Band length dilemma

[spearstudtx]

Hey guys, new spearo here. I need to replace bands on a Beuchat Arka 90cm gun. I want to use 18mm bands. The only bands I can find are 18mmx26cm and according to Beuchat's specs I need 22cm bands so what gives?
I think I will lose key power if I get bands that are that much longer. Any suggestions?

Here is a link to Beuchat's suggested length charts:

Beuchat Arka Sport 900 Band Speargun: Scuba Gear and Diving Equipment

 

[beamjoel]

you can always modify If need be. Check out the "Idiots guide to rigging a spear gun" forum you can get info on tying bands if you need it.

Are the bands circular or threaded at the wishbone and the muzzle? I guess either way it does not matter in order to modify the bands you "can" get tot he bands you "need"

Have you checked out scubasworld.com if not ask for Ulises he works at a great shop and can be very helpful in finding needed gear.

good luck

Joel

 

[mishu1984]

hope this helps

 

[mishu1984]

you can trim your bands. i find that using pruning shears provide the cleanest cuts. you might want to buy bulk rubber. its cheaper and more fun. depending on the rubber, you might also need to buy a wishbone insertion tool. i used to get all that stuff from norcalfreedive, but i think they went out of business. find Jimdoe2you. he should be able to point you in the right direction

 

[spearstudtx]

Thanks for the responses. My bands are threaded (screw on at muzzle and at wishbone). I have looked at how they are attached to the thread and see no way to "trim" them effectively. I was hoping to just be able to buy the bands without having to make them myself, but if need be I can do so. I just don't understand how there isn't a replacement band for this gun.

 

[Old Man Dave]

All the big internet suppliers should list many sizes of bands. A 90cm euro gun with screw in bands needs 22 to 25cm length bands. The threads are standard so you can use other makes of band not just Beuchat. Check out the DB shop by clicking shopping at the top of the page. Assuming the link doesn't time out I've done it for you. Slings 18mm BEUCHAT Accessories Guns Guernsey Dive Scuba store .com

Dave

 

[spearstudtx]

Thank you Dave,
that was exactly what I was looking for.

 

[ulysses]

You can always destroy the platic threaded part which attaches to the wishbone, remove the bead inside the bands and cut the rubber to the desired length. Subsequently, you can attach either a dyneema wishbone as depicted in the links above or use an articulated wishbone without the plastic caps and a spherical nuts. As a matter of fact, I always do this semi bulk-rubber set-up which has various advantages over the traditional one (the threaded plastic part creates a sort of parachute-effect).

Cheers, ulysses

 

[spearstudtx]

Once again, thanks for the responses. ulysses, i am not confident enough to "destroy" anything I have to pay for quite yet. if i have another band break i will look and see how everything fits together though.

 

[Ron Bakker]

18 mm rubbers will make quite an impact on the way the gun shoots, in a good and bad way.

 

[spearstudtx]

I realize this. i bought 16 and 18mm bands and am trying them in the pool this weekend. will post my findings....

 

[spearstudtx]

Put my new bands on (16 and 18mm). Here are the results, they are pretty predictable:

16mm - very accurate, no recoil, med range, little power at more than 9 ft.

18mm - slight decrease in accuracy, slight increase in recoil, significant increase in range, good power to 12 ft. FAST spear speed. Expected more bad, but no shaft whip or anything else noticeable. Leaving these bad boys on for my trip to the gulf, but will take them off again for freshwater and limited vis applications.

I tested the bands in a pool, shooting at a suspended bowhunting target. I had to hold high after 6 ft and even higher past 9. I shot several times @ 15 and though I got pretty good at that distance, there just wasn't enough power to stone fish (even with the 18mm band). Funny how much penetration suffered in 3ft of distance. Part of this is the fact that I am using a 6.5mm spear. Will upgrade to 7 soon and see how much that extends my range, power-wise.

Also tested some 5/8 bands for my little 32 AB Biller and although they helped, the increase in performance wasn't as dramatic. Am going to shorten them a little and retry in the near future.

spearstudtx

 

[calinitalia]

You could also order the bands you need. Acquasport - Pesca subacquea - Apnea - ARA euro 18.50.
( Gomme megatone nere 18 Beuchat cm22 )

 

[Paul B]

Hey mishu with your band chart are we talking about the total length of the rubber or are we talking about the muzzle to wishbone length. I ask as with RA guns a single length is used unlike some of the screw in euro styles and I unsure which length these charts refer to. I have a RA90 with about an 18mm and a RA120 with a 19mm so its about time i actually tested the recommended measurements especially for the 120 as i have been having some issues. Cheers Mate.

 

[Mr. X]

I could read the table on the above link for some reason, so here it is:

The RA chart is for the length of the rubber not inc. wishbone. Best to start too long, you can always shorten later if necessary.

 

[Paul B]

i understand the charts i just am never sure if in the RA case we are talking about the entire length of the loop of rubber of just one side. what would the total length be for a 1200 with a 19mm?

 

[Mr. X]

i understand the charts i just am never sure if in the RA case we are talking about the entire length of the loop of rubber of just one side. what would the total length be for a 1200 with a 19mm?

It's the entire length of the rubber. Thinking in terms of sides is a eurogun mentallity - where you get one rubber on each side. Railguns are simple - just one piece of rubber, cut to length. I suggest you err on the long side though. BTW according to the RA website, the RA bulk rubber muzzle holds 10cm of the rubber (beyond what you would get with traditional eurobands).

 

[ulysses]

Even though I only trust my own empiric 'studies' when it comes to band length, I believe this is quite helpful (don't be put off by language difficulties, the tables, pictures and formula are self-explanatory):

http://www.bluworld.com/test/Spiegazionielastici.pdf

Cheers, ulysses

 

[liberte]

got a question... i have a beuchat arka 75. instead of replacing the standard bands that screw into the muzzle, i want to know if there would be any advantages or disadvantages to just making a circular band through the hole in the muzzle and have that be my only band.
i know there are the little plugs that screw into my muzzle and allow me to use bulk rubber and make bands. just wondering if i can save myself a buck by only using the circular band. would it cause the gun to fire any differently? anyone done this before.

 

[Ron Bakker]

Hi Liberte
Having rap arounds on a gun without a rail wiould almost certainly make it shoot incosistantly. If you gun had a rail then I would say it will be fine. I think getting the muzzle inserts would be a better option. Plus the rubbers would stay centered if you use the inserts. If you use the rap around rubbers, it will pull the back of the spear down when fired.