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Read this DISCLAIMER Before you Proceed              

Any person(s) using informations from this website constitutes acceptance of this agreement.
Advanced electrical knowledge is REQUIRED to begin and or complete this kiln modification
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Informations here are Not recommended for children under 18 years of age.
Keep products and all related products away and out of reach from pets and children.
Improper installation, care or use of products could result in property damage, Fire, electrocution, blindness, serious injury or death.
Safety goggles are required during this procedure. Avoid inhaling fumes or dust. Must use proceed with proper ventilation. Must dress properly, wear shoes that completely cover the foot, Full length pants and a shirt are required during installations or modifications.
Must wear heavy leather gloves accompanied.
Consult your physician before you proceed if you suffer from any Breathing illnesses, bleeding disorders, tendentious, carpotunnel or any other discomfort before proceeding.
If problems and or discomfort result, discontinue use and consult your physician.
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Proceed and or use at your own risk.

A common question: Why do I need to convert my pottery kiln to heat treat flint?
1. Ceramic kilns do not have the fine tune adjustments needed for heat treating flint.
     (Unless they are one of the newer computer controlled or programmable type, in that case conversion is pointless)
2. They use a crude method that uses "cones" that trigger the kiln to turn off at the cone's designated temperature.
3. These temps are far too hot for flint and knappers need to achieve temperatures within 15-20 degrees fahrenheit.
4. The Robertshaw infinite switches allow better controls for temperatures ranging from 150-800 f. using only 110v.

It's always best to take those whopping big kilns and cut them down to size that they will barely hold a 5 Gal. bucket of spalled or bifaced rock. Always trim your rock as far down as your skill lever permits before heating them. The results can make or break your hard earned stone. Your basicly going to be junking all the electrical "guts". The original elements and switches are useless because the Ohmz are too low and will damage the new switch and create a serious fire hazard.


Switch Installation

Proceed at your own risk. This switch, Robertshaw 5500-135 commercial infinite switch, is designed for 120v. It can be purchased from any appliance parts store. I recommend the commercial grade switches. Each switch is to be used with one (1) element ranging from 13ohms to 18 ohms. If your kiln holds one 5 Gallon bucket of rock then one switch will be enough. I have a kiln that holds 18 gallons of rock and I have three switches on it. The temps should not be allowed to exceed 800f. NEVER use the kiln on or near the "high" setting. Use caution when settings are near the "high" setting, the kiln could get stuck in "high" mode and will cause overheating and damage to your stone and possibly element(s) too. Never operate your kiln near any flammable vapors including, Glues, solvents, fuels or others. Infinite switches produce small sparks as they "toggle" in their operation.
The switches have a dial with numbers from 1 to 6 on them with quarter and half marks on them. The dial settings are NOT temperature settings. For example: You must experiment with your kiln to find out what temperature dial setting #4 produces. It might be 375f. Make a chart and write down the final values of each setting. Be sure that you are allowing at least 24-36 hours for your kiln to max out at the dial setting you have selected. Don't become tempted to monkey with the dial when your trying to establish final values for a dial setting. Always fire FULL loads of material to get accurate temperatures for your chart. If you don't have flint to test your kiln, get some red bricks and fill it up as full as you can.

Read this carefully!!!
If you are unfamiliar with proper and safe installation listed below or lacking in electrical expertise, DO NOT PROCEED!
1. Unplug all power before working on your kiln!
2. Mount your switch in a grounded metal box on the side of your kiln. Mount with good and safe clearance from any electrical connections to the element, power cord or switch itself.
3. Be sure switch is mounted with the "top" indicator is facing upwards. See diagram below.
4. Use a 14 or 12 gauge cord with ground wire to ground the metal switch box. The best option is to buy a new one or remove one from an old appliance with a ground wire still intact. Full size freezers, refrigerators, microwaves ect… are suitable choices. Fully inspect for any flaws and discard if any are found. Fully test with a continuity meter to be sure there is good continuity.
5. Wire switch as shown in the diagrams below using good quality crimp connectors.
6. Check all connections with a multi-meter to insure there are no "shorts" or "longs".
7. Double check your element to be sure it is in the proper Ohms operating range for this switch (as per diagram). Do Not Use old or original elements with this switch. They are NOT compatible.
8. See diagram Below for details. Please note: the "P" (pilot light) terminal is not used on this configuration!
9. Use proper terminal leads on all connections, NEVER use electrical tape! NO connections should be located inside the kiln. All connections should be completely outside the kiln and clear of any metal or conducting parts!

Installing the element
The elements are hand wound by us. So if you need one, email me and I will make one up for you. They are $18.00 and $6.00 to ship here in the USA.
1. The element's ohms must be between 13-18 for the Robertshaw© Infinite switch. Nothing more, nothing less.
2. The new element will need to be stretched to fit your kiln so that it pushes against the sides of the kiln and seats itself in the channel in the refractory bricks. This is important: The element must be evenly stretched or you will shorten its life. Bunched areas will get much hotter than the rest of the element.
For a kiln that is near the diameter of a 5 Gallon bucket, you should be able to have stretched the element around the inside of the kiln twice.
Once the kiln is used for the first time, the element will shrink a bit and you will have to re stretch it. Be gentle, they will be more brittle.
3. Do NOT cut the element for any reason! If you break the loops, you can straighten some of the coil to create a new loop. The loop must wrap against itself to reduce ohms resistance and also heat near the point of connection to the wire leads that go to the switch. These wires should all be 14 AWG minimum.
4. Connect the element to the switch. (H1 and H2 marked on the back of the switch).
5. You can use solderless wire butt connectors 10-12 AWG rated for 24 amps. Or use 10-12 AWG lugs. Be sure that these cannot and do not ever come in contact with ANY thing conductive. Do Not rely on ANY insulators other than the appropriate ceramic type. Don't fool around with this stuff! If you are unsure, consult a certified electrician.

Operate the kiln safely!

1.NEVER operate kiln on a wooden or flammable or combustible surface.
2.Place kiln elevated on concrete blocks or metal stand. Do NOT set directly on any floor concrete or otherwise!
3.Keep kiln at least 20" from any walls or other objects at all times.
4.Use cement fiberboard on near by walls for an extra-added protection!
5.Use a "dedicated" outlet for each kiln on a 15-amp breaker.
6.Never heat-treat large blocks of stone. Stones could and will likely, violently break apart. This could knock the lid right off a kiln ejecting VERY hot Fragments, creating a serious fire hazard!
7.Keep your kiln under a roof and out of the weather, Damage to electrical parts will result.
7.Never operate kiln with flammable, combustable or explosive fumes, liquids, solids or vapors present.
8.Avoid heat-treating in your home or living space. Heating certain rocks can produce toxic or poisonous vapors, especially if cut on rock saw!
10. Never open the lid on your kiln when temperatures are above 140 degrees f. You'll get burned and can cause temperature shock to the rock resulting in cracked stone.
11. Chip an arrowhead.