Thursday, April 29, 2010

#300.

I test drove the hoopty today, it did well. We had extreme winds and I had all kinds of problems with the pilots popping out early on. I loosened the bracket and tilted the pilot& thermocouple up so the thermocouple was almost in the burner flame, shortened thermocouple life but problem solved. The remainder of the firing was in a decent time frame. After 20#'s of salt the rings were still a tad on the dry side but I didn't have anymore salt so here's hoping it was enough.

Crash cooling.



I finished teaching my last course for the semester today, I still have to give finals but that's a piece of cake. For the final in my kiln building class they are submitting a kiln design(with burner and btu requirements of course!) with parameters that I gave them, hopefully they learned something. They also have to each submit a name for each of the three kilns that we built. I feel the names should have some sort of significance either personally or to the kiln, serious or funny, doesn't matter. We'll then vote, and if I don't like it I'll remind them my class isn't a democracy and pick my favorite. The salt kiln was built entirely of used/salvaged brick, except for the door. It has an air of "ghetto-ness" to it, so I've submitted "hooptie ride" as my choice. When I was in college we named all of our kilns after Elton John songs. There are some stories there but we'll save that for another day, I've got to go home to build a deck and organize the showroom.

Cheers!

Monday, April 26, 2010

spring sale

The spring sale is upon us, this weekend and next. For the first time I'm not rushing to unload kilns the day before the show! We are extremely well stocked this year. For some reason I think I need to feel that last minute panic so yesterday I decided to start building the small deck on the front of the showroom and I won't be able to work on it again until Friday. I imagine it will be finished Friday at dusk. I love pressure, I eat it for breakfast.

This years postcard, credit to Saybra. The only thing I did was make the pots and get in the way of the photos. Well, I made the cabinets too, just ignore that crooked door.

Here is the almost completed salt kiln. We'll be using a piece of culvert pipe for the stack because we are out of hardbrick. My next few firings will be in this kiln so that I can tweak it and experiment with drip-feed oil.


The brick-up door. We know how to fit brick. We'll coat it with...I dunno, something.


This is a small raku kiln that will double as a small cone 10 test kiln. It will have a sprung arch and a swinging door with a stacking space of approx. 12x12x18h. This is a fun little project that can easily be built in a day. Want a small gas kiln to play with but little money? You could build this guy for $5-600 and you could more than likely run it off your standard household sized gas line.


Finally, just to prove that I've been making some pots here and there.
This is the last teaching week of the semester. I'll be spending a portion of may doing some home renovations, we'll be replacing our windows and we're knocking out a wall, etc. I'm looking to do a first firing of the salt kiln this week, post 300 is the next one up so I'll have to come up with something good for that.





Thursday, April 15, 2010

burnin.

One of the many tasks in my kiln building class is learning how burners work and how to build/maintain them. We have a pair of Ward Burners on our reduction kiln and they perform wonderfully but they're about $2000 for the pair. When building your first kiln, or any kiln for that matter you may not always have that chunk of change to shell out on burners. If you have natural gas your options can be fairly limited so I think it's important to know how these things work and then more importantly you can build them yourself for a fraction of the cost. Plus it's fun to talk about things like btu's, cfm's, and orifice sizes...makes you sound more intelligent than you really are.

We had to come up with a solution for the salt kiln, the space was tight so we couldn't have burners sticking out and being primarily hardbrick we needed a hefty btu output. The burners had to have safety systems as well. So here is the solution we came up with. This burner(s) is capable of about 700,000 btu/hr. The blower and the valves are mounted vertically, the blower above, the valves below. I decided to split off one larger blower rather than 2 seperate blowers. Why? We got that blower for $20 brand new. The specs called for 100cfm to each burner so this one is rated at 200cfm. We also got most of the harder to find parts brand new off ebay (pilots, heavy duty thermocouples, baso valves, speed controller.) I was trying to show that there is a cost-effective way to build these things.

The only part I don't like is the duct pipe from the blower to the burner, but it was the only cost effective solution for making a 4x2" rectangle meet up with a 2" circle. It will work just fine, I just think it's ugly. One of the things I stress is craftsmanship, things should look clean and well made. An ugly kiln and burner system may fire just fine but it's a matter of taking pride in you craft.


As you would see it if looking at the kiln.

Here is a cost and source list:

Flame Retention Nozzles from Ward Burner: $70 X 2
Baso Valves, brand new off ebay: $15 x 2
Pipe, fittings and valves from local hardware store: approx. $100
Honeywell Target Pilots from ebay: $20 x 2
K16 Husky thermo couples from ebay: $10 x 2
Dayton Pole Blower from ebay: $20 + 10 shipping
Solid state speed control from ebay: $10
Misc: $30

Total: $410


Cheers!

Tuesday, April 13, 2010

kilns n' shrapnel

Well, I just decided to cut that sucker in half. Eh, what can you do.


We got the back wall up today, lot of brick cutting. The top part of the arch is a homemade castable and there are some soft brick in the arch that have been completely immersed in a homemade refractory coating...the kiln also is set up to potentially fire with a drip-feed waste oil system. We're experimenting with all kinds of crap on this kiln.


I was cutting hard bricks on our ghetto chop saw and the blade shattered and the shrapnel cut one of my fingers to the bone and a large piece flew very near to a students head. Yikes! Looks like I won't be making pots for a few days. It doesn't stop me from kiln building though. Thank goodness I have a "real" job, right?

I have some neat little lidded pieces that I'm fond of and I'll try to get a post up later.
Cheers!

Saturday, April 10, 2010

bummer.

There are times when you just can't think of everything. Now, how to get this out without destroying the form? Hmmmm.........

Wednesday, April 7, 2010

go big or go home.

Since I've found my camera I can give some photographic evidence to prove that I'm still a potter. I'm pretty well stocked so for this cycle I've decided to give more attention to my runs of pots. Ususally each firing is a cycle and I try to pack the kiln with a diverse selection of pots which means that I'll make 3-4 baking dishes, 1-2 platters, 10 plates...etc. This works well for me because I'm not one for making dozens of the same thing in one sitting, I've done that and I'm over it. The bad side is I don't really get to explore some forms extensively. So this time around I'm making a bunch of everything. I remember a quote by John Glick that I try to live by:"I prefer productivity to production pottery." Or something like that. Basically he was saying that he makes lots of pots but gives each its due attention rather than busting out 100 of the same thing.

Dessert plates and steins.


Tall footed yunomi and a jug. I'm excited about these guys, I think there are some nice things happening here.


Baking dishes.


And more baking dishes.


Big bowls and bigger platter/bowls.


Here is something new I've tried...layered slips with wax in between. I did a couple like this but this is my favorite. I spent more time waxing the lines than making the piece.

When I try new things I have a tendency to do it on larger/time consuming pieces, none of this testing on small pieces. Go big or go home, succeed big or fail big. Eh, what the heck...it's just clay right?
Cheers!

Monday, April 5, 2010

treadle photos.

I received an email asking about my treadle wheel so I've taken some detailed photos of how I built mine. The basic plans came from an out of print book...can't remember it's title but it's in our school library here. The same plans can also be found on Simon Leach's webpage.

Here's the wheel from the side. An improvement to be made here is to eliminate the sharp corners on the rail on top of the tray, it digs into my left leg and I have to place a towel between it and my leg. The seat is covered with a thick layer of foam and a towel to be a little less uncomfortable on the bum. I initially left the angled crossbrace off the wheel but added it later for a bit more stability. Notice that it's not stained...when I bolted it in to check the fit I snapped the head off the bolt....so it's permanent now.


This is the chain attaching the treadle to the tray. On my version I resolved to use bearings everywhere something needed to move, this makes everything a little smoother and I never have to oil/grease anything. The bearing is called a swivel bearing, it spins like a regular bearing but also swivels up to 60 degrees. They're not too expensive, I got mine from Mcmaster-Carr.


Another larger swivel bearing, this allows the treadle and the block to move up and down on the shaft as the treadle arcs, it also eliminates some of the clickity-clack noise(that may be a good or bad thing depending on your level of nostalgia...)The block is attached to the shaft with a piece of Teflon...it's super smooth and doesn't need to fussed with like leather that the plans call for. I'd like to cover this with leather for aesthetic reasons though. The extra hole in the treadle arm is because I misplaced the first hole...oops. The piece underneath the block is called a shaft collar, again from mcmaster. It keeps the block from sliding down the shaft and binding.


This is where the treadle attaches to the leg, the plans call for this beefy metal contraption which I didn't have the proper tools to fabricate so I came up with this. The threaded rod makes it adjustable. Note the use of a swivel bearing again, are you sensing a theme? It works but it's kinda ugly though.


The wheelhead is stripped off an old kickwheel. It's a 10" wheel and the holes closer together were already there, I drilled the wider ones for my bats.


This is the bottome of the wheel, a taper fits the shaft onto the wheel and there's a little notch to keep it from spinning on the shaft. In the tray I glued a short piece of pvc pipe to keep slop from falling through the hole and onto the bearing. Wheelheads are expensive, I got this old kickwheel for cheaper than a new wheelhead.


The tray sits loose on the frame for easy removal, it's held in place with pegs on the front corners and the edge of the seat. Here you can also see how the frame fits together. The T shape is mortised, glued and pegged. The angled braces are bolted in and removable, The wheel is 32" wide on the shortest side so making those guys removable makes it easier to get through tight doors.


Here is the top shaft bearing, bolted to the underside of the frame. These have to be periodically oiled, I got the pair of them off ebay for cheap. They are 1" bearings.


The bottom bearing is mortised into the frame about 3/4" and sits directly under the flywheel.


The angled braces fit into mortises in the legs and are then bolted. The braces have threaded inserts in the ends that the bolts thread into, I thought this was a clever idea but it doesn't hold as tight as what's in the plans. The front legs and top T braces are finished 2.5X3". The bottom T brace and the rear leg are 3X3". The bottom brace holds a lot of weight, and the rear leg has all the braces tying into it so I wanted them a little beefier. The plans call for everything to be 3x3" though but I couldn't get that much thick stock locally.


Well, there you go. Any other questions let me know.
Cheers!