Bloom Compaction : Phase One

 

Raw bloom compacting - modern tools

(video shot and edited by Neil Peterson)

 

- Pieces heated in a propane forge, which only reaches about 1150C (well below 'welding' temperature - only to a 'bright orange' * )

- Work under my modified 30 ton hydraulic press.

 

Note how much mechanical compaction is taking place. A close look will see how there are still fractures, clear as colour shifts along the edges. 

 

The two individual blooms started at roughly 7 kg, and were compressed to brick shapes, then cut into rough quarters. The video shows the later part of working bloom # 35, which had already been compressed and cut into to pieces. One 'half' is flattened, then further cut into two plate segments.

Bloom #91 - top	Bloom #91 - side
Bloom #35 - top (in video)	Bloom #35 - side (in video)

Bloom # 35 is an early one, March 2008, one of three made at Smeltfest that year. Specifically the test was using the 'bellows plate and blast port' design. The ore used was Lexington Limonite, in this case the yield is uncertain as this was the third use of this furnace and the previous firing had been problematic. 

Starting weight was : 7.60 kg (corrected)

 

Bloom # 91 is the latest, June 2022, created in a slightly smaller short shaft furnace, in this test using lower air volumes based on the previous (more accurate?) measurements of human 'smelt bellows' supplied air in experiment # 90. 

Starting weight was :  6.65 kg
Results

Bloom 91	Bloom 35
1162	625
977	741
1156	1211 v
2130	1568 v
236	239
total	total
5661	4384
loss	loss
981	3216
15 %	42 %

 

In addition, there were a total of 2806 gm of metallic gromps collected overall (smaller fragments, collected magnetically), which included about ten fragments roughly 'half walnut' sized (deemed too small for forging. This puts the loss due to slag expelled at 1391 gm (from the total starting weight of blooms at 14.25 kg)

Bloom # 35 was visibly more spongy at the start of this process, so the higher loss due to possible slag inclusions, and more significantly, simple fracturing during the compressions, was expected. This suggests the bulk of the recovered gromps (overall 20% of the starting blooms) was from # 35.

This process has created a number of smaller, partially compressed pieces, which will allow a second phase of heating in coal, and the ragged edges forge welded into the remaining mass. Additional hammering and folding will eventually yield individual working bars.