airguns: Sporasub One Air 2012!!!

[tromic]

David, can you see, is there some tapered seat for the O-ring? How long is it, approximately... 5, 6 mm?

 

[Diving Gecko]

David, can you see, is there some tapered seat for the O-ring? How long is it, approximately... 5, 6 mm?

I have looked, but can't tell. To the naked eye it doesn't look tapered, but if the taper is really small, maybe I would be able to tell from just looking anyways. I don't have calipers here and the ones I have at home couldn't measure it anyways since it is in a deep recess.
Seatec says to open the muzzle one full turn before firing and since the thread is really coarse it means the muzzle opens quite a bit, maybe 5-6mm. Definitely enough to let the whole ring escape from its seat and into the bigger area in front of it.

D.

 

[Broseidon]

That make sence.
Most of my shooting is on
Scuba. I'm going to do some
Test in the pool when it warms up.
I guess I can set a target and see witch
Way has more power loading above water or
Below.

Why do you always.
Write your sentences
In this really odd
And slightly annoying way.
It really is
Rather strange
Maybe it's a symptom of spearing on scuba?
That would explain
a lot.

 

[tromic]

I have looked, but can't tell. To the naked eye it doesn't look tapered, but if the taper is really small, maybe I would be able to tell from just looking anyways. I don't have calipers here and the ones I have at home couldn't measure it anyways since it is in a deep recess.
Seatec says to open the muzzle one full turn before firing and since the thread is really coarse it means the muzzle opens quite a bit, maybe 5-6mm. Definitely enough to let the whole ring escape from its seat and into the bigger area in front of it.

D.

That cone, if there is a cone, could be about 8 deg. In that case you might notice it. But it is possible there is no cone at all. In that case loosening the nut would not have effect except if the nut is compressing the O-ring.

 

[Diving Gecko]

Why do you always.
Write your sentences
In this really odd
And slightly annoying way.
It really is
Rather strange
Maybe it's a symptom of spearing on scuba?
That would explain
a lot.

With the risk of insulting our Haiku inspired (scuba) spearo I have to say, this is funny as hell, haha. I have being posting for a while now back and forth with bmwgsboy and have gotten used to it, perhaps even to the point where I might miss it when narcosis wears out

Peace to ya both,
D.

 

[Diving Gecko]

That cone, if there is a cone, could be about 8 deg. In that case you might notice it. But it is possible there is no cone at all. In that case loosening the nut would not have effect except if the nut is compressing the O-ring.

I am pretty sure that the nut is indeed compressing the o-ring. The o-ring is oversized on the internal dimensions (6.75mm spear). It is also oversized in regards to the recess it sits in, so it compresses a bit from just being in the recess. If the o-ring is out of the muzzle (imagine a spare o-ring) and sits on the spear it wont sit tight, there's a gap. That gap is closed, but not firmly, when the o-ring sits in the muzzle and spears is inserted with muzzle not screwed in tight. But when the muzzle is screwed tight the o-ring puts more force on the spear leading me to believe there is a fair bit of compression going on.

At least that's how I remember it. My gun is with a friend now and I only have the first muzzle which was sent to me by mistake (wrong thread size for a Seac).

D.

 

[tromic]

I am pretty sure that the nut is indeed compressing the o-ring. The o-ring is oversized on the internal dimensions (6.75mm spear). It is also oversized in regards to the recess it sits in, so it compresses a bit from just being in the recess. If the o-ring is out of the muzzle (imagine a spare o-ring) and sits on the spear it wont sit tight, there's a gap. That gap is closed, but not firmly, when the o-ring sits in the muzzle and spears is inserted with muzzle not screwed in tight. But when the muzzle is screwed tight the o-ring puts more force on the spear leading me to believe there is a fair bit of compression going on.

At least that's how I remember it. My gun is with a friend now and I only have the fist muzzle which was sent to me by mistake (wrong thread size for a Seac).

D.

O-ring should not be compressed axially between the nut and the opposite surface of muzzle wall, just radially when the shaft is inserted.

 

[Diving Gecko]

O-ring should not be compressed axially between the nut and the opposite surface of muzzle wall, just radially when the shaft is inserted.

Well, I could be wrong. But I think I remember that with spear inserted and muzzle loose, the friction is less than with spear inserted and muzzle tight. So, I guess (if that observation is correct) that would mean that the nut does compress the o-ring axially (leading it try to expand even more radially and inserting more force on the spear).

I might be able to do one test - If I have time tomorrow I'll take the spare muzzle and play around with the 7mm spear from the One Air. (The Hunter 90 and its 6.75mm spear is with a friend on a yacht cruising to Burma as we speak).

D.

 

[bmwgsboy]

Why do you always.
Write your sentences
In this really odd
And slightly annoying way.
It really is
Rather strange
Maybe it's a symptom of spearing on scuba?
That would explain
a lot.

Lol!!! Most of the time im diving.
And I'm not afraid to use a air gun.
Are you getting another air???

 

[Broseidon]

Lol!!! Most of the time im diving.
And I'm not afraid to use a air gun.
Are you getting another air???

I would rather.
Chew off my own arm
than ever use an
air gun rofl

 

[bmwgsboy]

I would rather.
Chew off my own arm
than ever use an
air gun rofl

Your are right about,some sort of safety device.
I'm looking at the bottom part of the Giga press,
That would be good just to hold the spear in place
While hand loading,but for my 90 at 27 bar, don't need
It. Will look into it,if a get a bigger one air 120. It's to bad
You lost interest in it(got scared)it looked like you we're very
Happy getting it.

 

[popgun pete]

Pete, where did you find this information, that there is a tapered seat for the O-ring? I missed that information. Some time ago, in a post I supposed there was a taper for O-ring in Evo-Air, but actually I do not know if it is ture. The early version of Evo-Air had not tapered seat. But if the new version has it, your proposal might be a solution for easier loading. The problem will be to determin the optimal depth for O-ring for 6.75 and 7 mm shaft. This is not an easy task as it seems. You can not rely on "feeling". Only reliable way is applying measurement and O-ring calculation.

I only figured it was a taper as it would be better than crushing the "O" ring. I have seen "O" rings mounted in tapered seats before. It was either that or a stepped change in seat, but I thought that unlikely as the "O" ring might catch on an angle going into the smaller seat diameter.

If I was spending 100 Euro (now reduced to 75 Euro) on one of these muzzles then I would expect a tapered seat on such a device. By the way if the seat was tapered then the "O" ring would not stay in place, but would pop out with the device fully opened up. There is what look like a metal rod in the plastic carry case and I thought that it would be used to initially insert the "O" ring in the muzzle followed by tightening the nose-piece up to get the "O" ring into position in the tapered seat and then pull the rod out. The rod would provide the alignment needed to get the "O" ring sitting square in its seat for subsequent operations (i.e. not tilted). The rod seems to have a step on it, but I am only going by the small web-site photo.

 

[popgun pete]

Your are right about,some sort of safety device.
I'm looking at the bottom part of the Giga press,
That would be good just to hold the spear in place
While hand loading,but for my 90 at 27 bar, don't need
It. Will look into it,if a get a bigger one air 120. It's to bad
You lost interest in it(got scared)it looked like you we're very
Happy getting it.

If the "Giga-Press" marks the spear by biting into it then that will not be good for the life of the muzzle vacuum seal!

 

[tromic]

I only figured it was a taper as it would be better than crushing the "O" ring. I have seen "O" rings mounted in tapered seats before. It was either that or a stepped change in seat, but I thought that unlikely as the "O" ring might catch on an angle going into the smaller seat diameter.

Yes, I agree with you, but it is likely there is not a taper. David could not see any taper in his kit. I asked the designer few times but he had not answered to me. I suppose he wished that be a secret? What a stupid secret! I had similar situation when was asking for O-ring size for Tovarich to help an Australian guy. At last Sub Fireman gave me the answer, and no one from Spanish forum. With the thickest shaft O-ring is much over compressed so loading effort must be unnecessarily high. And shooting speed could not be noticeable higher than with any other kit. On other hand it sounds nice to have one kit for a range of shaft diameters, but is it worth? I would not make such design.

 

[popgun pete]

Yes, I agree with you, but it is likely there is not a taper. David could not see any taper in his kit. I asked the designer few times but he had not answered to me. I suppose he wished that be a secret? What a stupid secret! I had similar situation when was asking for O-ring size for Tovarich to help an Australian guy. At last Sub Fireman gave me the answer, and no one from Spanish forum. With the thickest shaft O-ring is much over compressed so loading effort must be unnecessarily high. And shooting speed could not be noticeable higher than with any other kit. On other hand it sounds nice to have one kit for a range of shaft diameters, but is it worth? I would not make such design.

I have a separate gun for each shaft diameter, so as far as I am concerned one dedicated size would be sufficient. Multi-size devices usually have problems, unless you can change an insert without depressurizing the gun.

 

[Diving Gecko]

Hi Pete and Tomi,
The small rod in the box is actually a screw-on tail end for a spear. But I am not sure why it is there? Maybe for 7mm normal pneumo spears, as they have a small step on the tail end to hold the washer for the slider, right? With this flush end one, one could use the original spear if it was 7mm.

I'll try to look at the insides of the Evo-Air kit again today, but as said, I could not identify a pronounced taper, but there is a step.

I was actually beginning to see one benefit to the Evo-Air when loaded per Tomi's instructions. As I see it, keeping the seal open when inserting the spear is a good way to make sure there is only what Pete called the accommodated amount of water in the muzzle. It should minimize the risk of water being pushed behind the piston.
But of course, the product is not perfect as per the earlier posts outlining 2-3 ways of making an improvement to reduce the friction on loading.

And this is a bit vain, but if a manufacturer one day wants to spend a few more bucks on a kit, they could make a better anodizing of these kits. Both the Evo-Air's and the One-Air's anodizing is very thin. They are def not hard anodized and I just hope the aluminum used is a good marine grade one.
I have used some very nice underwater housings for DSLRs and the hard anodizing on one of them is really, really hard. It has stood up surprisingly well with a lot of tough use where the Evo-Air's anodizing is rubbing off from light use - even the knurling nut from just turning it.

D.

 

[Diving Gecko]

Just played around a bit with a 7mm spear and the left over Evo-Air kit that I have. But I have not been able to replicate what I thought I observed in the water.
I could not sense that the friction was noticeably more when inserting the spear into the loosened muzzle as opposed to a fully tightened one.
I did notice that the O-ring must be very, very close to 7mm I.D, perhaps it is 7mm exactly.

So, I am sorry about this but either my observations in the water were wrong or this muzzle behaves differently than the setup on my gun.

David

 

[tromic]

Just played around a bit with a 7mm spear and the left over Evo-Air kit that I have. But I have not been able to replicate what I thought I observed in the water.
I could not sense that the friction was noticeably more when inserting the spear into the loosened muzzle as opposed to a fully tightened one.
I did notice that the O-ring must be very, very close to 7mm I.D, perhaps it is 7mm exactly.

So, I am sorry about this but either my observations in the water were wrong or this muzzle behaves differently than the setup on my gun.

David

You should check that with another muzzle too. O-ring is 7 x 3 mm.

 

[popgun pete]

Hi Pete and Tomi,
The small rod in the box is actually a screw-on tail end for a spear. But I am not sure why it is there? Maybe for 7mm normal pneumo spears, as they have a small step on the tail end to hold the washer for the slider, right? With this flush end one, one could use the original spear if it was 7mm.

I'll try to look at the insides of the Evo-Air kit again today, but as said, I could not identify a pronounced taper, but there is a step.

I was actually beginning to see one benefit to the Evo-Air when loaded per Tomi's instructions. As I see it, keeping the seal open when inserting the spear is a good way to make sure there is only what Pete called the accommodated amount of water in the muzzle. It should minimize the risk of water being pushed behind the piston.
But of course, the product is not perfect as per the earlier posts outlining 2-3 ways of making an improvement to reduce the friction on loading.

And this is a bit vain, but if a manufacturer one day wants to spend a few more bucks on a kit, they could make a better anodizing of these kits. Both the Evo-Air's and the One-Air's anodizing is very thin. They are def not hard anodized and I just hope the aluminum used is a good marine grade one.
I have used some very nice underwater housings for DSLRs and the hard anodizing on one of them is really, really hard. It has stood up surprisingly well with a lot of tough use where the Evo-Air's anodizing is rubbing off from light use - even the knurling nut from just turning it.

D.

If it is a spear tail to convert the standard shaft by replacing the existing tail with the stop diameter then it must be of a particular OD, in which case the kit must be for a particular shaft size or you would have more than one tail supplied, i.e. the muzzle kit could then accommodate a number of shaft diameters by switching tails on the respective shafts. The cut back rear section on the supplied tail of a smaller diameter may be there to defeat hydraulic lock as the spear tail will reach the piston before the muzzle seal takes up, in which case there will be no excess water, or very little.

I am sure the standard of anodizing is not what it was, my older guns have maintained their coatings while that on later muzzles is very easily removed by rubbing and impacts. I made note of this on my thread on a Sporasub "Stealth", the anodizing came away just by the act of removing the muzzle by passing a rod through the muzzle relief ports, the twisting force from the rod causing chipping of colour around the ports. Probably a cost saving measure to reduce the standard of coatings.

 

[tromic]

Hi Pete and Tomi,
The small rod in the box is actually a screw-on tail end for a spear. But I am not sure why it is there? Maybe for 7mm normal pneumo spears, as they have a small step on the tail end to hold the washer for the slider, right? With this flush end one, one could use the original spear if it was 7mm.

I'll try to look at the insides of the Evo-Air kit again today, but as said, I could not identify a pronounced taper, but there is a step.

I was actually beginning to see one benefit to the Evo-Air when loaded per Tomi's instructions. As I see it, keeping the seal open when inserting the spear is a good way to make sure there is only what Pete called the accommodated amount of water in the muzzle. It should minimize the risk of water being pushed behind the piston.
But of course, the product is not perfect as per the earlier posts outlining 2-3 ways of making an improvement to reduce the friction on loading.

And this is a bit vain, but if a manufacturer one day wants to spend a few more bucks on a kit, they could make a better anodizing of these kits. Both the Evo-Air's and the One-Air's anodizing is very thin. They are def not hard anodized and I just hope the aluminum used is a good marine grade one.
I have used some very nice underwater housings for DSLRs and the hard anodizing on one of them is really, really hard. It has stood up surprisingly well with a lot of tough use where the Evo-Air's anodizing is rubbing off from light use - even the knurling nut from just turning it.

D.

That screw on tail end is for usage with slider on the shaft if you talk about x-power. That might be 8 mm OD what is common for 7 mm shaft. If that tail end goes through the hole in adapter (in front of the sealing) than hole in delrin insert is probably 8,5 mm. If you use same delrin insert for the free shaft (7 mm) there is about 1.5 mm gap around shaft. That all means x-power is safe to load under water. Water has a lot of free space to exit from muzzle during loading and after shooting. On other hand too big gap is not very good because during the loading of the gun, shaft will not be centered well and flooding may happen. Especially if using thinner shaft than 7 mm. Solution is to use delrin insert specific to each shaft OD. I hope you understood what I was trying to explain!
On TombaF gap around the shaft is 0.1-0.2 mm so the shaft should be loaded above water. Flooding could not happen unless the O-ring is broken.