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October smelt at Owens


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We eventually got together last Thursday to run a smelt. This time there was only the two of us to see if our limited experience would produce some betters results. If not we could only blame each other.

 

We changed a few things from the way we have done them in the past. We have always had the bloom area with sloping sides. This time the walls were vertical which we decided would give us more room for the bloom to grow and not clog up the air holes. We usually have 6 tuyeres, but this time we only had 4. Also these were at a very shallow angle,about 20 degrees, and pointing more to the centre. Another change we made was to have larger holes for the air. These have been as small as 1/4 in the past. We both decided that they always end up wearing away and get bigger from using a rod to clear them. So this time they were about 5/8" dia. One other major change was not breaking up the charcoal, as no one likes this job. All we did was grade it through a steel 1" square mesh and then againg through 1//2" mesh. This got rid of the tiny pieces of charcoal and all the dust. It took about 1 hr to do 130 kilos. The very large lumps we did break up.

 

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The width between the two large curved bricks is 12", and the depth under the wooden formers to the base is about 8". After we had constructed this part we put about 3" of charcoal fines at the bottom. So the area for the bloom, if we got one, was 8 x 12 x 5" deep.

 

After we had put the base together we used our two pre formed stacks. All these are, are frames about 18" square made out of 2" angle iron and lined with fire bricks. The inside area is about 12". We made these sometime ago with the idea of them being re usable rather than destroying expensive fire bricks, every smelt. This will be the 4th or 5th time they have been used.

 

 

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We used the same blower for the air but this time Owen redesigned the layout. It worked better than ever with the gate only half open. One thing we have decided that is very important is to have the supply to all tuyeres the same. We noticed that the air supplied from the T fitting was less than the air through the elbow. So the next time we will have a couple of Y fittings so all the air is equal. The difference through the T fitting was that that end run a lot cooler and the slag was an orange gloppy type. The other end run alot hotter with yellow slag runs.

 

 

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The mixture for the hot face was 2 ball clay, 1 cement and 1 turkey grit. This we used in the base and the first section. The top section was not lined. Once the stack was built we used bonding plaster to cover the outside.

 

We run the smelter for about 4 hrs to dry it out and then started to add our charges. These were at 10 minute intervals. Over the course of the next 5hrs we fed this "pet volcano" of ours 130kgs of charcoal and 50 kgs of iron ore with small amounts of oyster shell in every charge.

 

 

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When we run out of everthing we left it running for another hour and turned of the air, plugged the air holes and left it till the morning. Another advantage of the frames is that all we do is lift them off and you are down to where the bloom should be. This is always a tricky moment as we could of just wasted the last 24 hrs, plenty of effort and money.

 

 

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Now we dug around to find our prize,

 

 

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The above weighs 18 kilos and appears to be good steel with the usual mix of some iron and small amounts of cast iron (we think). When we broke it up it came apart in 4 pieces of roughly the same size. These we split between us and called it a day.

One piece I have weighs about 3 kilos and today I tried to break it up with a sledge hammer. All I managed to do was dent it. So I set about cutting it up with a slitting disc and hammer and chisel. All the sparks appeared to be showing high carbon. Here is a photo of the slice, complete with hammer and chisel marks. The cut face is about 5" by 3 1/2".

 

 

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One last photo of the hot face in the bottom stack. Ball clay, cement and turkey grit certainly seems to work very well.

 

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I think this has turned out to be our best smelt to date.

 

 

Mick.

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Thanks for posting this Mick .

we have been swapping emails (post smelt) to try and consolidate some of the ideas we had through the smelt .

The last time we did this there was a bundle of phone calls with ideas for great improvements that we forgot by the time of this smelt!!!

This was certainly the smoothest running smelt so far and i think for the next one we will do exactly the same build process and alter one parameter .This was the first smelt where we could have kept it running for a lot longer than planned (had we had the ore or indeed the energy) it did not block the tue holes up nor over run with slag or charcoal dust.Feeding it for longer would have certainly given a bigger bloom ,it was however good to see that almost all the ore and charcoal was used up it made the whole thing less waist full .nice to finish on your own terms!!!!

we added the ore mixed with a small amount of ball clay and water ,a great idea (of colins ) and no blown out dust .I think having a bigger catch space for the bloom was defiantly a bonus with the bloom growing under the tue iron holes.

the ore to charcaol mix was higher than we had done before and although this is heading towards iron rather than steel the results seem'd good no more or less steely than any other smelts we have done and a lot more consolidated .I am not worried about getting iron or steel (or cast) as they are all ingredients to be used and I am keen to work some bloom iron and blister it.

 

I now have quite a bit of bloom from the smelts i have been involved in (probably 25 to 30 kilos or so),there does have to be a katana on the cards ,however there is a large lump of iron in one of my bits from this smelt that I will use to make a hammer .Making a hammer from ore has long been on my must do list .

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Mick and Owen,

 

Great work. Thank you for sharing it. It is both very inspiring and a dull ache of envy to see the pictures B)

This is beautiful material. Can´t wait to see the things that hatches from it. The hammer idea is very appealing.

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we added the ore mixed with a small amount of ball clay and water ,a great idea (of colins ) and no blown out dust

 

it is well documented, that madness and genius often go hand in hand ;)

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Nice work!

If I understand well, the bottom part with the tuyeres is bricks and the top is two cast parts?

Humm, what is "turkey grit"?? A strage use for a strange bird? ;)

 

Awsome!

 

Antoine

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Jesus, I don't have any plans for the bloom as yet. I may do something a little different.

 

Antoine, turkey grit or poultry grit is also known as rotten granite and can be found in farm shops or large pet supply places. Poultry use the stuff to help their digestion.

As you say the lower part of the tatara is made from bricks, put together on the day. The two stacks we used are already made. These are just angle iron frames that hold refractory bricks in place.

 

It sounds like Owen and I know what we are doing. That is true to a certain point, but credit must go to Mike Blue, who came over to the UK about 4 years ago and showed us how to built and run one of these and passed on years of accumulated knowlegde. Thanks Mike.

 

Mick.

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Great work.

 

Bloom looks nice.

Lookign frwd what your plans are....Hymm ^_^ ...what may this little different be at end ;) ?

 

I like this re-useable segment idea too.

Hours of hard work will saved whit those.

 

Did you notised how bloom started to grow, Was there unburned

charcoal under or sides of bloom?

 

 

Winter is ahead...so no more smelts this year for me.

But...maby new tatara at some point.

 

Great work.

 

BR

 

Niko

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Niko, I didn't take alot of notice about where the charcoal was around the bloom. I would say that there was more at the sides than underneath. What does the position of the charcoal tell us.

 

These frames are the same ones that you used at Owen's. They have worked well considering how many times they have been used and you gave them a good roasting too.

 

 

Mick.

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This is great guys! nice photos, and congratulations on the bloom.

 

 

I think having a bigger catch space for the bloom was defiantly a bonus with the bloom growing under the tue iron holes.

 

didn't you mean to say tuyeres??? :blink::P

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Hi Mick.

 

Yep. Frames looked familiar ;)

I think maby hi temp roasting will infact make those stronger..to point.

Some materials do make ceramik surface and it can be hi temp resist more than material

even should be. I talked guy how works in factory that makes hi temp systems..ovens..ex.ex.

And he said this too...some materials after surface glaze holds temp better than before.

 

But some materials and gases will erode materials differently.

Like oxides and flux..even CO CO2.

 

If surface is glazed too eroded its difficult to repare..glaze need to grid or some other ways remove..other vise new cast / any material dosent stay in it.

 

 

About charcoal..

 

To days knowledge that I have unburner charcoal tels how effect was burn.

If there is much unburned charcoal it might bean too big size and / or air velosity to small, temp lower.

 

Ideal thing would be case were bloom starts to grow bottom, agents charcoal bed that is loaded at buiding state of tatara.

Bloom grows and charcoal burns totally all aroud it. Leaving space drips and drops to weld bloom...and making its mass even heavyer...small pits of charcoal may get traped in bloom...but if its heavy and temp aroud it is hi enough...bits burn and I think these make those bubble...I may be wrong..but when I cut my bloom in junks...I find small bit ( 2mm ) in side one of these bubbels.It may be also gases..or both.

 

Back to charcoal

 

So if tuyeres are in right hight all charcoal will burn and bloow will grow in free space.

This is why I think erosion is important factor in tatara system

It needs this...sens tuyeres are guite low in japanese style tataras of any size...earlyer to later styles.

 

Im sorry I dont have experience about this stucture...only one gone bad tatara 2007..it was not even worth of post.

But it gived some info about low tuyere effect.

 

We haveto remember that in japanse tatara bloom is all the time all most dirrectly contact to tuyere line/air blast...so it may decarb and carb at same time....and only the sides of kera are front of tuyeres..So I think "best" parts tamagane are in middle of kera...Out side layer / crust of it may be cast/iron.

 

Mick I hope you did get some out of this babble of mine....

 

And anyways smelt looks nice...even there was some unburned charcoal sides of bloom.

 

Niko

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