Introduction: How to Make a BBQ Burner

For a DIY griddle project I'm working on I need a propane burner that will heat up the cooking surface, I thought the build of the burner would make a good Instructable. Buying a burner was out of the question as the size and power I require is not available of the shelf. If you need to replace or repair a BBQ burner this might help you as well.

But a warningfirst, playing with propane is dangerous, so if you decide to try this you do so at your own risk and peril. At minimum wear safety glasses, gloves and non-flammable clothing. Also do this in a very well ventilated area, outside or in an open garage, you don't want carbon monoxide poisoning.

Step 1: Materials and Tools

This is what I used but other materials could be used as well depending on the application:

  • 1" x 1/16" stainless steel tubing (could substitute this with regular steel but stainless will last longer)
  • 3/4" to 1 1/2" black iron reducer fitting
  • 1/8" brass NPT pipe nipple
  • 1/8" brass NPT end cap
  • 1/8" ball valve rated for gas
  • 3/4" steel bar stock
  • Low pressure BBQ regulator and hose (depending on how many burners you hook up you will need to increase the capacity of the regulator)
  • Flare fitting to go from the propane hose to 1/8" NPT thread
  • Propane Tank
  • PTFE tape or pipe dope

Tools:

  • Drill and Drill bits
  • Small Drill bits (1mm or 1.2mm) - you can get a set off amazon if you can't find them locally
  • Tap and Die set (8-32 tap and 1/8" NPT tap)
  • Welder with cast iron welding rods or MIG Welder with stainless steel wire (this makes things easier but it is possible to braze the parts together as well with a propane torch)
  • Bandsaw or hacksaw
  • Center punch
  • Angle grinder with cutting disc

Step 2: Theory and Design

So lets talk about theory, at least in my layman's terms:

This burner design works off the venturi effect, as gas is being forced out through a small orifice mounted at the end of the burner, it pulls air along and mixes inside the burner tube. The mixed propane and air then is forced out of the burner holes or slots and when ignited it burns.

Propane needs to mix with air to burn at a specific ratio, but with trial and error I was able to get the burner to burn with a nice blue flame. If you get a flame with yellow or orange, it means that there is un-burnt fuel and not enough air has mixed with the propane to get proper combustion. The size of the orifice hole is very critical to the size of the tube, if the tube is too small and the orifice hole too large you get incomplete mixing and incomplete combustion.

For this design I tested many different orfice holes, from:

  • 1/32" - too small - very small blue flame
  • 1/16" - too big - lots of yellow but a very powerful flame
  • 0.8 mm - too small
  • 1.0 mm - just right - no yellow flame
  • 1.2 mm - just right with a bit of yellow but a very strong flame

I landed on a 1.2 mm orifice hole.

Step 3: Video of the Construction of Burner

Check out the video for how I build the burner, the written steps follow:

Step 4: Orifice Assembly

The orifice assembly is made from

  • 1/8" brass NPT pipe nipple (length is dependent on the application)
  • 1/8" brass NPT end cap
  • 1/8" ball valve rated for gas
  • 3/4" steel stock

The center of the 1/8" brass NPT end cap was center punched and then drilled out using a 1.2mm drill bit, cutting oil was used too. This hole is the orifice and propane will flow out from this hole at high velocity.

Also pro-tip, if the drill bits are too small for the chuck of your drill use some metal tape and wrap it around the drill bit so it will make the shaft large enough to be grabbed by the chuck.

Center punch the 3/4" steel stock and drill a hole that corresponds to the 1/8" NPT tap. Using lots of cutting oil cut threads into the hole. This hole will thread the 1/8" brass NPT pipe nipple. Once the pipe nipple has been threaded through the hole, cap off the opening of the tube with the cap that has the orifice hole drilled in from a previous step.

Thread the ball valve onto the other end of the nipple. Be sure to ensure a leak free seal between all the fittings by using PTFE tape or pipe dope to seal the threads.

Step 5: Building the Burner Tube

The body of the burner is made from a piece of stainless steel tubing, stainless is really hard to work with as it work hardens. I first was going to drill burner holes in it but it would take far too long and far too much work so I decided I would cut small thin slots in the tube spaced 1cm apart for the burner "holes". I used my portable bandsaw and made short work of this but a hack saw could be used too.

The end of the stainless steel tube was heated and then bent closed in a vice. This allows the burner tube to be crimped and "capped" off, making a flat spot where a hole can be drilled and used for mounting the burner. The end of the tube was welded shut after crimping (this could be brazed as well).

Next the tube was welded on to the 3/4" to 1 1/2" black iron reducer fitting, the reducer fitting makes for a great burner intake for air and mount for the orifice. Two 3/4" steel tabs were welded on to the sides of the reducer that were tapped with a hole (3-32 bolts is what I used) to accept a bolt for mounting the orifice assembly. Again if you don't have access to a welder this could be brazed and the holes could be tapped directly into the end of the reducer fitting. I chose to weld on some tabs as it made it easier to work with.

A note about welding the black iron reducer fitting: these fittings are typically cast iron which do not weld very well or easy. Since I am just tack welding, it's not really an issue, also the cast iron should be preheated before welding. I am using a MIG welder with stainless steel wire, which I have heard that can be used to welding cast iron. So far I have had no issues with cracking. A nickle welding rod can be used too.

Line up the orifice of the orifice assembly so it's in the middle of the 1 1/2" opening of the reducer fitting, you want the propane to shoot straight down the burner tube so it can mix with air, clamp in place and mark the holes with a marker. Holes were drilled into the orifice assembly that match the steel tabs with the tapped holes so the orifice assembly could be bolted to the reducer fitting.

Step 6: Hooking It Up and Testing

To hook up the burner to the propane I used a fitting that went from the flare fitting on the propane hose and regulator to 1/8" NPT threads, in my case the ball valve. This will depend on the fitting you used so just use what I have done as a guideline, check your local area for a propane supplier or fitting shop and they will be able to get the proper fittings for you.

The propane regulator I used was low pressure one for a BBQ, it needs to be large enough to handle the capacity of the number of burners, in this case I sized this regulator to 80,000 BTUs, more than enough. It's better to have excess capacity than not enough. Remember the flow rate of the regulator is different than the pressure it can provide. Low pressure propane regulators (less than 1 psi) are very common and are plain gray or silver in color, a high pressure regulator is red in color. An adjustable high pressure regulator could be used as well but it depends on how forceful you want the flame to be.

Clamp the burner securely into vise or table before testing.

Turn on the propane on the tank and open the ball valve 1/4 of a turn ,you should hear gas flowing, using a BBQ lighter ignite the gas flowing from the slits cut in the burner tube. The whole burner should light, if it doesn't turn up the flow of gas. There should be a nice blue flame if everything is working properly. Trying adjusting the flow of gas and see if the flame is burning correctly, it should be blue when turned up low or high. If it isn't try changing the size of the orifice or the position of the orifice assembly.

With this design one could make a large burner provided you find a tube that is large enough to allow for proper mixing of the propane and air. Also remember a stainless steel burner tube will outlast regular mild steel but mild steel can be used as well especially if you are doing a proof of concept.

Good luck and be-careful!

Update: Also if you are interest, here is another Instructable on my other account for the project I used these burners in (Outdoor Griddle): https://www.instructables.com/id/How-to-Make-an-O...

Comments

author
gwv2002 made it!(author)2017-06-13

Nice job.

Question: Can this burner be done the same way except with flattening the end of the tube and not welding it? I realize that this end needs to be air/gas tight so would a little exhaust pipe glue or tape along with the flattening work?

author
Mark+42 made it!(author)2017-06-13

You could flatten and fold the end & it should work just fine.

author
stiltdancer made it!(author)2017-06-19

Folding works just fine. There's very little pressure pushing against the end. You're pushing propane through a holey pipe.

author
mpikas made it!(author)2017-06-13

It would work but almost any kind of reasonable stainless will be pretty hard to get flat enough to seal. "Exhaust pipe glue" wouldn't last long (typically a very stiff ceraminc compound that would just crack out of the joint after a few heat cycles) and is fairly toxic.

author
MaxPower1977 made it!(author)2017-06-13

Hmm while what you suggest would work for the short term not sure how it would work for the long term. If you don't have a welder you could try brazing it with torch.

author
pmk222 made it!(author)2017-06-14

An upgrade to this to make it a radiant burner instead of a blue flame burner is to wrap the slots with stainless steel (or higher temp metals) cloth/mesh. I have no idea what size of cloth/mesh should be used and if anyone has experience with this I would appreciate the knowledge. Be sure that the cloth/mesh is either stainless steel or a metal that has a higher melting point and a high oxidation resistance or the heat could melt/oxidize the metal. If the metal oxidizes too much it will fall apart.

author
stiltdancer made it!(author)2017-06-19

Use stainless steel wool.

It will also keep flames from being blown out in windy conditions.

author
ale18 made it!(author)2017-06-18

How to calculate the pressure, the diameter of the orifice, the burner power, the burner diameter and the diameter of the burner nozzles?))

I'm sure exists some formula for this calculations...

author
JoshB9 made it!(author)2017-06-13

side note, and unlikely to be a real problem but worth stating anyway. Do not use galvanized steel parts in your burner. This can, over time and with heat, result in health issues.

(extened version: galvanized metal has a layer of Zinc on it. At high heat, or when cutting/sanding/abrading it you can release Zinc into the air. A small amount won't do much harm, but a lot with repeated exposure cna make you ill. Extended repeated exposures can have permanent effects on your health.)

author
MaxPower1977 made it!(author)2017-06-13

Yup black iron fittings only, or soak in vinegar to remove the galivanization.

author
Kalle+Kl%C3%A6p made it!(author)2017-06-17

Vinegar won't do it..! Don't use galvanized at all. The fumes of that stuff, will leach into your food.

author
mpikas made it!(author)2017-06-13

I'd be pretty shocked if vinegar removed it in any reasonable period of time. Typically you need to resort to mechanical grinding or muriatic acid.

author
Kalle+Kl%C3%A6p made it!(author)2017-06-17

Oh, I forgot. For those of you that haven't access to a welder, just screw a pipe into the end of the reducer, with a through going bolt that holds the nozzle attachment.

author
Kalle+Kl%C3%A6p made it!(author)2017-06-17

Replace the ball valve with a cheap needle valve and you have a much better control. Your burner will work with the larger holes in the nozzle too.

You'll get a brass or plated brass one thrown at you on E-bay.

author
CPUDOCTHE1. made it!(author)2017-06-13

FIRST OFF. Heating galvanized coating and oxidizing the zinc WILL KILL YOU, if you breathe in much. There are tables online that will give you the size of the orifice (hole for propane to go through) for a particular BTU value at a given pressure. Also other people might want to consider putting a shutter on the air intake to adjust the air flow to set the air flow to match the orifice size rather than trying to make the orifice size match the air flow.

author
SeanN38 made it!(author)2017-06-13

One thought for anyone working with propane. It is a heavier than air gas and tends to pool in low places if there is not any air moving. So if you do plan on trying this make sure that you have some moving air and no low places where the gas can collect and then go BOOM at the first spark. I had a pool heater pop on me once. One of the first orifices on the bar had been plugged by small spider web and the flame had not moved from the pilot to the first burner and so on down the line. The pooled propane at my feet got it spark and I got a good flash and whoosh. My boss paid for a fresh haircut and sent me to school for heater repair. i did have on safety glasses and avoided that injury.

I did like the plans and you have given me an idea on something I have beeen thinking about. The trick is going to make a round burner for my project.

keep up the experimenting.

Thanks

author
av8tor1977 made it!(author)2017-06-13

Never happened to think of using slots instead of holes, but I do like the flame produced. Thanks for the idea!

author
Wallythecat made it!(author)2017-06-13

For longevity of the tube I would think holes better than the slits. The tubes burn out at the orifice and the more material there, the longer they will last. I have a drill press and that and a v-block make the hole drill easy.

For me, this started with my gas stove which ceased being manufactured about a year after I bought it, about 25 years ago. About 8 years into this, the S-shaped burner tubes had just given up. No replacements available. I took the burner out to the shop and realized the tube was nearly identical in diameter to some scraps of steel conduit I had laying around. The tube only seems to burn in the straight runs, the loop ends are just fine, maybe because the heat is concentrated in the straight sections. I cut the bad sections out, drill holes down the conduit matching the original hole diameter and spacing and welded the two together. Lasted for about 8 years and had to repeat the process.

I have repaired gas BBQ's the same way and honestly haven't seen much difference in the life span of stainless vs. the conduit of a similar wall thickness. I don't think it's corrosion the causes the burnout of the tubes. Probably depends on the grade of metal.

I figure the galvanizing burns off about as much as it's going to in the first hour or so of burning. Not something I lose sleep over.

The savings over the years of keeping these things alive and working fine has been huge and satisfying.

author
mpikas made it!(author)2017-06-13

AAMOF, doing a quick google search it looks like most cheaper grill and oven burners are galvanized and you know that stuff is thinner than even galvanized conduit

.

author
mpikas made it!(author)2017-06-13

Yea, you have me wondering about that... conduit would make this cheap and REALLY easy to make and almost as durable. I'm pretty sure that I have seen galvanized burners before (I know they weren't stainless and they had some sort of coating keeping them from rusting out right away). Galvanizing burns off at electric welding temps (MIG, TIG, stick), but I doubt a propane flame will do it (likely 1/3-1/4 the temp at the hottest point which is away from the burner).

Taking that a step further galvanized iron pipe would would likely last longer then thin wall stainless if you're OK with the galvanizing.

It is "oxidizing" (rusting) but it is accelerated by heat and oxygen in its vicinity. I suspect that if you run it a little rich (some extra yellow flame) they would last longer but I wonder if the mercaptans mixed with the propane would mess with the flavor (you can bathe your food in raw propane and it won't hurt you).

author
Mr+Maker+McMakington made it!(author)2017-06-13

How many BTU's/hr does it run at assuming the rate shown in the beginning of the video?

author
Chipper+Bert made it!(author)2017-06-13

Inspiring build. Great video too.

I've been want to convert my Weber to gas for a long time but didn't really know where to start. Now I have no excuse...

Any reason not to use copper pipe? Thing is, where I live, getting hold of a short bit of stainless is not going to be easy but 22mm copper I have plenty left over from plumbing jobs and brazing that will be a piece of cake.

author
MaxPower1977 made it!(author)2017-06-13

Copper would work and I have tried it on other projects, issue is the longevity of the burner, copper would not last. But on the plus copper is so much easier to work with.

author
MikeAlmogy made it!(author)2017-06-13

is there a reason for cutting lines and not drilling a hole?

author
MaxPower1977 made it!(author)2017-06-13

What rednecknerd said and stainless steel work hardens like crazy, not a fun material to drill.

author
Rednecknerd made it!(author)2017-06-13

He actually explains the reason for this in the instructable. It was to save time and work during construction. Drilling holes takes longer. Using a bandsaw or hacksaw to cut slits is faster.

author
MikeAlmogy made it!(author)2017-06-13

Ok thanks:-) I just saw the pictures. did not had the time to read. Will do it soon.

author
jimwi made it!(author)2017-06-12

Nice burner will try this on the next beer barrel spit I make.

In you finished burner did you drill holes in the side of the 2" to 1" reducer or did it draw enough air though the end.

author
MaxPower1977 made it!(author)2017-06-13

It draws enough from the end, drilling the holes made no difference.

author
jimdooris made it!(author)2017-06-13

Good job I plan to replace my burner tube! What grade of stainless steel did you use?

author
MaxPower1977 made it!(author)2017-06-13

304 is what they stocked but the type is less important than the wall thickness, thicker walls = longer life.

author
sst4270 made it!(author)2017-06-13

Finally! Will be building this shortly... How deep did you cut the slots in the tubing?

author
MaxPower1977 made it!(author)2017-06-13

Honestly I just guessed about 1/4 to 1/3 of the way.

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