SCBA Tire filler help needed.

I have no idea about SCUBA, never looked into it. I went to my local volunteer FD(I know the chief), and he had a couple that were out of HST. So he gave me one, and they fill it with breathing air.

 

Upset? Not in the least. Confusion about someone getting in the weeds about certs and gauges for shop / tire air, beyond the fact that your two word or one liner posts never struck at a point? Yep!

 

The fire dept. fills out of hydro tanks? That's scary! And they give tanks away rather than rehydro them? That's awesome!

My local dive shop gets $12 for a hydro test. They are good for 5 years.

 

That is a great price. It looks like the current cost at my shop jumped to $50. It was $30 or $35 the last time.

It might be time to check the other local shops since my fill card is just about full also.

 

That's not including VIP or fill, so another $15 or so. Not sure SCBA tanks need VIP like scuba since they don't get wet?

Nitrox O2 cleaning is where they get you......

 

Yeah, $50 without a fill. Fills are $10 now. They used to be $7. Not a big deal, but a 10 fill card is now $90. A friend got a shoebox compressor, but has been slacking on the standard compressor. I keep telling him that I will split the purchase with him. It would be money saved.

The only other air bottles that I have experience with are for paintball. No VIPs there. It could be just SCUBA?

I do see a big jump for Nitrox fills, but nothing about cleaning. It is a great area around here to dive, but I never pulled the trigger. I keep thinking about it.

 

I just swapped TPMS's from a set of 17" 4runner wheels to a set of 16" Tacoma wheels. My air tank is a 72CF scuba tank. Inflating the tires to set the bead, letting the majority of the air escape while installing the schraeder valve, and then airing to 34 psi - I completed seven of the eight tires before the 72 cubic feet was exhausted. You will be able to air up your tires numerous times with 66CF. You never know for sure how many fills you will get because it varies with temperature.

If it was me and I didn't have a pressure gauge on the tank, when I thought I was getting near the end of the tank I would add a little air to each of the four tires in sequence in case you run out before you're done - that way you will have enough air in each tire to get you somewhere that has a compressor.

 

That is where @Shellshock 's DIY inflator is pretty cool. As shown in his thread, it can do two at once, and is easily expandable to four at once.

 

Hey everyone,
Thanks for the contributions. I still cant do the math, but my sister did this. Pick it apart, and let me know what you think.

 

The math looks reasonable, although I'm a bit lazy to verify the tire volume. 23 fills does seem like a lot for my 120cf 3,500psi tank. Relating that to 60cf 4,500psi has me wondering. In the end that is ideal gas law, so there will be losses. If you either assume half to 3/4 of that and / or check the amount remaining by weight or a gauge, you will develop some feel for what it is in real life.

 

Yeah, it was just a theoretical exercise. Once I get it, I'll run a couple tests. It was mostly for fun trying to figure it out on paper.

 

Yeah. Running the numbers can be interesting. It gets the head going.

I think you will be happy with the tank. A lot easier than a compressor and good for a lot of other stuff.

 

A pressure gauge is $25 on Amazon. Zero equations.

 

Do you have any Links or pics for the tanks and fittings lines your using . TIA

 

A little off topic .I dive with and 3000psi 80 cu ft scuba tank and the air weighs I believe 7 lbs or so when it's full. What gets my mind going is take a full scuba tank and toss it over the edge of a boat and it'll sink like a rock. At bottom say theres a heavy object you want to lift with underwater air lift bags so take the compressed air in the tank that's sunk on the bottem. Let the air out of the tank into the underwater lift bag and it will lift say a car very easily yet the air in the tank wont make it float yet releasing the compressed air from one scuba tank could probably lift a hundred full tanks sunk at the bottem. I understand its compressed but still amazing it works that way.

 

It is amazing. And, the fact that we can toss these things around and keep on using them. It does blow my mind.

When I was playing paintball, having more than enough air for an entire day was way better than waiting in line for air.

Good stuff.

 

Air is 0.08lb/ ft_3

https://huronscuba.com/equipment/scuba-cylinder-specifications/

 

The science of flotation is amazing to think about. I used to work on large vessels and have stood under several in dry dock. Trying to wrap my head around the idea that this massive chunk of steel floats in water all because it displaces more water weight than it weighs itself. Blows my mind on how it works. We live in a truly incredible world of wonder if you look around!

 

Then I bought the quick connect fittings and heavy duty 25’ hose at harbor freight tools