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
Ok, they're batch rockets. But the pictures of my building technique might give you some ideas.
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!
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!
You might get away with .5mm thick.
But you experiment with it. And we'll watch I'll carry on using refractories
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.
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...
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.
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.
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.
Thoughts on this conglamerate idea?
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.
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.
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 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.
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.
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.
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
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
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.