Slingshots Forum banner
1 - 15 of 15 Posts

·
Premium Member
Joined
·
3,465 Posts
Discussion Starter · #1 ·
Following on from Jörg's Condom Catty/ Durex Destroyer and my own ill-fated experiments with rubber band chains, I continue my personal grail quest for fast bands.


Jörg's video where he shot a huge amount of very thin medical latex was my inspiration. Very thin latex has excellent shooting properties, but there's sooo much of it that I think there'd be an issue of controlling it. I could cut many strips and have a stack of bands, but that would exacerbate the second problem, namely thin bands tend to tear and tears often start at the edge. Many edges and thin bands would make for a very short-lived band.

My initial idea was to contain a roll of the very thinnest exercise band in a sausage-type party balloon. Well, it took me about an hour, but I managed it, a full width of exercise band rolled inside a balloon. I shouldn't have bothered and I don't recommend that anyone does. The result pulls and returns much like a solid rubber roll, only it has a tendency to kink and has very poor wear characteristics, having been so badly abused by a bloke with a stick.






FAIL

Then I got to thinking. A balloon is just about the thinnest dipped latex tube you can hope for and they're cheap and easily obtainable. So instead, I just strung up a frame and pouch with three balloons per side doubled because they stretch so long.





The result is a short bandset that still draws to full length and returns very fast indeed. When I shoot it facing a white wall, I can catch a glimpse of the pouch and bands flying out straight and unhindered right between the forks. The pull is about 15lbs and it feels a bit like two one inch wide bands of Thera-band silver per side. Theraband Gold gives about 35lbs. It shoots straight and very fast. Everything from 6mm steel BB to big lead sinkers zipped down range very flat and straight.

I've been using special balloons from balloonbed.com. These are supposed to be very durable; durable enough to sleep on for a night on rough ground. They're expensive and probably not as good as the regular party balloons which would be thinner.

Despite their heavy duty, these balloons offer a spectacular cross sectional perimeter-to-area ratio of 7.2x, triple that of Thera-band gold or a stationary store rubber band. In addition, the very high elongation ratio means that the shot is under tension for a greater distance. These two properties explain the speed.

As I said, I've been shooting 3 doubled bands per side. I need to get a chrony and do some proper testing, but depending on the balloon and the weight of the shot and pouch, I'd say the ideal would be between 2 and 4 bands per side.

Durability hasn't been bad, considering how thin the rubber is. Balloons are engineered and formulated not to split on stretching, chafe or perish quickly and of course there is no edge. If a balloon breaks, you can just cut off a the bad band and one from the other side. If it breaks during a shot, it shouldn't be too dangerous, as it has only a small draw force and little mass.

Further enhancements are possible. I'm not sure I have, but if you have the skill and strength to shoot butterfly stance, not doubling the balloons would mean an even greater effect of the superior elongation. Com-bow rollers and long fork extensions would help too. I'm also working on ways to achieve a taper. I suspect that if I include a length of Dyneema braided fishing line to selected balloons, I can get the same effect.

There are some downsides to using balloons. Firstly, it's ugly. Secondly, there is a whole tangle of bands. Tying the bands in the middle with elastic thread would help.

Ooooooh, bundles of elastic thread: now there's an idea!
 

·
Registered
Joined
·
2,100 Posts
Good work! Balloons might indeed work. It would also be very interesting for the youtube crowd, as many young folks can't do ebay and therefore are in need of good sources for rubber.

I will pick up the idea (if you don't mind) and do some chrony tests. As I am on business trip (Spain), this will have to wait 10 more days. I may do a video if it works, and of course will name you as the original inventor.

Regards

Jörg
 

·
Premium Member
Joined
·
3,465 Posts
Discussion Starter · #3 ·
Of course I don't mind. I'd love to see what sort of speed it develops. If you publish velocities with 2-3 different weights, we can extrapolate a velocity:mass curve. This will tell us what the unladen (dry fire) velocity is and how it's affected by inertia.
 

·
Premium Member
Joined
·
2,177 Posts
Ive tried the thin type balloons what the clowns blow up and make animals and other things with, i seemed to get a good few hand slaps with them, and fork hits, think its cos all the balloons look the same but have the tinyest differant thicknesses, would like to see the video though, jeff
 

·
Registered
Joined
·
691 Posts
Great !
I was thinking about this allready in December but I am too lazy to do I am happy to see that it actualy works.
 

·
Premium Member
Joined
·
3,465 Posts
Discussion Starter · #6 ·
Jeff, it seems to work with the balloonbed balloons. I've no complaints on accuracy, or so far on fork hits or band slap.

I've now run out of the original bands but today picked up a hundred party balloons in two grades 'good' and 'too thin', if my Cantonese serves me right.
We'll see if thickness/ quality if a factor.

Great !
I was thinking about this allready in December but I am too lazy to do I am happy to see that it actualy works.
It's one of the easiest, cheapest and most readily reversible mods.
 

·
Premium Member
Joined
·
102 Posts
Another source of bands that I found was Tourniqet bands like they use at the doctors office when they draw blood. I have a set that I set-up on one of my forks and they seem to shoot well but I have no equipment to gather specs. with. But "shoot well " is just an assumption without specs.

-Scott
 

·
Premium Member
Joined
·
3,465 Posts
Discussion Starter · #8 ·
Here's another version, the Rainbow Warrior, with 6 ballons per side on a contrasting black acrylic T1 frame.

 

·
Registered
Joined
·
691 Posts
Here's another version, the Rainbow Warrior, with 6 ballons per side on a contrasting black acrylic T1 frame.

I noticed you tie the ballons on 2 places between the fork and pouch. Doesnt it affect shooting?(I 've tried it with regular bands long time ago and if was useless)
 

·
Premium Member
Joined
·
3,465 Posts
Discussion Starter · #10 ·
It's not tied, but I have used the cut-off rolled end of the balloons. They are very light and more importantly loose so they don't create wear or over-stress the bands. The rings just save tangles.
 

·
Premium Member
Joined
·
3,465 Posts
Discussion Starter · #12 ·
Here's a close up of the front attachment:

 

·
Premium Member
Joined
·
3,465 Posts
Discussion Starter · #14 ·
Curves, I love curves.



jephroux, will something this do, or are you hoping for a wooden frame?
 
1 - 15 of 15 Posts
Top