Aluminum Tanks vs Steel Tanks
Whether you’re interested in renting or buying, it’s helpful to know the difference between a steel and aluminum tank. Both designs have their own advantages and disadvantages and will have an effect on your overall dive.
If you’re looking to do some research on the topic before you head to the dive shop, we’re here to answer all your questions about each tank.
Brief Overview of the Differences
Whatever tank you choose will likely have a capacity of 80 cubic feet of gas at 3000psi, according to most manufacturing standards. That means that the tank you buy may have a different weight and wall thickness but it will still hold the same amount of pressurized gas as any other of the same holding capacity. So here are the more significant differences between the two:
Aluminum Tanks. As a metal, aluminum is softer and more pliable than steel. Therefore, tanks made of aluminum have thicker walls to protect from dents and damage. This makes them a bit heavier on dry land, somewhere between and will affect buoyancy, as we’ll see later on.
Steel Tanks. Steel is a more rigid type of metal, giving it a higher resistance to damage than aluminum. Because of that, the walls can be thinner and the tank is lighter than others on the market. This difference in the material also makes these tanks smaller than the aluminum ones.
Buoyancy can be kind of a tricky concept to understand when it comes to your tank, but here’s a general idea. The air in your tank has weight that is, of course, lost as you consume it. So, the weight that you enter the water with is not the same as it will be at the end of your dive. Because of this, the weight and buoyancy of the tank can be pretty important. A tank that is positively buoyant floats to the surface while a tank with negative buoyancy sinks.
Steel tanks, even though they are lighter, have negative buoyancy, meaning that you won’t have to weight yourself as much as some other types of tanks. Aluminum, on the other hand, is more positively buoyant, and you’ll have to consider how much weight to add to prevent yourself from floating as you consume the air in your tank.
Aluminum is a much cheaper material than steel and will, therefore, cost less than the steel models. But, as we mentioned, aluminum is more susceptible to damage so you may find yourself repairing or replacing the tank sooner than you would with a steel tank.
In fact, when steel tanks are taken care of, they tend to last longer than aluminum tanks. One thing that could affect this, however, is the fact that steel tanks will rust if you’re not careful. Rust significantly lowers the lifespan of a tank and can be dangerous to you. You can avoid this by using only fill stations that are reputable and avoiding an empty tank at all times. If you do find rust in your tank, it’s going to have to be treated, adding another expense.
Type of Diving Experience
At this point, you may feel like steel is the superior, if more expensive, choice. This may be true, but there are a few other considerations as well.
Because steel is so expensive, it’s probably not cost-effective to buy one if you’re not going to put it to much use. After all, aluminum tanks are the popular standard for a reason: they’re reliable and cheaper.
That said, if you’re at a dive shop deciding between renting a steel or aluminum tank, then, by all means, go for the steel. You’ll be less likely to put dents in it and have to pay for the damages. Plus, you’ll be able to enjoy the benefits of a steel tank, like the smaller size and negative buoyancy.
Now that you’ve got some basic information about the difference between steel and aluminum tanks, it’s a good idea to familiarize yourself with the most popular brands, as of 2017. Here are a few of the more well-known favorites:
Sea Pearls 80 Aluminum Scuba Diving Air Tank
Here’s a great example of a high-quality aluminum Scuba Diving tank. It holds a standard amount of 80 Cubic Feet of air at 3000 psi. This cylinder also has a negative buoyancy when full.
It is in the same size range as all competitors and is Oxygen and Nitrox compatible up to 23.5%. This model weighs 31.5 pounds on dry land.
Catalina 80 Cubic Foot Aluminum Tank
This tank is pretty standard. In fact, it’s the most popular among dive operators and dive shops on the market.
It is Nitrox compatible up to 40%, has an empty weight of just 31.6 pounds, and is one of the most affordable, yet high-quality tanks you can get.
Faber 85 Cubic Foot Steel Tank
Like any good steel tank, this one is extremely durable because of its material composition. It’s made of Chromium-Molybdenum Steel.
It also has a corrosion-resistant finish which will help protect against rust. Its empty weight is 31.2 pounds and pricing is mid-of-line.
Faber 80 Cubic Foot Blue Steel Tank
This tank is pretty top of the line when it comes to steel scuba tanks. It is a high-pressure tank, and Nitrox compatible up to 40%.
Its dry land weight is only 28.6 pounds. Perhaps not surprisingly, because of its quality, it is also on the more expensive side.
The Right Choice For You
The choice between aluminum and steel tanks is one that many divers will have to make over the course of their careers. Here’s a final takeaway that may help you make a decision:
Pros: cheaper, more popular for beginners and the standard for recreational use.
Cons: heavier, with thicker construction to make up for its more malleable construction, usually slightly larger than steel, positive buoyancy
Pros: longer lifespan, more resistant to damage, lighter and with negative buoyancy.
Cons: expensive, susceptible to rust.
As always, talk to your local dive shop, ask your community, and learn as much as you can before making a final decision!