Emergency quick and small batchbox for the 400 sq ft wofati (0.7)

Just pretty night shots

Enjoying this project a lot, thanks for sharing !

Curious tho, why all the work for the octagon instead of a circle ? Turbulence ?

Robert Dearborn wrote:Enjoying this project a lot, thanks for sharing !

Curious tho, why all the work for the octagon instead of a circle ? Turbulence ?

Ease of making. Well, for someone not wanting to use sonotube.

The octagon vs circle was thoroughly debated and conversed earlier in this thread. In many ways a circle can be easier but in our case the octagon was the way to go.

Four videos of the cast riser firing

Detail of the P-channel. The front had a cut out for a piece of angle iron it will sit on top of.

Mike prepping the barrel hole for the duct outlet.
We cut it small and flanged it outward so it can shoot inside the starter duct. This will keep our seal easier and no inward projections to slow the gasses from flowing into the point.

The lid that Mike cut out and flanged which is the bottom of the barrel bell. The flange is so that it can be sealed around the riser with dura-blanket or super wool.

The riser with the first section of metal cut out to fit against the brick box. This cut was too short, I was thinking of the port height, had to lengthen it to the brick box height. The sides of this cut run parallel to one half inch above one of the octagonal planes.

Now for the don't do this at home part. Sometimes the crazy answer IS the best answer. This was my answer after I didn't have the chainsaw available to use with the leftover bad chain.

After the rough guess work and no blood yet.

Checking the fit for adjustments

Also you might notice the riser looks shorter. When we went to pick it up, it snapped in two at the joint between the oil drum and the sheet metal. Turns out this was fantastic for weight issues and final install later.

After a thorough thrashing with the heavy artillery

From the inside.

7 1/4" turbo diamond wheel on a 4 1/2" angle grinder was just the trick.

Still no blood.

The real work of the box finally begins on site. End of day 1

Start of day 2

Box done.

Installing P-channel. Stuffed gap with super wool for no leaky

P-channel stuffed and positioned

Securing the P-channel into place.

How it looks on the inside.
Also the ramp bricks on Mike's side (the right) are much nicer. Actually at 45 degrees. I put too much clay behind my bricks and had to rotate them in and up. In case anyone was wondering why the asymmetry.

Putting the ramp into the bottom of the riser. This was half Lincoln 60 fire clay and half fine sharp sand kneaded with some perlite.

Preparing the pad, box and riser for docking. Using Lincoln 60 and sharp sand mixed to a slip mortar. Same as used on fire bricks.

Don't you Permies get worried about that chunk missing from the opening in the riser on the low left side. Once installed that gets filled in nicely with the clay sand perlite mix.

A look down the riser at the ramp and smoothed out opening to port. The ramp ended up being steeper than I'd planned, but I don't think that will have negative effects.

A look at the ramp from the box through the port throat. The transition from brick port to the riser entry slot had been smoothed with the clay, sand and perlite mix. Also a good view of the P-channel termination.

Mudding the mating surface of the riser halves for reatachment.

Bravo!! Just like new. The rocket engine is now complete. Speaking of engines this is reminding me of an old steam locomotive.

Looking down the complete riser.

4 brick pillars and a barrel base and it's starting to take shape.

End of day 2.
Need to measure riser height. I think it will be 43.5".
The barrel support pillars ended up taller than planned which I think will give me a 7" gap between riser and barrel.

Tomorrow:
Super wool stuffing front of P-channel entrance to box.
Super wool sealing barrel base to riser.
Sealing barrel to base.
Connecting and sealing duct to barrel.
Making dura board door with primary air intake 20% system size. 2 3/16" wide x 2 9/16" tall.
Making duct penetration through wall.
Installing all exterior chimney pipe.
Test fire.

Now it's time to clean my wooden levels and treat them to some well deserved raw linseed oil.
They performed admirably.

The stove will get a 1 1/2" angle iron frame around the front for later permanent door.
The stove will be cobbed over and under barrel against riser between brick pillars.
The parascope will receive a layer of cob as well.

Damn Rick, you scary! No blood is good, so nice job. Seriously though, thanks for posting all that, really cool to follow along with you. Just for the folks following along at home, casting that riser in place would be the preferred way to do that to avoid the cutting and shaping. Also, as you are finding out, the diy mix doesn't hold up well to a lot of moving around, so it's best to minimize that as much as possible. Not a criticism of what you've done there Rick, you are a ninja.

Wow! This is a speady build Rick, I'm so curiously what the first fire will bring but I have to wait till tomorrow. Don't forget to heat up the chimney stack beforehand and maybe during the first ten minutes of the burn as well. As far as I can see the back sweep in the riser schouldn't be that large, especially in combination with a round riser. Since your riser is octagon there will be enough turbulence to prevent too high gas velocities.

You are doing good work by publishing the proces. I know how difficult it is to stop working again and again in order to take pictures.
This heater will be very powerful, a worthy little brother of the monster in the auditorium.

Matt and Peter, thank you for the kind words. You guys are just as much a part of this as I am though.

Peter said:
As far as I can see the back sweep in the riser schouldn't be that large, especially in combination with a round riser. Since your riser is octagon there will be enough turbulence to prevent too high gas velocities.

Can you extrapolate on this please. I'm not following your meaning.



Got lots more pics to post, but first the sneak peak.

DAY 3!


The riser height from floor is 43.75" The high side from the formulas are 43.3". Close enough.

The top gap is right at 7"

Some of these pictures are out of focus, too busy working.

First shows the flange and screw tabs for the barrel outlet.

Second shows the barrel floor looking through the outlet opening. We stuffed the super wool between the bottom flange and riser wall.

Third shows the self adhesive backed flat braid gasket stuck to the outlet flange. This was also used on the barrel bottom's groove which worked perfectly to set the barrel on top of, then clamp the seal ring.

Mike is holding the outlet starter collar in place for me to secure with 3 screws. This was trimmed to fit the curvature and ridge of the barrel. We got a good seal against the braid and no protrusions inside the barrel. Also, I always use #8 x 1/2" self drilling stainless steel screws for attaching duct . Anything else will corrode away surprisingly fast.

The rest of the parascope attached.

The familiar dura board door.

Also, I hate not being able to see in this thing through the top. I am definitely spoiled.

Tim and Mike had already stuck some piping out a window for a test run of the engine.
We primed the chimney side of the duct by starting much fire inside the last clean out section.
Then started the engine...

And it worked fantastic...

Until the chimney side cooled down and all smoke broke loose.

The system definitely has promise, time to finish the duct run out the wall and give it what for before the end of the day.

Batteries are running low (mine and phones), I'll share the rest tomorrow.

Rick Edwards wrote:

Peter said:
As far as I can see the back sweep in the riser schouldn't be that large, especially in combination with a round riser. Since your riser is octagon there will be enough turbulence to prevent too high gas velocities.

Can you extrapolate on this please. I'm not following your meaning.

Somehow, a round riser and a large back sweep seems to be not a good combination. Nothing wrong with the same ramp and a square or octagon riser, though. Best results overall are with a back sweep which is hollow, both in the direction of the port and across. Starting just an inch before the heart of the riser. But these are minor differences as far as I can tell.

About first fire: I said so, heat up the chimney stack. But you guys were too impatient and stuck a pipe out of a window without the stack. You could get away with this when one of you guys kept heating the vertical exhaust pipe with a soldering torch. But then, maybe there wasn't a vertical pipe to speak of...

Thank you for the report, I'm sure we are all awaiting the final verdict. The sneak peek look and sound fabulous though!

Day 2 of running was much better, after first batch used with vacuum at the end of the chimney, system ran on its own from then on with no problems.










The pictures below are attaching our starter collar of double wall stainless insulated pipe to the interior boards of the front wall.

Same starting collar.

First, from the inside view.

Second, lagged.(that's Aussie for insulated)

Third, covered.

Mike stepping in as resident duct wrangler.

He finished the stack to the penetration while I was starting the outer collar.

Note he had to screw the duct together because this shoddy duct from Lowe's wouldn't stay together at all.
(This is why I boycotted Lowe's in my hometown. Too many products like this)

Closer... (with 15° elbow and different brands of pipe, we used a sheet metal band and screwed them together)

Warmer... (where there is smoke)

FIRE!!!

Tomorrow, I'll prep some items for the vertical chimney install and be done Tuesday or Wednesday.


BIG AL. INCOMING CANDY!

All caught up.

Here's some marshmallows, you guys bring the chocolate and graham crackers.

Hi Rick.

So, are the back and sides of the firebox glowing red when you near the ember stage, after two or three loads?

I would say you're not far off with this one.

https://permies.com/t/41202/a/23413/thumb-KIMG0829.jpg

Oi, i need my fix!

Three days without news! da't's ney good!

Sorry, got lots more. Including finished chimney and custom cap. Will post soon.

Satamax, don't know about bricks, is that a joke or actually possible. I can have Mike sand Violet see on the evening.

Rick, it's totaly possible, no joke there!



What you're seing here is a pic of my green machine's firebox. Remember it's IR filtered, from my mobile phone cam.

But the heat riser's back, behind the port at the very back is as clear as the rest; why?

Because all that stove end was glowing orange!

Yes, Max is right. I've seen it with hard firebrick and castable refractory as well. When run full tilt, the riser did shine as a lampoon, visible through the port. Even a ceramic fibre riser will do that, see picture.



The floor of the firebox can be as hot as 1650 F, measured it.

This almost looks like a traditional japanese forge. Is it possible you could make knives/forge metal as an added bonus of this type of stove?

(Here's insturctions on building a japanese forge, for reference http://www.twinoaksforge.com/BLADSMITHING/FORGE%20BUILDING.HTM)

We have started having a severe smokeback issue.

I don't know what's relevant, but on wednesday, we went to 12 hr intervals between loads instead of 2 hrs, and also added the last of the insulated pipe and cap outside. On friday we started having more smoke push out the pipe joints. This continued through the weekend but the stove was useable. Sunday night, we primed as usual with small pieces of paper and cardboard in the riser, then let a few pieces of kindling burn down, then kindling and two pieces of wood, then a full load (leaving three inches at the front and top.) This burned cleanly for ten minutes with all the wood in the box ignited. Suddenly the p channel started belching smoke, followed by every possible gap. We pulled the caps and inspected for blockages, and removed a wad of paper. Waited until the next night and got the same behavior.

Yesterday i piped up a bypass to omit the ground loop and the stove ran with no major issues, although it seemed cooler and dirtier than i expected. No temps, sorry.

Last night we tried the same startup with a cleanout outside on the last vertical uncapped, and got the same behavior, except that during failure mode, smoke poured heavily out the open cleanout.

At paul's suggestion, this morning we tried opening the building door as soon as it started smoking, and it was no better.

Would appreciate any suggestions. I'm just learning about these beasts and I'm not sure what to try next.

At this moment, I think the vertical exhaust duct next to the wall is full of cool, moisture heavy exhaust. The coolness and the moisture is too heavy to get pushed out. So the heat riser is pumping, but the vertical exhaust is going the opposite direction.

With the door open, temperature inside the wofati is the same as outside the wofati.