Instructables

Rocket Grill!

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Want a D.I.Y. way to cook food WITHOUT using fossil fuel L.P. or having to buy charcoal? I know I did. That's why I built a "Rocket Grill"!
This is just one variation of a "rocket stove" - a simple appropriate technology for cleanly burning bio-fuels.

The rocket grill is fired by twigs, wood scraps, wood chips, or nearly anything else you can put in it. It naturally drafts air to maximize combustion. Once the the grill is really going, NO smoke comes out the top, only heat, and the grill really does sound like a rocket!

The grill is designed to not only grill, but also boil, bake, braise, and roast!

Because of the simple design and robust construction, it is nearly maintenance free. Unlike an LP grill, the burner will never burn and rust away to nothingness. (And cost good time and money to replace.) There is no piezo-electric starter or other "modern" technology in the grill, which would be prone to failure.

Despite how it looks, the grill is small and light enough for one grown man to lift into the back of a pickup truck. That way, it can travel with for camping or tailgating. (The lid and side tables are also removable for storage and easy packing.) Because it's covered and enclosed, it also qualifies for use as a "backyard fire-pit" in areas that do not allow open fires.

This project is mostly simple metal work. While it does require welding, it's pretty straight-forward. This was really my first-ever welding project.

So lets' gather together our tools and materials and get started!
 
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Very cool grill, I'm busy making a "Franken-webber" pizza oven and thought a rocket stove beneath would heat up the oven in no time. I made the rocket portion this morning and fired it up, got it sounding like a rocket in no time.

jshultz514 days ago
Nice job.. I've built small rocket stoves but never thought of doing one this size. I'm glad I saw this because I have lots of stainless pipe in all sizes and I'm gonna start on one this weekend. I'll post pics and I have a few ideas on making it easier to clean. Also I have a great idea on the diffuser..pics coming soon..great job man..thanks for the instructable

Damn, you're lucky, I wish I had some stainless steel lying around. I made mine out of scraps of steel I had lying around, looks a bit like Frankenstein's monster. Works like a beast though.

bennelson (author)  jshultz514 days ago
If you have the material and welding ability to work with stainless steel, your project should turn out GORGEOUS. Many of my projects are either "rat-rod" or "steam-punk", but it's great to see what people can do with different materials and skill levels!
jimbus_com23 days ago

Have you considered cutting and sleeving the vertical tube near the base to ease ash removal? You could leave it as a lift off or put some set screws to secure it, like a Christmas tree base.

Great project!

kelms11 month ago
I like your grill a lot i'm going to make one but I'm going to use high temperature grill
paint just make it look better
bennelson (author)  kelms11 month ago

Let me know how the grill paint works out for you. Please share a photo when you finish!

tpagels2 months ago

I built one a few years back. I've never been able to get it to work though. My buddy who did most of the welding said he had it working but that was before adding the tank to the top. My pipe is a bit smaller and I actually used an old charcoal grill on top. Recently messing with it has come to mind as it's time to make it work or take it to the scrap yard.........

diamondemb6 months ago

I love It! A steam-punk grill!!

Great job.

tnowling7 months ago

Just welded mine together. Still need to finish the lid

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bennelson (author)  tnowling7 months ago

I like the base!

It is sweet, very heavy. it won't fall over but makes it a bit of a pain to move. gotta love trash reclaimed from work. This was all made from things that were either being thrown away, or recycled. didn't buy a thing, just cost me some labor and my grandpa made all the welds pretty for me.

thoover672 years ago
Neat. Not sure I understand the process of burning completely. Is wood fed from the top (is there a hole on the inside), or just through the feeder tube?

Does the grill draught through the hole in the bottom (implement disk) & out the feeder tube, or are other vents involved?
bennelson (author)  thoover677 months ago

Both wood AND air come in through the side tube. It is divided in half with a plate. The wood goes inside the side tube on TOP of the divider and air is drafted in through the same tube on the BOTTOM of the divider. The divider has air holes in the end of it for the air to get up through the wood (and the fire.)

Gunther459 months ago

Like the BBQ .Just a thought about Ash Clean up. Attached is something I made to clean out pipe going to my furnace. It is basically just PVC pipe reducers and then a valve with a quick connect to attach to an air line from your compressor. It is attached to the pipe with a coupler with 2 worm drive bands. I am not saying the person cleaning the ash is not going to get dirty but it still would be easier than trying to scoop out ash down that long pipe.

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Great JOB !!!!
I will make one soon
Thanks
yummyribs1 year ago
That's really cool! Excellent the idea of grilling over wood,

Could you just make some holes in the bottom and make the whole input pipe into a fuel holder ? So you could remove the ashes through the air holes, and more fuel would fit in.
bennelson (author)  yummyribs1 year ago
The only thing that I could think of for why NOT to do that is that air-holes through the bottom might be a good place for hot coals to escape through or that perhaps they could easily get clogged with coals or ash.

So far, the divider plate is simple and works well. If anyone makes a variation of this project with the suggestion made by yummyribs, please post a photo and let us all know how it turned out!
can you up load video of you grill in action some ware please
mkrepel1 year ago
Excellent work! I am inspired.

I was curious...what did you do with the rest of the water tank? I thought it would make a good insulated base (fill it with vermiculite) between the grill and the disk. Of course, that would make the thing quite a bit heavier.

Another idea for emptying the ashes would be to use a shop vac...if you have one. Of course, make sure the ashes are cold first!

I am going to start looking for a used water tank.
aroberts252 years ago
this is fantastic. thank you for the inspiration!
SIRJAMES092 years ago
This is just too awesome!!!!!!!
Before reading this, I had never heard of a rocket stove....
This is something that I would like to learn(welding/metal work) so that I could make a similar project.

TY for sharing Sir!! 8)
Sl0whand2 years ago
bennelson!
Thank you very much for your ideas and your taste in expressing yourself through your words and your creations.
Enjoy your cobs!
sethcim2 years ago
Fantastic! Love the simplicity and effectiveness.
Where might I source the thick-walled pipe you used? I've been looking all over but just can't seem to locate 4-5 inch pipe with a thick enough wall. I'd like to build a very-long-life stove for our conservatory.
bennelson (author)  millenniumtree2 years ago
This was salvaged metal that was at a friend's house. I believe it was well casing.
Try looking at a metal salvage yard sometime, they are fun places to visit.

Since this project doesn't require new materials, the costs to build can be kept low.
smpash2 years ago
Hmm i have always wanted to weld

for grilling certain woods are better than others for southern or mexican if possible use mesquite wood for grilling mm
although it might not work because there is little to no smoke to smoke da steak
iFirefly3 years ago
What causes the "rocket sound" you referred to? Is that from the air drawn in from the bottom? If so, that could probably be mitigated by the airflow design.

A note of caution: I have seen many older water tanks of this type that are galvanized, which will emit toxic gases when heated, so try and make sure your materials are not plated; the galvanizing can be removed safely using different methods, but the effort is hardly worth it, since grinding it away also produces toxic airborne particles and acid treatments are hazardous in their own right.

Alternates to water tanks are decommissioned welding gas tanks, which come in either short, wide tanks or the more common thin style (making a smaller grill for a really compact outfit).
So, I would feel more comfortable if someone confirmed this, but I'm pretty sure galvanized steal will have the galvanized part burn off after the first hot temperature. That's why I tend not to worry about the fact things do release toxic gases, because the first time I have a coffee can stove, grocery cart (galvanized steel), etc, I just burn it off in a very hot fire that I shortly step away from after starting up.
Even welding galvanized steel is problematic. It needs to be done in a well ventilated area, with a fan set up to carry welding fumes away from the operator. I'd certainly not use this grill for cooking food until all the the zinc has been burned away.
Yes. It burns off, or is reduced to oxide VERY quickly once heated. Stand well away, "zinc fume fever" is a work-related illness and is reportable !

Steve
The risks are mixed, but the simple answer is to not use galvanized material; if you wish to have a comprehensive view of the subject, I just found the following PDF available from a quick Google search for welding galvanized metal:

http://www.sperkoengineering.com/html/articles/WeldingGalvanized.pdf
bennelson (author)  iFirefly3 years ago
There were not galvanized metals here. It was all bare steel, other than the water pressure tank, which was only painted.

The stove makes a pretty cool sound when it's really running full tilt. It's because of how much are naturally drafts through it. I wouldn't change that at all. I really like the way it sounds and how the air and fire travel through it.
heelercjwww2 years ago
Great instructable. This is a really great idea, kills two birds with one stone. I think I will have to make one of my own here soon. Thanks.
Bubbler2 years ago
A great grill. How easy is it too get the ash out of the bottom, and what do you do with the ash once you get it out?

It really is a major rocket stove. LOL
bennelson (author)  Bubbler2 years ago
Originally, the base-plate had a hole it in.

When I would lift up the grill, the ash would fall right out the bottom. It also left nice little burned holes in my lawn! So, I welded that spot shut.

As it is right now, I just turn the grill upside down. It is lighter than it looks (without the side tables and lid) and I just dump it out into a steel bucket.

It doesn't make that much ash. One advantage of using fuel more efficiently is that there's less waste in the end.

I put some of the ash in my compost pile and the rest spread out in my brush pile.

I've played around with the idea of cutting a "door into the bottom-back of the grill base, and hinging it as a place for ash-removal, but really, it's just so easy to tip the grill over to dump it out when I need to.

An ash clean-out would be a nice feature for a larger or more permanently mounted version of this project.
I don't know about the original one, but mine you just lift the stove off the little pile left after the burn. The ash makes a good fertiliser
Absolutely awesome! Love the rustic look, hate buying charcoal and like the various uses.. I've not welded before but have wanted to start...and I want a new grill this year...thanks for the inspiration..I hope to post my own here soon!
Sonoffar2 years ago
What a great build.
I heat my 2 story house with 2 wood stoves and a LOT of wood. For a few months I have been looking at various alternatives to the old wood stoves and your project has FINALLY made it clear to me that builds like your Rocket Grill are the basics of a Rocket Burner that can be simply adapted to a host of heat required applications.Thanks for providing one of those sorely needed, "palm slap to the forehead", moments that has started the ball rolling.
Thanks :0)
bennelson (author)  Sonoffar2 years ago
For whole-house heating, another great related technology is "wood gasification". It can also be used to create fuel that can power a generator, so it's a neat concept for both heating and powering an off-grid home! Here's some info on one here on Instructables. http://www.instructables.com/id/Building-the-GEK-Gasifier-in-seven-parts/


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