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Insulation around riser  RSS feed

 
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Hi everyone...I'm building my first RMH and the perlite/clay inside my hardware cloth form surrounding the heat riser is loose and crumbly in some places.....like I maybe didn't pack it in tight enough. Is this a problem? Will the hardware cloth burn up and all my perlite fall into the manifold?
 
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Micki Blanco wrote:Hi everyone...I'm building my first RMH and the perlite/clay inside my hardware cloth form surrounding the heat riser is loose and crumbly in some places.....like I maybe didn't pack it in tight enough. Is this a problem? Will the hardware cloth burn up and all my perlite fall into the manifold?



Miki Blanko : Congratulations, It is possible that you do not have quite enough Clay mixed in with your Perlite.
You didn't sat if you used dry clay and sprinkled it repeatedly over dampened Perlight of mixed clay slip into damp perlite

Or you may not have mixed everything thoroughly, if you can I would just start over recycle the ingredients and try again,

Chicken wire, which is a much lighter gauge wire has held up in that location for at least 10 years, your weak link if any,
will below you wrapped the ends together !

Keep coming back and tells how you are doing, we all want to hear! Big AL !
 
Micki Blanco
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Thanks for the timely reply Al! I am using the Bonny 8" blueprint as a guideline and have bought the RMH book. My bench sits on brick air channels with a 4" air gap from the wall. It is roughly 9'x3' with the end section about 2 ft wider from front to back to make a chaise. I do have a couple more questions.

1. I want to make a backrest to have soft cushions to lean against. Would it be better to make the backrest from cob or wood? If I use cob, will it be too much mass and reduce the heat from the bench?

2. I was concerned about having too many turns in my duct work, so the chaise part of my bench has no duct in the front section (maybe I can post a pic) I am wondering if this will reduce heat also.

3. Since I'm a girl I'm already thinking about making it pretty...do the cushions have to be 100% cotton inside and out? I promised hubby I wouldn't burn the house down... so your help is greatly appreciated!

4. Do I have to wrap the ducts in cob? Or will sand be just as effective with bricks and rock for filler?

Thanks, Micki
 
allen lumley
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Micki Blanco wrote:Thanks for the timely reply Al! I am using the Bonny 8" blueprint as a guideline and have bought the RMH book. My bench sits on brick air channels with a 4" air gap from the wall. It is roughly 9'x3' with the end section about 2 ft wider from front to back to make a chaise. I do have a couple more questions.

1. I want to make a backrest to have soft cushions to lean against. Would it be better to make the backrest from cob or wood? If I use cob, will it be too much mass and reduce the heat from the bench?

1a)I will specifically send you to a second build done by E & E, that I helped on, thee backrest in that case has a 'Wattle and Dab' core and has held up very well ! Both will work fine, there are many
benefits to aWooden back which could be modified to make it adjust able at some future point, other wise have it custom built to your personal dimensions including an area dished to receive your
backside and heal rests !

2. I was concerned about having too many turns in my duct work, so the chaise part of my bench has no duct in the front section (maybe I can post a pic) I am wondering if this will reduce heat also.

2a) It certainly will reduce the heat in that area !

3. Since I'm a girl I'm already thinking about making it pretty...do the cushions have to be 100% cotton inside and out? I promised hubby I wouldn't burn the house down... so your help is greatly appreciated!

3a) Wool is more fire retardant than cotton, has a higher ignition temperature and can be more springy to sit lie on, This is a personal choice based on how various grades of wool feel next to your skin
and also what you nose thinks of the smell of the finished product,and the finished product depends on what your nose and skin tell you !

4. Do I have to wrap the ducts in cob? Or will sand be just as effective with bricks and rock for filler?

4a) Sand is easiest but it is slightly insulative, to absorb ,hold, and reradiate out the same amount of heat energy that you can create with wrapping the duct in Cob, and then adding a topping of Rock and Cob Lasagna
requires more thermal mass if made with sand !

5a) watch the video and tell me what you think !

http://www.permies.com/t/25435/rocket-stoves/video-great-rocket-mass-heaters#320868

Thanks, Micki



Micki The link works, it just delivers you to the bottom of that Thread And what you actually want is the First Video at the top of the Page, just scroll up to the top !

For the Good of the craft ! Big AL
 
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allen lumley wrote:

Micki Blanco wrote:

4. Do I have to wrap the ducts in cob? Or will sand be just as effective with bricks and rock for filler?



Micki, the problem in using sand without a binder (clay, fire clay, etc.) is that loose sand has lots of air spaces and is thus insulating. So you'll want to mix in some clay with your "masonry grade" sand.

 
allen lumley
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Byron : There is absolutely nothing wrong with doing it your way, if you have Lots of help!

Here is the lazy mans way, a base layer of Cob and bricks to reduce the Temperature at floor level, after the Stove pipe has been laid out and its final
lay out has been determined and secured with screws and taped joints, the pipe is bedded into wet cob, with the whole piping indirect contact with its bed
and/or painted with clay slip, then fill in around the piping with minimum cob and maximum stones, filling the whole thing to a common layer before adding
height, then finish with a Rock and Cob Lasagna!

The more Rock you bed, stack, paint with clay slip and cover with a thin layer of cob, the less Cob you have to make! And it dries faster Too!

The Four best things about Cob or Adobe is 1) it wont rot, 2) it will not Burn, 3) insects won't eat it, 4) it's as cheap as Dirt! -But it can be a lot of work for
someone, and can be very hard on your back ! For the Good of the craft! Big AL

 
Byron Campbell
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Al, your way and my way are exactly the "same way". For clarification, binder (clay, fire clay) + loose masonry grade sand + water = cob or "cobcrete", which is very handy for binding all the loose rock, pieces of brick, stone and any other masonry "filler" materials embedded in the bench, around the ducting and etc.

Just dumping loose sand in a RMH bench with masonry rubble would not be the correct construction method. At least that is how I read the question. Or is this a "Cool Hand Luke" day?-)
 
Micki Blanco
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Thanks everyone for the info. I will use mason sand/clay 70/30% to coat the ducts and fill all the voids, using as much rock and brick as I can, lasanga style.

With brick air channels, felt, 2layers of aluminum foil, and 2" of perlite/clay under my combustion chamber....how hot will the floor under the chamber get?
 
Byron Campbell
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Micki Blanco wrote:Thanks everyone for the info. I will use mason sand/clay 70/30% to coat the ducts and fill all the voids, using as much rock and brick as I can, lasanga style.



It's a good idea to first coat the ducting with clay slip, before packing the first layer of your sand/clay "cobcrete" around the ducting.

Micki Blanco wrote:With brick air channels, felt, 2layers of aluminum foil, and 2" of perlite/clay under my combustion chamber....how hot will the floor under the chamber get?



If you're closely following the plans, building exactly as per design, the floor will never get much more than just barely warm to the touch, after extended firing of the stove.
 
Micki Blanco
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OK, thanks Byron. I will use clayslip first...and in between bricks when stacking to fill.
 
Micki Blanco
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Al, you mentioned wattle and daub method for constructing the backrest...what do you use for the "lattice"? I am wondering if wood is ok or if it would get too hot.
 
allen lumley
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Miko Blanco : Willow or split willow Make sure you have the stuff truly and well buried in there !

The "Day Bed'' in question is going into its third heating season now, for the first two years it survived without a top coat of Structural Cob, mostly because it
was holding up well without it and a slight worry that with a larger outside diameter and a further insulating layer of structural cob, it might be a little cooler !

No difference was reported, My point here is that even without that structural layer for strength, and a finish layer for protection no crakes have been reported

For the good of the Crafts ! Big AL

 
Micki Blanco
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I don't think I will find any willow wood at the lumber yards here in Kansas. What would another option be? Could I use metal pupecor rods?
 
Micki Blanco
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That's supposed to say "metal pipe or rods". Lol
 
Micki Blanco
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Should I burn to dry the layers as they go on? Or is it better to finish building the bench first? The cob and rocks are about even with the top of the duct work now...its kind of slow going cuz I am usually working alone.
 
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You wouldn't get willow from a lumberyard... you would get it as branches from a willow tree along a stream somewhere
 
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Micki; Yes , definitely burn while you are adding mass ! It takes weeks to dry out your mass ... the sooner you can start burning the better .
 
Micki Blanco
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Glenn, thanks for saying that so tactfully. Lol...yes that would make sense...duh. Now the hunt for a willow tree.
Thomas, Yay! I've been wanting a reason to fire it up!! Tonight we burn!!
 
allen lumley
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Micki : You could get a hold of someone who canes chairs, i.e. replaces the basket weave'd seats- while just about everyone now uses a boughten product pre treated

and sized, They MAY know someone who is a basket maker who still works with willow they gather themselves I have seen two other RMHs with chaise-lounge backs

and the builder found two old Bent wood chairs and embedded the back rest part deep in the Thermal mass and went down to the local river bank and quickly

harvested all he need to inter weave the Wattle part of the wattle and daub ! It is important that this gets emplaced while the Cob is still workable and you know where

the rocks are!

The link below is a picture similar to what a traditionally harvested patch of ''Coppiced Willow '' would look like just be fore a 'gather', very fine, very straight willow
withes and a few longer lengths ready to be worked on to be turned into bows!


http://www.gardenworldimages.com/Details.aspx?ID=9191&TypeID=1

I am sorry I was not able to get back to you sooner as I now see your hurry to 'build a fire' ! I hope you can still find a way to use this information, if you try, make
sure to bury at least as much of the Bow as the rest of the wood above it ! This part should be the fist part to get its coat of structural cob ! Big AL

Late thoughts : you may have local Amish basket weavers who could grasp the Idea of a basket weave chair back, generally a pack basket weaver works with Ash,
and might have a little more trouble bending his mind around what you want !

I find when I do a search for anything if I stick the word images, or Pictures at the end I can find an interesting picture click on it- and it usually takes me to a good
article,l if you write crappy articles you generally don't download great pictures ! I hope at least some of this was timely and helped ! A.L.
 
Micki Blanco
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I am not feeling very confident in my ability to do the cob backrest properly.....seriously think I'll do a wooden one instead. Plus its less cob.....can I hear an amen? So any advice on how to do the wooden one will be highly valued. Thank you guys for your kind help!
 
allen lumley
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Micki : nothing ventured nothing gained, when you told us you were going with the 8'' bonnie system I Assumed that the backrest plans were laid out for you.

All I have to offeris a series of short video clips which is approximately 3/8ths of a Professionally shot DVD of their build, that muck of the DVD is free, if you
have already seen this then it is not a big deal. To get the Videos to play in order click on the link below get comfortable, get some popcorn and select the
playlist marked rocket mass heater Scenes


http://www.youtube.com/user/villagevideoorg/playlists

Hope this helps ! Big AL
 
Glenn Herbert
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Willow may be a classic wood for weaving backrest structure from, but it is far from the only feasible one. Any wood that you can gather which comes in or can be split to thin flexible withies will do. Ash works well, as do "weedy" brush species which tend to form clumps or thickets 5-6 feet high with many stems springing from a central base. You don't want a tight basket form, but a very open one with at least a couple of inches between withies so that the cob is continuous throughout the backrest.

The cob also needs to be thick enough, especially at the bottom of the backrest, to take the force of people leaning on it - probably 8" thick or so, but you will have to experiment with your actual materials. This is a place to use the best clay you have for the cob. Will you have a freestanding back, or can it be supported by a wall behind it at regular intervals?
 
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Hi Micki Blanco, et al,

Do not over think this Wattle and Dub stuff too much…its not that hard to do and there are countless forms of it. Actually, as a traditional woodworker and builder of many things in the historical vernacular forms of many different cultures I would venture to say that cobb over wattle work is much easier to do than even average good woodworking…especially when it comes to a furniture piece like a back rest.

For one thing,…Willow wood is not a “wattling wood”…willow is for “picketing” and related work, as well as one of the many basketing materials.

Traditional wattle work is Ash and Oak…and in Asia, of course is bamboo


400 year real wattling


same...maybe older



similar without cobb...take a guess...some of the oldest of its type out of Asia (hint...its way older than Europe's wood culture)


This is what can be done with just scrapes fo black oak and maple with a cheap contractor's table saw...


600mm x 1200mm panel

So again...DON'T....overthink it....

j
 
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