Monday, July 08, 2019

Elora Sculpture Project - 2019

Being a 'teaser' overview of this year's presentation.
Exhibit Guide - showing full names and locations
'Expecting' : Eva Ennist
'Urban Pulse' : Pamela Rojas
'Green Strata' : K.J. Ross
'Crow's Nest' : Holly Atkinson
'Marine Architecture Study A' : David Cross
'Aizpute' : Kip Jones
'Red Face Walking' : Mike Truelove
'Leader of the Pack' : Mike Hintermiester
'Temporary Shelter' : Susan Lehnen
'Grandmothers - Ode to Joy' : Rosalinde Baumgartner
'Capacitance Chamber' : Dylan Paczay
'Toy Giraffe' : Thoreau Bakker
'Dance Me To The End Of Love' : Beverley Cairns
'All The Things She Gave Me' : Theresa Pankratz
'Leap of Faith' : Tim Dolman
'The Shed' : Jane Longstaffe

'Standing Grove V' : Susan Rankin

My own contribution ' Tipping Point' has been discussed on an earlier posts here:

Note : The images of the various artist's work have been presented as close up - with the intention of provoking interest in the individual pieces. 
I encourage all to visit Elora and Fergus making the short walk around to view the sculptures for yourself. Both villages offer interesting shops and some very great restaurants - make an afternoon of it!

Saturday, July 06, 2019

Any PORT in a ...

Myself and a couple of others are in the initial process of fabricating a cupola furnace.  I am wondering about the glass for the tuyeres and remembered yours.  So I wondering what what diameter and thickness you used for your tuyere?  I assume it was high temperature glass.
Air piping - here fitted to a ceramic tube tuyere. The end fitting to the upper left is sealed with the clear lens under discussion here.
We had looked into special filter / high temperature glass at the beginning.
Getting a disk of filter glass the right size was going to be horribly expensive.

What we ended up with is a piece of simple, 1/8 thick plexi (plastic)
What we totally forgot - there is no heat at that point in the system!
With our rig, we have the input air coming in via a T or Y joint, located 'down stream' towards the furnace. This means the view port end is being washed with cold (ambient temperature) air.  The plastic was cheap, and we figured easy enough to replace if needed. That end port you saw has been through something plus 50 smelts at this date!

With the use of a copper tuyere - there is some heat transmitted back along that metal (which is how the copper keeps from melting btw). This effect is not significant with the ceramic tube tuyeres we use as out other standard.
I have one Y tube actually made of ABS plastic with a leather cover (used in historic demonstrations). So far that unit has gone through about a dozen full smelts! 
ABS plastic Y, leather covered - here fitted to a steel pipe tuyere

So - I would suggest you consider the tuyere material (may be steel pipe, set flush to the refractory interior lining on the furnace side?) Conduction down the tuyere itself is more likely your consideration.

There would be some value to using a dark colour plexi (would avoid the use of the welding lenses I have). I know you can purchase replacement plastic filters for welding helmets, something like $5 for enough to easily cut two end caps.

Friday, July 05, 2019

'so damn WET'... Ore Analog consideration

A potential correction on reported yields?

For a good long while, the iron smelt experiments have used an artificial preparation we call 'DARC Dirt'.
The origins of this preparation go back to 2008, when we started on the 'Vinland' series. Here at Wareham, there is no available natural iron ore of any kind. (As I have mentioned in previous posts, Wareham sits at one end of the massive block of limestone that forms the Niagara Escarpment - a block roughly 400 + km long and about 100 m thick!). Although 'primary bog iron ore' can be found 100 km north of here (up on to the Canadian Shield), I have never found any more than the faintest traces of iron locally.
Primary Bog Iron Ore - from L'Anse aux Meadows (early 1970's excavations)
For the Vinland series, we wanted to have a dependable quantity of an iron 'ore', which would also at least approximate the chemistry of that known to have been used at L'Anse aux Meadows by the Norse. Our solution was to mix up an analog, using commercially available 'Spanish Red' Fe2O3 oxide powder.
One huge advantage is that use of the analog has given us a very consistent baseline within our many variations on furnace design and air systems testing. There have been slight variations of this standard mix, usually by adding various amounts of forge scale (so Fe3O4) to 'enrich' the basic mixture.

DD-1 analog as added in a working smelt (Vinland 1)
Details of this mix  *

Chemical analysis
Fe2O3    81  %
SiO2      5  %
CaO      2.3 %
MgO2     2  %
Al2O3    2.6 %
Loss on ignition 7 %

As DD#1
Red Oxide          82 %
Wheat Flour          8 %
Water (after drying) ≠ 10%

Adjusted Fe2O3 content = 66 %

It is the WATER here that may be throwing off our reported yield numbers.
The iron oxide powders used as the basis for the analog mixtures are extremely fine. Originally, in an attempt to match the reported chemistry of the L'Anse aux meadows samples, whole wheat flour was added to create the 'organic' component. The physical process was to combine the dry materials, then add water to make a thick paste, roughly the consistency of butterscotch pudding. This was then ladled out on to trays to dry in the sun. It was found that the flour acted like a binder, producing loose lumps of finished 'ore', which also had about the same consistency (porosity) as the natural ore.

How much of the added weight was water?
Although sometimes a sample of the ore used in a specific experiment is pulled off to be completely dried (Usually baked in the gas forge) this 'loss on ignition' (LoI) is not usually recorded. Typical is about 10 - 13 % of the 'as used' weight.

This all occurred to me after the last smelt experiment ('Icelandic' stone block).
Both being somewhat rushed for time, and with an extremely rainy early Summer at Wareham, I had a lot of trouble getting that analog mix dried from the 'pudding' phase. On dry baking a measured sample, it was found that the LoI was actually almost double - at 18%.

I'm not sure exactly how best to apply is considerable difference (10 to 18 % LoI) to the recorded results. One thing would be to consider 'apples with apples', as most commonly the water weight is * not * considered in past recorded results.
- The difference in water weight on this last smelt is then about + 8%
- Reduce the ore weight to 'standard' (29.3 kg x 92% = 27 kg 'adjusted')
- Effects (increases) reported yield (7 kg from adjusted 27 kg = 26 %)

( * )  If you are interested in the long development sequence of our bog ore analog, the easiest way to read the many earlier commentaries is a simple search :'bog+ore+analog'

Thursday, July 04, 2019

Stone block furnace

Ryan (L) and Avery (R) - 2/3 through main sequence
Perfect 'chocolate covered cherry' image just as bloom is exposed (Image by Travis Sweet)

Initial compaction : (L-R) Ryan / Rey / Kip / Avery / Darrell (Image by Travis Sweet)
June 23
Furnace related to ongoing studies of possible historic Icelandic systems.
Granite blocks with clay cobb sealing.

Result was 7 kg bloom (about 25% yield)

Readers: I have been buried under a combination of research, project preparation, demonstration, academic presentation, newsletter editing - for the last month.
Up until now, there was a requested news blackout on the upcoming Iceland iron smelting project in August. Expect more entries related to all that, soon!

February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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