Any RMH or BB gurus in Maine? How about someone that built their own?
I'm upgrading the 70 year old family summer camp on the coast. We've had the old, crumbling concrete posts replaced with ICF foundation after excavating to ledge (or below), got more light by creating a full dormer (with lots of glass) across the SW face, and will be adding some rigid insulation to the exterior (there was none before). Heat was provided by a sizable fireplace with Heatilator insert (long rusted out and sealed). Now I want to use a batch box or RMH since I still have a ton of softwood that the Northeast storms topple.
I'm hoping to find someone up here that has experience building something akin to the Walker stoves or other efficient and flexible wood eaters.
Lets hope there is someone within reach of you to help.
If not we can help guide you thru building your own.
There are only a few choices. Two types of cores. The traditional J tube in 6" or 8"
Or the newer Batchbox core in 6-7 or 8".
Both are rocket mass heaters.
For the mass you can have a traditional bench with pipes.
Or a stratification chamber (brick bell).
Brick bells can be any shape your space allows.
Proper floor support is very important.
You should be able to utilize the existing chimney as long as it is in good shape.
Foundation is no problem - the base will be sitting on the new 4" concrete floor which is sitting on granite bedrock. If it moves, we're all in big trouble!
I removed all the masonry, including the chimney, as the structure got lifted 3 feet for the foundation and a partial cellar, so I'l be completely rebuilding from scratch (but yes, I will be re-using the bricks). Since we will have little people around, I prefer the batch box, and based on calcs I made from Peter VDB, I think I'm looking at the 8". I do want heat as the primary use, but white oven for baking and bell(s) for storage are also on the list. We are located near the very end of the power line and heavily wooded along the way - therefor I'm planning on continued outages. One more reason for a multi-purpose appliance.
So your thinking an 8" batchbox! Just how big is your camp? cathedral ceilings?
My auto shop is 24 x 32 with tall ceilings. I built a 7" Batchbox for it on Peters recommendation, as in his words an 8" Batch is a beast!
I am very happy with the 7" version. Peter was correct (as usual) the 7" was plenty for my shop.
So, no matter what size you or a contractor build, there are some supply's that you will need. And some you might want.
Sounds like you have plenty of bricks. Being a fireplace hopefully some of those bricks are fire bricks and the rest are clay brick. Concrete brick is a poor choice and only usable down very low in a bell.
You will need several #50 sacks of fire clay. You will need sand, a LOT. Three times the amount of clay. Sharp sand... unfortunately ocean beach sand is super fine and small. It could be used but is a poor substitute.
If you wish to build this to the absolute best you can. Then you will want/need 15-20 Insulated firebrick's good to 2700 F. (Highly recommended)
You will want Morgan super wool ceramic fiber blanket to build a five minute riser. You may want some 2" ceramic fiber board as a roof on your box.
You will want angle iron to build a support inside the brick bell. This will place your batch box up off the floor but completely inside the bell and make loading easy for an adult and place it high enough that little ones can't touch it.
About an oven. If you build a batchbox with bell. You would need to build in your own oven. Could be done but adds more time consuming masonry work.
An external cook surface could be easily incorporated into a bell.
Now , Matt Walkers large stove is set up with a black oven and utilizes his riserless core. He sell complete plans with a total build list of materials.
Another thing about buying plans from Matt, he is super friendly, super knowledgeable and you get unlimited free build advice, thru email or phone if you run into difficulty.
I have no idea of his costs but Matt will travel to build for you if that is something you might consider.
Thats enough for now. Let us know what your thinking.
Yes, I think I have have plenty of clay bricks. There isn't a new one in the three pallets (about 300 per pallet) - and I'm not sure there are any two with precisely the same dimensions!
There are a handful of hard fire bricks (not enough I'm sure) and the only concrete bricks/blocks will be for the foundation - just to lift the unit up to a comfortable loading height.
You say I'll need several #50 sacks of fire clay. I found a source in Portland, ME but they only have a dozen different types and mesh. Can you be a little more specific on the right one(s)? And yes, I want to do this so that it lasts.
As far as sand goes, I wouldn't use the beach version around here - way too much salt in it. But a four yard dump trailer of washed concrete sand is readily available.
I have yet to find a local dealer for Insulated firebrick or ceramic fiber board and blanket. But the ones I have found on-line seem to supply blocks with ratings in 200 degree increments. Is there any advantage to go much higher (some have ratings above 3k)?
Angle iron for internal supports is not a problem. I have a small stash plus it's only a 15 minute drive to the scrap yard.
Now for the oven. Neither the wife nor I care for the taste of smoked food, so it's definitely going to require a "white" oven. That said, has anyone tried to slip an electric oven "casing" into the upper end of a bell? It looks like self cleaning ovens hit nearly 900 Fahrenheit, - isn't that well above what I'd get after the riser?
As for camp size, the main area is open floor plan and just about the same dimensions as your shop. But the insulation will be minimal. There are two BRs upstairs and the central balcony between them leaves what amounts to a cathedral ceiling in 1/3 or so.
The other consideration - I'd like to keep the wood, ash, bark, etc in the (ICF) cellar. Please correct me where I go off the normal path here but, my thought was to build the heater with firebox around 30" off the floor, that would put the top of the riser between 5 1/2 and 6 1/2' high. Cellar is just barely 7' floor to bottom of upper floor. Isn't the top of the bell normally about a foot above that? And can it be higher? Could I make the bell top at 40" off the first floor and have a priority bypass for 1) oven; 2) heat; 3) bench (maybe)? I do plan on a bypass for easier starts - even though some folks say you don't really need one.
Parts of what you want are on the path and some may be a bit off the path.
Let me get my numbers right here.
Your basement has a 7' ceiling and you would like your batch box to be down there? That is doable.
Your planning on the brick bell coming up thru the floor?
What size bell are you thinking? Have you run Peters isa numbers on bell size?
In your basement, you plan on the B box being 30" off the floor.
The riser for an 8" batch is 57.5" . That makes it almost 7.5 ' to the riser top and bare minimum 8.5 ' to go over the riser.
That makes for a serious masonry build. Sting lines and level's or it will not be square at the top.
Now lets talk about clay. Fire clay is one product. There are no choices. Lincoln 60 is the common brand out west, Hawthorn is a brand I hear of back east.
I suspect the shop in Portland is selling refractory cement. That has many choices.
Using refractory cement is more durable than using clay. If you choose to go with refractory you will not need sand at all.
Be aware that both products will crack over time and need repair.
Your oven casing idea is way off the beaten track.
Consider a large thick plate of steel that caps your bell (several feet min above riser)
Part of that plate becomes a hot plate. Part gets a steel insulated box (oven)
Your Bypass thoughts are spot on. Absolutely yes you will want and even need them!
What are your chimney plans?
Chimney plan is to build one. Sorry, that's my techie coming thru...
Since I am effectively on bedrock, I plan to arrange some cement blocks to whatever footprint I need for the base of both heater and chimney. When filled with rocks, rebar and concrete, that will provide a sufficient monolithic base at a level that will allow me to put the firebox door at a comfortable height. The whole chimney (close to 30' tall) will be tile lined. The base that is visible in the cellar will be concrete block, what shows from the first floor to the cap will be either brick or local flat stone (I think it's called gneiss). Since the kids may want to someday put an additional heat source in, I think I'll run two 8" square flues all the way up. Independent, but adjacent - each with it's own ash pit and cleanout door.
So the steel plate and insulated box - is that cast iron or mild steel? And do I insulate with ceramic batt or board or something else? Oh yeah - when I was at the junk yard last time they had a stack of 4x8 sheets of 4" thick stainless steel. Probably overkill, huh? I don't think I want to know what he's asking for them!
Sure hope I'm not monopolizing your time - but this information is awesome!!!
When folks talk about using a clay mixture in their cob or mortar - is that the same thing as marine clay? What I have locally is really heavy, gray and a bit slimy to work with. Seems like it would be difficult to thin to a working consistency.
Yes , your local heavy slimy clay can be used.
Here's how. You'll want a bunch of 5 gallon buckets... Fill part way with clay and add water. Leave alone for a few days and come back.
The clay slurry should be in the bottom of the bucket.
If this is for general cob then add 3 parts sand and mix. This can be accomplished with a tarp or other's have used a tractor tire in a hole. pour in ingredients and back and forth with the tire until it is mixed.
If this is for mortar then that clay slip will need to be screened for rock. Your sharp concrete sand should be the largest pieces in the mix.
For making mortar this is where #50 sacks of dry fireclay shine. They cost about $10-15 each here and I'm sure Portland would have it at a Masonry supply house.