DARC Iron Smelt - July 28,2011

Iron Smelt - OABA - CanIron VIII, Fergus, ON - July 28,2011

Date:July 28,2011

Location:OABA - CanIron VIII, Fergus, ON

See also: Darrell Markewitz's ironsmelting site

Team: Neil Peterson, Richard Schwietzer, Dave Cox

Premise: Teach blacksmiths to smelt

Furnace Design

Type	EconoNorse in a can (enclosed fire brick), tap arch
Extraction	dismantled
Diameter	25 cm
Height	85 cm
Volume	41703.125 cm³
Tuyure Type	ceramic tube
Tuyere height from base	20 cm
Tuyere penetration into furnace	2 cm
Tuyere angle	22 deg
Base design	natural set base cm

Burn Details

Bellow Type	blower
Avg Air rate	unknown litres per minute
Total Charcoal Mass	46 Kg
Avg Burn rate	min per 2 Kg
Ore Type	DD1
Total Mass of Ore	22 Kg
Burn Duration	5.5 Hours

Results

Mass of Bloom	5 Kg
Bloom Type	high carbon
Yield	22%
Notes	nice soft workable iron

Reports of all of our iron smelting efforts along with more articles and information are available on the "Iron Smelting in the Viking Age" CD from the Wareham Forge. Copies of the CD can be purchased here.

Discussion:

This smelt was rather amusing. For 90% of the smelt things seemed to go along just fine. At two points we did get some "burbling" from the airflow and needed to tap. But things were so mellow Richard even had time to try (and fail) at making a bead with the tap slag. We had the chance to show many folks what was going on by offering tours of the view down the airpipe. What we didn't know was that the bloom had formed off to the side and the slag bowl had formed quite high.

Each time we tapped it re-sealed much more solid leaving us at a point where we needed to tap again but couldn't get it to tap. We tried from the sides, we tried pulling out the fines in the base but we couldn't get anything through the base of the slag bowl. We even tried running a rod down from the top to poke a hole straight down, but only managed to weld the rod onto the bloom, which led to some funny comments when we extracted.

This inability to execute a third tap meant we needed to finish early in order to not lose the airflow and have everything freeze. We dragooned a couple of blacksmiths to hammer for us, and grabbed Darrell who was ordered to pull the bloom as we freed things up. We then knocked down the smelter - even though there was still charcoal and ore in the stack. 4 Kg of ore was in the stack but not yet down to the bloom when we opened.

The opening and extraction went well sending the bloom over for a good consolodation. Our efforts to keep a forge going in the smelter didn't go so well as the tuyure was nearly frozen off. We did keep things hot enough that we could keep the bloom very warm until another forge could be prepared (it was nice being at a blacksmith's conference!). When another forge was ready we walked the red-hot bloom over to it. At that forge they consolodated again, then cut it into quarters. One quarter was then further worked until it was ready to use in the blademaking workshop.

Conclusions:

Overall set up
As usual this setup roved its worth. It took less than an hour to set up, Less than an hour to pre-heat. Then a simple straight forward 5 hour smelt - until the hassle at the end. Without that problem we would have had no issues in finishing off the smelt as planned. Even with the problem it produced a very nice little bloom.
Reaction to problems
Again this smelt proved the need to react FAST when problems crop up. We did react fast enough to save the bloom. We also reacted fast enough to save the smelt - it is just that our efforts to fix the problem failed. By reacting fast we actually had time to try different methods to save it one of which might have worked. If we had delayed our reaction we would not have had that opportunity.
Planning for failure
A little fine tuning on the plinth design leaving more accessable openings would have allowed us more opportunities to move the base and perhaps succeed on a tap.

Photos:
(copyright David Daciw)

Dr. Ross looking for more charcoal to smash Smelter 2nd layer Furnace Tapping slag

Pulling bloom Compacting bloom

Raw Data:

TIME EVENT ORE CHARCOAL AIR

REL. ELAP. ADD
(scoops) AMT
(Kg) TOTAL
(Kg) ADD
(buckets) AMT
(Kg) TOTAL
(Kg) SET. VOL.
(litre/min)

0 Switch to graded charcoal

1205 X 2 2

7 1212 X 2 4

7 1219 X 3 6

1229 X

21 1230 It is likely a bucket of charcoal was missed here X 4 8

1233 X

1237 X

12 1242 X X 5 10

1243 X 1

1249 X

11 1253 X X 6 12

1256 X

1303 X 2

1304 X

13 1306 X X 7 14

1313 X

10 1316 X 8 16

1317 X 3

1319 X

1325 X

12 1328 X 9 18

1329 X

1337 X

16 1344 X 4 X 10 20

1345 X

1350 X

1351 X

11 1355 X 5 X 11 22

1359 X

1400 X

1401 X

1404 X 6

1407 X

1408 X

15 1410 X X 12 24 9

1417 X 7

1418 X

1420 X

1423 X

14 1424 X 13 26

1425 X

1427 X 8

1429 X

1431 X

1433 X

13 1437 X 9 X 14 28

1441 X

1444 X

9 1446 X X 15 30

1447 X 10

1449 X

1451 X

1454 X

1456 X

12 1458 X X 16 32

1500 X

1503 X

1505 X

10 1508 X 11 X 17 34

1512 X

1513 X

1514 X

1514 X

1514 X 12

1515 X

1516 X

1518 X

1519 X

12 1520 X 13 X 18 36

1523 X

1523 X

1523 X

1524 X 14

1527 X

1528 X

12 1532 X 19 38

1533 X

1534 X

1534 X 15

1536 X

1537 X

1538 X

1539 X

1543 X

1543 X 16

12 1544 X X 20 40

1545 X

1547 X

1551 X

1551 X 17

1554 X

1555 X

12 1556 X X 21 42

1557 X 18

1600 X

1601 X

1602 X

1607 X 19

12 1608 X X 22 44

1610 X

1610 X

1612 9.5

1613 X

1614 X 20

1615 X

1615 X

1617 X

1617 X 21

10 1618 X 23 46

1619 X

1619 X

1625 X

1625 X

1626 X 22

1626 X

13 1631 X 24 48

1632 X

1632 X

1637 X

1637 X 23

1638 X

1638 X

1641 X

1641 X

13 1644 X X 25 50

1644 X 24

1646 X

1647 X

1653 X

1653 X

1655 X 25

1656 X

13 1657 X 26 52

1659 X

1700 X

1700 X

1703 X 26

1703 X

Reports of all of our iron smelting efforts along with more articles and information are available on the "Iron Smelting in the Viking Age" CD from the Wareham Forge. Copies of the CD can be purchased here.

Text © Darrell Markewitz, 2011
Photographs © Darrell Markewitz
Copyright details
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Dr. Ross looking for more charcoal to smash	Smelter 2nd layer	Furnace	Tapping slag

Pulling bloom	Compacting bloom

TIME		EVENT	ORE			CHARCOAL			AIR
REL.	ELAP.	EVENT	ADD (scoops)	AMT (Kg)	TOTAL (Kg)	ADD (buckets)	AMT (Kg)	TOTAL (Kg)	SET.	VOL. (litre/min)
	0	Switch to graded charcoal
	1205					X	2	2
7	1212					X	2	4
7	1219					X	3	6
	1229		X
21	1230	It is likely a bucket of charcoal was missed here				X	4	8
	1233		X
	1237		X
12	1242		X			X	5	10
	1243		X		1
	1249		X
11	1253		X			X	6	12
	1256		X
	1303		X		2
	1304		X
13	1306		X			X	7	14
	1313		X
10	1316					X	8	16
	1317		X		3
	1319		X
	1325		X
12	1328					X	9	18
	1329		X
	1337		X
16	1344		X		4	X	10	20
	1345		X
	1350		X
	1351		X
11	1355		X		5	X	11	22
	1359		X
	1400		X
	1401		X
	1404		X		6
	1407		X
	1408		X
15	1410		X			X	12	24	9
	1417		X		7
	1418		X
	1420		X
	1423		X
14	1424					X	13	26
	1425		X
	1427		X		8
	1429		X
	1431		X
	1433		X
13	1437		X		9	X	14	28
	1441		X
	1444		X
9	1446		X			X	15	30
	1447		X		10
	1449		X
	1451		X
	1454		X
	1456		X
12	1458		X			X	16	32
	1500		X
	1503		X
	1505		X
10	1508		X		11	X	17	34
	1512		X
	1513		X
	1514		X
	1514		X
	1514		X		12
	1515		X
	1516		X
	1518		X
	1519		X
12	1520		X		13	X	18	36
	1523		X
	1523		X
	1523		X
	1524		X		14
	1527		X
	1528		X
12	1532					X	19	38
	1533		X
	1534		X
	1534		X		15
	1536		X
	1537		X
	1538		X
	1539		X
	1543		X
	1543		X		16
12	1544		X			X	20	40
	1545		X
	1547		X
	1551		X
	1551		X		17
	1554		X
	1555		X
12	1556		X			X	21	42
	1557		X		18
	1600		X
	1601		X
	1602		X
	1607		X		19
12	1608		X			X	22	44
	1610		X
	1610		X
	1612								9.5
	1613		X
	1614		X		20
	1615		X
	1615		X
	1617		X
	1617		X		21
10	1618					X	23	46
	1619		X
	1619		X
	1625		X
	1625		X
	1626		X		22
	1626		X
13	1631					X	24	48
	1632		X
	1632		X
	1637		X
	1637		X		23
	1638		X
	1638		X
	1641		X
	1641		X
13	1644		X			X	25	50
	1644		X		24
	1646		X
	1647		X
	1653		X
	1653		X
	1655		X		25
	1656		X
13	1657					X	26	52
	1659		X
	1700		X
	1700		X
	1703		X		26
	1703		X