compact 6" RMH hybrid with cook top and dutch oven

Actually I kinda like that idea... I might have to better insulate my riser, or completely replace it, and I may even line my burn chamber and/or feed tube with store bought slim fire bricks... I'm still in development as I said, and I have yet to complete everything I want to do. But she's coming along.

If my stove fails or any part of it fails, what do you guys reccommend I use for the Jtube on my next EMBER RMH HYBRID 2.0? I was thinking I should have used nickel, monel, or a clay chimney liner for the riser.

I want to improve upon the design if I have any issues. So what's the best way to keep the same design concept, but with better materials? If I need to make changes for version 2.0?

I'm open to suggestions, and I'm willing to use whatever materials are stong and hi-temp

John, check thoses two threads.

Ok, they're batch rockets. But the pictures of my building technique might give you some ideas.

http://donkey32.proboards.com/thread/1817/starting-build-220mm-rocket-double

https://permies.com/t/35569/rocket-stoves/Range-retrofit

The pics are not necessarilly on the first page. But they're pretty much self explanatory.

What i try to do with this tubes and bricks system, is to get standardized components availlable localy. Which can be replaced easily if needed. Encasing the refractory material in metal is perfectly fine by me. It's the other way around which i find bad practice. Since refractory materials have far less movement than metal. And the metal pushing theses ends up in cracks. Since we know that metal won't last, the question when i see people doing this, is why! Why bother!

Metalwise, i don't know anything which is cheap enough for diyers, which could whistand the heat. Mind you, if we could find one. It would be verry intresting to use in the heat riser. Which, when all red, at 1000C° let say. Would act like a catalitic wall. I mean, refractory heat risers act like this. But don't transfer the heat on their whole lengh. A metal might do. And it would be very intresting to be sure to burn everything on the whole lengh of the heat riser. Anything which would be in contact or near that glowing metal would disintegrate. Mind you, you'd have to have some tough insulation outside.

Since steel might be bad, I want to figure out a good idea for a better riser from strong and hi temp materials. This is a prototype and I will be improving upon it, possibly making a system portable and better than a Zaug for my EMBER RMH HYBRID 2.0

The best heat riser material soo far, as i have been told, is rigidized superwool or kaowool. That's foundry stuff.

You asked about Inconel in Paul's thread about metal in rockets. It could may be hold a while. I'm not absolutely sure.

It's melting point in the 600 grade is rather low, 1370/1425C° They're pretty much all in that range after checking.

One square metre of inconel 625 costs 456 sterling pounds!

https://www.alloyshop.com/inconel-alloy-625/sheet-plate/alloy-625-1-0mm-thick.html

You might get away with .5mm thick.

But you experiment with it. And we'll watch I'll carry on using refractories

I was refering specifically to MONEL and/or cheaper Nickle nickle alloys. I might be able to slip a sheet of that into my riser, and line my burn chamber with slim fire brick? Or can I use fiberglass and hi-temp concrete to make a riser liner? Any sort of flexable sheets or board that could be formed into a round liner, line a sheet of stinless, but something better?

monel 815C° no good!

Satamax Antone wrote:monel 815C° no good!

thats operating temp, not melting point. many of the stronger temp metals have an operating temps around that. and if John wants to use one of those metals besides basic steel and keep his system at 815c or lower he wont have a system that will fall apart like his steel system.
frankly as if i would speak anything less i wouldnt mind a system at those temp and it would do what i need it to do. its been admitted that most RMH that reach over 1000F degrees are doing much bettr than a conventional wood stove and put it in the RMH category. not everyones RMH gets over 2000+ degrees F.

i would reccomend to John to at least get him self some high end refractory cement like this heat stop

make your slurry and soak your favorite high temp fabric or flexible material in the refractory slurry and paper mache it around your existing steel and when the steel burns out your refractory shell core will stand firm. use your 10'' or more duct around that heat riser and fill the space with perlite and thats all you may have to do and your done. $26 is what a pale of that costs and seems affordable to keep your system without a major failure.

When I poured my cast riser I ran low on perlite, and low on mix, so I mix up extra concrete and mortar. My steel riser used to work well for making heat and made good draw, but now that I've poured mostly conductive mass around it after running low on perlite, it seems to be slowing the performance.

I need to make improvements obviously: The steel parts are holding up fine so far, the mass heats up gradually as it should, but its not producing the heavy draw like it used to, or the heat to the cook top nearly as fast as it used to. Pouring the cast riser with not enough perlite, too much conductive mass, has altered the heat output and the draw. Clearly I need to redesign the riser, or re-pour the mix with much more perlite. There isn't nearly enough perlite or insulatuion to keep the heat where I want it at the cook top.

The stove works, it doesn't smoke back, it burns okay, but I'm definately lacking heat up top.

So can I use fiberglass and hi-temp cement to make a insulative liner in my riser? Should I start a new stove from scratch? Break away the cast riser and cut it off with a torch and rebuild? Should I keep working/learning before I make EMBER hybrid version 2.0?

I'm learning some good stuff here, so hopefully version 2.0 will be much better, with help from. You guys...

F styles:

I have heavy sheets of fiberglass here, will that work for a liner, soaked in the "slurry" you mention? Otherwise I have to likely buy something. I'd be willing to round a sheet of Monel or titanium and slide it in into my existing riser, and line my 5x5 burn chamber with slim firbrick. Will that give me more draw and better heat up top? People say 2000 degrees, but I'm struggling to boil water lol. I thint the new cast mass is pulling too much heat from my riser, for one thing

John McDoodle wrote:F styles:

I have heavy sheets of fiberglass here, will that work for a liner, soaked in the "slurry" you mention?


I thint the new cast mass is pulling too much heat from my riser, for one thing

i have used the concept of the slurry soaked material on my heat riser as you can see on my RMH post. it has worked great so far for me. if i had your system... i would break off all the cement and perlite mix around your burn chamber and heat riser and crunch it up into tiny pieces. then if your refractory cement is in fact high temp 2000+ F then make your slurry and soak your fiberglass in the slurry and slather it evenly around in thick layers like paper mache as you can around your burn chamber and heat riser. then i would take your 10'' or so duct and put it around the heat riser and then take the crushed cement and perlite crumbs you broke up earlier and re-purpose it back in loosely without mixing cement in it between the 10'' duct and heat riser. keeping it loose allows more it to work like insulation instead of absorbing the heat. you could do all this in an hour or two without forking out a bunch of money and i think your system will be good to go for a while. problem solved.

I like the sound of that.

Accoring to wikipedia: "the basis of glass fiber is silica, in its pure form it exists as a polymer. It has no true melting point (I like the sound of that also)but softens up to 1200 degrees C where it can start to degrade, at 1713 degrees C most of the molecules can move freely"

I have glass fiber heavy sheets/matt here on hand. I used it for making fiberglass auto pannels with resin, but if these same heavy sheets will work for thermal insulation also (without resin of-course) , I'm game. It would save me buying more stuff.

Also, just curious, would that glass fiber and hi-temp cement work INSIDE the 6" steel riser as a insulative liner? If so, I think the cast mass surround will keep the steel regulated, while the "paper mache" keeps the heat in, and off the steel...?

John McDoodle wrote:would that glass fiber and hi-temp cement work INSIDE the 6" steel riser as a insulative liner? If so, I think the cast mass surround will keep the steel regulated, while the "paper mache" keeps the heat in, and off the steel...?

that refractory cement slurry you soak that in and apply around your burn chamber and heat riser will end up being the inside when your steel eventually burns up and breaks apart leaving the refractory shell. if you want your heat riser to be insulated you will want to repurpose the perlite/concrete crumbs you smashed off of the burn chamber and heat riser and then fill it loosely between the 10'' duct and the heat riser. dont forget to take step by step pics so i can see how awesome its going to work.

Okay, but would that work as a liner on the inside of my riser? Seems to me it would be similar concept to lining my burn chamber with firebrick... Which I may do. Both of these ideas might keep all of my steel intact...

If you're starting with a 6" diameter system, adding any amount to the inside will make it significantly smaller with an even smaller maximum heating capacity. A 4" system has less than half the cross section and much less than half the capacity.

If I made a fiberglass liner, it would not be any thicker than 1/4" or 1/2" max. If I put slim firebricks in my burn chamber, that will likely cause a greater draw in that area, I noticed it burns better when "half choked off" or stuffed with wood, because the air has to push and pull harder to get by the burning wood, which makes it burn better. I think I can insulate the inside of my burn chamber and riser also. I just need some of that "heat-stop" hi-temp stuff, I think.

... And maybe 2 or 4 slim firebricks, for the burn chamber

either i am doing a horrible job of explaining the idea or you completely understand and are trying to do it different than i was trying to explain.

putting anything on the inside of flame side of the heat riser will restrict the air flow and hinder your RMH function.

i was trying to explain:

1 break out old concrete/perlite

2 make refractory cement slurry

3 soak fiberglass material in slurry thoroughly

4 wrap slurry coated material around the OUTSIDE of the burn tunnel and heat riser. the thicker you make it the stronger it will be.

5 place 10'' or larger duct around newly wrapped heat riser.

6 crush cement perlite busted out of the stove and repurpose it to fill the space between wrapped heat riser and 10'' duct and keep it loose cement perlite crumbs for greater insulation.

is that better? i mean if i was in your exact shoes, thats exactly what i would do to save my system and do it affordable.

I understand, I understood what you meant, I just thought it would be a great idea to keep my existing materials intact and put a thin liner INSIDE my riser. I like your idea mate, the concept. And I feel if it were on the inside, and if it lasts, it would save me a lot of chipping and it would likely insulate even better, since the condustive metal would not be in the path of the fire much, or at all.

Thoughts on this conglamerate idea?

... *the conductive steel would be out of the path of the fire* I meant sorry.

I've taken everyone's advice into consideration and I've learned a lot about my "weak spots" and possibly future problems with my steel.

I've decided to make one minor modification rather than re-design or re-build. A few simple insulative liners. I will insert a thin insulative liner in my riser, and I will line my burn chamber with fire bricks.

I'm hoping these simple liner additions will be super-beneficial and replacable. So if they wear out or break down, they can be replaced hopefully.

Freezing fog with a freezing drizzle advisory lol. Ya don't hear that one everyday

heh... you said "more tidy" you got enough jun....er i mean treasure to build all kinds awesome contraptions...
the whether report says -6 and "feels like -6" yup its -6

if you feel it will work putting inserts in your system go for it. instead of a 6'' system it will "feel like" a 4'' system.

My entire dwelling is only 18x18' and its at least halfway below the frost line, giving me slight geo-thermal conductivity with the earth. All my walls and ceiling are 8" concrete. I think a true 6" rocket would be way too big/hot for my home anyway. I just want better heat at the cook top, and better draw would be nice. I won't be restricting much, hopefully...

Possible riser liner ingredient A

Well I got good news and bad news. Good news is : I got some legit refractory firebricks and legit refractory cement, both from the same company who make the fiberglass stove gasket kit I bought. Anyway, bad news is, the bricks fit in the 3/16" feed tube, where I don't need them, but they won't quite fit into the 3/8" burn chamber where I DO need them... So either I should have used 3/16" in the burn chamber, or I need to shave these bricks down slightly.

I also need to mix and "mache" my new refractory cement with this glass fiber and build the insulative riser liner, which I borred the "mache" idea and ingredients from Fstyles. Gotta give credit where it is due. I will keep updating this for you curious folks. Thanks again for letinng me share my development with yall

A 5 x 5 x 3/8 burn tunnel is about 4 1/4" square inside already, and a firebrick split liner would make it less than 2" square... not what I think you want. I would try the fiberglass mat soaked with refractory for all of these if you want to line the insides.

A 4" system would probably be appropriate for a small space like yours, as long as there is some insulation outside of that 8" concrete. Concrete is not insulative and will suck heat straight outside... you would be melting the snow off in deep winter. Also, the inner surfaces of the walls would be very cold and condense tons of interior moisture, as you have described. I don't think this space is ever going to be dry and warm without good insulation around it.

Glenn has made some very good points. i hope you got that place insulated. have you thought about slicing 1/4 thin slices and place them inside? if you got an angle grinder with cement cutting discs you should be able to do it.

I would like thinner slices, but I don't have a mason or diamond wheel for any of my power tools. I have angle grinders and 14" chop saw, but not the right wheel.

I only lined the sides of the burn chamber thus far, not the top or bottom. The "tight spot" seems to make it pull harder where the flame is, and draw better, burn better. Its like having the slight restriction right where you want it to be. I noticed this before also when the more wood you choked it off with, the better it would burn that wood, because it has to suck hard exactly in the area where the flame meets the wood, making the "restriction" beneficial.

My place is insulated on the inside and I run a dehumidifier when I need it, but the dry heat makes up for the condensation, and the more I insulate, the less condensation I seem to get...

Anyway, I used a mason chisel and hammer and I made the bricks fit on the sides of the burn chamber. Seems to help, but I really need to insulate my riser better. Ever since I poured the cast surround and I ran out of perlite, it doesn't draw nearly as good as it did. The riser heat is being absorbed into the steel riser and into the cold concrete. So the bricks are in, they are removable and I NEED do the riser liner very soon. Maybe tomorrow. For now I need some rest. I'm done for the day.

hows the slices coming along?

you got a purple moose check it. take a look at my system and youll see my updates.

John, it's a shame to see you wasting your time. Use this temporarily, and let it die it's good death. Switch to number 2. You have good welding skills. Bricks you can do, and encase theses in metal if you want. Insulation and all that you can do too. Rockwool/roxul held by sheet metal is plenty good enough, if protected by bricks. Try to use splits. As the less mass you have to heat, the more efficient your core will be. Then after you recover the heat and store it in mass. I think with a good plan, you could build a rocket core and barrel in one day. Then what you do for heat recovery will decide how long it takes to build the rest. But, still, if piped, you can heat your place while doing the mass/heat recovery system.

I even have left the fire to die, things to cool an hour, may be, and modified the layout on the fly, prety much. Aluminium sticky tape comes very handy at that stage.

If I had known I was going to line with firebrick, I would have used 6" square tubing for the design.

Maybe if I build the Compact RMH Hybrid 2.0, I will use 6" square, allowing for more flow after lining with firebrick. Also, 4 firebricks would fit perfectly into a 6"x1/8" tube, I believe...

I might take another one of Fstyles suggestions and cut the bricks even thinner, I'm not sure yet... After I insulate the riser I will figure out the rest hopefully

Does structural steel tubing not cost you anything? There is really no particular benefit to it as burn tunnel containment, and it has the drawback of increasing mass and drawing heat away from the combustion zone unless totally insulated on all sides. Making a scrap brick (or even cob) container with stabilized perlite insulation to hold the firebrick split lining is infinitely flexible. The heat riser wants a container, but light sheetmetal or ductwork does that fine.

Here's a "kickstart" to my "2016".

Is it a bad sign that I've already begun design concepts for EMBER Hybrid 2.0?

I've learned a lot in a short time while having my "hands on" experience, and some advice from other experienced folks, enough to start making a new design concept for the 2016EMBER2.0 model.

If only I had known then what I know now lol

Back to the drawing board for the next model, but I will keep developing the original design model for learning purposes, and to share with all you curious folks, so stay tuned for my updates.

As my fist post says "I tinker with this in my spare time" so I'm sorry if I don't have all day to work on this, but I am making progress when I do have the time.

Thanks again for stopping in, your interest, and reading all of these pages of development and opinions. Your time is valuable too

so youre saying its too hard to break the concrete out and repurpose it?

Nothing is too hard, since I'm a go-getter. I just prefer to insulate INside rather than outside. If that makes sense?

John McDoodle wrote:Nothing is too hard, since I'm a go-getter. I just prefer to insulate INside rather than outside. If that makes sense?

that fire brick is not going to give you insulation you may be looking for. it will serve as protection from the high heat but its not high insulation. the perlite is the insulation.