Custom Pnuematic Speargun Sizes

[Gazz]

Hi Guys,

I wanted to look at making some custom sized pneumatic spear guns. I have a mate who's a machinist and a family friend who does powder coatings etc. I wanted to make a custom sized inner and outer barrel and use the parts from a smaller pneumatic speargun to complete it.

So first question as I don't have any pulled apart spearguns atm.
What is the standard IDs (size and thickness) of the inner and outer barrels (both 11mm and 13mm) and also what grade?

Question 2: Does anyone know where this sized seamless tubing?

Question 3: Does the inner barrel need any special coating?

Thanks any info appreciated.

 

[kwtony]

QueStion 1 + 3 = titanium for rust free use. But honestly, if you are just wanting to build a custom one off gun I understand the want and desire for this, but you can easily buy a shorter gun for cheap online and get to killing fish right away., or maybe after a quick rebuild.

Anyways, the barrel isn't that complicated, when you get it all figured out, I want a 165cm air gun, so please let me know what thatll cost

 

[Gazz]

QueStion 1 + 3 = titanium for rust free use. But honestly, if you are just wanting to build a custom one off gun I understand the want and desire for this, but you can easily buy a shorter gun for cheap online and get to killing fish right away., or maybe after a quick rebuild.

Anyways, the barrel isn't that complicated, when you get it all figured out, I want a 165cm air gun, so please let me know what thatll cost

I was thinking a 125 and a 150.

They don't make them n those sizes so I need the parts custom made.
I have located material for the outer barrel (6060), I just need the inner barrel gauges and supplier.
Of course I could get a hold of an asso 135 inner barrel for the 125custom, but it would be easiest do it all in one hit.

 

[kwtony]

all you need to make are the inner and outer barrel, if you use preexisting parts from other guns. Otherwise, the handles can be bought here in the states but not sure where in aus. The asso or the sten would be a good platform, add a dry barrel and viola, one hell of a blue water cannon. i was just trying to imagine how one would load such a gun, but with a little finesse im sure it could be done. Actually, i have a cressi sub gun that im not using that i might can send you. it needs a new outter barrel and would be a good test gun for you to help start making what you need. Let me know if that could help.

 

[Gazz]

Thanks Kwtony,

That was my plan all along get a little gun (I was thinking cressi as they are the cheapest over here) and swap the inner and outer barrel.
I was thinking 125 for the cressi.
I would be happy to take your old gun off your hands if you don't want it, just let me know what you want for postage.

I just measured the gauges from an old nemrod ID=2.2, OD=15.9. That's useless to me

 

[Diving Gecko]

Perhaps look up the thread size of, say, the Evo Air. I think I saw it somewhere... That should give you a good idea.
Other than that, PM Tomi or Marko, they would likely know.

It's funny how after a while, this seems like the natural progression of our modding obsessions; custom lengths.

I myself is actually pondering cutting down my One Air 120. It's quite the cannon as it is now. But supposedly it's easier to cut it down than the other way around, so I should wait until I am 100% sure;-)
Maybe better to find a cheap 100 somewhere. Doesn't have to be a One Air.

I do think, at one point, I'll look at sourcing titanium for an inner barrel. I am tired of these guns being nose heavy. I am in China, so I might actually find something that's affordable.
(I remember reading something about Pippin getting a Ti inner barrel for the weight reduction on a long custom gun, but even for my small Seac 90, I could use it)

And then we just need to wait for 3D printing to become strong and affordable enough so that we can actually make muzzle cones, handles and bulkheads

Until then, good luck with your bluewater monsters!

D.

 

[Diving Gecko]

Thanks Kwtony,

That was my plan all along get a little gun (I was thinking cressi as they are the cheapest over here) and swap the inner and outer barrel.
I was thinking 125 for the cressi.
I would be happy to take your old gun off your hands if you don't want it, just let me know what you want for postage.

I just measured the gauges from an old nemrod ID=2.2, OD=15.9. That's useless to me

BTW, this HK company makes clones(?) of the Asso guns.
Also, they look very much like Pippin's new guns, I woudn't be surprised if he sources them from there. If he actually designed them, or at least the color scheme, they should not sell them to you. But maybe it's "their" design.
Maybe you can buy handles, cones etc. from them? Maybe even the inner barrel?
They may not do it, as they'll think they'll be cannibalizing their own business.
Also, I don't know if this is actually a copy/clone in the rip-off sense or if it is a proper OEM manufacturer. That's worth taking into account as well.

 

[kwtony]

It's common practice to rebrand and resell things in this industry. It's very Clear there was nothing designed by pippin and it is only a marketing strategy. Hes not an engineer and certinaly doesnt desing anything they sell. All they do is suck ovwr at persistent. Dozens of manufactures sell rebranded items from the same molds that others were made from. No ones feeling is going to be hurt if you buy anything from them in pieces. But those guns are all just sitting in a box ready to ship out.

 

[Gazz]

BTW, this HK company makes clones(?) of the Asso guns.
Also, they look very much like Pippin's new guns, I woudn't be surprised if he sources them from there. If he actually designed them, or at least the color scheme, they should not sell them to you. But maybe it's "their" design.
Maybe you can buy handles, cones etc. from them? Maybe even the inner barrel?
They may not do it, as they'll think they'll be cannibalizing their own business.
Also, I don't know if this is actually a copy/clone in the rip-off sense or if it is a proper OEM manufacturer. That's worth taking into account as well.

Those guns are rebranded and sold all over the place (you can buy them in bulk on alibaba), they are dodgy asso Clones. I got the chance to pull one apart, many parts looked identical to the asso, but all the threads were different. The gun had design issues (particularly in the trigger and softer plastics used for the handle) and was poor quality. I wouldn't touch these "knock offs" ever.

I didn't realise titanium was lighter than aluminium? I hadn't considered it as I thought it was too expensive and hard to machine, perhaps I will look into it.
I am still looking for inner barrel material.

 

[kwtony]

ti would be the inner barrel, there has to be somewheree that you can buy a 10 foot or 15 foot made tube to your specs online somewhere. but you can use al for the outter like used on. I used one of those persistent 90 cm for a long time. it actually worked, pretty well. i bought a 9.32 dry barrel kit and then lost the gun when moving. ....and i havnt had the chance to get another. other then my 133 sten that i use almost every time i dive.

 

[popgun pete]

Titanium is heavier than aluminium, it does not normally get used as an inner barrel tube. Bore wear may be a problem, most titanium pneumatic guns have stainless steel inner barrels. I seem to remember that Pippin had a special "Sten" gun made for him by Mares that had a titanium inner barrel, a 150 cm, but that was something reported on a forum and not necessarily accurate. There were "Pippin" pneumatic models available a decade ago, all much longer guns than what was then normally offered, based on the Mares "Sten 2001" models. A number of them were sold brand new on eBay at the time. His product range seems to have headed down-market since then with the rebranded Hang Fung guns, the "Persistent" models appeared at exactly the same time as the "Asso" clones.

Cutting the screw threads is probably the hardest part in making new inner barrels as they need to be straight, otherwise the muzzle and inlet valve body will not be aligned properly with the axis of the barrel. A job for a lathe really, taps and dies are hard to get cutting on-axis unless you start the threads using the lathe and then finish with the screw thread cutters to clean up the thread forms. A competent machinist should be able to do the internal thread using just the lathe and a boring bar.

I remember that someone on a spearfishing forum was trying to source the alloy inner barrel tube, I don't know if he had any success. At the time I thought that his reason may be connected with his earlier purchase of a "Kayuk" Belorussian pneumatic speargun and his subsequent communications with that company, the amount of tubing being sought was considerable, not just the quantity needed for a couple of spearguns. My guess is that alloy inner barrel tubing is especially made for the major manufacturers in 13 mm and 11 mm bore diameters, there probably being only one actual manufacturer subcontracted by the various brands to produce the finished barrels. There may also be a separate supplier in China for this tubing if they are now making their own materials locally. The tubing requires a precision bore and a high standard of internal surface finish or the piston will not run smoothly along the inner barrel.

This is the thread that I was referring to above: http://forums.deeperblue.com/spearfishing-equipment/73262-mares-cyrano-700-a.html