AusBonsai

Now, it's back into the glaze room to apply the glazes.

Glazes can be applied in a number of ways. They can be brushed. dipped, sponged, poured, and my method of choice, sprayed.

Once again, a good respirator with P-100 filters is a required tool for this part of the process.
Also required is something to apply the glazes, like the spray gun shown in the next photo.
Another requirement is a compressed air supply set to 60 psig.
Additional (but not required) equipment include a spray booth, a hydrometer, and an over-spray guard.
I begin by opening the snap-top glaze container and thoroughly mixing the glaze as shown in the next photo.
Next, I will screen the mixture through a 50 mesh sieve.
Then I will transfer the glaze mixture to a storage bottle as shown in the next photo.
At this point, I will check the specific gravity of the mixture using the hydrometer and adjust as needed.

The next photo shows the second glaze mixture at this point in the process.
The next photo shows the first pot set in the spray booth with the spray guard in place.
The next set of photos show the first pot after the glaze has been applied.
The first pot is then set aside to dry and the second pot is processed in the same manner.

The following photo shows the second pot at this stage of the process.
After the pots have dried, I will remove any over-spray from the insides and the bottoms of the pots with a damp sponge. I will then take a brush and touch up the inside and the top of the rims.

The following photos show each of the two pots at this point in the process.
Finally, the pots are set back on the shelf and allowed to dry for at least 24 hours before moving on to the next step.

That's all for now.

Stay tuned - more to come in the next installment.

Cheers,
Paul

soltan wrote:Still following Paul but now you've overtaken me
We are packing the kiln for a bisque firing next week but I have only just finished attaching the feet to my wheel thrown pots and as I had that first one warp from drying too quick I am drying real slow and they won't be ready for that firing.

Brett,

Slow is good.

As I was once told by a wise gentleman, "You can never dry a pot to slowly."

I look forward to seeing the fruits of your labor.

Have a great day.

Cheers,
Paul

Now it's time to load the kiln.

Below is a photo of the kiln that will be used to fire the two pots. It is an antique, gas fired, up-draft kiln.
The next photo shows the interior of the kiln. This is where all the action takes place.
Next, it's time to clean the inside of the kiln. I like to brush down and vacuum out the inside of the kiln before firing. I do this to remove any loose bits of refractory or kiln wash so they do not wind up stuck to someones work.
The next photo shows two of the four cone packs that will be used for this firing.

From left to right, we have cones 08, 4, 6, 9, 10, and 11. These cones are sometimes referred to as witness cones and each of the cones represents a different level of heat load. The witness cones are the mechanism by which we manage the firing of this kiln and our target is cone 10.
The next photo shows the first pot loaded into the kiln with the spacers in place.
The next photo shows the second pot loaded into the kiln with the spacers in place.
The following photo shows the loaded kiln. Note the cone packs which are located in the upper right and lower left of the kiln. These are placed so they can be viewed through the two peep holes on the door of the kiln.
Once the kiln is loaded, it's time to get this party going. Each of the two burners will be lit and tested for proper operation.

The next photo shows the left side burner during this stage of the process.
When the burners have been properly checked, it's time to close up the kiln as shown in the next photo.
It is now 4:30 pm on the 49th day of this project. The kiln has been started and at this point, the gas pressure is set to .5 psig, the flue dampers are set to 1.5", and the blower speed is set to 20 on the dial. The kiln is now left to candle (slowly heat up) over-night.

That's all for now.

Stay tuned, more to come in the next installment.

Cheers,
Paul

Hi Paul.
Do all your kilns have blowers? I can see now why you take so much trouble cleaning the kiln. All that equipment at the right side is for - pyro, blowers, gas pressure and anything else? Does it fire evenly? How long does the cycle take? Am I jumping in too soon again?
Penny.

mudlarkpottery wrote:Hi Paul.
Do all your kilns have blowers? I can see now why you take so much trouble cleaning the kiln. All that equipment at the right side is for - pyro, blowers, gas pressure and anything else? Does it fire evenly? How long does the cycle take? Am I jumping in too soon again?

G'day Penny,

Yes, each of the two burners has a blower.

This particular kiln is very finicky and requires a watchful eye to keep the temperature even.

I normally shot for a 24 hour firing cycle.

Cheers,
Paul

It is now 8:30 am on the 50th day. All firings are logged and the following photo shows the kiln log for this firing.
The kiln has been candling since 4:30 pm of the previous day and the internal temperature is approximately 1300 degrees F.

This next photo shows what it looks like inside the belly of the beast. If you look closely, you can see the cones.
For those having trouble making out the individual cones, I have labeled them in this next photo.
At this point, adjustments are made to the gas pressure and the blower speed to increase the temperature gain of the kiln.

The next photo was taken at 10:30 am. As you can see, cone 08 is starting to fall. For clarity, I have outlined cone 08.
As you can see in the next photo, cone 08 has fallen. This is the indicator to start the first reduction cycle.
At this point, adjustments are made to the gas pressure, the blower speed, and the flue dampers. The net affect of these adjustments is to reduce the amount of oxygen available within the kiln. In order for the combustion process to continue, it must get oxygen from the materials inside the kiln. Thus the term "reduction firing." This first reduction is known as the body reduction and will last for about 30 minutes.

The next photo shows the flames coming out of the top of the kiln at this point of the firing.
The following photo shows the tongue of flame being forced out of the top peep hole. This is one of the indicators that a good reduction is underway.
That's all for now.

Please stay tuned for the next installment.

Regards,
Paul

After 30 minutes the body reduction is complete. Once again, adjustments are made to the gas pressure, the flue dampers, and the blower speed to set the kiln into a neutral to slightly reduced condition for the middle part of the firing.

The next photo shows that we are approaching the second reduction point. It is now 2:00 pm on the 50th day and cone 9 is starting to fall.
The next photo show that cone 9 has dropped, which is the indicator to start the second reduction.
As before, the gas pressure, the flue dampers, and the fan speed are adjusted to create an oxygen starved environment within the kiln. This second reduction is called the glaze reduction. It is at this point that the glazes are starting to mature. This reduction helps this process along. Again, this is a 30 minute reduction.

Once the second reduction is complete, adjustments are made to the gas pressure, the flue dampers and the blower speed to clear the kiln and put it on the path to complete the firing.

In the next photo you can see that cone 10 is starting to fall. It is 4:30 pm on the 50th day and the end is in sight.
The next photo shows the completed kiln log for this firing.
Once the firing is complete, the kiln is shut down, the flue dampers are closed and the air holes are plugged. The kiln is then allowed to cool for several days before it is unloaded.

That's all for today.

Cheers,
Paul

OK I have to work out how to make these pages printer friendly the Ladies at Pottery would get a thrill from this thread.
Thanks heaps Paul this is sure to be invaluable information for many years to come for many members.

soltan wrote:OK I have to work out how to make these pages printer friendly the Ladies at Pottery would get a thrill from this thread.
Thanks heaps Paul this is sure to be invaluable information for many years to come for many members.

Brett,

You are most welcome.

I'm glad you are enjoying the ride.

Have a great day.

Cheers,
Paul

Well mates, we are getting near the end.

The kiln was opened and unloaded on Monday and as usual it was just like Christmas time.

I am happy to announce that both of the remaining pots survived the glaze firing.

Here is a little teaser for you.

The following photo shows the inside of the kiln when the door was first opened.
The next photo shows the two sets of cone packs from this firing.
As you can see, it was a fairly even firing from top to bottom.

The next photo shows the second pot that was loaded.
And finally, this next photo shows the first pot that was loaded.
I will get decent photos of both pots posted as soon as they are available.

Please stay tuned for the Grand Finally.

Regards,
Paul

Another enthralling installment Paul. I'm really looking forwards to the finally but I'm also disappointed that this thread will be coming to an end
Regards,
Steven

AusBonsai wrote:Another enthralling installment Paul. I'm really looking forwards to the finally but I'm also disappointed that this thread will be coming to an end
Regards,
Steven

Steven,

Thanks for the kind words, however, all good things must come to and end.

Cheers,
Paul

Here is what everyone has been waiting for - the finished pots.

Following are a few photos of pot #1:
The final outside dimensions for this pot are: 35.5 cm x 26.5 cm x 6 cm
The final inside dimensions for this port are: 34.5 cm x 25.3 cm x 4.6 cm

Following are a few photos of pot #2:
The final outside dimensions for this pot are: 35 cm x 28.5 cm x 6 cm
The final inside dimensions for this pot are: 33 cm x 26.5 cm x 5 cm

Feedback is welcome and I would like to thank everyone that has participated in making this thread a success.

And that ladies and gentlemen ends this potters tale.

Have a great day.

Cheers,
Paul

YOU ARE DA MAN PAUL!!!



Thankyou so much for such an amazing education. your pots are beautiful! i love them. now i just cant wait to be able to put out work like that.

Thanks paul this is one of the best threads I have ever read! All bonsai students should be made to read this to show the level of work going into a hand made pot. I for one had no idea, it makes the cost (of the finished pot) seem so insignificant! Now I am awaiting the pottery course I have recently signed up for but by the looks of things that will only be the beginning of my journey!

once again thank you for this excellent thread!

Scott.