Bad experience with LDS

[MXGratefulDiver]

A steel 100 (PST, Worthington, or XS Scuba) cylinder weighs roughly the same as an aluminum 80 (Luxfer or Catalina) ... somewhere between 32 and 35 lbs. But the steel cylinder is about 6 lbs more negative ... so you have to wear less weight. So the steel cylinder allows you to carry less weight ... and in exchange you get about 23% more gas to breathe.

... Bob (Grateful Diver)

 

[guruboy]

A steel 100 (PST, Worthington, or XS Scuba) cylinder weighs roughly the same as an aluminum 80 (Luxfer or Catalina) ... somewhere between 32 and 35 lbs. But the steel cylinder is about 6 lbs more negative ... so you have to wear less weight. So the steel cylinder allows you to carry less weight ... and in exchange you get about 23% more gas to breathe.

... Bob (Grateful Diver)

Is the difference in buoyancy a result of tank volume (size)?

---------- Post added July 23rd, 2013 at 08:11 AM ----------

It all has to do with the buoyancy characteristics of the tanks and the total weight of your entire rig. Lake Travis is 55' below full pool so many dives involve taking your gear for a nice hike. That is unless you have access to easy boat rides and shore dives where you park right at the waters edge.

The truth is I dive a variety of tanks depending on the dive that I'm doing that day. I see that you are in Houston. Do you dive locally or only on vacations? If vacations, it's probably all boat diving and only AL80's available anyways so it really won't matter. For local diving it probably won't matter that much either as SE houston is pretty flat and the water is pretty warm and shallow. You'd have to be doing something like Flower Garden trips in a 7mil to care. Otherwise it's just noise.

I see. Haven't made it out to Travis yet.

I just started diving but I plan to dive everywhere I can. Did a trip to the Clipper and hoping to do something more tropical later this year. Been hitting the local lakes in the meantime to get more time in the water.

I'll probably care about my tank later but I'm not at that point yet. A simple Al80 is good enough for me now.

 

[Jim Lapenta]

Not tank volume, tank composition. Steel is much denser than aluminim. Therefore it is more negative.

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[guruboy]

Not tank volume, tank composition. Steel is much denser than aluminim. Therefore it is more negative.

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If the size and weight are about the same, do steel tanks have thinner walls?

 

[HIGHwing]

If I were the LDS owner, I would have credited your rental fee toward the purchase of gear in the next 30-days.

 

[nimoh]

If I were the LDS owner, I would have credited your rental fee toward the purchase of gear in the next 30-days.

I agree, offer something up, especially when you have new divers that don't have their own gear yet. They will be buying their own gear soon, and the best way to get them to buy their gear at your shop is to keep them happy. The cost of a tank rental in insignificant when compared to buying gear.

However, I will add that I don't think the store did anything wrong, it just wasn't good business. In other words, I don't see anything that would indicate that they owe the OP anything, but in the same respect, the OP doesn't owe the LDS anything and may choose to buy gear elsewhere.

 

[Croomrider]

If the size and weight are about the same, do steel tanks have thinner walls?

Yes, they do. Also, steel HP 100's are physically shorter than Al-80's. The higher pressure and the thinner walls still allow them to hold more gas volume!

Mike

 

[chrpai]

If the size and weight are about the same, do steel tanks have thinner walls?

Compare an AL80 (actually 77.4cf ) and a PST HP80 (80cf). The AL80 is 31.38lbs and 4.4lbs+ when empty. The HP80 is 28.6lbs and -3.3lbs when empty.

That means you can take 7.7lbs off your belt (assuming you have that much there in the first place) and take 2.68lbs off your back.

How does this work? Yes, steel is denser but it's also stronger. Because it's stronger the service pressure can be higher (3500psi instead of 3000 psi ). This means the internal volume of the tank can be smaller and therefore the tank can be smaller and displace less water.


So the question is, for your local diving, do you have 8lbs on your belt in the first place?

 

[MXGratefulDiver]

Of the 30 or so cylinders in my inventory I only own two AL80's (aka, "oversized beer cans"). I only use them as pool tanks, or occasionally as stage bottles.

Most of my diving is shore diving. Most folks I know who shore dive regularly around here prefer steel cylinders, for the reasons already provided.

... Bob (Grateful Diver)

 

[chrpai]

Of the 30 or so cylinders in my inventory I only own two AL80's (aka, "oversized beer cans"). I only use them as pool tanks, or occasionally as stage bottles.

Most of my diving is shore diving. Most folks I know who shore dive regularly around here prefer steel cylinders, for the reasons already provided.

There's a big difference between shore diving in Lake Travis and shore diving in Seattle. Your warmest temp is our coldest temp and we are fresh water while you are salt water.

The weighting needed for salt water dry suit dive and a fresh water 3mil dive are entirely different.