Garden bonfire/incinerator

[Steve Maskery]

I have one of those dustbin-with-a-hole-in-the-lid type of garden incinerators. I don't use it very often, just a few times a year, I guess.
However, they don't last very long, do they? A year, maybe two, before they rust beyond safe use.
I'm thinking of building something a bit better. Please critique this for me:

Prepare a flat area and lay 4 paving slabs.
Loose-stack breeze block, with air gaps between them, to a height of, say, 3ft square and the same height.
Use the bin-thing inside it for stuff like sawdust, or use it naked, I.E. WITHOUT THE DUSTBIN, for garden waste.

Anyone got any better (but equally pocket-friendly) ideas please?

 

[DrPhill]

....use it naked for garden waste

Can the neighbours see?

 

[Steve Maskery]

Boom-boom!

 

[flh801978]

Steve i use a 220 litre old oil drum generally FOC ( ask at garages they want to get rid of them)
Cut the lid off and drill 4-6 30mm holes near the base
Works well and lasts 5 years or so. Drill holes for drainage in the bottom if you dont cover it when not in use
Ian

 

[dynax]

Boom-boom!

only if you fart too close to it,

 

[TFrench]

A washing machine drum works pretty well - it might look a little "ghetto" but it works!

 

[Steve Maskery]

I'm more wondering whether the breeze blocks will stand the heat or will they crumble if I have an open fire in the pit?

 

[MikeG.]

Concrete can go off bang in a fire. I'm not sure the paving slabs will be up to the task. Does your fire really have to be contained?

 

[Steve Maskery]

Concrete can go off bang in a fire. I'm not sure the paving slabs will be up to the task. Does your fire really have to be contained?

It's not very far from a garden fence. No problem if it stays upright, but if it falls over for any reason, I will be in trouble.

 

[Beau]

A family friend made one using lose concrete blocks. Hard to explain but the blocks were laid in a circle but leaving gaps at an angle so as the air got drawn in it created a vortex inside it making it burn very efficiently. Never saw it in action but the guy was not one to exaggerate.

 

[Steve Maskery]

That sounds interesting, Beau, what sort of size was it?

 

[Beau]

Not sure as I never saw it but I guess 6 or 8 blocks per layer. Pretty sure he said they were on edge so you would need a flat base. I guess if it gets a vortex going the air coming in around inside will keep the blocks cool to an extent. I can vouch for blocks going pop when too hot and think this is worse when they are wet and water turning to steam.

 

[Beau]

I like the vortex idea myself but not the idea of making it in blocks. If you got an old oil drum you make flaps in the side to fire the air in at an angle and get same effect without the risks of it turning into a pile of crumbs on first firing. Purely speculation though

While sitting on the throne I thought of a way to make the vent in the barrel. If you made some vertical cuts into the side of a barrel( 3-4" long) and then taped it in on one side just enough to get a pry bar in. Then with a bar you could lever one side out and the other in so you end up with a sideway pointing vent........Just a thought.

 

[Bm101]

Far as I know at least exploding blocks, chimeneas etc occur when people add moisture to an already hot equation. It's sudden temp changes or air pockets that make things get startlingly and suddenly explodey.
If you're set on building something more permanent I reckon I would install some sort of metal grill/ plate with holes etc as a base to aid burn efficiency. Wood fires start well on an ash base if it's dry so if you're burning very regularly might be worth considering a lid. Google home built fire pit etc. There's loads of info/ideas.
Alternatively.
Why not treat yourself?
:shock:
https://www.houseology.com/ak47-design- ... gLyWfD_BwE

(the bbq kit is an added extra! Really?)

 

[MikeG.]

Far as I know at least exploding blocks, chimeneas etc occur when people add moisture to an already hot equation. ..........

No, not so. At least, not only so. I've made fires on concrete bases without the slightest hint of moisture (in Africa), and the resulting explosions have been enough to scatter the embers 2 or 3 feet. Now, if you do something more than once with the same (bad) result, it is difficult to argue against the charge of "slow learner"..........so I'm just hoping to make up for that by preventing someone else going through the same learning experience.

 

[Eric The Viking]

As an adjunct to the oil drum thing, If you find someone chucking out one of the roughly spherical Weber-type barbecues, the round gridirons in them (there are two of different size) seem to be practically indestructible. Would be a useful as a base to build the fire on, so air can get under it. Either that or some small mesh rebar, cut to shape.

Our Weber has been standing out in all weathers, unused, for about four years. I've just cleaned it thoroughly and test-fired last night. I'm amazed how well it's survived British anti-barbecue weather. The gridirons inside came up really well with a bit of elbow grease - a touch of rust but really very little, and the "sphere" itself is almost like new.

 

[gog64]

I think the heat does something to the galvanising, the dustbins with holes rust out pretty quickly. If you can weld, an incinerator made out of angle iron and weldmesh lasts for years. The bottom rots out MUCH quicker than the sides, so just cut it out & weld some more in, only takes a few minutes. If garden waste, much better to compost of course!

 

[AES]

Hi Steve,

I'm pretty certain that you'll find them in UK as they're very common here - what about those yellowy-coloured slabs which are designed specifically for lining the insides of outdoor pizza ovens, BBQs, etc? In every DIY place and garden centre here.

Here the basic BBQ (or oven) structure can be metal, brick, or concrete blocks, but the point is that these yellow slabs (available in curves and flat slabs in various sizes) actually reflect the heat back into the fire, so preventing any overheating problems with the basic structure.

These things are made of something called "schamott" stein (stone) here. Not sure how to translate schamott (not in my dictionary, sorry, and I can't find it online) but it's basically a refractory lining as used in professional kilns, heat treatment ovens, etc, and here anyway, they're as cheap as chips, so I PRESUME it's to a lower spec than the professional stuff.

Just FYI, I use about 4 or 5 slabs of the stuff (depending on the job) to make a temporary "hearth" for brazing, hardening/tempering , etc. Works fine, no probs, just set them up to the shape/size wanted on a steel plate placed on a concrete garden wall. In your case I guess you'd need to cement them into your basic block/concrete/ steel drum structure.

HTH

 

[Roland]

The oil drum is a good idea because you get a good draught of air through the fire. Rather than make holes in the sides, which weakens the structure, you just need to raise it off the ground. You can use a ring of bricks, or make a metal stand. Either way it will need a grid over the top of the bricks to stop stuff falling through. I use an old wire shelf from an electric oven. If you don’t want a hole in your lawn then you can lay the bricks on concrete slabs. Concrete can explode if it gets too hot, and when it does it spits out small stones like shrapnel. However with the fire raised on bricks it doesn’t get that hot.

 

[DrPhill]

Hi Steve,
These things are made of something called "schamott" stein (stone) here. Not sure how to translate schamott (not in my dictionary, sorry, and I can't find it online)

https://dictionary.reverso.net/german-english/Schamott

Fireclay? Fire Brick?