ghetto fabulous garage / shop heating

[char5]

I have a 374 sq ft uninsulated (for now) garage/workshop that I am attempting to heat using a open loop (no boiler effect) wood fired firebox (outdoors) which will have a coil of copper tubing and a one-way check valve feeding a radiator in the garage. This is very much how a coffee maker works, at least in principle.


As this is all an experiment, I'm going cheap till I know it works and only buying thing that are REQUIRED. It's never the big things, but all the nickle and dime stuff that kills ya... $3 here, $7 there, it starts to add up quickly.


My "firebox" is a newspaper rack that I will line with custom molded concrete blocks as I already have the concrete. The "radiator" are the cores for an OLD Montgomery Wards window air conditioner that I've harvested. I have a 20" temp controlled box fan to blow across the radiator. The "reservoir" will (more than likely be) a 5 gallon bucket hung on the outside wall with a float valve to maintain it's water level (once I run supply line to it that is, till then the garden hose).


FLOW:
1) Firebox with copper coil
2) Radiator in garage
3) Bucket reservoir gravity fed to firebox
4) one way check valve
5) Back to #1, lather, rinse, repeat.


I'm at 2500 feet elevation, water boils around 207F.

I'm in a VERY HIGH FIRE HAZARD ZONE, and would rather not have a stove/firebox IN the garage.

The average low at the coldest time of year is 28F, a 35F rise would be awesome (63F).
If I could just reduce humidity levels during the night, that would help prevent tools from rusting at least.

As a reference, BTU calculator says I need 34,000 BTU/hr. Once I insulate, it'll be less.

I need to use a dust collector much of the time, which will exhaust to the outside at 900 CFM.

I have a MrHeater Big Buddy 'indoor safe' propane heater (18,000 BTU) on a 5 gallon tank that I can use to supplement as needed.

I have NOT bought he copper tubing yet, but I do have a piece of 1/4" thick-wall stainless steel tubing I'm going to try/test things out with first on the bbq before attempting with firebox.

As of now, the core are 1/4" tubing, and I plan on using 1/4" PE tubing between the firebox coil and the radiator. I really don't know what capacities I really need, so this is a start and could always jump up to a car radiator and 1/2" tubing. I don't *think* I would ever need to go any larger than that, but I guess we'll see how it goes.


In my wood stove, there is a reburner(?) pipe that jets the woodgas once it's up to temp. I'd like to replicate that in my ghetto firebox, but I haven't seen (photos/video) of how wood stoves are designed to do that. Links would be appreciated.


This all sounds good... on paper. But we all know nothing ever works out as planned =)

Does anyone have any positive thoughts/suggestions that might help improve what I've outlined above, or to avoid any mistakes/gotchas that I may encounter?

 

[brenndatomu]

Welcome Char, I'm not one to poo poo on a lil DIY home ingenuity because BTDT, but I think you will be disappointed with the results here. For one thing 1/4" tubing not near big enough, I would think 1/2" minimum, probably bigger. Search in the boiler forum about water line sizes...the boiler guys often make the mistake of putting in too small of line to the house and can't get enough flow to transfer the heat properly. They often use 1" (because of price) when 1-1/4" or 1-1/2" is needed. Huge difference in flow between those sizes.
As far as a "reburner", check the "pre EPA" stove forum, there are tons of threads where people have added secondary burn to old stoves. Maybe some in the boiler/furnace section too.
Careful with this project...don't wanna make steam if something goes wrong...steam can go "BOOM" in a hurry!
Good luck!

 

[maple1]

Not much about this is sounding good to me, on paper or otherwise.

 

[Fred61]

Prepare yourself for disappointing results.

 

[stee6043]

Is the woodworking situation preventing you from considering an inside the garage solution to wood heat? Seems like a barrel stove would be a great choice for you if you can manage the dust properly. Dirt cheap, makes plenty of heat.

I think you could be in business for under $100 based on what I see around at local Tractor Supply or other stores.

 

[stee6043]

Wait a minute....isn't burning wood illegal in California??? ha. Good luck!

 

[char5]

As far as a "reburner", check the "pre EPA" stove forum, there are tons of threads where people have added secondary burn to old stoves.

Thanks, will check them out!

 

[bholler]

Is the woodworking situation preventing you from considering an inside the garage solution to wood heat? Seems like a barrel stove would be a great choice for you if you can manage the dust properly. Dirt cheap, makes plenty of heat.

A barrel stove is not a great choice for any situation. You are relying on a barrel made of pretty thin metal to contain the fire. I have seen to many of them really distorted from heat to ever recommend one. And we will not service them either there is just to much liability if we work on it

 

[char5]

Is the woodworking situation preventing you from considering an inside the garage solution to wood heat?

I think you could be in business for under $100 based on what I see around at local Tractor Supply or other stores.

I only have 374 sq ft of floor space, most of which is already used. Adding a barrel stove plus wall clearances would reduce that by about 9%. Floor space is a premium, while outside is abundant. The other thing is the increased risk of fire hazards, so I'm not totally opposed to the idea, just reluctant.


I may consider using the newspaper rack instead of barrel stove. It's upright (less floor space), has a door already, I can cut a lower one for ash removal, and it even has a flat top to keep the coffee warm.

 

[char5]

A barrel stove is not a great choice for any situation. You are relying on a barrel made of pretty thin metal to contain the fire.

Barrel or newspaper rack, both are thin gauge. What I was thinking of doing is lining the rack with either firebricks or pouring my own custom bricks. Would you still consider this "too thin", or ???

 

[bholler]

What is a newspaper rack stove?

 

[bholler]

Barrel or newspaper rack, both are thin gauge. What I was thinking of doing is lining the rack with either firebricks or pouring my own custom bricks. Would you still consider this "too thin", or ???

Ok I missed that in your original post. I would pick the barrel stove over trying to use a newspaper rack as a stove any day. And I absolutely hate barrel stoves.

 

[char5]

Ok I missed that in your original post. I would pick the barrel stove over trying to use a newspaper rack as a stove any day. And I absolutely hate barrel stoves.

I already have the newspaper rack (below), I can line the insides with firebrick and the bottom section can serve as ash catcher.


Why would you pick the barrel over the rack?

 

[bholler]

Why would you pick the barrel over the rack?

Well to be clear I would not burn either anywhere in or near my house or shop but atleast with the barrel there was some design and development put into making a wood burner. I am sorry but a newspaper rack? I am moving on now because you obviously have no concern about safety at all. Just go buy a used stove for a couple hundred bucks and be done with it.

 

[TreeGoomba]

At 375sq feet, in california, in a "VERY HIGH FIRE HAZARD zone", keep it simple with the mr buddy propane heater you already have. Or go with electric heat and maybe, just maybe, a small kerosene heater if you need to tinker with fire. A kero heater will heat coffee too...

 

[maple1]

I'm in a VERY HIGH FIRE HAZARD ZONE, and would rather not have a stove/firebox IN the garage.

I somehow missed that the first time around.

I would say forget about heating with wood all together - sorry, but that bolded part combined with things you are thinking of doing just spell bad news, loudly.

Stick to what you have, or electric - or better yet, get a mini-split.

 

[electrathon]

From someone who has water coils in two stoves at my house, I want to impress that you will not get enough heat with what you are planning on doing to get any noticeable amount of temp gain in the shop. I have a lot of concerns with your plan. Starting with the coil you are using in the firebox. DO NOT USE COPPER! Use iron pipe or stainless. You need a minimum of 1/2" pipe for circulation. You need a lower and an upper inlet and outlet on the stove and up above to generate circulation. You need make up water or you will just boil the water off. If you don't seal the system you will have a huge moisture issue in the area the open top tank is sitting, so you will have mold and rust. The list goes on.

As a youth we heated our house for many, many years with a barrel stove. They can produce a lot of heat for little investment. Not as nice as a plate steel stove, but they do work. I would not personally build a stove out of a box like you are planning.

 

[wardk]

Is the woodworking situation preventing you from considering an inside the garage solution to wood heat? Seems like a barrel stove would be a great choice for you if you can manage the dust properly. Dirt cheap, makes plenty of heat.

I think you could be in business for under $100 based on what I see around at local Tractor Supply or other stores.

The issue for the OP is the 900 cfm dust extractor, I have one in my wood shop as well as a wood heater. If both are going the dust system will depressurize the shop and suck the smoke out of the wood heater.