Twin 30's

[in too deep]

i bought 2 sets of twin 30's in 1990, since then i seperated the cylinders for stage/deco bottles. i got out of diving about 10 years ago and sold off the tanks...
anyways, doing some online research to replace the tanks and get back into the sport for RECREATIONAL/SHALLOW diving, i'm looking for 30's or 40's with a diameter of no more than 5" to fit the manifold.
any suggestions?
thx

 

[Jimmer]

Luxfer 30's are the only thing that fits your description that I know of.

 

[Garrobo]

I suspect that any dive shop can order them for you.

 

[WD8CDH]

Make sure you get the Luxfer tanks, not Catalina. The Catalina 30s are 5.25" diameter and shorter. The Luxfer 30s are just under 5" diameter.

Is your manifold the one with the centered outlet or offset outlet?

 

[DA Aquamaster]

Any Luxfer 30 or 40 will work.

 

[El Orans]

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A ScubaBoard Staff Message...

Threads merged and moved to Tanks, Valves and Bands.

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[in too deep]

thanks for all the info, i looked up the specs from luxfer and it shows 5.25 for the 30 and 40, i looked at the catalina and the same, does anyone know if there is a misprint from luxfer, i'll email them anyways
manifold is offset

 

[Scuba-Stu]

i also think double steel 45's are particularly sweet

 

[NorthWoodsDiver]

if nothing else, dive rite sells a manifold and bands for ali40's . you should be ok if the new tanks are 5.25" and the crossbar on the manifolds should have plenty of adjustment. if your manifold is like the dive rite's you might be able to just get the new crossbar/isolator and be set.

I just threw a caliper on one of my 2008 luxfer 40's and it read 2.1825" the specs on the ali 30's at the dive rite express site claim 4.9". I cant say for sure but I bet if you call DRE they would be glad to measure (with a tape or ruler at least) for you. tanks run a bit different in each manufactured batch so seeing 20-60 thousands difference wouldn't alarm me but .25" is a significant amount for production products.

You might also call Mike at Dive Right In Scuba, he was selling Hymark tanks for like $120 +/- a week or so ago. those tanks are claimed to be almost identical to luxfers. maybe they will fit your needs if they are a bit smaller than luxfers.

The problem with the manifold spacing comes down to the bands really, maybe a different set of bands will be necessary. take some measurements of the landing area where the bolts go through, if the new bands are .25" smaller your in business.

the tanks are only going to be over your size limit by .125" each anyway so coming up with a way to drop a total extra width of .25" shouldn't be to hard. any welder could modify your existing bands.

 

[DA Aquamaster]

I have the same little black solid bar manifold and took a pair of Luxfer 30's off it several years ago. They are the same diameter as Luxfer 40's, so no need to dig out the micrometer.

For those who are not familiar with what the OP is taking about, the only potential issue is the greater lenght of the 40's as there are no bands per se, just a rubber piece that fits between the tanks and provides a rounded surface for the cam pack or STA. The tanks are then held in place on the BC or plate by a normal cam band. However, unless you really abuse them the extra lenght is not going to put that much more stress on the manifold.

Personally it makes more sense to me to have two 40's and 80 cu ft rather than two 30's and only 60 cu ft. The twin 40's will weigh 7.4 pounds more than the twin 30's but the twin 40's and manifold will be almost identical in weight to an AL80 and valve, so the benefits are 3 more cubic feet and a lower profile set of tanks that is slightly shorter and will trim better than an AL80.

The downside is that two 40's will probably cost close to twice as much as a single AL 80 and your VIP and hydro costs over time will be twice as much. If a shop charges you for filling doubles, rather than what they'd charge to fill an AL 80, they are just being greedy.