Sounds like it will work…But I to am a Firefighter and I would not want to have that Scuba cylinder or SCBA in my truck/car if I was in a crash. That’s a 3000-4500 PSI Bomb in your truck car.
Ok. I just finished my technical research on this issue and I created a simple Excel workbook which shows the differences between using a standard air tank vs. a scuba tank. Here are a few things you should understand before looking at the data:
[ul]
[li]Normal air tanks are rated in gallons based on the amount of air that they hold at normal atmospheric pressure.
[/li][li]Normal atmospheric pressure is 1 atm or about 14 psi.
[/li][li]Scuba tanks are rated in cubic feet based on the amount of air that they hold when fully pressurized to the tank’s stated pressure limit.
[/li][li]Most common scuba tanks are designed to hold 80 cubic feet of air at 3000 psi.
[/li][li]I based the chart below on my actual setup. Your details might vary. When using the workbook, you simply enter the values highlighted in green and the workbook will calculate the rest of the data for you.
[/li][/ul]
Now we can move on to look at the comparison data:
Some conclusions:
[ul]
[li]One full scuba tank will last about as long as 7 or 8 full air tanks when both tanks are drained to an empty state. This is based on my current 7 gallon tank.
[/li][li]The scuba tank will provide a much higher quality experience because each honk will be at 150 psi for the entire duration of the honk, and there will be no downtime between honks for the tank to recharge. There also won’t be any noise or heat from the compressors.
[/li][li]The scuba tank will not require any DC wiring or consume any amperage from your vehicle battery.
[/li][li]The scuba tank will be quicker and easier to install.
[/li][li]The scuba tank will need to be removed and refilled periodically. This could be an inconvenience unless you buy a spare tank and keep it charged and waiting. This also depends on the location of your nearest dive shop or refill station.
[/li][li]The cost of the scuba tank system plus refills will equal the cost of compressors and a standard tank in about 3-4 years based on my current setup and usage. This seems to be about equivalent to the life span of most average compressors based on what I have read, so from a cost perspective these options seem to be about dead even in the long run. Scuba actually holds a slight advantage because you can pay for the refills as you go and quit at any time.
[/li][/ul]
If you have a different system with a smaller/larger air tank, higher/lower psi, or the systems cost more/less in your area then just download the Excel file and change any of the values that are highlighted in green to form your own comparison. Click here to download the workbook.
I hope someone finds this helpful. I know it has helped to convince me to switch to a scuba setup, at least for a trial period to see if the math really does hold true. 
Interrresting. I might give this a try on the truck.
“I actually tried something like this and it didn’t work. The problem wasn’t pressure in the tank (a SCUBA tank is durable enough, and could be filled to just 1000 lb). The problem is air flow and pressure loss at the valve and in the lines. The air port on a SCUBA tank has a small hole - less than 1/8” Air horns require a considerable amount of flow to blow properly."
Found this on yahoo answers. Do you know what kind of ports a scuba tank has? 1/8" would be no bueno.
You would have to get a paintball fill station, then a high pressure regulator to regulate the 3000 psi down to 150 PSI.
Give Glen Palmer a call. (916)923-9676
Tell him what you need, and he will custom make a regulator for you.
We use the same setup for our paintball tanks on our team. No, not like an air tank, an actual TANK.
http://pbjunkie.com/uploads/gfgjester/MPPPorkChop/Previews/MPPBC-PC-PREV-026.jpg
I’m wearing the clown mask.
I am not sure what size ports are normally on scuba tanks or scuba regulators but I planned to replace the tank fittings and regulator with a high-flow unit that can step down 3000 psi to 150 psi with a minimum 1/2" I.D.
This should do the trick nicely and shouldn’t be hard to do, but if for some reason the scuba tank fittings can’t be changed to a large enough I.D. then I would just use a paintball fill tank or other commercial gas cylinder with a similar or greater capacity.
Went to the local scuba shop today…
It is a 1/4 pipe fitting, so way smaller then 1/2". I’m sure you could replace it, but then they wouldn’t be able to fill it for $4. If you put a regulator on that 1/4 hose at 3000PSI, would you be able to drop it to 150psi AND step it up to 1/2" and still have the volume behind it?
Its funny they had a customer, the owner of a customs shop a few doors down, who uses their tanks for his air horns (K3LA it turns out)… I went to ask him how he did it but he was sort of an a**hole. The most I could get out of him was “Its good for about 100 honks before refilling” and “go buy a scuba tank and figure it out”. Guess thats what i’ll have to do!
How much air do these horns use? A GW valve is 70 CFM, right? Would the horns use less then that, or does it all get pushed through. IE a 80 CF scuba tank would last a little over 1 minute at full throttle? Maybe 1.5-2 minutes with the metered valve?
Does anything i’m saying make sense about a regulator though? Could I attach a regulator to that 1/4, step it up to 1/2" and still have 150psi running through?
If the regulator was only 1/4" then you would only get 150 psi at 1/4" output which would be ok for some horns but way too low for my 9-trumpet setup.
I should be able to change the fittings on the scuba tank to use 1/2" I.D. flow to the regulator and horns and still leave a standard port for the scuba shops to charge it like normal.
I don’t know how much air the horns use. They need to publish the CFM ratings but it would be more like a table of figures because the consumption rate would vary based on air line type / size, psi, regulator, temperature, ATM pressure, number of horns connected, etc.
The Excel file which I posted above will calculate how long a given scuba tank will last you based on your current standard tank setup and horn usage. In my case a scuba would last about 7-8 times longer than 1 full 7-gallon tank filled with compressors. Not 100 honks, more like 22 in my case, but still worth it for the reasons I stated above.
Interesting… Has anyone done this yet?
i havent done nitrogen but my first horn set was on co2
i think air better
lol
ok well i ran the nitrogen and i have already swapped back to dual 380C and a 8.5gal tank and you can tell a difference in the tone of the horn and the price. It cost me $15 a month to fill the nitrogen. And i could only have a short blast with my nathan and it still woukdnt ggive the nathan enough air to really honk.
I’ve got to say I use a 10 lb co2 bottle in my truck for airing up my tires and a set of mack air horns at 100 psi and my tank last me around a yr. And my horns are plenty loud enough so just my two cents
Welcome “bluebullit”. Have you run out of CO2 when you really needed it? How do your air lines and valves react in winter?
Get some airchimes and you’ll probably use a lot more CO2…LOL
Airchimes will EMPTY a bottle of CO2/nitrogen. Thats why Im back using compressors.
Only way to supply the demand of air to an Airchime is a tank with 1/2" ports and 1/2" airline. K3’s would suffer with a CO2/nitrogen bottle.
Thanks for the hello. I keep a mindful I on my tank so i dont run out and I can tell when its low cues the horns start to sound weak. In the winter I have never had a problem with the tank or lines. This well be the first winter for the new solinod . But I would take the tank out it the winter cause its just gets to cold sometimes in md and I just worry the bottle will freeze . But never any problems when I did leave it in . In the winter. and i looking to buy a set of. Horns from a frined when my check comes in for round 200 bucks and I have three horns to choose from
I use an 80 cubic ft nitrogen tank feeding into a 5 Gal air tank, then to the horns. All with 1/2 inch airline. Works ok even with the K3HA, although I’ll admit I’m not a heavy honker.