Remy Olson

We are remodeling our 8-apartment building as DIY/earth-friendily as possible. In one of the units we're going to pipe our flues into the old coal-burning chimneys to vent the wood burning stoves.

In both units there are original late 19th C. cast iron fireplace faces that extend 9.5" from the plaster/brick wall/chimney and go 44" high with a stone mantle.

I'm wondering others' thoughts on reusing this as a heat barrier.

Current design ideas and questions:
- Use the cast iron face as it was before: 6 to 9.5" (6" near base, 9" extension as mantle support) off the wall and attaching to the wall somehow -- any ideas!?
- Line the wall/old chimney hole behind the cast iron face with with sheet metal or cement board -- which would be better?

There is no permit required in the city where I live though we want to be safe and follow standards. The wood stove in question is 22"x22"x24" vermont casting.

Update:

Finished the riser insulation and put a cap of sand/clay and then pure smooth clay and will trip the hardware cloth once the barrel is fitted/placed. We also put a layer of pure well-filtered clay on the riser and it's smooth-er than the hardware cloth but still not as smooth as I'd like. https://www.flickr.com/photos/remyolson/16205296781/in/set-72157648483903247

Would love feedback on the bench composition and clean-out angles.

Thank you, Glenn. I will experiment without it first then. I cut 12" of electric water heater length if I end up needing it. Would love input on the other Q's. Are they 'bad' questions? Too many? Wrong forum format? Or is it slow due to the holidays? Newbie forum user here...

I'm building an outdoor RMH bench 8" system (overview). Lots of questions/feedback desired on these topics if anyone's willing!


Clean-out angle:
Do I want to angle this down slightly toward the ground from the pipe level to afford any condensation an opportunity to run out of the pipes? I thought about having so many clean-outs for this reason and also to keep the pipes clean.
For that matter do I want to the whole system to angle slightly downward toward the creasote trap at the end?

Pipe angles:
As you can see my goal is for benches around an open fire pit so the angles for a hexagon will be 135*. I'm planning on sculpting these angles, with the straight lengths of steel pipe running up to the angle and then rounding out a turn with brick/clay. Perhaps I would get less drag though by just using a stove pipe 45* elbow like this?

Bench Composition:
I'd love a fast (30-45 mins?) time to heat up the bench for our bums/calves in the winter/spring. Hence the offset pipe/limestone toward one side. Is there a model to look to for this specific requirement (outdoor, quick heat-up, but not burn the bum)? Ianto's 2"/hr for stone is appealing but still slow. How much stone can I get away with to transfer heat faster and do I need to increase sand content to hold it all together better? Here's a sketch...


Or what about a sand 'pipe' or trough just above the pipe for super-fast conduction to a limestone-rich 2-3" cob topper?

Straw in cob near pipe:
Also, I accidentally used some cob that had straw in it around the chamber/manifold at the base/exit from the riser. Remove it? What's the risk of having straw there?



Riser insulation:
I'm finishing up the riser insulation per Ianto's book. This perlite/clay mix is making me nervous... is this stuff really going to hold together once the hardware cloth burns away? I used about 1:1 by volume clay (pudding texture after wet sifting of all rocks) and it ends up pretty sticky and compacted once mixed and tamped in. Is this what it's supposed to look like?



Also, do I need to put a thin coating of well-sifted wet clay on the hardware cloth after scraping off the excess that pops out?



Feed tube size:
Is it necessary to add the additional 14" barrel (section of water heater)? If so why? And the book says 12", but does that make sense for my specs? Seems it would skew my ratio. Also if I do add the 12" of barrel over the brick part of the feed tube then does it need a top to make the mouth smaller and if so, is smaller better? Same 7x7" appx dimension?
https://www.flickr.com/photos/remyolson/16132011792/in/photostream/


Gratefully!
Remy

I have gotten other great input on other topics on this forum that I'm grateful for which has helped get me to this point: https://flic.kr/p/q2u427

My riser is fire brick (yellow ones) and old chimney brick (red ones) both salvaged from chimneys, mortared with pottery clay and river sand (about 1:3) because that's what I had available. The base is concrete (to get it above ground level since it's outside) insulated by the following layers above: cored brick, cement board, perlite/clayslip boxed in by cored brick, cored brick, fire brick, and then another layer of fire brick which is the burn tunnel (so about 10" of insulation under the burn tunnel, fingers crossed that's enough to insulate cement).

Tomorrow I go to work cobbing a base on which to set the riser insulation and eventually drum. I'm looking for ideas for how to keep the cob from touching the ground and wicking moisture and cracking the cob? Materials I have: urbanite, cinder blocks, plenty of brick of all kinds, limestone (hoping to save for conductive material in benches), clay chimney flues, plenty of clay mixed with gravel. I have a budget for some river sand I was planning on buying.

Also, this will be my first cobbing experience ever. I was planning on starting with 1:2 clay:sand with some straw mixed in. My clay is dirt that is clay-y, some of which has quite a bit of gravel (probably 1/4-1/5 of the volume). How much of the gravel do I need to pick out? What am I risking by leaving it in?

Also, I sifted some of my dirt of gravel but it's been sitting in water. Is there an easy way to drain the water other than sieves? Can I just dump it out onto my piece of plywood and let it dry out a bit before mixing in river sand? Is this necessary?

Yes I can just play and experiment and I will but any any experienced ideas are welcome

Thank you!

@Kirk Mobert, this was a great overview of making cob for this application! I have gotten other input on other topics on this forum that got me to this point: https://flic.kr/p/q2u427

My riser is fire brick (yellow ones) and old chimney brick (red ones) both salvaged from chimneys, mortared with pottery clay and river sand (about 1:3) because that's what I had available. The base is concrete (to get it above ground level since it's outside) insulated by the following layers above: cored brick, cement board, perlite/clayslip boxed in by cored brick, cored brick, fire brick, and then another layer of fire brick which is the burn tunnel (so about 10" of insulation between cement and the burn tunnel, fingers crossed that's enough).

Tomorrow I go to work cobbing a base on which to set the riser insulation and eventually drum. So this description of ratios was useful. Thanks for any input!

I can't seem to find this question answered anywhere. I have Ed. 2 of Ianto's book and there are conflicting dimentia: the tunnel in written suggestion as 1/2 riser height but in a sample combustion unit sketch the riser height is measured (the arrow span) from the bottom of the tunnel whereas another sketch shows it measured from the top of the tunnel. This is a big difference.

What is best practice and specifically from where are the dimensions measures for riser height?

I just realized I may have to go with larger flues? Isn't "C" or CSA of burn tunnel supposed to be smaller than CSA of everything else?

The assurance from White Cloud and a little more reading was enough to pull the trigger. I got to work mixing 4:1 Ohio River sand to potters clay. Here's what I've got so far before rains started in again: https://m.flickr.com/#/photos/remyolson/15714789372/

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.

allen lumley wrote:M.R. : You have 90% of it ! The ball when squeezed in your fist should stay intact but when squeezed between thumb and fingers
should easily pop apart !

Because the Clay slip reduces the insulation value of the perlite slightly it is important to use enough at least 2 inches, 3'' would be
better!

If your C.S./P is at least 2'' thick you should be able to wrap it in hardware cloth or stuff the C.S./P. between the heat riser and a
large piece of H.E.V.A.C. cold air retune pipe, here we are not worried about its eventual failure directly under the drum, but just
supporting the C.S./P.

This is where we both are going to get excoriated by our Fellow Members!

The current building codes do not allow for any use of asbestos, but does allow for the encapsulation of it where it is found,(I Think)
usually when this is found in public buildings it is just ripped out and hauled off to a remote $ Location $

We are trying to prevent inhalation of the fibers, drinking or bathing it are not the problem, a neighboring town has asbestus pipe
for its municipal water supply, not ideal, but not deadly !

I am stymied on visualizing what you have, perhaps if you had a retaining box with some sand in it you could carefully bed the
asbestus sheets on the sand and cover with more sand this should improve the protection at floor level, otherwise the golden rule
should be to handle it as little as possible ! and use a mask and wash your work clothes immediately after as a separate wash !

Check for the county agency that deals with 'Solid Waste', usually a given region has one day a year where you can turn in hazardous
waste without penalty ! Give them a call and pump them for information ! AND Share what you learned ! Big AL

Hi again Big AL, looking for info on how to pack the insulation around the riser. Am I packing it on and just using the hardware cloth at the end of getting it on there? Or am I making a cylinder out of the cloth and then packing in the CS/P mix? Seems like the former would be easier (reaching down into the cylinder to pack the CS/P mix would be tough...

Also, what about turbulence from the rough CS/P surface? Does that impede flow?