Why is this SPG so cheap?

[lizardland]

I do think that some of the markup on dive kit is absolutely dishonest and it is preying on people who don't know any better. A bit off-topic but I have been fleeced by dive shops (and dive manufacturers) far too many times so I'm a bit cynical.

With so much kit these days now just being rebadged Chinese stuff with added dive tax slapped on it then I have to agree. There's a Chinese light brand called SecurityIng who make really good, really reliable 3xC cell LED twist-on back-up lights that sell for around £35 on Aliexpress. I've seen about 4 or 5 different dive brands selling the exact same light with their logos slapped on it for £100-120. dSMB's are similar, tons of dive brands are selling the exact same buoys with 3-4x markup compared to what they go for on Aliexpress without the badge.

 

[lowwall]

Regarding the temperature, which I find odd but interesting, I wonder if it is reading the gas temperature or ambient temperature? It would be interesting to know the actual temperature of the gas that is behind the pressure rating.

It's measuring ambient temperature at the gauge. It's highly likely that big button in the middle of the thermometer covers a bit of coiled bimetallic strip.

Bimetallic strip - Wikipedia

en.m.wikipedia.org

Even if the bimetallic element was surrounded by gas from the tank, it would still read close to ambient. There's not enough gas movement between the tank and the SPG to meaningfully affect the reading.

 

[kdlv]

Aren't most SPGs made in Italy by "Termo Industria" Milano?
I have only one Chinese made tech SPG, which is honestly brilliant, but slightly thicker.
All the Lexan and standard size tech Bourdon SPGs come from Italy otherwise.

 

[OTF]

How's this for a cheap gauge: Pony Bottle Gauge (BLACK FACE)

This is my preferred SPG. Made in Italy by the company mentioned above, $46: HOG 1.5

The analog thermometer is cool. It would be especially nice for shallow recreational diving without a computer. Of the many many non-essential numbers that modern computers can display, temp is one of the very few that I actually like to check underwater sometimes.

 

[Failed captcha]

I bought one like this new and it works well. It came with a boot and hose through.

Thank you, having used it, your view has some value.

 

[Failed captcha]

I really cannot tell from the pictures, it looks to be a plastic case. I am sure it works fine and the thermometer probably goes up and down as the ambient gets warmer or cooler. Accurate, probably close enough.

Do yourself a favor and purchase a made in Italy B&G (brass and glass) spg, either a standard 2.5 inch or consider one of the 1.5 or 2 inches spgs if weight is a concern. Dive Gear Express or any of a number of other retailers or online stores should have them under different brands (Hog, Deep Six, DGX etc) at cheap enough prices for something that could last you many years and is much more rugged than a plastic unit.

This is where I'm leaning. I do like how legible the dial is though with this. My current SPG is B&G, made in 2002 in Germany and I don't see why it wouldn't last another 20 years. I do want to be ready if it fails and it is getting a bit rough and hard to read but I imagine plastic would be worse than glass in that regard. I wouldn't buy anything made in China, not for such a vital piece of equipment.

What's wrong with a plastic body though?

 

[Failed captcha]

Mostly likely it is so cheap because the seller bought a console - possibly on clearance - for the computer and the SPG was basically free. Or they bought a console for the express purpose of taking it apart and selling individually for a profit.

For example:

i330r console with this exact SPG for 299

i330r by itself for 399

Sure you might still need a wrist boot for the PC "by itself" in my example, but you get the idea. Also, Americans are going to be the primary buyers on ebay US and the vast majority of Americans don't want metric instruments so the demand is low

I'm American but have joined the rest of humanity in embrace of the metric system. That definitely explains the price. Do you know where it's made?

 

[Failed captcha]

My current and only SPG. I do have a wrist DC now, a Garmin Descent Mark 1.

 

[Failed captcha]

How's this for a cheap gauge: Pony Bottle Gauge (BLACK FACE)

This is my preferred SPG. Made in Italy by the company mentioned above, $46: HOG 1.5

The analog thermometer is cool. It would be especially nice for shallow recreational diving without a computer. Of the many many non-essential numbers that modern computers can display, temp is one of the very few that I actually like to check underwater sometimes.

I like the thermometer. I recently got a dive computer after refusing for years to use one and seeing the temperature has been nice which surprised me since I would have said before that I didn't need it since I could feel it.

 

[Failed captcha]

It's measuring ambient temperature at the gauge. It's highly likely that big button in the middle of the thermometer covers a bit of coiled bimetallic strip.

Bimetallic strip - Wikipedia

en.m.wikipedia.org

Even if the bimetallic element was surrounded by gas from the tank, it would still read close to ambient. There's not enough gas movement between the tank and the SPG to meaningfully affect the reading.

So that's a really simple mechanism and would be almost completely superficial at the face of the dial, in the unused portion. So it wouldn't require any change in the design of the SPG. Thank you, I haven't forgotten how helpful your expertise was in another thread a couple years ago.