Salvimar vacuum barrel kit

[tromic]

Agree! Vacuum cuffs in separate sizes would be better solution, also different muzzle tip(s) for "free shaft".

 

[Jegwan]

Yes; dedicated vacuum cuffs will be the most optimal. A dedicated muzzle tip for free shaft is also a good idea. It is very easy to unscrew the muzzle tip - so both the seal and muzzle tip is easy to replace and it can be done with the gun pressurized and without any tools.

The Super Sten arrived yesterday. It's muzzle is 73mm long so the gun is a little shorter with the Salvimar Vuoto kit. I measured the difference in distance to the shock absorber in the two muzzles. The piston travel distance is 13mm shorter with the Vuoto muzzle. So I now have a dry Super Sten 99

The special 8mm shock absorber has not arrived yet.

The weather here is stormy and cold. Less than zero degrees Celsius during night and a little above during the day. So the test will have to wait for either a indoor pool test at the local swimming baths or next season.

Jégwan

 

[Jegwan]

... No wonder you need to load the "Salvimar" vacuum muzzle gun wet, .....

Wet and under water are not the same in my opinion. All types of kits need to be wet when loaded if you care for the seals or O-rings.
The small area around the spear tail between the cuff and the shock absorber will be filled with water if the gun is loaded under water (see photo of the cut through muzzle). Could it be that this water helps the process when the spear tail needs to pass trough the cuff?

Jegwan

 

[popgun pete]

They rely on that water to lubricate the "dry" inner barrel and seals, it was discussed in the "Tomba" thread and in the "Vacuum Barrel aka Dry Barrel" thread. If you subtract the volume of the spear tail and shaft portion inside the muzzle before actually pushing on the shaft then the remaining volume represents the water accommodation space inside the muzzle and inner barrel. That same volume is reached prior to the shaft tail detaching from the piston as the latter stops during the shot and the water reforms into a solid mass from the vapour and droplet state that it was in during the "vacuum" conditions with the gun cocked to shoot.

 

[Jegwan]

Yes. My thought was that the volume reached just prior to the shaft tail detaching from the piston, would be a tiny bit smaller due - the force from the piston making the anvil and piston move that little bit further, compressing the O-rings on the anvil - making the excessive (and incompressible) water open, lubricate and leave through the cuff..

The use of O-rings as shock absorber then makes sense - as rubber also is incompressible.

Jégwan

 

[popgun pete]

The question is how much extra water volume can be obtained as at initial spear insertion the "O" rings in the damper are already squeezed up by the chamber pressure acting on the piston which is leaning hard on the anvil, so any pumping action from the shock absorber will come out of how much more they can compress with respect to the intervening gaps between the "O" rings becoming even smaller. And does the volume change as the rubber ring sections flatten because they also expand in their height, so their volume does not change? Maybe water shifts around, but is not actually pumped.

Movement of the piston seal closer in to the vacuum cuff will pump some water, so the damping sleeve itself does not have to possess any gaps in it, such as being made up of "O" rings.
View attachment 37398

 

[Jegwan]

Many thanks for your reply, drawings and time Pete

Yes, the O-rings will change form, but not volume.

The system with the O-rings instead of using a solid rubber tube, leave a little more room for the rubber to flatten (the small "triangle" areas between the O-rings) by the pressure in the gun before it is loaded and maybe to flatten a little further at piston impact - making the piston and anvil travel a bit closer to the cuff - Just like shown on your drawings.

I might over-interpret the meaning of the O-ring design.. I don't know..

Anyway; water will leave through the cuff at piston impact if the piston travels a bit further than its "neutral" position in the muzzle before the gun is loaded.

Jégwan

 

[tromic]

Here is a link that might be interesting:

http://forums.deeperblue.com/threads/shock-absorber.95313/#post-886013

 

[Jegwan]

Here is a link that might be interesting:

http://forums.deeperblue.com/threads/shock-absorber.95313/#post-886013

Wow.. Very relevant thread and test results - and you have tested a shock absorber using O-rings! Interesting results.
Many thanks.
Jégwan

 

[Jegwan]

Oh, if you email him again, then please ask him for the minimum size of spear. Do they go down to 6.5? 6.75...?

Salvimar has informed me that the minimum size of spear that can be used with the kit is 6,5mm.
Jégwan

 

[tromic]

Salvimar has informed me that the minimum size of spear that can be used with the kit is 6,5mm.
Jégwan

Very nice!
One cuff size for all shafts from 6.5 to 8 mm, with or without slider.
It is possible, but for how many shots for each shaft size? I hope will soon have some answers.

 

[Diving Gecko]

Salvimar has informed me that the minimum size of spear that can be used with the kit is 6,5mm.
Jégwan

Thanks for checking. Indeed very interesting.

 

[Jegwan]

The special shock absorber for 8mm spear arrived today. The anvil is black and the hole through the anvil is 9,2mm. Everything else is same-same.



Jégwan

 

[popgun pete]

A spring stainless steel spear is another "kit" requirement if your existing spear shaft is not stainless steel. Spring stainless steel for the longer spears as short ones, which are harder to bend, are OK in standard stainless steel. The surface of the spear shaft has to remain very smooth, although the vacuum muzzle seals may be tolerant of very fine scratches that produce that dulled appearance as in going from a "gloss" to a "matt" finish with fine particle scratches, such as when shooting down into sand after punching through your prey. Spring stainless steel may be more resistant to such scratches, but I have never checked it out, as the precipitation hardening may produce a more scratch resistant surface. Plated spears lose their smooth surface over time as rust specks and pits develop unless you wipe your spears down with an oily rag after the post-dive clean up or give them a shot of WD40, which is what I use on all my spears.

 

[Markusfugit]

Does anyone know if the Salvimar muzzle would fit my Airbalette?

 

[Jegwan]

Does anyone know if the Salvimar muzzle would fit my Airbalette?

It does not.

The muzzle design on the Airbalet is quite different than on the classic oleo design from Salvimar, Mares and Cressi.
The muzzle enters and seals towards the front of the reduced diameter outer barrel. The same is valid for the new Mares Evo HF.

I know LG and STC makes kits for Airbalette - and I'm sure that you can have a Tomba kit made also.
I have a Tomba kit on some of my Oleos and I'm very pleased with it. There's a lot of different models to chose from. You can PM "zmajmr" on this forum about the Tomba kits.

Jégwan

 

[Markusfugit]

It does not.

The muzzle design on the Airbalet is quite different than on the classic oleo design from Salvimar, Mares and Cressi.
The muzzle enters and seals towards the front of the reduced diameter outer barrel. The same is valid for the new Mares Evo HF.

I know LG and STC makes kits for Airbalette - and I'm sure that you can have a Tomba kit made also.
I have a Tomba kit on some of my Oleos and I'm very pleased with it. There's a lot of different models to chose from. You can PM "zmajmr" on this forum about the Tomba kits.

Jégwan

Much obliged. You just saved me fifty bucks and I'll probably have to spend a whole lot more! I appreciate the info.

 

[istriker22]

Would the Salvimar muzzle fit the mares Cyrano guns? I've seen them for sale but not much info on it. I assume it does but is it worth it?


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[Jegwan]

Would the Salvimar muzzle fit the mares Cyrano guns? I've seen them for sale but not much info on it. I assume it does but is it worth it?


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Yes. The 11mm kit will fit the old model Cyrano with the long nose cone, orange safety switch and the black/blue handle.

Yes, I believe its worth it.

Jégwan

 

[istriker22]

Yes. The 11mm kit will fit the old model Cyrano with the long nose cone, orange safety switch and the black/blue handle.

Yes, I believe its worth it.

Jégwan

Thank you! Let's see if the Scubastore has them in stock.