Propane Gauge for Your Grill

Propane Gauge for Your Grill (BBQ)

For those of us cooking outdoors, we regularly rely on our trusty propane gas grill. But is it really all that trustworthy? I've been let down multiple times by my grill - and it wasn't because of anything I said or did....

Well...

It was what I didn't do! I didn't get PROPANE.

Yep, I ran out of propane.

How's a guy supposed to know he is about to 'flame out' on the grill? Well here's a handy little modification to your grill that will give you ample notice to make sure you have a full tank on hand.

I wanted a propane gauge. Specifically one that used weight to determine the amount of propane in the tank.

After looking at some different scale concepts online, I decided that I wanted use a "steelyard" scale. It is simply a beam with unequal arms. The tank weight is applied to the short arm and a fixed weight is placed on the long arm until equilibrium is achieved.

Step 1: All a Matter of Balance...

With my 'steelyard' scale I decided that the beam should be balanced when the propane tank was empty. The sketch shows the arrangement.

I used the grill's wheel axle as one of my pivot points for the arm under the propane tank. The beam is suspended below the grill frame where the side shelf attaches to the fire box.

The tank arm is attached to the beam by galvanized wire. The beam is provided with an indicator wire on the far left. This wire pokes up though some convenient vent openings in the side shelf.

The beam is balanced by adding some weights (washers) to the right side of the beam until it balances horizontally.

With an empty tank balanced, the amount of indicator wire poking above the shelf surface would indicate an empty tank. A red marking on the wire is exposed.

Step 2: Running Out of Propane Is a Weighty Matter...

When the tank is full or has more than zero propane in it the weight of the tank and propane applied to the left side of the beam will deflect the washers upwards and the indicator wire downwards.

This position of the indicator wire only shows green. The indicator wire remains green until the propane has been reduced to some arbitrary level where you want to indicate a warning with yellow band on the indicator wire.

Step 3: Materials and Tools

Materials:

3-foot long 3/4-inch square steel tube

12-inch long thick gauge (~3/32") steel tie strap (the thin flimsy ones will not work)

5/8-inch galvanized steel washers (3 - 4 or more depending on your weights and lengths)

Galvanized wire sufficient to tie it all together (~4 feet)

I have found that suspended ceiling (t-bar ceiling) hanger wires work great. They are 6 feet long, 12 gauge and come 10 to a pack for less than $4.

Acrylic Paint (green, yellow, red) to paint the indicator bands on the indicator wire.

Spray paint to paint the entire assembly to protect it from rust and make it look 'pretty'.

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Tools:

Electric Drill and bits

Pliers to bend and cut the wire (locking pliers and lineman's pliers came in handy)

Hacksaw to cut the square tube to length

File to round the tip of the indicator wire and any other wires that may be a hazard.

Small Paint Brush and fine tip marking pen

Step 4: Add the Tank Arm

First off, you are modifying a propane grill. Your grill may be different than mine and there may be design features that are important safety features that keep your grill from overheating or exposing the propane tank to radiant heat, etc. You have to decide if the modification is safe. It appears that most grill manufactures use some means to fasten the propane tank down to the grill frame. This propane gauge Instructable keeps the tank 'floating' on the tank arm. This may make the grill more hazardous. You have to decide what is acceptable for you. You make the call, and you take the risk. You accept full responsibility for modifying your grill. These instructions may not apply to your grill or may make your grill unsafe. You have to decide or inlist the help of someone who can make the determination if your grill will be safe with this modification. I take no responsibility for your actions. If you are unsure, don't do it.

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There now that that is taken care of lets get going...

The tank arm ideally should be under the center of the tank. I mounted the tank arm to the grill's axle. I also angled the tank arm so the far end of the arm would be in the proper location under the the short end of the beam. I drilled a hole in the tank arm at an angle to allow the tank arm to fit into this position/location.

I drilled a small hole in the far end of the tank arm for the galvanized wire to go through to pull down on the beam. Cut any excess square tube off so that it all fits under the grill frame. If the grill axle bends under the weight of the full propane tank it may be necessary to either block up the axle or to install a wire hook around the axle and tie it to the grill frame to support the axle.

My design worked very easily because the propane tank protruded out the bottom of the tank shelf/holder. If your tank does not 'stick out the bottom' you may have to build a small platform on the tank arm to fit up under your propane tank in order to be able to lift your tank.

Step 5: Hang the Beam

The beam is a heavy duty thick galvanized tie plate used to tie building structures together. It has pre-punched holes that work out perfectly for this project.

The beam is located directly under where the grill side shelf meets the fire box. I drilled a hole in the frame (not the fire box) large enough for the galvanized wire I was using to hang the beam. I bent an s-shaped hook out of the galvanized wire to hang the beam.

Step 6: Connect It All Together

With the beam hanging I 'installed' an empty propane tank and lifted the tank arm up until it would go no farther. I cut my galvanized wire to tie the tank arm to the beam so that in this 'full up' position the beam would be horizontal and excess wire would stick out the tank arm through the small hole in it.

While holding the tank arm up as far as it would go I could move the beam to the horizontal position then bend over the wire sticking out of the bottom of the tank arm.

I cut and bent another s-shaped hook and placed it in the rightmost hole position in the beam. I hung several large steel washers until the beam balanced.

I took another piece of wire and made the indicator wire fit into the beam and extend up and out the vent slot in the grill side shelf. If your grill does not have these vent holes it is certainly easy to drill a small hole in the shelf for the indicator wire to extend through.

I marked the level on the indicator wire as this is the 'empty' level and should be painted so a band of red shows, indicating tank empty.

Step 7: Full Tanks

I now placed a tank with more than zero propane (full would be best, but I don't have a full tank right now) and checked out the indicator wire. The indicator wire was significantly retracted and this portion of the wire will be all green.

All that's left is to paint the indicator wire green, yellow and red and paint the rest of the parts of the 'gauge' to keep them from rusting and to make it all look great!

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That's about it!

Now you should have ample warning of low propane and not run out half way through your perfect steak!

Comments

[sidecar123]

If the sun is allowed to shine directly on the propane tank for a few minutes, you can then feel a difference in temperature on the side of the tank. Cooler is the liquid and warmer is the gas. The fuel level is the point where the temperature changes. Hope this helps.

[Omnivent]

You could paint (or magnetically hold) a thin vertical strip of thermo-color-changing paint (like used in e.g. mood rings and "LCD thermometers"). when you want to know the level of gas, just pour some 40°C..50°C hot water on the strip and for a moment, the level will be visible due to the liquid gas having a higher cooling effect than the bottle alone - back in time they sold such strips for this exact purpose, but I have no idea if they're still in production. Not hard to DIY though :)

[wannabemadsci]

I remember those too. They have not disappeared. There are at least 3 different models of this type of temperature change gas gauge. I think most now do not require the hot water to take a reading. However, with this type of gauge you have to be using the tank to allow the cooling from the gas expanding, so taking a measurement before starting grilling is not possible.

[Omnivent]

Ah OK, I never tried one, just read about it in a mag of sorts. If my memory serves me, it was the difference in thermal conductivity of the liquid gas vs. the "gaseous" gas, when the hot water was added, but I'm sure you have more current info on the subject.

Did you consider a load cell of sorts, perhaps just a quarter of a bath scale (which contains 4 of them to counter for different postures and positions - COG really)?

Then you could have your grill tweet your supplier for a replacement ;)

[markcaesar]

I wonder if a gas pressure gauge would work too...

[wannabemadsci]

Thanks for the comment.

Gas pressure is not an indication of remaining propane because the propane in the tank is gaseous propane sitting on top of liquid propane, all under pressure. The liquid evolves into gas as propane is used. The gas pressure remains constant until the liquid has all be changed into gas (just before empty).That's why I'm suspicious of any of the pressure type gauges providing any meaningful information.

[longwinters]

I know what you're talking about, I mean really how much fun is it to say look at my bath scale, if ya really want to impress the ladies add some LEDs...

[longwinters]

I love your ingenuity but go to the discount store and buy a bath scale mark it where it's full mark it where it's empty.

[wannabemadsci]

Touché I like your simple solution! Thanks for the suggestion!

(I did however enjoy the creative process and the build. I guess part of the fun is how you get there.)

[Biscuitus]

this is a forehead slapping moment for me. Good instructable, but I'm wary of using an idea involving propane from a person who's profile pic looks explody.. kidding it's going to be my weekend project for a friend