How to Make a Propane Dual Zone BBQ Burner

Welcome to Matt’s Metalworking, in this tutorial I will be showing you how to make your very own dual zone BBQ burner. From what I’ve found, some of those off the shelf burners don’t last very long. At $60 new for a BBQ burner locally and not even lasting two years, it’s quite the waste in my opinion. Once these burned get to a certain stage, they basically fall apart. Ideally it’s best to make this out of stainless steel, but unfortunately my flux core welder doesn’t work on stainless steel, so instead I am using mild steel.

Required Tools

• angle grinder
• cutting discs
• grinding discs or flap wheel
• file
• drill bits
• center drill
• drill press
• marking chalk
• marking paint
• scriber
• square
• tape measure
• flux core mig welder
• wire brush
• locking pliers
• clamp
• welding shield
• welding coat
• welding gloves
• screwdriver or screw gun
• bench grinder

Required Materials

• 1"x3" 1/8" thick steel tubing 15" long
• 1/8" steel plate
• 2"x2" 1/8" thick steel tubing 2" long
• self taping screws

So I went down to my local metal supplier and purchase not even $10 worth of steel. This is 1 inch by 3 inch tubing, 1/8 inch thick and 15” long. I tried to roughly match the existing dimensions of the old burner. The old burner was made of very thin sheet metal and apparently stainless steel but obviously a very low quality.

Starting out, I’ll need to cut this tubing in half using a cutting disk on the angle grinder. My plan is to weld a divider in between so this can be a dual zone burner, just like the old one. I don’t have cut off saw, unfortunately, so this can be a little touch keeping this square. To mark out my cutting points, I’m using a caulk which is typically used on metal fabrication.

Now the cutting begins. Using an angle grinder with a cutting disk, the tubing was cut into two equal sections. After cutting, I removed any burrs using a file to reduce the chance of cutting myself. Once done, the pieces are within a 1/16” of an inch and I can easily square them up with a grinding disk or file. I decided to clamp the two sections together and then using an angle grinder with a grinding disc, the two piece were squared up.

Next is marking out the holes. What I’ve done in the past is used marking paint to outline my workpiece as it’s cheap and easily viewable when I make my scribing lines.

First is marking out the main feed holes for the propane. I’ll mark out the center of the large holes, drill them, and then mark out screw holes.

After that is the layout for the flame holes on the sides of the tubing. The burner intended for the BBQ does have curved ends allowing the flame to go around. In this case it can be a harder to make that, so instead I’ll be creating holes on the front and rear, while the ends remain solid. There will be two rows of holes, each row is 3/8” away from the top and the bottom portion of the tubing, therefore a 1/4” from each other. Then the holes are spaced a 1/2” apart and each row is also staggered by a 1/4”.

Once those holes have been marked out, a center punch with a hammer is used the mark all the holes so the drill doesn’t wander and their locations remain fairly accurate.

The holes will be 3/32” in size and I wouldn’t drill them any bigger as this may affect the performance of the flame. If possible, a 1/16” hole would probably be better. However, I have found it’s a bit tough with this drill press as it doesn’t have an overly high rpm speed. With a smaller drill bit, you do need a higher cutting speed, cutting fluid is certainly recommended, and not overly excessive pressure as you can easily break the drill bit.

A file can be used after to remove any burrs created from drilling. This will ensure there are no obstructions in the holes which may jeopardize the performance of the flame.

For drill those feed large line holes, use a center drill first as a pilot hole and cutting fluid is recommended. The cutting fluid provides lubrications, keeping the bit cool, reduces the chance of the bit burning out, and helps make a clean cut.

I picked the correct sized drill bit needed for the feed lines, this was based on the gasket size which you’ll see a further on. With a larger bit, a slower speed is needed and cutting fluid is a must. Being that this is a bigger bit, there is a greater chance of the piece grabbing where you can possibly hurt yourself. So it’s best to clamp the workpiece down.

After those large feed holes were made, I used the square to make a center line and then marked out the holes where the feed tube screws on, basing it off the gasket. These hole sizes are based off the self-taping screws I’ll be using. Some models of self-taping screws can drill their own holes, however I prefer to drill a pilot hole. This allows for easier installation and prevents them from wandering.

The end and center caps are made from 1/8" sheet metal and the size is based on the inner dimensions of the tubing. Marking paint can be used to provide an outline of the cap, then using an angle grinder with a cutting disc, cup the cap to size. The size can be finalized using a bench grinder and file, the caps should have a tight fit.

Where the burner meets in the center, a chamfer is applied to the end of the tube to help with welding penetration. The metal does need to be cleaned to remove any contaminants which may cause imperfections in the welds.

Using an abrasive pad on the grinder, this worked great for steel prep before welding. It doesn't risk marring the surface like a grinding disc or flap wheel, but it still cleans off the surface efficiently. Any marking paint was also cleaned off using the abrasive pads.

The end caps get installed. As mentioned earlier, they should have a tight fit so they're able to stay in place when applying tack welds. A hammer is used to tap them in place, then they're squared up.

Tack weld the caps into place on opposite ends. When welding, due to the excessive heat, parts can pull or warp causing distortions in your workpiece. So tack welds will help keep those parts in place to some extent. While this isn’t overly critical on a BBQ burner, it’s still good practice and keeps your projects looking clean regardless of what they are.

Once the tack welding is done, you will need to clean them up using a wire brush. I’m using a flux core mig welder, so slag is present and needs to be removed when applying new welds otherwise, you can cause imperfections in the welds.

Full beads can be applied now. I’m using a small hobby welder which only has a high and low heat setting. This is thicker steel and to ensure I have proper penetration, the highest heat setting is used. The wire is 0.035” in thickness. As a tip when welding, welders have a duty cycle. This means that you can only weld for a certain time and then the welder requires a cool down perfect. This is needed so the welder doesn’t become damaged internally.

You may need a mix between locking pliers or clamps to help keep the workpiece in place making welding easier. Another tip, when there is slag you drag. Meaning that the tip needs to be pulled away from the welding area so no slag is pushed into the weld. Instead, it floats to the surface and is removed using a wire brush or chipping hammer.

Clean those welds up using a wire brush again. An anti-splatter spray can also be used to keep the piece a little clean. This prevents welding splatter from sticking, something which is common with a flux core welder.

Connecting the two separate burners, I have a scrap piece of tubing kicking around, the one side is missing which makes it a great jig to keep this burner square. The center divider was inserted in place just like the end caps. Once that piece is clamped into place, tack welded will keep everything together until beads are ready to be laid.

The welds can be cleaned up with an angle grinder and flap wheel or grinding disk and then the welds are inspected. If you have noticed any low or empty areas, they will need to be filled using the weld to ensure we don't have a risk of a leak.

The legs were cut from another scrap piece of tubing I had laying around. The leg height was based off how the old burner sat in the BBQ. It's best to have a wider stance with the legs as it keeps the burner stable and prevents it from falling over. Unfortunately with this design of BBQ, the burned doesn't fasten into place, so it can slide out of its position to some extent when the BBQ is moved.
Once the fabrication has been done, now it's time for assembly. The old gaskets and tubes were reused as they're still in good condition. Ensure the gasket's sealing surface on the burner is clean and free of any imperfections which may cause a poor seal. Self tapping screws are used to install those tubes and gaskets with a screw gun.

Install the newly made burner into the BBQ and connect the feed lines.

And finally a test. I’ll need to play around with the igniter, but using a light you can see it fires right up. Unfortunately, this doesn’t have continuous holes all the way around, so for the most part it needs to be manually lit.

The update as to how it cooks food, I couldn’t be happier with it! I have found if I keep the lid closed it does maintain a fixed temperature better. After playing around with the igniter, I was able to make the burner light up in one shot rather than doing so manually. To give you a view with the infrared meter, the left side is on high and the right side is on low. The cooking temperature can vary depending on the temperature outside which is quite common with any BBQ in general. As kind of a warp up of what I learned, smaller holes will definitely give you a finer flame. With the thicker steel, it does hold heat extremely well and despite having fewer holes, the heat output seems to be better. So far we’ve been using it to cook hot dogs, burgers, and steaks which excellent results.

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