Aluminum vs Stainless Steel backplate

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Of course the best "general rule" is that there are very few good "general rules."

For this reason I have two BP/harness rigs. One steel and one aluminum. Paired with either a singles wing (+/- STA) or a doubles wing I've got just about any environment knocked:

- fresh water and steel doubles: AL plate
- fresh water and steel singles: steel plate
- fresh water and AL singles: never dive this way, but guessing a steel plate plus weighted STA plus 4-6lbs would do it

- salt water and steel doubles: steel plate
- salt water and steel singles: steel plate plust weighted STA
- salt water and AL singles: steel plate plus weighted STA plus 4-6lbs lead

One question, I understand these are "general rules" but to me it seems like the plate/tank relationship is totally independent of what thermal protection is worn. The reason I bring this up is that I plan on moving to BP/W, have an X7-100 steel tank, and would like to set up double HP100s. I dive in either a dry suit (w/ undergarments) or 6.5mm neoprene semi-dry. For the semi, I would think that a steel plate would be better, but if I double my 100 with another and dive dry, would I really need the -6lbs of the steel? Would it make more sence to go with an ali plate + v-weight (& possibly STA) with single steels and simply remove STA and v-weight when diving doubles?

I'm probably just going to get a steel plate because of the thermal protection I wear, the fact that I will (hopefully) be doing some off-shore wreck dives this year and because I found one for $96 on sale
 
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I am a sinker, I can easily sit at the bottom of the pool in my bathing suit (6'3", 180#). In the pool for practice, I wear a 3mm wet suit, AL80, and Turtle Fins (they are negative something or other all by themselves).

I use a SS BP and am very comfortable with it. I don't wear ANY weight and that's exactly how I like it. Trim is perfect. I can swim the rig up, so I am not worried about ditch-able weight. If I go South this Spring, I'll take the SS plate just as it is.

For fresh water diving with my dry suit, I dive a steel tank and that is fine with my usual undergarments. If I wear the heaviest, winter undergarments I can bolt on additional weight or even my 12# single tank adapter and again I won't need ditch-able weight.

So I can't speak for the "general" rule, but I'm happy with a SS BP. Most of the people I know who dive an AL BP use it with steel doubles, where the tanks are so heavy they are trying to keep all the other weight down.

To expand a little on what Reg said, I'm a sinker as well. I'm 6 feet tall and 185 pounds, and I can literally sit on the bottom of the pool in just swim trunks as well. I wanted to get a backplate, but I didn't want to buy more than one. I bought an aluminum one, and I've been pleased with it. When I dive fresh water with a 3mm suit I don't use any weight at all, the weight of an AL80 is enough to sink me, and I can control my breathing enough for a safety stop when it has 500 PSI left in it. I do have to use lead to sink when I am in the ocean (or quarries with a 7mm wetsuit), but I wanted one plate and one plate only, so I'm pretty happy with my aluminum one. I think you should examine your particular situation and make a decision based upon what you want.
 
I have both. Steel set up with a harness for “heavy diving” and the aluminum for light. For example, dry suit I need the weight and I also need the harness a little bigger. For warm diving or springs, the harness is smaller and aluminum plate. In the scheme of things, plates and harnesses are not that expensive and allows me to match the plate and wing for the dive I’m about to do. I would check out eBay or craigslist to get a used plate. They are virtually indestructible and essentially universal. (Shipping might be more with steel)
 
Wow, another morgue thread revived after 9 years!
Cool

Since we’re here, aluminum goes about neutral in the water, so a 2 lb al plate topside doesn’t equal 2 lbs off your belt underwater.
 
SS for everything IMO
 
Aluminum isn't neutral. It has a density of 2.7 g/ml. A 2 lb Al plate is about 1.24 lb negative is seawater (1.25 in fresh). Even a nice 6lb steel plate is only actually 5.25ish lb negative since it's displacing roughly the same 3/4lb of water.
 
Aluminum isn't neutral. It has a density of 2.7 g/ml. A 2 lb Al plate is about 1.24 lb negative is seawater (1.25 in fresh). Even a nice 6lb steel plate is only actually 5.25ish lb negative since it's displacing roughly the same 3/4lb of water.

He said "about neutral." I think of a pound and a quarter negative as being pretty neutral.

Yeah, zombie thread.
 
Durability is not an issue, both are more than tough enough.

A stainless plate on avereage is about 6 lbs negative while an AL plate is about 2 lbs negative. Be advised thorugh that there are soem SS plates available that are thicker and heavier - up to 12 lbs negative.

As indicated above an AL plate is lighter for travel and nice when you don't require much weight with your configuration. Consider this though - you can't make a heavy plate lighter but you can make a lighter one heavier. There are weighted single tank adapters, channel weights, V-weights and tail weights available that will all add weight to a plate and there are plates designed for add on weights. Those are all options if you want one plate and harness and need to go from a lighter to heavier configuration such as when switching from warm tropical diving to cold water diving.

Most plates come in a standard size but a few are available in shorter or taller sizes. Most brands of plates also differ in design features. Some are flatter than others (can make a difference in bolt lenght with double tanks), some have slots for cam bands and some have multiple holes to adjust the doubles or STA up or down on the plate.
What are the differences between stainless steel and aluminum backplates. I know aluminum backplates are lighter. However, besides the weight, what are the advantages and disadvantages for either one. How does each effect performance and boyancy? How does it differ for comfort? Whom is best suited for each type of backplate. For example, is a stainless steel backplate more suitable for lighter and the aliminum for heavier divers? Does the type metal effect the kind of diving (, technical, drift, deep, ice, etc) you do?

What about durability? Which one tends to last longer and is less likely to sustain damage from use or transportation?

For divers with a wing set up, what kind of backplate do you use, and why?
 
https://www.shearwater.com/products/swift/

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