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RMH for Dummies! Please help guide me through my first build!  RSS feed

 
Posts: 31
Location: Australia Zone 10a
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thomas rubino wrote:Hi Dan;
  When you are creating your post , down at the bottom left of the page is the attachment button. click it to attach photos. It will prompt you to upload a file (photo) after the first you click on add another attachment  If your photos are on your computer it will automatically take you there. Photo size is important as well. Too large and they won't down load.  I think it likes 900 x 700 ???  for a size but it will do larger slowly sometimes.

Your idea of covering the bricks around your feed tube.
  If you bring that stone up even with the edge of the feed tube to cover the firebrick , then you are effectively raising the height of the feed tube.  This could be allowed for in your build by shortening the feed tube, the thickness of your decorative stone.
If your feed tube becomes too tall, then it will try to become the riser. Not a good thing.
Average feed tube is 16" deep. if you shorten that to 14" and lay a 2" thick slab of soapstone on top of your bricks ... I would guess you would be looking at temps of 400-500 F at the bottom of your stone.  I think granite would crack.



Thanks Thomas,

Cracking Granite was my fear. Do you think if I was to make the hole wider (say an extra 1" an all sides of the feed tube) would it A: still account for the height of the feed tube and B: be far enough away from the heat. Soapstone is not found too often here (and certainly not cheap off cuts etc.) like granite is. There is so much granite from kitchen remodeling that is going free or very cheap. I have planned to have the seat, ledge and feed tube facia in a matching stone so making it all from soapstone is going to blow the budget. Making this a thing of divine beauty is the main goal (I use the space to teach permaculture workshops and it will be most peoples first experience of a mass heater (of any kind))
Thanks again
Dan
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Wouldn't some extra insulation, like a piece of ceramic fiberboard under the stone slab solve any issues?
 
Dan Hatfield Ii
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Hi All,

Rather than hijacking Staci's thread I have started my own.
Masonry RMH first build
I would really appreciate if you were all to jump in a help where you can.
Thanks
Dan

 
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Hi,
  Been a little stuck in my build.  I have been firing up, with okay results.  Still not hot enough, but I know the cob is still wet.
I am also learning about wood.  Much of the free wood I have scavenged is pretty crappy.  I supplement with pallet wood and some of the better wood.  I think I may have to buy some (going for $120/half cord out here), or locate a load of pallets.
Other than that, I am just spinning my wheels in how to move forward.  I have about 4" left height on the bench, to get the needed 6" of mass above the pipes.

Questions
:

  -  When do I transition to structural (straw) cob for the bench??

  -How thick a layer of structural cob should there be, before the final finish layer.  (that will be another can of worms!)

-In trying to mold/shape the bench and outer manifold (creative juices), can I just slap cob and rocks and go to town??

Thank you.

 
Dan Hatfield Ii
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Staci Kopcha wrote:Hi,
I am also learning about wood.  Much of the free wood I have scavenged is pretty crappy.  I supplement with pallet wood and some of the better wood.  I think I may have to buy some (going for $120/half cord out here), or locate a load of pallets.



Hi Staci,

I can't help with the hard questions as I'm a newbie too. I can help with the wood questions.
I think getting a moisture meter would help to get you understanding about the water content.
I'd buy a cheap one as you may find it redundant once you get a feel for the weight of a particular wood
or the sound of it you tap it on a solid object will tell you how dry it is. There are a few video reviews on youtube of wood moisture meters.

I have one with prongs that you stick into the wood for a reading.
Most of our wood (I'd say 80-90%) is hardwood around my area (you cannot buy pine firewood (other than bags of kindling) anywhere.
I have a one acre (forest edge) property with a few hundred trees.
There is not a single softwood tree here.
Anyhow...the point is the pronged type are damn hard to force into anything other than fresh wood.
If you don't get them in properly, you get a false reading. Trying to check the moisture in a piece of semi-dry hardwood
is virtually impossible and I've near broke the meter several times and bent the prongs
There are others that you just hold on the wood and they give you a reading.
I wish I had got one of those and I may still do.

As for your wood. You need a good shed for starters and you also need to know that pallet are often made from
greenwood and are not dry.
It may be the case that you should get yourself a 1/2 cord of dry wood for this year and keep collecting scrap wood for next year.
It makes a huge huge difference having bone dry wood.

I have a friend who lives of a forest block in a shed with an abundance of wood.
We are in a drought and our normal rainfall is about 35" so you'd expect their wood to be dry. but it is still far from dry.
I gave them a trunk load of my wood for them to burn as they don't have a woodshed.
They came back praising how incredibly better it burnt and how much warmer they were.
They also only burnt a couple of pieces a night rather than a wheelbarrow load of sub-par wood.

Anyhow. I live somewhere hot and pretty dry and you live somewhere cool and damp so it's a lot more important for you to have a good drying setup.
Perhaps ask your husband to build a small solar wood kiln rather than a woodshed.


Thanks
Dan
 
Staci Kopcha
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Dan Hatfield Ii wrote:

Anyhow. I live somewhere hot and pretty dry and you live somewhere cool and damp so it's a lot more important for you to have a good drying setup.
Perhaps ask your husband to build a small solar wood kiln rather than a woodshed.


Thanks
Dan



Hi Dan-
  Great info, thank you!!  I will look into the moisture meter and the solar kiln.
Probably will get a half cord of decent wood to supplement this year.
We do have a nice storage shed: we just re-roofed the failing asphalt shingles ourselves this summer, with metal roofing, so nice and dry.
I have such a mix of wood: pine, cottonwood, plum, cedar, madrona. maple, birch, and plenty of "mystery wood". Some wet, some sort of past their prime (rot).
I am learning the need to be selective in what I bring home.
Not sure what grows out your way except the cliche'd eucalyptus. I love the regional diversity of plants/trees!

Kind of you to share with your neighbor!

Thanks, again!
Staci
 
Dan Hatfield Ii
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Staci Kopcha wrote:

Dan Hatfield Ii wrote:

Anyhow. I live somewhere hot and pretty dry and you live somewhere cool and damp so it's a lot more important for you to have a good drying setup.
Perhaps ask your husband to build a small solar wood kiln rather than a woodshed.


Thanks
Dan


Not sure what grows out your way except the cliche'd eucalyptus.
Staci



You have just about got it. We have mostly eucalyptus in my Area (Greater Sydney area). You won't find much else (if anything else) for sale as firewood commercially.
It's pretty good firewood. It only just falls short of Osage orange and Black locust as far as BTU output (the 2 highest outputs of wood I believe) but is widely available.
It can be hard on your body to process but you only need half as much wood as softwood. I looking forward to my RMH and not splitting so much wood.
I do usually get one load of pine from tree loppers each year to use as a starter fuel. It's like cutting cake compared to Eucalyptus.
Last year I got a bunch of "Ironbark" from a tree lopper. Never again. That stuff if like cutting rocks (actually I think rocks would be easier to split)
Even a 6" diameter took 5-10 blows with a splitting axe. Most of it I had to partially dry before attempting to split it again (with more success).


 
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Hi Stacie; 
Your now at a part of your build that I have never done.
Any advice I give you from now on is from what I have read ...
I have heard 2"- 3 " of  straw cob is recommended.
Your finish layer can be as thick or thin as needed.
Yes, slap cob and rock anyway you like to mold / shape your bench.

Dry wood is essential to a happy dragon
Construction cut off pieces of kiln dry lumber burn really well.
A moisture meter would be a very good tool for you to have.
If you buy an overpriced 1/2 cord of wood make sure it is really truly dry wood , maybe by using your new moisture meter.
 
Staci Kopcha
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thomas rubino wrote:Hi Stacie; 
Your now at a part of your build that I have never done.


Hi Thomas,
  Directions seem a bit "fuzzy" at this point, even from what I have read/watched/tried to research. A bit disconcerting.

I am gone all weekend, but hope to get back to cobbing next week. Will just muddle forward.

Today I removed the top perlite layer that I added to the tower.  Didn't notice any difference.  I am thinking perhaps you were right with weather/pressure systems in terms of the difference in draft.  It was only twice out of the more than a dozen fires I have done. 
  I think learning wood, etc. is key as well.
I will keep you posted.

Thank You!
 
Gerry Parent
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Staci Kopcha wrote:
Questions:

  -  When do I transition to structural (straw) cob for the bench??

  -How thick a layer of structural cob should there be, before the final finish layer.  (that will be another can of worms!)

-In trying to mold/shape the bench and outer manifold (creative juices), can I just slap cob and rocks and go to town??

Thank you.



Hi Staci,   I'm with Thomas on this one too. So.....as it is written in the scriptures "Thus have I heard"..., the structural cob is mainly for areas that are going to take any kind of abuse to help keep it together better. Not that a rock lasagna is going to come apart any time soon, but extra straw can help with corners, scratch and dent places.
I don't think there are really any hard and fast rules anyway, only suggestions that may or may not apply depending on your intentions, time/money you want to invest into it or skill levels.

If it is going to be a plaster finish, then you may want to let the cob thoroughly dry out before putting on the finish coat. This way, the cob will have finished all its cracking and shifting so its less likely to transfer through to the thinner plaster layer.

I have done some tile work on mine and really enjoy the brilliant contrast it gives to a more dull earthen finish. Mosaics are nice also, made from old smashed up decorative plates too or some special rocks collected through the years partially embedded into the final coat. Or how about a bass relief of an ivy plant or tree growing out of the floor and embracing your bench?
At this point I guess what I'm really trying to say is experiment and have fun with it as this is where your personal touches will be seen on a daily basis and all that hard work will really shine.... so yes.... "go to town"!
 
Dan Hatfield Ii
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Staci Kopcha wrote:

thomas rubino wrote:Hi Stacie; 
Your now at a part of your build that I have never done.


Hi Thomas,
  Directions seem a bit "fuzzy" at this point, even from what I have read/watched/tried to research. A bit disconcerting.

I am gone all weekend, but hope to get back to cobbing next week. Will just muddle forward.

Today I removed the top perlite layer that I added to the tower.  Didn't notice any difference.  I am thinking perhaps you were right with weather/pressure systems in terms of the difference in draft.  It was only twice out of the more than a dozen fires I have done. 
  I think learning wood, etc. is key as well.
I will keep you posted.

Thank You!



I don't have any experience with clay plaster but I have a little owith lime plastering. I had a friend plaster my studio and he did a marvellous job. We were short on time so he plastered and I prepared the mix.
Screen the sand though aluminium window cloth/screen (i don't know what you call it) I'd screen the clay too through it..
Sorry, that's all I have. I believe clay in much easier to work with than lime. Lime dries quickly
 
Staci Kopcha
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Hi!
After being away for the weekend, I hope to get some cob/RMH work done today.

Two (more!) questions/concerns operationally:

1)  Back of benches (2nd pipe run) temps at 56 degrees, even after being fired up for a few hours.  I can see that when I peak under some rocks, it is still wet.  Should I be concerned???

2)  Fire:  In tending the fire, it is VERY high maintenance  and finicky.   There are quite a few instances where the flames rise up out of the fuel feed and/or smoke.  It seems to happen most with any bits of wood that are NOT round:  Flat pieces of pallet wood and pieces of diced up wood rounds...regardless of the length of the piece. 
   I am VERY conscious of not over-stuffing the feed box and maintaining good airflow into the tunnel and through the tunnel.

   
Any thoughts on these 2 questions would be appreciated!!
Thank you!
Staci
 
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Hi Stacie; 

Those are all symptoms of a not dry mass.  My mass is larger than yours and it took almost 2 months of all day burning, before the pipe at the end of the run really started heating up.

I think you are  having a less than bone dry wood issue.

Before you thought you were having excessive draw issues, if now at times, your wood is burning out the feed tube , your not having that  problem anymore.  If it wants to draft up the feed tube then block off part to increase velocity.

You don't want to baby it...You really want to get it going hot, its the only way it will dry out.  Pick your driest wood , split it down , get the fire going well and Fill the feed tube.  You don't want it back drafting so be prepared with bricks and or a small hand held fan,to keep it going the right way. MAKE that dragon roar , even if it doesn't want too yet, it has to dry out before winter really sets in. The top of your barrel should be hitting 500 F at least.  The drier and warmer that mass gets... the better everything will work!  I had puddles of water on my floor from drying ... it takes time... every drop of water you added has to evaporate away ,that's a lot of water.

Keep cobbing and keep BURNING! I promise it will get better!
 
Staci Kopcha
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thomas rubino wrote:Hi Stacie; 

Those are all symptoms of a not dry mass.  My mass is larger than yours and it took almost 2 months of all day burning, before the pipe at the end of the run really started heating up.

I think you are  having a less than bone dry wood issue.
Keep cobbing and keep BURNING! I promise it will get better!



Thank you, Thomas, for the reassurance and feedback!!
I will feed that dragon without mercy!!  (I have contacted someone about obtaining dry wood, as well. And will get a moisture monitor ordered this week.)

Staci

 
Gerry Parent
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Staci Kopcha wrote:
2)  Fire:  In tending the fire, it is VERY high maintenance  and finicky.   There are quite a few instances where the flames rise up out of the fuel feed and/or smoke.  It seems to happen most with any bits of wood that are NOT round:  Flat pieces of pallet wood and pieces of diced up wood rounds...regardless of the length of the piece. 
   I am VERY conscious of not over-stuffing the feed box and maintaining good airflow into the tunnel and through the tunnel.


Staci,    Your experience can be quite common during first starting up, drying out stages or during odd wind or weather pressures. As you have experienced, the two flat surfaces close together coupled with not enough draft are acting as a mini chimney. Splitting the flat wood will definitely help out. However, even with good draft, as a general rule its best not to put a flat piece perpendicular to the flow of the flame. Parallel is always best for good air flow.
Also, if when you look down into feed tube and notice any lazy flames, this is a good indicator that sooner or later it will begin creeping up the wood and could make its way to to top. Repositioning the wood until the flame starts to roar again everywhere is helpful.
Bottom line though, when there is enough draft, no wood shape should cause smoke back to occur. Something you may not experience until your bench dries up more but do know, easier times are just around the corner!
Thank you for all your updates!
 
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The solution to not having to babysit the fire, for ma; has been to build a batch.
 
Staci Kopcha
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Satamax Antone wrote:The solution to not having to babysit the fire, for ma; has been to build a batch.



I see definitely see the appeal in that!  Perhaps once all is said and done, I will revisit the j-tube format.
Is it a modification that could be done to my current system, or does it demand another?  Regardless, it is for the future.

I AM pleased that tonight my little RMH raised my entire house temp. to 71 degrees!! I have never set the heater thermostat that high, ever.
Worth a little babysitting, I suppose.

S.
 
Staci Kopcha
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Gerry Parent wrote:[ easier times are just around the corner!
Thank you for all your updates!



Thank you for all of your help and advice!!
 
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Staci Kopcha wrote:

Satamax Antone wrote:The solution to not having to babysit the fire, for ma; has been to build a batch.



I see definitely see the appeal in that!  Perhaps once all is said and done, I will revisit the j-tube format.
Is it a modification that could be done to my current system, or does it demand another?  Regardless, it is for the future.

I AM pleased that tonight my little RMH raised my entire house temp. to 71 degrees!! I have never set the heater thermostat that high, ever.
Worth a little babysitting, I suppose.

S.



http://donkey32.proboards.com/thread/1361/converting-8-6-batch


 
Staci Kopcha
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Hi,
  I have read that there should be 6" of cob above the ducting.  I also read "in the book" , that in the second angle/side of the bench could be less thick to allow heat to come out in the bench areas that don't get as hot.

Question:  Is there a specific reason for 6"? I am at 3" now.  If I add another coarse of thermal cob and then structural cob and then finish layer, I should be close to 6".
  (read: this is my lazy-self trying to get by with making less cob, and having to buy another couple bags of fire clay.  I am up to 8 bags so far... more than 1/2 bag batch goes fast.)

Would I be better off doing another course of "mass/cob" for thermal retention?

Thank you.
 
thomas rubino
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Stacie; In my opinion , Add more mass.  You can't have too much.

Sorry but you asked...
 
Staci Kopcha
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Realities of Cob stomping in November.
Hard to capture in pictures, but the boots hold onto the cob and they become quite weighty.
My daughter had a laugh at my "hairy moon boots"
I am factoring this in as part of my half-marathon training- just sayin'.


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Gerry Parent wrote:!



Here is my modified smoke holder/bung hole.  It doesn't have an opening, but it will contain the smoke for a bit if I need to step away from the early stages of fire up.
After a solid hour or so, it settles down and becomes much less needy.
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Gerry Parent
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How to Train your Dragon .... from being a Puff the Magic Dragon!
 
Staci Kopcha
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Gerry Parent wrote:How to Train your Dragon .... from being a Puff the Magic Dragon!



<laughing>
 
Staci Kopcha
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Hi,
  I got another lasagna layer of rock/cob on all the benches, and have 2 batches of straw cob made up in the wings and ready to go.

Questions: 

   1)  Can I just add the straw-cob on top of the rocks as the final layer before the finishing layer? OR should I add a layer of thermal cob first?

   2) As I build up some cob around the barrel (I understand that up to 1/3 is okay), I began to add some bits for mass... any reason this would be a problem?

I am hoping to get ALL basic cobbing finished this week/weekend.  Then allow for complete drying for a couple of weeks before finishing layer.

Thank you!!

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thomas rubino
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Hi Stacie; Looking good ! Is it drafting better ?
Yes, add the straw cob on the rocks (sounds like a bad mixed drink) give me a straw cob on the rocks please...
Add all you like for mass, more mass is good.  1/3 up is normal 1/2 is fine, some (like me ) cover over 75%. do not cover it all.
I think you will want give it a good long time to dry before your final coat.
 
Staci Kopcha
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thomas rubino wrote:Hi Stacie; Looking good ! Is it drafting better ?



Hi Thomas,
  Straw cob on the rocks it is! :)  With a l o n g drying time. Can I use the moisture meter on the bench?

Question: Does this layer get smooth finish or finger hole/rough??

It does seem to be drafting a bit better, for the most part.  Still some smoke issues sometimes.   Barrel temps are consistently getting up to 400-500 degrees!!

Thanks!!
 
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Hi Stacie;  Can I have a little umbrella with my straw cob please ???    400-500 Now that's getting more like it !

Remember I'm guessing here but, I think a smooth finish , as much as you can with straw.  Then just let it dry. 

I doubt your moister meter would give accurate readings on thick cob but... give it a try.

I think if it were me , as much as you want to finish this project (so you can start a new one) :)  I would wait until summer before I did a final coating (I could be wrong) You really want all the moisture out before you put a sealing finish coat on, (I think) Also let it do its cracking thing ,we know its going too. Patch them thru the winter while you and your family stay nice and warm, by spring / summer it should be ready for that final coat.

That will give you plenty of time to sculpt dragons or designs or your kids names , whatever you want, when your finished playing and the cob is finished drying it will be time to put the FINAL coating on.

EDIT)  Oh and take lots of final photos !
 
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