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Bluewater Pneumatics - Pros and Limitations

popgun pete

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Jul 30, 2008
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Australia
A series of ring or doughnut type floats could be added to the barrel to counter its weight when loaded, that is what the red circled items are. The Hydra was supplied with both short and long barrels with spears to match in the "Hydra Sprint" version. With the gun mostly full of water except the rubber bladder in the rear they are very heavy guns.
 
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Gazz

Gazz

Well-Known Member
Jun 22, 2005
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Sydney Australia
I think in the world of bluewater and "high stakes" fishing you want your gear to be as reliable as possible. I think the simple version of modern pneumatic spearguns like the predathor which are tough (glass filed nylon), powerful and simple are the best way forward. When operating at crazy high pressures things tend to break, I have never had any failures that i can recall from my salvimar pneumatics, aside from the vacuum gaskets.

I am wondering at what point does terminal velocity occur? At what point will the gun be over powered and loose accuracy?
I remember reading the Asso 115s with the tovarich kit and 130cm 7mm spear was performing optimally at 24BAR (any more and things breaks and recoil or jump can affect the accuracy), I know I have used an Asso 115 in standard form and found their accuracy to be jeopardised at high pressure.

I can fit a 9mm spear on the salvimars but vacuum Sealing this sized spear becomes a issue, has anyone tried the 9mm spear? I am also wondering about recoil.

Pete my Predathor vuoto 130 (power reducer removed and with 1000pumps(maybe 20BAR?)) is a absolute weapon against kingfish, i have shot 3 in one shot before and the gun has been entirely reliable. This is why i think they have real blue water potential. i would be keen to get my hands on a 150cm version.

I am keen to do some more blue water hunting and be able to record a pneumo getting the job done.
 

popgun pete

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Jul 30, 2008
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Australia
You can convert any gun if you can source a longer inner barrel tube and tank tube, which is what Mares did to make their longer “Pippin” models of the "Sten" which went up to 150 cm. There were three different Pippin gun lengths, all greater than 100 cm, but they were not widely distributed and I remember some of them being sold off on eBay, brand new! They were relatively expensive, but prospective owners had to think about loading them and that affected the demand. The actual parts manufacturer brings in stock lengths of alloy tubing for both barrels and tanks and then cuts them off to the desired lengths for different models and has them machined and anodized. This machining and anodizing is probably done by a sub-contractor and the tubing itself will come from a metal extrusion plant making stock size tubes. Find the source of the alloy tubing and you can get someone to machine it to the required dimensions.

The alloy barrel tube for the Sten has been around since 1967 and there must have been tons of that tubing made, and most likely all Italian pneumatic guns use the same stuff for their 13 mm inner barrel models. Ditto for the 40 mm tank tubing. There may now be another supplier in China, but of the exact same alloy who knows?
 
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popgun pete

Well-Known Member
Jul 30, 2008
3,711
901
153
Australia
Just had a quick check of alloy tubing. https://www.ebay.co.uk/itm/ALUMINIU...60:m:m0VUPkSlVaEa28jw1I42T2g&var=493045007858

The problem is you need the correct alloy and the correct heat treatment that gives it its strength. When I tried buying materials to build a hydropneumatic gun I found tubing about the right sizes, but telling the sales guy what the application was he said if you use this stuff it will explode because a lot of aluminium extrusions are for architectural purposes such as handrail or decorative columns and are too weak for the job. So finding the correct tubing is vital. I ended up buying a gun rather than building one and that is how I met Sergey Kravchenko.
 
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tromic

Well-Known Member
Aug 13, 2007
1,626
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Croatia
Just had a quick check of alloy tubing. https://www.ebay.co.uk/itm/ALUMINIU...60:m:m0VUPkSlVaEa28jw1I42T2g&var=493045007858

The problem is you need the correct alloy and the correct heat treatment that gives it its strength. When I tried buying materials to build a hydropneumatic gun I found tubing about the right sizes, but telling the sales guy what the application was he said if you use this stuff it will explode because a lot of aluminium extrusions are for architectural purposes such as handrail or decorative columns and are too weak for the job. So finding the correct tubing is vital. I ended up buying a gun rather than building one and that is how I met Sergey Kravchenko.
Look at this site: https://pescasubapnea.forumfree.it/?t=77464535
It seems that with Salvimar piston might be some corrosion issues..?
Maybe salt water can past by the piston easier than with Mares piston..
 
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Vlanik

Well-Known Member
Jan 19, 2009
123
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Sothi
[QUOTE = "tromic, post: 992642, member: 13775"]
Посмотрите на этом сайте: https://pescasubapnea.forumfree.it/?t=77464535
Кажется, что с поршнем Salvimar могут быть некоторые проблемы с коррозией ..?
Возможно, соленая вода может пройти мимо поршня легче, чем с поршнем Mares.
[/ QUOTE]
Все поршневые ружья пьют воду...
 

popgun pete

Well-Known Member
Jul 30, 2008
3,711
901
153
Australia
Most likely a vacuum barrel gun has been leaking and letting water enter the inner barrel after the gun is cocked. During the shot the piston drives water along the inner barrel which squeezes past the temporarily blown open vacuum nozzle, but not fast enough and a hydrostatic pressure spike in the barrel blows the rubber seal on the piston rearwards in its seating groove allowing water to enter the gun across the pressure boundary. Saltwater inside the gun gobbles up the sear lever and any parts on the piston made of steel if left for long periods in the gun, especially if there is next to no oil in the gun.
 
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Gazz

Gazz

Well-Known Member
Jun 22, 2005
224
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Sydney Australia
Most likely a vacuum barrel gun has been leaking and letting water enter the inner barrel after the gun is cocked. During the shot the piston drives water along the inner barrel which squeezes past the temporarily blown open vacuum nozzle, but not fast enough and a hydrostatic pressure spike in the barrel blows the rubber seal on the piston rearwards in its seating groove allowing water to enter the gun across the pressure boundary. Saltwater inside the gun gobbles up the sear lever and any parts on the piston made of steel if left for long periods in the gun, especially if there is next to no oil in the gun.
Hi Pete, how has the performance of the Black sea been? Have you used it for
Just had a quick check of alloy tubing. https://www.ebay.co.uk/itm/ALUMINIU...60:m:m0VUPkSlVaEa28jw1I42T2g&var=493045007858

. So finding the correct tubing is vital. I ended up buying a gun rather than building one and that is how I met Sergey Kravchenko.
How has the Black sea speargun been? Have you used it for any Bluewater diving, do you know any performance figures?
 

popgun pete

Well-Known Member
Jul 30, 2008
3,711
901
153
Australia
The "Black Sea" hydropumping hydropneumatic is a powerful shooter, much like a souped-up pneumatic to aim and shoot, but until one is made to float after the shot it is not so useful in deep water as drop it and you may never see it again. Unless you can hand it off to someone while despatching your victim it becomes a liability, whereas my other powerful guns can just be cast aside and will head for the surface where they look after themselves. My thoughts are the real application for these guns is scuba spearfishing which of course is now prohibited in many places. In recent years my “Black Sea” gun has not fired a shot, too much steel and titanium to be a floater, the price for the gun holding its pressure without blowing to pieces.
 
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popgun pete

Well-Known Member
Jul 30, 2008
3,711
901
153
Australia
Salvimar, who used to be Salvis and FIgli, made metal gun components for other companies' pneumatic spearguns and they may be worth writing to and asking where they get their barrel tubes from. For sure it is a specialist metal extrusion plant in Italy and it will make a range of tubing products.

Alloy tubes sources, you want seamless precision bore high pressure tubes (not pipe, tube has tighter tolerances). https://www.simposiodeilambruschi.it/32151/honed-aluminum-tubing-retailer-iran/
 
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Diving Gecko

shooter & shooter
Jun 24, 2008
1,552
383
138
Shanghai
I remember Dima kept referring to italian barrels as “Duralumin. So, I looked it up and it’s an old trade name for 2000 series alu, perhaps 2024, which when tempered is quite hard so it could fit the bill. On the other hand it was mentioned that it doesn’t have much corrosion resistance so that doesn’t jive with our barrels.
Maybe it’s just good old 7075-T6 or could be some 5083 (I think that’s the common marine grade). But though I’ve tried for a long time to find out I am still no closer.
If Salvi don’t want to share, there must be someone in one of the Italian forums who knows. Perhaps not where the barrels are made but at least which alloy and temper it is.


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popgun pete

Well-Known Member
Jul 30, 2008
3,711
901
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Australia
Found this: Aluminium alloys commonly used in the marine industry include:
  • Aluminium-magnesium alloys - 5000 series, used primarily for rolled materials (sheet/plate). Most common are 5083 & 5383.
  • Aluminium-magnesium-silicon alloys - 6000 series, used primarily for extruded sections. Most common are 6082, 6061, 6005A & 6060.
Applications for 6061-T6 Aluminum

Aluminum in its purest form is too soft and reactive to be of structural use. However, its alloys, such as 6061-T6 alloy, make it structurally stronger and more useful in the manufacturing of durable products.

6061-T6 aluminum properties make it a material of choice for builders of boats and watercraft because it’s strong and lightweight. It is ideal for sailboat masts and for hulls of larger yachts that cannot be made from fiberglass. Small, flat-bottom canoes are almost entirely fabricated from 6061-T6, although the bare aluminum is often coated with protective epoxy to improve its resistance to corrosion.

Other common applications of 6061-T6 aluminum include bicycle frames, applications where heat transfer is required, such as heat exchangers, air coolers and heat-sinks, and applications where 6061-T6’s non-corrosive characteristics are important, such as water, air and hydraulic piping and tubing.

Aluminum 6061-T6 alloy conducts and dissipates heat well. Since it can be extruded, it can be formed into almost any imaginable shape. With our advanced processing and heat-treating equipment, Hydro has developed an improved machinability 6061 formulation used in the ECON-O-ROD®, ECON-O-HEX®, ACC-U-ROD®, ECON-O-PLATE®, ACC-U-BAR™ and ACC-U-PLATE® products, which conforms to industry specifications.
 
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Diving Gecko

shooter & shooter
Jun 24, 2008
1,552
383
138
Shanghai
The 6061 I’ve cut for Mirage pumping barrels is quite easy to cut but then again it’s probably untempered or a lower temper. With a good temper and anodizing perhaps it’s good enough for barrels.
Anodizing is a small rabbit hole on its own and you can actually get a deeper and harder “hard anodizing” done but iirc it tends to become dark grey which is what led me to assume our barrels are not hard anodized. But maybe you can hard anodize and still keep it from going dark. When you cut salvi’s barrels they definitely have a bit of a hard crust to them.

I have an underwater camera housing made from tempered 5083 and then hard anodized (and coated) and the surface on that is very, very hard and scratch resistant. Some day, I’ll have to do some mods on it which involves milling and drilling but that’s way in the future. But will be interesting to cut it.


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