The GrillGun – Understanding a 400,000 + BTU propane torch


Although the GrillGun is designed to screw right onto a 1lb propane bottle, there is an inherent drawback to using these small tanks, and it has something to do with physics, not the GrillGun, but since it effects the GrillGun’s performance you really need to know and understand this topic.  The topic is the freezing up of the propane bottles and resulting fuel flow reduction. 

As liquid propane expands and turns to gas as it comes out of the bottle through the torch, the gas expansion inside the propane bottle causes the propane in the bottle to cool-down and get quite cold. In fact, you will feel the bottle start freezing up and frost building on the outside after prolonged usage (about 2 minutes) of the GrillGun.  As the propane chills it loses its ability to evaporate which causes the velocity of the escaping gas to be significantly reduced. So, in practice what you see is as follows: If the propane bottle is full and is at room temperature when you start, you have a little more than 2 minutes before the output volume of gas is significantly reduced. So, if you are lighting your grill in under 2 minutes, you will notice your bottle getting quite cold but there will not be any reduction in fuel flow.

Once the torch is turned off and the fuel stops flowing, the bottle will start to warm up to the ambient temperature of its surroundings and the process will repeat the next time it starts from room temperature again. Lastly, as the fuel is slowly depleted from the bottle, the cool-down time will speed up because there is less volume of liquid in the bottle to chill. Ultimately, the fuel supply in the bottle will be totally depleted and you will either need to dispose of or refill the bottle. The same thing happens in the 20lb or 30lb bottles too, but there is so much more mass of fuel and steel to cool down, that you will never notice any degradation of torch output, until the tank is nearly completely empty.

An additional benefit to using the larger tanks is the cost propane in 1lb bottles is quite a bit more expensive per pound than 20lb propane tanks; therefore I always use the 20lb bottle to power my GrillGun when I am at home and grilling, smoking or barbecuing. So, consider using the 1lb bottles regularly when portability is desired, or when you use the GrillGun so infrequently that the fuel cost of operation is negligible, otherwise go big.

Now for some more technical stuff that set GrillGuns apart from the other torches and makes the GrillGun a superior tool.

Unlike other high capacity (400,000 to 500,000 BTU) weed torches, the GrillGun has patent pending technology used to be miserly on the fuel consumption by leaning out the fuel mixture and premixing it before it gets to the fire bell.  Compared to some weed torches, the GrillGun will use 1/4th the fuel in the same amount of time, which is why it can be used effectively with small portable bottles.

Another real cool design element of the GrillGun is its fuel ignition system.  The spark igniter element inside the GrillGun is rated for 28,000 sparks and the ignition electrode and fuel diversion is designed to never wear out, because it is stainless steel and not situated in the fuel flow which causes most other torches to have their self-igniters burn up within a few weeks.  

There is another advantage to the design of the GrillGun’s ignition system, one of safety.  The GrillGun may not light when the gas is turned on more than just a slight (very slight) cracking open of the gas valve.  You must just barely turn on the torch to pull the trigger and light it. Anything with higher velocity fuel flow than just barely flowing out, may blow out the flame.  This reduces the likelihood of a powerful burst of fire coming out of the fire bell when you are lighting it. A big burst of flame may be startling to some people and counter to the purpose of the torch.  You will want to just barely turn it on when lighting and then turn up the gas or pulse the flame with the squeeze handle, only when you want the intense heat, not before. This way you won’t accidentally flame something more than you wanted.