( think sand box) and simply reshape the fire bowl when you build a new fire. The problem with sand is that sand is silica, sand is the source of the silica slag that formed in a coal forge. Simply enough, sand melts. So strait sand is a problem. Ash seemed to act as a flux and keep the sand from causing as much of a problem. 

Had to go shopping today so I picked up some bentonite while at it(Cheap even in Finland, what is this witchcraft) Have to see about mixing the stuff next monday when I have some home alone time. Could I use wood shavings instead of straw etc.? I have a small mountain after making a kantele body a while back. Of course logic dictates someone would have mentioned using wood shavings before if they were any good for the purpose...

What you need is some form of fiber to bridge any tiny cracks, this prevents them into becoming big cracks. This is where straw comes in,  manure and paper being esentualy the sa,e thing in this case, one can shred paper, soaked it and run it threw your blender like you do for making artisinal paper. Drier lint is an alternative. 

 

Chopped dead grass is straw 

Horsehair is a traditional additive to plaster to help prevent cracking.

what about the age old tradition of using bird cage wire as reinforcing? Would that work in this sort of application?.

So longer fibers are the key. Time to put all that junk mail to good use. Should I worry about the additives? Most ads are coated with a PE film and the paper itself has kaolin added to it during the forming. That's why burning junk mail gives you a lot of ash. I could be overthinking it of course.

Just feed your cats a high fiber diet.  

I am curious about this frozen soil situation, never lived in that sort of climate. Is it really impossible to dig a hole even using a fencing bar? 

What about an auger attachment to a tractor?

Only asking not suggesting the OP should do this

Impossible? No.  Impractical?  Yes.   The "standard" auger attachments I've seen for a tractor would make little progress or would be destroyed in frozen soil.   It depends quite a bit on how deep the frost line is though.  If it's just a few inches then you can usually power through the tough stuff and dig decently in unfrozen soil.  If you have a couple feet or more of frozen material the effort/reward ratio is definitely tilted the wrong way.   Undoubtedly there are machines designed well enough to dig holes in that stuff; just not the usual attachments I'm familiar with.

Finland?  I'd wonder if they used the DuPont's "Blaster's Handbook", AKA "Better Living Through High Explosives".  (Used to be in the Engineering Library at the University)

Instead of cat litter can you use floor dry? That stuff us mechanics use to soak up oil. It is made of clay also, not sure what kind, and is usually cheaper and comes in much bigger bags than cat litter. 

Just wonderin.

dry Sweep, floor dry same thing

 

Coline is clay

Check the MSDS for your exact product as I have run across differing  types including diatamaceous earth and  Montmorillonite Clay, Calcined

I am not sure if I missed this but when making your own clay, what are your thoughts on mixing the bentonite (cat litter) with sand and cement. Would the cement hold it together in a similar fashion to some straw? 

20 minutes ago, D4UNC36 said:

Would the cement hold it together in a similar fashion to some straw? 

No. Cement gains strength from absorbing water and forming hydrate compounds. Above a certain temperature, those hydrates lose their water content, which then flashes to steam, sometimes explosively. 

I see that this was your first post on IFI. Welcome, but please READ THIS FIRST!!!

Honest guys mud pies made buy your 4 year old work just as well. Less fuss.

But overthinking it is soooo much fun!

I started on my JABOD last august and finished it just a few weeks ago. I spent the winter planning and overthinking every aspect despite doing a ton of reading here prior to and during the build stages... Once I started mixing the filler I felt quite silly, since I was basically making a huge mud pie. If you don't have straw, use wood shavings, drier lint, anything fibrous that won't turn into a breathing hazard when heated. I used coarse wood shavings(made with 35mm forstner bit) from a past project. They seem to hold up well. 

12 hours ago, JHCC said:

No. Cement gains strength from absorbing water and forming hydrate compounds. Above a certain temperature, those hydrates lose their water content, which then flashes to steam, sometimes explosively. 

I see that this was your first post on IFI. Welcome, but please READ THIS FIRST!!!

Thanks, I’ll get on the things in the read this first section! I’ll steer clear of the cement then, just asking because I am just starting out and making a forge out of an old stainless steel keg and I am needing to line it. Here’s a pic of part way in (if anyone is interested haha) 

6 hours ago, D4UNC36 said:

I am just starting out and making a forge out of an old stainless steel keg

Not sure what your plans are for the keg, but please read the threads about the JABOD forges before you proceed further.

A small hooded forge makes working long stock difficult, as it dose large scrolls. If all you do is horseshoes from pre cut stock you will be ok, but otherwise you will find your self frustrated with the limits of your design

This is my Mark II JABOD forge (John coined the fraze) 

This is some musings about design

This is the latest version.

None of these are plans persay, but they are intended as road maps for you to experiment with to find what works for you. These are small forges optimized for charcoal. A similar concept can be used with coal, either side blast or bottom blast (a ducknest as aposed to a steel or castiron fire bowl). I recommend prototyping your forge desighn in this way to save money and time. Once you know what makes a forge work for your fuel, air supply, work habits and class of work then go a head and make your self a work of art of a forge. 

 

 

And if you have a source for stainless steel kegs, save one for use as a non-rusting slack tub.