Precise Inner Diameter of a Seac Asso/Hunter Outer Barrel?

[Diving Gecko]

Yup, subject line says it all.
I was wondering if I was so lucky that one of you have an outer barrel lying around and nice set of calipers...

Though my gun is in another country I am playing with the thought of sourcing some carbon fiber tube and swap it for the alu barrel.

After my dry barrel mod, the gun is a tad too heavy in the water and I wouldn't mind the bling either;-)

Yup, I know there are risks involved and no one wants CF fibers flying all over, but I will drop test it and try to do it all as safely as possible before I expose others to the gun.

I suspect the original barrel is 38x40mm but would like to know the exact dimensions. If it happens to be 37.8mm ID, that's important.
(I have a quote for custom mandrels, so an off-size like this might still be OK).

I am thinking I'll go to 41mm OD on the CF tube. It would still be lighter than the original barrel.

Anyways, let me know if you can help out.

 

[Jegwan]

I'm sorry that I can't answer your question as I don't own an Asso - but what an interesting project. Looking forward to hear more.

I suppose you have considered a lighter spear or adding some floating material around the outer barrel, but have decided to go with this idea instead...

Have you found a CF tube physical spec. or have your supplier of the CF tube given you indications of the maximum working pressure for different thickness's of CF tubes?

I have seen CF tube break on bicycles if something hard and heavy (a tool or similar) is dropped upon it. Tape or folio could make it safer - but I guess it looses the bling..


Jégwan

 

[Diving Gecko]

Jegwan, we meet again!

Yeah, I have considered scenarios of eg. the gun being dropped onto a hard edge on a boat or on a rock on land.

I really don't want to add a float and the spear is not that heavy. I'd say probably less heavy than the original one.

I have seen a spearo on pescasub mill the Evo Air muzzle down a bit, that could certainly be an option as well as it does seem a bit over-built.

Also, if you search youtube for "ibba" then you'll see some amazing deep diving with a heavily modded oleo - eg. with a carbon barrel. Even without looking at his awesome gun, his videos are very inspiring and to a point, very Italian;-)

Also, on the latter ones, he has an optic fiber sight and though it is surely/mostly bling, I want that as well! Haha. And I even had the idea before I saw his gun with it. (Not that it matters, I would have stolen it anyways;-))
But that's just because some Thai friends dragged this pacifist little Dane out to a shooting range once and one of the handguns had fiber optic sights. Seemed like a fun idea for a speargun.

I am inquiring right now about stock sizes for CF tube here in China. I have found 38x42mm which will be heavier than alu.
I have also found 38x40mm but I am not sure I'd trust that it would be strong enough.

The real issue I have is the quality of the fibers, the epoxy, the lay-up, curing and ratio of fiber/epoxy. All these aspects have a huge impact on the final strength of the tube.
I could possibly go to the factory if it is nearby but I would still only have a say in the lay-up. Eg. I am thinking that the bulk should be 45 degrees of uni-directional fibers.

I have been quoted a nice, affordable price for a mandrel (the tool needed for the lay-up/winding) in a custom size, but it doesn't really make sense until I am sure of the above issues.

The problem here of course is that sometimes they use CF on the inner and outer most layers and then glass in the middle...

I might not make it in time for the upcoming trip, but then it would be a mod for later.

The gun certainly is a bit too nose heavy for long days in the water.

 

[Jegwan]

Yes we do

Wow. Impressive videos from Ibba. The CF barrel sure looks great. I love the look of the gun with the CF custom handle.

My buddy is also a bow and arrow hunter. He uses an optic fiber sight on his bow and he also want to try it on spearguns.

Thanks a lot for your inspiring post. I'll have a look of what's available in CF tubes here in Denmark.

Jégwan

 

[mighty kc]

Check this out; Pneumatic Speargun Inside Barrel - Spearfishing World I wonder if the 135 Asso barrel would fit the sten ?

 

[Diving Gecko]

Yes we do

Wow. Impressive videos from Ibba. The CF barrel sure looks great. I love the look of the gun with the CF custom handle.

My buddy is also a bow and arrow hunter. He uses an optic fiber sight on his bow and he also want to try it on spearguns.

Thanks a lot for your inspiring post. I'll have a look of what's available in CF tubes here in Denmark.

Jégwan

Yup, Ibba's videos are pretty sweet.
I think there's another guy called Memo. He dives insanely deep as well.

I have been looking into sourcing the fibers and while fibers for bows are an option, I think ideally they should be a bit thicker. Bow sights fibers seem to be less than 1mm. I am thinking 1.5 - 2mm would be ideal.

But these fibers aren't as easy to source as I thought - but as you know by now, I don't mind trying and somehow I think it should be possible in the World's factory..

 

[Diving Gecko]

Just in case you are wondering - I'd still love to have that precise inside diameter of an Asso/Hunter outer barrel/tank.
It would help a ton!

Best,
David

 

[kwtony]

replicating that exact tube out of carbon fibre is not only going to be near impossible, but tough to make absolutley perfect. The tolerances of the piston and tube need to be precise and making the inside of the cf tube to slide frictionless and effortless for a long period of time will be tough as well . Make it out of titanium if you want to do anything not ordinary. The handle tank and muzzle are all held in place by the compression of this tube, I just dont think itll be possible with carbon fibre

 

[Diving Gecko]

Hi Kwtony,
I appreciate you elaborating and I totally agree but... it was never about the shooting barrel - I am inquiring about the tank/outer barrel;-)

So, I am afraid the question still stands.

 

[Gazz]

you are lucky, I got my new salvimar vintair 130 today and I have just taken it apart to get rid of the power reducer.

According to my digital callipers
The outer barrel is:
ID : 38mm (exact)
OD : 40mm

Inner barrel is:
ID: 13mm
OD:18mm

I have noticed some parts of this gun are identical to that of the asso and mares, I think the Italian makers share some parts suppliers.

 

[Diving Gecko]

you are lucky, I got my new salvimar vintair 130 today and I have just taken it apart to get rid of the power reducer.

According to my digital callipers
The outer barrel is:
ID : 38mm (exact)
OD : 40mm

Inner barrel is:
ID: 13mm
OD:18mm

I have noticed some parts of this gun are identical to that of the asso and mares, I think the Italian makers share some parts suppliers.

Yeeha! (or however you spell it;-))
Thanks a ton.

Yes, I remember Pete often mentioning how they share a lot of parts between the companies or moulds have been sold to new start-ups and such.

Let us know how you like the Vintair. Is it the dry barrel version?
(or come to think about it, that might not be available yet and might even have another name).

Cheers,
David

 

[Jegwan]

Hi again David,

I have checked the Danish home marked. I found two suppliers. None of them has CF tubes with large diameters in stock - they can be made to order - and none of them had technical specs. on their tubes telling anything about how much pressure the tubes can take.

They knew a lot about their strength when used as columns and bars, but not any of the common specification figures for pipes transporting or containing liquids or air.

I'm working in the heat and water supply business, so I can arrange a pressure test with water of a given CT tube if needed.

Jégwan

 

[popgun pete]

The vacuum barrel version of the "Vintair" is the "Vuoto-air", according to early photos, with green replacing the orange colour used on the wet barrel guns.

If a carbon fibre tank explodes sending shards of cracked resin tubing flying in the wrong place then you may find yourself in a difficult legal situation with any bystanders being injured. My advice is to steer clear of such things unless you have the tube material hydro-tested for its new application as a pressure vessel before using it on a pneumatic speargun, including sustained pressure application. If the tube bursts then a bit of water leaks out. You could always put a carbon fibre sleeve over a metal tank if you want the carbon fibre "look"; lightweight high pressure vessels have fibre wound metal tanks as the metal is impermeable and ductile while the fibers boost the circumferential strength of the otherwise thin wall tank. I would be taking weight out of the muzzle, not the tank, if you want to lighten the gun at the front end. As the vacuum barrel gun has no water in the inner barrel when cocked to shoot then it should be more buoyant, so if it is heavier then the muzzle is the culprit. Any parts forward of the muzzle that are not part of the nut that takes the load and which holds the gun together can be lightened, or buoyancy added with a collar.

 

[Gazz]

The outer Ali barrel on the vint air is very very light, I would not bother replacing it.
Carbon fibre can spit at the ends,

add foam if your gun is too heavy.

Ps. the dry barrel kit should make your gun lighter not heavier.

 

[Diving Gecko]

The outer Ali barrel on the vint air is very very light, I would not bother replacing it.
Carbon fibre can spit at the ends,

add foam if your gun is too heavy.

Ps. the dry barrel kit should make your gun lighter not heavier.

Admitted, at least half of this is for bling factor and the fun of customization.
I for sure don't want to add foam. It annoys me that I would have to add something to make up for a gun being too heavy.

The dry barrel muzzle is certainly heavier than the original one though the spear might be about the same or a tad lighter. I went from 8mm to 6.75mm but I also went for a longer spear.

I think the weight saving on the barrel would be around 50 grams at the most. Not much, granted.
I still want to try it.

Yes, CF can split. But I still want to try it.

I actually just landed a lot of work, so now let's see if I even have time to get this done.

 

[Diving Gecko]

Hi again David,

I have checked the Danish home marked. I found two suppliers. None of them has CF tubes with large diameters in stock - they can be made to order - and none of them had technical specs. on their tubes telling anything about how much pressure the tubes can take.

They knew a lot about their strength when used as columns and bars, but not any of the common specification figures for pipes transporting or containing liquids or air.

I'm working in the heat and water supply business, so I can arrange a pressure test with water of a given CT tube if needed.

Jégwan

Yeah, I have never seen pressure stats either. I think it would have to be tested.
Landed some work though so all of a sudden my modding time is being impounded on.

 

[Diving Gecko]

The vacuum barrel version of the "Vintair" is the "Vuoto-air", according to early photos, with green replacing the orange colour used on the wet barrel guns.

If a carbon fibre tank explodes sending shards of cracked resin tubing flying in the wrong place then you may find yourself in a difficult legal situation with any bystanders being injured. My advice is to steer clear of such things unless you have the tube material hydro-tested for its new application as a pressure vessel before using it on a pneumatic speargun, including sustained pressure application. If the tube bursts then a bit of water leaks out. You could always put a carbon fibre sleeve over a metal tank if you want the carbon fibre "look"; lightweight high pressure vessels have fibre wound metal tanks as the metal is impermeable and ductile while the fibers boost the circumferential strength of the otherwise thin wall tank. I would be taking weight out of the muzzle, not the tank, if you want to lighten the gun at the front end. As the vacuum barrel gun has no water in the inner barrel when cocked to shoot then it should be more buoyant, so if it is heavier then the muzzle is the culprit. Any parts forward of the muzzle that are not part of the nut that takes the load and which holds the gun together can be lightened, or buoyancy added with a collar.

Ah, as so often before, Pete brings up a very good point. Hadn't thought about collateral damage...

My initial idea was to order the tube, build end caps for it and pressure test it to 30 bars and then do some drop testing.
But then I thought a bit more gung-ho - why just I don't order the tube, assemble the gun and take it up to pressure. Bang on it a little with a hammer or such and if all is fine and dandy, proceed with in-water testing.

Let's see. I might not have time after all. I am a freelancer and all of a sudden, a lot of work is coming in.

(I have seen this done though, but don't have the specs of the tube used.)

 

[Jegwan]

Well; my offer regarding doing the pressure test is open if you decide to go down that road.

I'm not sure how much weight you can take of the Seatec Evo muzzle - if that is the one you are using - Take a look at it and estimate how much material you can remove. Then compare that to the weight of aluminium per cm2 and what can be gained by shortening the spear.

I understand that the new spear probably is lighter than the original one - but even so - will a longer spear increase the torsion on your wrist. (weight x distance to the handle).

I have for the same reason shorten my spears on my oleo's, as I (for my use) don't see any benefit in long spears on a oleo with the inner barrel in the centre of the gun. Other may very well have a different opinion - it all depends on how, where and what you're hunting.

Jégwan

 

[Diving Gecko]

Admitted, at least half of this is for bling factor and the fun of customization.
I for sure don't want to add foam. It annoys me that I would have to add something to make up for a gun being too heavy.

The dry barrel muzzle is certainly heavier than the original one though the spear might be about the same or a tad lighter. I went from 8mm to 6.75mm but I also went for a longer spear.

I think the weight saving on the barrel would be around 50 grams at the most. Not much, granted.
I still want to try it.

Yes, CF can split. But I still want to try it.

I actually just landed a lot of work, so now let's see if I even have time to get this done.

Got it, at some point, I might take you up on the testing offer.

Very good point on reducing the overhang of the spear as it is not needed to counter tail whip.

 

[Diving Gecko]

So, I went ahead and ordered a CF tube. Will let you guys know how it goes.
Went with 38x41mm which is 1mm larger on the OD but it should still be lighter than an alu tank.

I could actually use one last favor this time around. Again, the issue at hand is that my guns are stored in Thailand as they are illegal in China where I live and work.

But I could really use the precise length of the barrel itself. I know an Asso 90 is around 97cm from tip of the muzzle to the end of the handle so the outer alu barrel itself is quite a bit shorter.
If anyone has a Seac gun and could do that measurement for me, I'd be grateful. At least for this, one doesn't need to take the gun apart.
Ideally a 90cm model but I think any model will do and I can just scale up or down by 10s of cms from there.