Tomba - All in One barrel sealing

[Don Paul]

Very nice job and nice pictures Don! There is only one think I am little concerned about this Tomba for Airbalete. Because there is no water escaping holes covered with rubber tubing which function like a valve, it would bi maybe good to let the water out from the muzzle after inserting the shaft and before pushing the O-ring in to the muzzle. It is possible that small amount of water after loading the gun get in to the place between the piston and the shock absorber. After shooting some of this water could be injected in the gun passing the piston's sealing. Maybe this would not happen but have on mind as a possibility. Waiting for you real test in the sea.
Regards, Tomislav

I studied the pre-assembled components on my desk going through different scenarios and outcomes and that thought came up briefly. I would like to treat gun like any other pneumatic loaded in white caps that I would use in the sea, then tear down,inspect and document the results to report back to you. .....That way I can keep the green eyed girlfriend :inlovehappy with fresh bass throughout the sea trials.:friday
Should a reed valve or foot valve prove necessary, a small port covered
by a thin elastic sleeve could be easily added with your approval for testing. I have started a log for duty cycle and fish harvest and the weekend forecast is warm and sunny, let the aquatic games commence.

All the best, Don

 

[foxfish]

Very sensible & logical Don, between you guys, you will iron out any little glitches.

 

[Don Paul]

Very sensible & logical Don, between you guys, you will iron out any little glitches.

''Glitches'' can and do sometimes lead one to a different path of understanding and new knowledge, a great tool for progress.

Cheers, Don

 

[Don Paul]

A delay of game....
Sunday in need of some upper body exercise I passed on my Nitrogen tank and fill setup, and attached the stock hand pump. Two espresso and a little techno music later my air gauge was at 21 bar @ 80 degrees.

Next step was to assemble the Tomba shaft seal parts and do a trail fit. After sliding the cone O-ring and slide ring into position I was surprised to watch it slowly rise and dislodge the O-ring with a slight hiss. I than inserted the shaft 75%
a couple of times to attempt to improve the piston seal/ inner barrel sealing.

A test submerge in fresh water reveled 5mm bubbles coming from the piston/seal every 2 seconds. Cocking the piston into the sear box only increased the rate of air bubble release. see image.

The Airbalete I have was used before I received it so I have no record of it's duty cycle or maintenance.The piston was cleaned with lint free wipes and re-lubed with Omer grease before careful reassembly. I cleaned and
pressured two times with the same result. I am ordering 2 new piston assembly's from my local Omer dealer today. Sorry for the slight delay in fish procurement and seal trials. No tank leaks were found and the Tomba kit parts fitted perfectly as expected.

Cheers Don Paul

 

[tromic]

I had same problem with my "new" Cyrano. It was probably long time under high pressure in the shop before I bought it and the sealing O-ring changed the shape from oval to triangle. I fixed it putting 6 x 2 mm O-ring instead of the original, maybe 8 x 1,5 mm. It would be better if I had changed both the cone ring and the O-ring with original parts but it works this way too. The friction is maybe little higher than should be but it seals good.

 

[tromic]

From this:

I made a new type of Tomba, Tomba10F, which can use both Free shaft and a shaft with the butt. I made a tiny slider so the line is near the shaft end.

At the last picture there is a regular Tomba10 with the line slider on the shaft. Above the slider there is the interchangeable tip for the adapter for converting Tomba10 adapter to Tomba10F.

 

[Don Paul]

I had same problem with my "new" Cyrano. It was probably long time under high pressure in the shop before I bought it and the sealing O-ring changed the shape from oval to triangle. I fixed it putting 6 x 2 mm O-ring instead of the original, maybe 8 x 1,5 mm. It would be better if I had changed both the cone ring and the O-ring with original parts but it works this way too. The friction is maybe little higher than should be but it seals good.

I will wait for the stick piston from Omer, I hope to hear back from my local dealer. I also see that Scubaworld shows them in stock, so as a back up I may give them a call as they ship same day. I would love to be in the water with it this week end .

The down time has allowed me to strip my gun and get a good look at the trigger and sear assembly. I now see where all the engineering went, this gun appears drawn from a blank sheet of paper.

Cheers, Don

 

[BocaRape]

Buen trabajo!!!!!
En España se está trabajando en cosas parecidas.
En especial Ramón Karayo.

 

[tromic]

Buen trabajo!!!!!
En España se está trabajando en cosas parecidas.
En especial Ramón Karayo.

¡Gracias! Lo sé. Compré un manómetro de él.

 

[tromic]

Some more pictures of Tomba10F.
On the first picture it is shown the inner assembly of the Tomba10F in a free shaft mode:

On the second picture the first shaft is 7 mm, the second 6,5 mm and the last 7 mm free shaft.
This is actually "All in one barrel sealing". If we remove the (green) rubber tubing we have water barrel gun.

 

[Don Paul]

I have a new Airbalete piston being shipped Fri from Scubaworld.
Will get in the water ASP.

Cheers, Don

 

[tromic]

I have a new Airbalete piston being shipped Fri from Scubaworld.
Will get in the water ASP.

Cheers, Don

Maybe you could have ordered just the piston's sealing kit.
Cheers, Tomislav

 

[martinbar74]

Great work Tromic !!
I am looking for an airbalete kit and your look very promising I will wait for Don tests
Can you help with an advice for below.
I have destroyed the sliders on my both spears ( 6.75, 7.00 ) of airbalete 100.
Now I have to make new one , what should be the material and the shape ?
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.
As for the leaking of air I also had a problem , when open the gun it was full of water and sands ( probably because I am hunting usually in murky, sandy and shallow waters close to the shore .
Probably it is not a bad idea to put some usual oil with the airgrease also , because I am suspecting that the grease is not working properly when used under low temperatures ( below 15 deg. Celsius ), and causing additional friction and abrasion for the piston seals.
Now the gun is fully repaired , only the problem with the sliders exists .
B/Rgds,
Martin

 

[tromic]

Let's wait for Don to test the kit and the slider. I would maybe make a slider that could be a combination of the cone steel ring and the slider in one piece, made in stainless steel. As light as possible, not more than 5 gr. I think vacuum barrel system would preserve your gun from the sand entering the barrel.

 

[Don Paul]

Maybe you could have ordered just the piston's sealing kit.
Cheers, Tomislav

Yes but I wanted to have a back up piston on hand for tests at max Bar after the shooting at 20 Bar.

I carried out a test with a O-ring from your kit installed in the space behind the stock leaking O-ring. Two days ago I pumped the gun with air @ 70 degrees.The shaft was cocked (safely in the bay behind my house)and the shaft O-ring slide slid into place. After being cocked for 48 hr the slide ring O-ring has not been dislodged by air leaking past the piston.
I will wait till next week to record shaft impact force, but plan on shooting the gun this Sunday in the sea while I wait for the fresh replacement piston.

Cheers, Don

 

[tromic]

Yes but I wanted to have a back up piston on hand for tests at max Bar after the shooting at 20 Bar.

I carried out a test with a O-ring from your kit installed in the space behind the stock leaking O-ring. Two days ago I pumped the gun with air @ 70 degrees.The shaft was cocked (safely in the bay behind my house)and the shaft O-ring slide slid into place. After being cocked for 48 hr the slide ring O-ring has not been dislodged by air leaking past the piston.
I will wait till next week to record shaft impact force, but plan on shooting the gun this Sunday in the sea while I wait for the fresh replacement piston.

Cheers, Don

OK, Don. What would be the max Bars? I suggest not to be more than 27 Bars. 25 Bars would be sufficient for very good performance and easy loading in the same time. If you find it useful you can put two O-rings on the shaft. There is enough place in the adapter and it could be useful to easier push the cone ring and the O-ring in the adapter because the line slider is short (not to be heavy).

Cheers, Tomislav

 

[zmajmr]

Tomba kit cartoon

[ame=http://www.youtube.com/watch?v=Qesx6zA6uJs]YouTube - Tomba kit[/ame]

 

[Don Paul]

OK, Don. What would be the max Bars? I suggest not to be more than 27 Bars. 25 Bars would be sufficient for very good performance and easy loading in the same time. If you find it useful you can put two O-rings on the shaft. There is enough place in the adapter and it could be useful to easier push the cone ring and the O-ring in the adapter because the line slider is short (not to be heavy).

Cheers, Tomislav

I would not exceed Omers caution of 30 bar. Here are some images of the rigged gun for a local hunt in poor 12' Vis.

Image# 1.non leaking barrel hand pumped to 20 Bar @ 70 degrees F.
# 2. shaft tail with 400# outrigger mono.
#3 Tomba Muzzel with protective film to quite line crimp rattles while tracking.
#4.Gun rigged for shaft storage on surf entry. Point is positioned into top of reel line with slide ring loom securing shaft tail at muzzle In Image # 5.

Sorry on dead fish pictures as I had no one to wait for me at the beach,
but happy to report the gun is just deadly even at 20 bar on 2 kg bass
12 feet from the tip. Low battery back later.

Cheers, Don

 

[Don Paul]

I am very pleased with the balance of the gun with the Tomba system and 7mm shaft..With one finger in the trigger hole the tip of the gun just hovers out there without any effort. The spot I chose to dive Sunday had Vis in the 10 to 12' range on the outside reef. Conditions inside were too surgey near the beach for target shooting so I kicked out to a reef 1/8 off shore with deep wary Calico bass in the 2 kg range. These fish are very smart in this are as they are targeted weekly by the locals. Many times the fish will face a stealthy diver head on as long as they feel they are just out of range. Several times I have pulled the trigger on fish that have dogged the shaft or hit the departing fish in the side as they bolted to the sound of the gun.

That was not the case with the Tomba Airbalete @ just 20Bar. I aimed at the head of the first dinner sized bass on the edge of visibility(12' from the tip) before he could respond to the slight clink of the shaft,was impaled through the head, flopper toggling a pectoral fin. After loading the gun this summer @ 30Bar I had the feeling I was cocking a beefed up pole spear and not a spear gun. This gun would make a nice camera gun for the complete lack of felt recoil even with unlocked elbow.

Two more 3 to 5lb Calico bass were taken, one broadside at 10' off the tip and another right at the end of the 13' outstretched 400# Mono. I do have the line latch spring removed from this gun, and shots were spot on at distance. The hydrodynamic slide ring assembly did not steer the tail in any way. I am confident this gun will brake the spines of 40 lb White Sea Bass at 28Bar when I seek them out next year. I have a new underwater camera coming for Xmas to record the harvest when I seek them out.
Rain has moved into the So Cal area for the next few days looking forward for some tests when I have some better Vis. Outstanding job on the kit Tomislaiv, it is a winner .:friday

Cheers, Don

 

[Don Paul]

OK, Don. What would be the max Bars? I suggest not to be more than 27 Bars. 25 Bars would be sufficient for very good performance and easy loading in the same time. Quote: tromic.

I agree but after the 27 bar tests I will set out to discover the catastrophic failure point of the stock piston assembly at 30 bar with a modded Mares snubber I will install at a later date.

Cheers, Don