Farm Collector

Firing With Green Slabs, Etc.

219 Hubbard Street Fort Myers, Florida

On- page 7 of the July-August issue is a comment on the Case
setting on a Dutch Oven like a hen on the nest. I am enclosing a
clipping from June 7, 1959 Tampa Sunday Tribune to throw a little
more light on burning green slabs. Several years ago some furnace
builders figured they could go the original boiler builders one
better and get more steam out of a given size boiler. They raised
the boiler sometimes as much as three feet higher from the grates
to give a greater fire space. And what extra steam they got was at
a loss, unless the fuel was oil. With too much fire-space, the fire
lost its heat before going through the tubes, which are the main
source of steam.

That same mistake was made only a few years back at a place
where a 135 H.P. H.R.T. boiler was set in a high furnace to be
fired with slabs. The very necessary high bridge wall held down the
length of slabs being burned and was plenty of trouble to keep
built up. Finally, when it became necessary to install another
boiler, I pointed out that other lower hung boilers that the
company owned steamed easier, and the new one went in with its
original 24′ fire space.


‘In this modern day of liquid fuels that don’t fizz and
throw sparks, the old-time fireman who fired with green slabs and
kept the steam gauge needle pointed skyward are becoming hard to

‘Burning green pine slabs fresh from the saw was an art in
those days. And keeping steam with green cypress was little short
of a miracle. But it has been done.

‘I used to fire a 20-horsepower Peerless boiler with a
20-horsepower engine mounted on top of it That did not give any
reserve steam and our fuel was green cypress slabs. All the way we
could keep steam was to watch the roller bed and grab every thin
slab with bark on it. We cut the slab into short pieces on the
butting saw and split it fine. By the time the bark singed off, the
wood was dry enough to burn.

‘There was not much smoke, but with the engine’s exhaust
going up the smokestack, every time the saw bit into a log, the
fire changed color. Between cuts the fire would be a dirty yellow
but when the engine opened up it would change to a windblown
purplish blue. It was hard work and took some close watching but we
usually had enough steam to blow the whistle at sundown.

‘The boiler fireman of today with his store of oil-burning
knowledge may class the fireman of yesterday with hands calloused
from handling slabs and cord wood as a back number. But it would be
fun to see him try to hold the old man’s job.

‘There was the time when the last big Dowling sawmill closed
at Slater, Fla., in 1944. Their biggest logging locomotive, a
10-wheeler numbered 44 was sold to the phosphate mines at Brewster,
and a Seaboard Air Line engineer and fireman came down to take her
to her new home.

‘The main line fireman was used to burning coal, and when he
looked at the tender piled high with slab sand the big cabbage head
smokestack he said that neither end of the engine looked familiar
to him. He made no bones about being new to firing with slabs.

‘I told him it was simple if he always remembered to throw
the slabs into the firebox with the bark side down. Then Roy
Collins added the most important advice any wood-burning man ever
got. That was to ‘Take care of the corners and let the middle
take care of itself.

‘The old time fire of slabs might have fizzed and spluttered
now and then, but they never exploded like an oil fire will.

‘Once at Clewiston a fireman was having trouble with an
oil-burning boiler at the feed mill. The new foreman took over the
job of lighting it, and after blowing a goodly supply of hot oil
into the firebox he poked a lighted torch in the door. He got
results all right, blew the furnace out and put three men in the

‘Another man who did the same thing turned on the oil, threw
in a gallon of gasoline and followed it up with a lighted
newspaper. He also got unexpected results. He blew the furnace away
and shut down the Carr Creosoting Company in Miami until a new
furnace could be built.

‘Frankly I do not believe gasoline was ever intended to fire
a steam boiler on, as was proved in South Georgia several years

‘A sawmill man bought a small locomotive with one and
one-half inch tubes in the boiler for a log engine. She did all
right after once getting steam, but that was a job in the

‘Finally the fireman hit upon a bright idea. He would swipe
the wash-up bucket of kerosene from the shop each morning and pour
it over his fire of slabs. Then came the day when the bucket
contained gasoline for a change, and the fireman didn’t notice
the difference until he heaved it into the open fire door. There
was a loud whoosh and he, bucket and all sailed over the back of
the tender.

‘Locomotive boilers were never intended to steam easy when
not in motion. If they did the fireman would have to close the
dampers each time the train stopped to keep the safety valve from
popping open with a roar.

‘Once I was working with a company that was considering the
purchase of a new boiler. I argued that a locomotive boiler would
be cheaper because of so many engines being cut up for scrap iron.
The boss refused to see my way by saying that he had seen
locomotives tried for steaming stationary jobs and they did not
steam well.

‘But no wonder. If one would figure the combined area of the
tubes and put a high smokestack of the same area as the tubes, it
would steam like any other firebox boiler.

‘Years ago, the Cornish type boilers, like the old
stern-wheelers used, was put on wheels and advertised as ‘slab
burners’ that would burn slabs, fence rails or green sawdust
but they did well on everything else, including oil. Their round
firebox was a natural combustion tube for oil burners, and today
most small boilers are of that type.’

  • Published on Jan 1, 1960
© Copyright 2022. All Rights Reserved - Ogden Publications, Inc.