What fire

[rary]

I have a small cast iron pot bellied stove which I was thinking of installing into my greenhouse, the problem is that it cant take large logs or very many but can anyone tell me if it will give heat output overnight if stocked up about ten in the evening

[Snoop Puss]

What's the biggest log it will take, Rary? And how small is it?

I have a small firebox in my range (it's ancient) and if I put a log in it about 40 cm long by maybe 20 cm in diameter at 11 pm or so, I often find embers in the morning, though not enough to put out much heat if any and the range is cool to the touch.

[Jimny14]

Well it depends on quite a lot of variables. Firstly would be what do you want to achieve? If it's to be used as a little supplementary heat then you're probably fine, if it's to guarantee the place being frost free maybe not.
There is something called slumber burning which it is recommended you do not do with a log burner in your home as it can produce carbon monoxide, however it may be useful here. Also different woods have different burning characteristics which may be useful here.
Firstly I'd want to run a fire in the pot for a while to get it hot first (maybe using soft wood as it burns faster) then putting on some slower burning hard woods (ash is OK but oak is excellent also hawthorn tends to burn quite hot with a small flame for long periods if dried well).
If you could get the pot hot first then get some long burning wood in it and strangle the air intake down to control rate of burn (effectively a slumber burn) then you could keep some Heat going through for quite a few hours

[veggiechicken]

Could you bank it up with some coal to keep it in overnight?

[nickdub]

You probably won't easily keep a small wood stove burning overnight, coal would be possible, but likely too expensive. As another way round it you could possibly use the stove to heat water in some way. If this warm water was in a copper tank, then that warmth would gradually dissipate and so keep the greenhouse warmer.

[Nicos]

How big is your greenhouse rary?

[rary]

My greenhouse is 14ft X 8ft and the fire can take 6in x 3·5in x 2in. logs which aren't very big but I could get 4 or 5 in at the same time, as for heating water, unfortunately I doubt this would be possible, or too expensive to install

[rary]

I should have added, I do have a stainless steel pot I use as a fire, with a central 6in. chimney that most of the heat goes up, it can take 6x12x18 blocks or logs of wood, but I can't regulate the air flow fine enough to keep it going all night plus I don't think stainless steel lets the heat out the same as cast iron does

[Snoop Puss]

Rary, with logs that small and a greenhouse that size, I think you'd be up and down all night refilling the stove to keep the frost off in your greenhouse. One big log will burn much longer than lots of small ones due to having less surface area. You're right that once it's hot, cast iron will hold more heat and give it off for longer than steel, but I'm not sure it's a practical proposition.

Would you consider paraffin? I have no idea how expensive a paraffin heater is to buy or run.

[veggiechicken]

I don't know what you're hoping to keep warm overnight but, if it very precious, could you put a small blowaway inside the GH and concentrate on keeping that warmer?

[Paulie]

How about having bricks on top of the stove? Perhaps they would beat up and then gradually give out heat during the night? This suggestion is based on the same principle as electric storage heaters, which would make use of cheaper electricity ('economy 7') overnight and store heat in bricks to warm a home during the day.

[rary]

Rary, with logs that small and a greenhouse that size, I think you'd be up and down all night refilling the stove to keep the frost off in your greenhouse. One big log will burn much longer than lots of small ones due to having less surface area. You're right that once it's hot, cast iron will hold more heayt and give it off for longer than steel, but I'm not sure it's a practical proposition.

Would you consider paraffin? I have no idea how expensive a paraffin heater is to buy or run.

I have always found paraffin creates too much moisture, as for keeping it stocked up, what are wives for

How about having bricks on top of the stove? Perhaps they would beat up and then gradually give out heat during the night? This suggestion is based on the same principle as electric storage heaters, which would make use of cheaper electricity ('economy 7') overnight and store heat in bricks to warm a home during the day.

I have fire bricks partially around the chimney, but not sure how well they work as the ones in storage heaters are chrome bricks, I also have the inside of the fire partially lined with fire brick, but again not sure if that is the best place for them, the fire sits within three concrete slabs but wondering if I would get better results if I put the fire bricks around the outside of the fire, as for using a blow a way inside the greenhouse, the only space I have for one is down beside the fire, and though there would be a concrete slab separating them I would not take the risk with it.
I think I will try the fire bricks placed around the outside of the fire, as I have said before you will never know till you try

[Potstubsdustbins]

Blooming heck Rary guess who's took 2 storage heaters to the scrap man today....There a lot of the older ones coming out later due to the advent of new regulations with regards to rented property if you know any plumbers/electricians ask them to keep an eye out for you.

[rary]

Thanks Potty, I will try that, could you tell me if the storage bricks just get binned or are they recycled

[Potstubsdustbins]

Binned mate, in fact unless you know some one who wants them they cost to get rid of.

I do believe my scrappy cheats and leaves the bricks in the heaters which he then tips at the scrap merchants yard and gets paid for the extra weight.

I have no proof but why else would he ask us to leave the bricks in the heater when it then takes two good men to lift them.......