Igniter Electrode for a Gas Grill

The igniter electrode on my Charbroil gas grill requires some force from a pair of pliers to snap onto the ignition side tube, but visibility is limited and it is easy to forget so that the pliers break the insulating porcelain tube shielding the ignition electrode. I wanted to replace mine because the electrode arcs to ground away from the propane to be ignited. This Instructable describes how I made a new igniter electrode assembly from an old spark plug that works better than the factory electrode.

Tools

1. Hacksaw
2. Rule
3. MIG welder
4. Spring clamps
5. Vise
6. Pliers

Materials

1. 1/2 inch EMT metal tubing
2. Old spark plug
3. Finish nail
4. Scrap of 1/8 inch steel
5. Scrap of 20 gauge steel

Twice in eight years I have had difficulty making the electronic igniter produce a spark. Both times gummy grease from grilling had insulated metal surfaces needed to conduct current from the ignition system as a ground return. That broke the circuit and made an igniting spark impossible. Cleaning metal surfaces was the solution to the problem. Usually these surfaces had to be separated before cleaning, and then assembled again.

But, it is also good to make certain the electronic igniter module is functioning. My grill uses a pushbutton with a AAA battery behind it. The battery lasts a very long time, but it is good to check its condition. It is also good to clean any oxidation from the ends of the battery.

I drew a red line as an overlay to the photo. Notice the small shiny dot at the lower end of the red line. It is the ground return terminal and presses against a metal shield that fits around the electronic module. I usually try to duplicate the circuit on a tabletop to be certain the module is functioning.

Here is an afterthought. A family member has one of these grills that is outside with no roof over it. The igniter uses a simple pushbutton. It failed. I expect rain got into it. Provide two leads. One grounds to the frame of the grill and has a spring clip. The other can be connected to the sparkplug boot on a weed trimmer or a chainsaw, perhaps a gasoline powered blower. Remove the ignition wire from the sparkplug and connect it to the lead on the grill. Connect the grounding wire to something grounded on the machine. Pull the starter cord once or twice to send a spark to the grill's electrode to ignite the propane for grilling. Then disconnect the machine and put the meat onto the grill. It would certainly work if a module failed, and it could work as a permanent method.

As I mentioned, I applied pressure to the ceramic rod that shields the metal electrode and broke it. Then the spark found a path to ground away from the propane it was supposed to ignite.

Replacement igniter electrodes are about $6.75 each and come in packages of two. I decided to see what I could do with what I had on hand. I cut a piece of electrical conduit to slide firmly onto the metal propane tube with its burner orifices. I welded an old spark plug from a chainsaw to it. I did increase the spark plug gap a bit, although that may not be necessary.

Propane is heavier than air and quickly falls past the spark gap on the old plug so that there is not a sufficiently strong concentration of propane to ignite. So, I made a little cup to fit around the spark gap and catch some propane so the spark can ignite it. I am very pleased with how well it works. I did weld a two inch finish nail to the top end of the spark plug. This provides a conductor from the top end of the spark plug to what is left of the grill's electrode.

First photo--Mark a little more than the length of the spark plug threads on the electrical tubing and cut to length.

Second photo--Slit the piece of electrical tubing lengthwise.

Third photo--Spread the slit on the electrical tubing to form a combination of a "U" and a "V."

Fourth photo--Use spring clamps on a piece of aluminum angle for welding.

Fifth photo--Weld the piece of electrical tubing to the spark plug so the electrical tubing is over the threaded section.

Sixth photo--Cut a piece of flat steel to cover the open end of the pan and weld it in place.

This chainsaw plug is very small in size. I wanted to weld it to more electrical tubing, but I was concerned the upper end of the plug would be close enough to the tubing to ground with a spark through the air so no spark ignited the propane in the pan. I cut a piece of 1/8 inch steel to add some distance between the plug and the electrical tubing that will be the mount for the assembly.

The propane burner tube has a line of holes that pass under it to allow propane to fall into the igniter pan. I cut a piece of electrical tubing as you see to avoid unnecessarily covering any propane orifices. I do have a metal cutting bandsaw, but used a hacksaw so a power tool could not take the electrical tubing from my hand and injure me.

The exact shape of the mounting tube will depend on whether the final assembly is mounted with the spark gap end of the plug pointing toward the center of the grill or pointing toward the front end of the grill. Space for the former was very limited, so I chose the other option as you can see from the third photo in the final step. I wanted to avoid part of the spark plug being too close to the metal frame of the grill and providing a convenient place for the spark to jump to ground before it could ignite the propane.

I aligned the mounting tube with the spark plug assembly and welded them together.

See the second photo. It was easy to clamp the assembly to a grounded piece of aluminum angle, but the electrode in the spark plug would not be grounded for welding. So, I attached the welder ground clamp to the locking pliers I used to hold the finish nail while welding it to the top end of the spark plug's electrode.

The first photo shows a clamping electrical connector I made. See my Instructable on making those. Some adjustment of bends in the welded nail was necessary to align with the old igniter electrode. Once aligned for a good fit, slip the connector over both conductors and tighten. (second and third photo)

When I was finished attaching the connector I twisted the igniter electrode assembly a little so no gas orifices were even partially blocked. (third photo)

This igniter electrode assembly works very well. For those who do not have access to a welder, different sizes of automotive hose clamps could work to hold parts in place. This igniter should work and last a considerable time. The burner tube is shielded from dripping meat grease fairly well. But, the assembly is very near to a strong propane flame, and severe oxidation could be a problem. Time will tell.

UPDATE: I tried making two of these. The one for one grill works very well. The one I made for an identical grill sparks well, but does not ignite the propane. Somehow the spark is too distant from the propane to cause ignition. I think it would work if I positioned it better to catch the flow of the propane as it comes out of the burner tube holes. Judging from the flame, quite a bit of the propane goes directly out to the side in the ignition area.