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Tomba - All in One barrel sealing
- Thread startertromic
- Start date
Thread Status: Hello
, There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.
It can take a long time to get an up-to-date response or contact with relevant users.
Thanks foxfish, I had a good holiday.
Here is a picture of how to detach the tip of the Airbalete muzzle:
This is a first step in converting the Airbalete to Airbalete-Tomba. The air should be first released from the gun.
The ability to seal both the shaft and muzzle against water intrusion with a single "O" ring is a very good idea, however it does rely on that "O" ring staying put while the shaft is being pushed down the inner barrel. If the spear is stopped momentarily and allowed to come forward slightly during a pause in loading then it can dislodge the "O" ring and therefore result in water being sucked into the inner barrel. This is a potential problem with all vacuum barrel systems using a sealed slider and has been mentioned earlier in this thread, but I am raising it again for the following reason. It occurs to me that this dislodgement could be prevented by restricting the slider from moving and thus immobilizing it in the muzzle opening during loading effort on the shaft. On tromic's latest design this could be achieved by inserting the shaft in the muzzle and wrapping the shooting line on the gun's line hook system before pushing the shaft in, however this would not be so easy to do on a longer gun due to the weight of the long shaft sticking out of the muzzle and being unsupported. Rather than use the tension in the "pre-wrapped" shooting line, or tensioning it up with the reel if one is fitted, it may be possible to temporarily "lock" the line by throwing a loop around the post of the front line hook and then holding the line immediately behind it firmly against the barrel with the hand that is holding the front end of the gun. The type of shooting line used will determine how effective this "temporary hitch" method is as monofilament is not as compliant as braided lines in tightly wrapping around smaller objects.
Peter, all you said is possible. Maybe I was lucky but I had not such a problem with any of my latest tomba setup (except the very first one with the sling gun tubing on the shaft). It depends on the right size of the O-ring. The force on the O-ring in any direction, during loading, should be even where the steel taper ring is very important. There should not be to much friction between the O-ring and the shaft. In that case the vacuum is sufficient to hold the O-ring in place. The vacuum is sufficient very soon after starting the loading of the shaft.
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Tromic, your Tomba kits look awesome!
STC X-Power has a much thicker rubber piece inside the muzzle (no o-ring on the shaft) so if you load the shaft and it comes out a bit, you don't have to worry about water entering the barrel. It might be similar to the Tovarich concept, but I've never actually seen it. The Mamba also had that problem where you have to push the shaft all the way in with one motion or water will get sucked in if the shaft comes out just a little bringing the o-ring with it.
STC X-Power has a much thicker rubber piece inside the muzzle (no o-ring on the shaft) so if you load the shaft and it comes out a bit, you don't have to worry about water entering the barrel. It might be similar to the Tovarich concept, but I've never actually seen it. The Mamba also had that problem where you have to push the shaft all the way in with one motion or water will get sucked in if the shaft comes out just a little bringing the o-ring with it.
Thanks peacenluv, I already know all those concepts. All are good, but all also have some disadvantages. Tomba is also not excellent. This problem with O-ring, although I had not noticed it with Tomba yet, is what I am at least concerned.
Mamba has too much hydrodynamic friction on the shaft due to sealing cylinder large diameter (14 mm). Often users report problem of water entering the barrel during the loading of the gun, maybe because of wear out of sealing elements or not a right O-ring/shaft diameter combination. There could be few reasons.
With Tovarich one mast tie the line to the front of the shaft, and it is possible, in case of O-ring damage, that some water enter the barrel behind the piston, under high pressure (see #134).
STC also could have problem with water entering the barrel in case of damage of the sealing part, like Tovarich. I suppose it is not so easy to buy a new sealing ring, like a regular O-ring.
With Tomba O-ring could be damaged because it is exposed on the shaft, but it is cheep and easy to replace. The O-ring could also be damaged if the line slider is too heavy, or if you catch a very large and strong fish.
So, no system is ideal.
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Whatever muzzle sealing system is used the rubber seals will wear out, so the easier that they are to source and replace the better. Tromic's system allows you to inspect the "O" ring on the shaft and replace it very quickly as the "O" ring simply slides onto the shaft, the only disassembly required is the removal of the spear tip or the spear tail. Most muzzle kits give you a limited supply of spare seals as they are consumables when used in this application. They have to live in the world of sand, grit, fish scales/slime, rocky bottoms and saltwater, unlike most of the seals buried inside the confines of the gun. The question is when do these environmentally exposed seals need to be replaced and how do you know this? Unfortunately you will only really know when the shooting performance suddenly deteriorates or there is damage to the seal which is readily apparent just by looking at it. "O" rings purchased in bulk are not that expensive, so replacing one ring on a regular basis would not be a major impediment.
Basically tromic has reduced the sealed slider to a single "O" ring which gives the lowest OD for drag, the "O" ring being sandwiched front and rear on the shaft by the rear cone which replaces the usual stop ring and the cone base on the new line slide which shields the "O" ring from the front end. I once considered using a single "O" ring for this task, but had thought that the "O" ring would be easily pushed off the spear tail, so the sliding conical element supporting the "O" ring from the rear is a great idea as it places the stop ring and its centralizing function inside the muzzle body, plus the combined shape of the grouped elements during shaft flight is nicely streamlined on either side.
Basically tromic has reduced the sealed slider to a single "O" ring which gives the lowest OD for drag, the "O" ring being sandwiched front and rear on the shaft by the rear cone which replaces the usual stop ring and the cone base on the new line slide which shields the "O" ring from the front end. I once considered using a single "O" ring for this task, but had thought that the "O" ring would be easily pushed off the spear tail, so the sliding conical element supporting the "O" ring from the rear is a great idea as it places the stop ring and its centralizing function inside the muzzle body, plus the combined shape of the grouped elements during shaft flight is nicely streamlined on either side.
You guys have a lot more info about the dry barrel system and I've learned a lot from you the past years. The only source for the larger/thicker o-ring for the STC is from STC, but it is quite easy to service. The cool thing about the STC system is that you can remove the very tip of the muzzle without letting out the air in the gun to check out the o-ring or replace it and you can change only that part of the muzzle to allow different size shaft diameters of 6.5, 7.0, or 8.0mm. And you can remove the tip to allow wet or dry barrel usage while in the water quite easily.
STC also has a very aerodynamic shaft tail made out of titanium now (the previous ones were made out of a softer metal so the would break if you loaded the gun at too high pressure) so you can choose between free shaft with mono tied to the shaft or use any slider ring without the o-ring on the outside which actually makes the shaft more aerodynamic that using Mamba.
STC also has a very aerodynamic shaft tail made out of titanium now (the previous ones were made out of a softer metal so the would break if you loaded the gun at too high pressure) so you can choose between free shaft with mono tied to the shaft or use any slider ring without the o-ring on the outside which actually makes the shaft more aerodynamic that using Mamba.
Wet barrel would not work like regular water barrel gun. It is not enough to change just a tip of the muzzle.
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Hey Foxfish! It was you who got me to the darkside a few years back when Mamba was all the rage! Yeah, the STC is costly - Euro100 not including shipping! But I like the system better than the Mamba and it was too difficult to get any service from Maorisub.
Tromic, you have much more knowledge than me about pneumatic guns and I really don't know much about wet barrel. The Airbalete 110 is the only wet barrel I've used. I got the original Mamba 90 and 110 directly from Maorisub and converted my Cyranos and Sparks directly to Mamba and X-Power without using them wet. But I do like to change between 6.5mm and 7mm shaft with my Spark 110 and when using the Mamba, I had to let out the air to change. But with the STC, I remove the muzzle tip and change to the other size and I'm good to go.
Sorry to be talking about all this other stuff in your thread. I'm excited to see your dry barrel conversion for the Airbalete and can't wait for Don Paul to receive it and put it to use!
Tromic, you have much more knowledge than me about pneumatic guns and I really don't know much about wet barrel. The Airbalete 110 is the only wet barrel I've used. I got the original Mamba 90 and 110 directly from Maorisub and converted my Cyranos and Sparks directly to Mamba and X-Power without using them wet. But I do like to change between 6.5mm and 7mm shaft with my Spark 110 and when using the Mamba, I had to let out the air to change. But with the STC, I remove the muzzle tip and change to the other size and I'm good to go.
Sorry to be talking about all this other stuff in your thread. I'm excited to see your dry barrel conversion for the Airbalete and can't wait for Don Paul to receive it and put it to use!
I have Tomba on my Cyrano 850. Without changing anything on the gun I can use 6,5 mm or 7 mm shaft interchangeably. Only the set for the shafts are different: cone sliding ring, O-ring and the slider. Similar I made for Seac sub Asso. It is possible to use 7 mm or 8 mm shaft interchangeably.
Hey there peacenluv, there is a link in my signature you might like & there was a little bit here http://forums.deeperblue.com/pneumatic-spearguns/87898-seac-hydrodynamic-2.html that might interest you.
Hi Tromic, I'm so jealous that I can't make all the cool stuff you have!
With Mamba before, I had to let the air out to change the different size muzzle and then pump over 1,000 times every time. Now I use a gauge and scuba tank when I want to change the Mamba muzzle. But I have found that pumping the gun with the muzzle on a rug and pump straight in the air mimics the loading motion so is great for beginners to do.
Foxfish, I love your Mamba mod reversing the o-ring holder and screwing it in! Nice!
With Mamba before, I had to let the air out to change the different size muzzle and then pump over 1,000 times every time. Now I use a gauge and scuba tank when I want to change the Mamba muzzle. But I have found that pumping the gun with the muzzle on a rug and pump straight in the air mimics the loading motion so is great for beginners to do.
Foxfish, I love your Mamba mod reversing the o-ring holder and screwing it in! Nice!
