Tank Size

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tc_rain

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If a steel HP100 tank holds 10% more air then an AL 80 (when both are filled to 3000psi), is roughly the same size, and you can drop 5lbs on a weight belt, why is the AL 80 so popular? I am relatively new to diving so if some of my facts are wrong, please correct them so I may better understand.
 
The aluminium tanks are more forgiving when it comes to abuse from the average renter, less prone to rusting if badly starched, if drained and water inside and mainly the price!
 
HOW much air are you saying the HP100 holds at 3000psi? My calculations say it's holding about 87cuft at that pressure. In order to get the 100cuft, it has to be at 3442psi, which not all compressors can push.

It's also concievable that the extra ~$200 in price, is a factor as well. With AL80s fetching between $125 and $150 around me, and the HP100 getting around $330-$350.
 
PerroneFord:
HOW much air are you saying the HP100 holds at 3000psi? My calculations say it's holding about 87cuft at that pressure. In order to get the 100cuft, it has to be at 3442psi, which not all compressors can push.

It's also concievable that the extra ~$200 in price, is a factor as well. With AL80s fetching between $125 and $150 around me, and the HP100 getting around $330-$350.
At 3000 psi:

Al80 = 77.4cf
HP100 = 86cf.

Difference = 8.3cf, which is about a 10% increase, as the OP stated.

The reason AL80s are popular is because they're super cheap. You're looking at about $125 retail vs $300 retail.

Moreover, the AL80 has been around a long time. The E/X7-100 may be a better tank, but it's pricey.
 
jonnythan:
At 3000 psi:

Al80 = 77.4cf
HP100 = 86cf.

Difference = 8.3cf, which is about a 10% increase, as the OP stated.

Good thing I dropped out of engineering school... DOH! :eyebrow:
 
I just bought a new AL80 and found when shopping price was an issue for me. Many around here want nearly twice as much for a steel HP80 vs an Al80. I've rented Al80's all the time and while it adds 3lbs positive bouyancy near empty I don't find it too much an issue as I use the weight trim pockets in my BC anyways and that's where that extra weight goes...so no problem in my book.
 

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