Steel for DIY Fire Pit - Advice Needed

[HeLa]

i posted this to rural living before realizing that this forum exists...

http://www.tractorbynet.com/forums/rural-living/327064-steel-diy-fire-pit-advice.html​

we've been through a few commercially-produced cheap fire pits - they're junk and just don't last. i'm looking for something bigger and a bit more utilitarian for the next round. after doing some shopping around i found that there does seem to be a niche market for heavy duty fire pits but they are expensive and for obvious reasons need to be found locally.

so, *considering* building my own. i like the idea of something like this built to about 4 ft. square.



so the first obvious question is: what to build it from? (type/thickness of steel) what can withstand the temperatures of a fire and being left outside? stainless is out for cost reasons and i really don't mind the look of the rust patina.

access to plasma/welding equipment and expertise can be assumed available. i'm an amateur but know my way around a bit.

help from those with experience greatly appreciated. thanks!

 

[FredH]

I would use 1/4" for the box itself . Although heavy in the end , it will withstand the temp. extremes that direct contact with flame will have . In that picture you posted , I would not build the fire directly on the bottom , rather I would have multiple small holes in bottom , covered first with any sort of screen , then small rock , then a final top layer of sand . Holes allow drainage without spillage of ash and it also allows some drafting capabilities from under the fire .
Although another option is use of fire brick but at a higher cost . Most wood stove firebox steel is at least that thickness that I have seen , Not light by any means , but direct flame contact requires it .

A high temp paint would also be useful , on at least the outside . Stove Black seems to hold up pretty good on wood stoves , maybe even a auto exhaust type paint would work , once it cures ???? ( Never have tried that in regards to flammable ?? Once cured I assume it would be O.K. , since exhaust can be pretty hot . )

I will be doing something similar next spring when we expand Our back Deck . Basically though I will build the deck around the elevated pit . First couple of layers of brick for stand will be cinder block , then it will switch to flagstone for the fire pit to rest on , thus no legs will be required for mine . Although I say elevated , it will only be app. 16" from Deck surface to top lip of pit and only the flag stone will be visible above deck floor .

Fred H.

 

[haroldy]

For a firepit,,, last summer I went to a car wrecker and bought a loader tire rim ( $10 )
Darn thing was 80 lbs
But it made an excellent fire pit
could'nt beat the price

 

[MitchellB]

Best I remember, I used scrap 3/16" sheet steel when I made ours. I left a hold in the bottom to draft and for ashes to fall through. I had some scrap pre-drilled framing steel that fit inside itself that made a handy sliding grill top. It has held up for 5 or 6 years so far.

 

[mikefromnh]

I don't know long it will last but I just picked up a front loader washing machine tub to make a fire pit

 

[Sodo]

I don't know long it will last but I just picked up a front loader washing machine tub to make a fire pit.

It will last,,,, but won't be so shiny. Mike do you know that the steel blocks the ~1200F radiance, you only get the remainder that shines thru the holes. There is the radiance of the hot steel but it's at a much lower temp.

HeLa I like the shape of that pit you showed. The angled sides are good - to not block so much radiance from the coals. Coals roll downward towards the middle where they can radiate outward to people around the pit.

Sorry to say this MitchellB but I don't like firepits that are a vertical hole and only shine the heat vertical upward. Those kind of firepits the fire has to be so much taller so it can start to radiate horizontally, piled ABOVE the shaded sides. You have quite a system there, looks like you do a lot of cooking on the fire! Not everyone uses their fire to warm the people standing around it but the pit type doesn't warm folks who are in chairs they have to use blankets!

If you make it from 1/8" or less (like the ones bought at the store) they "can last" if you're there, at every fire, to prevent the fire from getting too big. Consider that someone along the line will pile a huge amount of wood on it and warp it. You can't stop everyone from throwing another log on it, that's just campfire camaraderie. It will get rusty and that's OK, but warped looks ugly. The firepits I've seen of 3/16" were OK so that might be a minimum.

 

[HeLa]

HeLa I like the shape of that pit you showed. The angled sides are good - to not block so much radiance from the coals. Coals roll downward towards the middle where they can radiate outward to people around the pit.

You can't stop everyone from throwing another log on it, that's just campfire camaraderie. It will get rusty and that's OK, but warped looks ugly.

The firepits I've seen of 3/16" were OK so that might be a minimum.

yup, i like the shape as well. should be nice for accommodating a small fire in the bottom, consolidating coals for heat, and allowing heat to radiate toward people standing around it. the larger outer perimeter will be useful when i use it to get rid of yard waste and maybe even an occasional broken pallet that needs to go (where the 4'-top edge size "requirement" came from). i think it's a nice balance between something big enough to be useful and attractive enough to be permitted in the yard by my wife.

it HAS to be able to withstand something more intense than a few twigs for exactly the reasons you cite. people like to feed fires and i want this thing to handle that without warping. agreed, warped looks bad.

I would use 1/4" for the box itself . Although heavy in the end , it will withstand the temp. extremes that direct contact with flame will have . In that picture you posted , I would not build the fire directly on the bottom , rather I would have multiple small holes in bottom , covered first with any sort of screen , then small rock , then a final top layer of sand . Holes allow drainage without spillage of ash and it also allows some drafting capabilities from under the fire .

A high temp paint would also be useful , on at least the outside . Stove Black seems to hold up pretty good on wood stoves , maybe even a auto exhaust type paint would work , once it cures ???? ( Never have tried that in regards to flammable ?? Once cured I assume it would be O.K. , since exhaust can be pretty hot . )

thanks for the great info Fred! i don't mind weight. i don't plan on moving this thing around much and the BX should be able to move it if necessary.

again, withstanding temps is my primary concern. i don't want to go through the trouble of building this, and saving a few bucks on material, to find that it warps after the first late night fire when someone gets ambitious loading wood.

stove paint is a good idea. i haven't really started researching finishes yet. I like the idea of a rust patina. Finishing it would only be if necessary to increase its lifetime by protecting it from elements.

agree completely re: adding some ventilation to the base, also to drain the pit since it will be permanently outside. i think the shape itself should lend pretty well for allowing air into the base of the fire.

 

[woodlandfarms]

3/16 or 1/4" Forget paint. Let nature patina it. Definitly cut drain holes and air vent holes. Fire loves to draw from the base so give it air down there.

 

[showcattle]

Just get an old tractor rim. Modify as you see fit. I've had intentions for this one, but it works fine as is.

 

[beeforty]

Just get an old tractor rim. Modify as you see fit. I've had intentions for this one, but it works fine as is.

I like the rim idea, I have an old 24 " truck rim that I cut the outside flange off to make it more of a bowl shape and found a brake rotor that just goes into the center hub hole. One of these days I'll get the two attached so the rim sets up on pedestal and the the lug holes provide an air intake down low.