Electrical System Inspection

In my last post, I described the physical condition of the kiln.

I later realized, by reading the reactions to my posts, that I must have sounded really whiny, complaining, and dire.  That was not my intent. I was just trying to convey that initial "oh crap" feeling I had.  Sorry everyone ! :-)

Today, I am going to cover the electrical systems, which is the heart of the kiln.  Then in the next post, I will start to cover the repair and rehabilitation processes.
 

Again, here is a picture of the kiln after I unloaded it into my driveway. Notice that the kiln sitter control system has separated from the kiln itself.  This will not be a problem, as I intend to install a digital control system in the kiln.  I plan to use the kiln sitter control box, to house the Type K Thermocouple in the new configuration.

The main control panel of the kiln looked to be in good shape.  So I took the control housing panel off and inspected the majority of the electrical internals of the system.
 

At this point, most people would have been in a more severe "Oh Crap" mode than I was when I inspected the exterior of the kiln.   Thankfully, I'm an Electrical Engineer and to me, this is the simple part of the rehab process.

It was not in good shape.  There was literally a rodents nest of some sort in the bottom.  And the aforementioned rodent had decided that the wiring had looked like a good snack at some point in time.

There was also significant deterioration in the insulation of other wire segments.  Some of the insulation  literally came off in my hands when I touched it.  This was not totally unexpected given the age of the wiring and the operating temperature of the kiln (even the outside, in near proximity to the walls).

The Paragon A-88B Kiln consists  of 4 separate heating elements, controlled by two 4 position switches, and the associated wiring.
 

This picture show how the elements exit the side of the kiln and are connected to the control system.  My Aunt originally told me that there were two elements in the kiln and "one" did not work.  In actuality, you can see where the first and second elements were badly burned at the insulator posts, and burned the connectors away.  Once a kiln elements are heated, they become VERY brittle and prone to breakage.  I may have  inadvertently broken one of the working two, when inspecting the connections.  They were THAT sensitive, given their brittle nature and their age.  I hope to be able to heat up the ends, unravel some of the coils, and be able to hook them up again.

With Paragon replacement elements running $45 per element (x4 for this kiln) plus shipping I really do not want to have to replace them.  That would literally add +50% to my costs on this project.

At this point, I have decided to do a total re-wire of the kiln.  The digital controller replaces most of the functions of the two 4 position rotary switches, and the original wiring is absolutely UNSAFE.  If it was used in its present state, your just asking for a major shock, or a fire.

I plan to use a simple main power ON/OFF switch, x4  ON/OFF switches for each separate heating element, and the digital control system (PID controller, SSR relay, Type K thermocouple) to regulate temperature, plus all new wiring.

On the interior, there are four major places where the firebrick is broken that has to be repaired, or a short will occur in the heating element.  When the element heats, without support they will sag under their own weight, and touch the element portion below, creating a short.  This will do very bad things to your kiln. 

Initial Kiln Inspection - Or OH MY GOD.... What Have I Done ?!?!?!? ;-)

Have you ever accepted a commission on a project or started an ambitious new project, when you all of a sudden you have the sudden feeling of OH MY GOD .... What have I done ? !  ? ! ? ! ? ! ?

:-)  Well after I did my Initial Kiln Inspection that was my feeling.

So I picked up the Kiln from my Aunt's farm. We moved it from the Barn, knocked off the cobwebs and the dust, and put it into my Truck.  She warned me that the bottom plate was rusted badly, and that the top element was not working, but I was optimistic ! :-)  I figured the bottom was a minor issue, and I could fix a single element.  The rest was cosmetic.  Plus She had the original manuals and wiring diagrams..... I was golden.

I arrived home and unloaded the kiln into my driveway.


 

The exterior is somewhat corroded ( yes even stainless steel can rust ) and its pretty dusty.  The original control panel looks to be in good shape though.  As you can see, the kiln sitter has broken away from the kiln exterior, but I am not too worried about that, because I am going to replace it with a digital temperature controller, a Type - K thermocouple, and a solid state relay (SSR).  
 

The Kiln lid is fairly battered but nothing major.  Just a factor of human nature that people tend to use them as handy shelves.  The hinges are badly rusted, but they can be cleaned up and painted.  It is evident that the lid became loose in its original mounting position at some point, and was moved to the next side of the kiln .

 






I am starting to get worried.  As I move the Kiln for inspection, I can feel major movement INSIDE the kiln.  Not good.


I then took a look at the bottom.  I was warned that the bottom was rusted, but I did not realize the extent of the damage.
 


The previous picture is a close up of the Kiln's bottom / edge.  See the gray fringe?  That is all that is left of the bottom panel of the Kiln that holds the weight of EVERYTHING else.  Remember when I previously said that even stainless steel rusts? This is a picture perfect example.  Under high temperatures or under corrosive conditions even stainless can have problems.  

 


That shot shows the Kiln bottom after I removed what was left from the rest of the Kiln.  It started out as around 22-24 gauge stainless steel ( my approximation ).  Now it is paper thin, and I literally tore it with my hands.

Without the Kiln baseplate, there are MAJOR structural problems.  It has allowed the firebricks, which are very fragile in a new kiln let alone a 40 year old kiln, to develop a major crack that goes entirely through the kiln bottom, and all the way across the bottom. 

 


 


The next couple of shots show the same problem from the inside.

 


 


At this point I am seriously worried about the viability of the Kiln.  Stabilizing the bottom has got to be the first priority, if this project is going to work and I don't want to end up with nothing more than more than a pile of gravel and dust.

My next post will cover the state of the electrical components and the elements.

Playing Catch Up on the Kiln Project

Over the past two weeks I have been working on the kiln, not on the blog ! ;-) So I am going to try and catch up the blog in the near future.

And in the begining there was fire.......

Well actually this was started because of fire.  A couple of days ago a family member gave me the "long term loan" of her Paragon A-88B Pottery kiln.  This kiln is from the mid-70's, and is in need of dire rehabilitation.  It has literally been sitting in a garage and then a barn for over 20 years.

I plan on documenting my work on the kiln, and if successful, its use in heat treating recreations of historical arms and armour that I work on as a hobby.

Note:  I am not a professional Armourer.  I do not sell anything.  I am not a Kiln repair man.  I can not give you advice or technical information beyond what I post here.  I am just a "hack" with a passion for Do It Yourself (DIY) projects.

Do NOT try these things at home without specific training and experience.  Some of these activities described in this blog can be extremely dangerous or even deadly.  If you injure yourself trying to do these things, it is your own fault.  Do not come back to blame me or sue me.