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Discussion Starter · #1 ·
So, I got the new Kent Elastomer Tubes in yesterday. The have a 3/16"ID and 3/32" thick walls. I decided to try them on my Marksman Folder, since it is the slowest slingshot. These tubes are VERY powerful. If you look at my Cardboard Penetration Test thread, you will see that I got similar or better numbers than I got with a couple different Flat Bands. It does have a fairly heavy pull, maybe 25% harder than the factory tubes.
 

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Resident Nutcase
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Hi Aaron.

In all these years I have never really measured the thickness of the latex walls, just buying the thickest available.LOL. The one in your photo's seem to be the ones I regularly use, but the real kicker is I didnt realize the "wimpy" ones I have on now are 2/32 and the thicker is just 3/32. Not much diff. in measurement but what a diff. in pull. Its also very evident in the inside diameter of the hole.

Like most others I guess I start out with longer bands like yours, and when torn or damaged around the forktips, I just cut off an appropriate length and recycle. The pooched ones I took off have only 7" measurement of latex in total, with the stretch part just 5.5 inches. I still pulled 30" after they again relaxed some. The thick walls are the only ones that last over a hundred or so shots, which is a lot of shooting.

I like the way you tie the pouch on, I just punch holes in the latex (which probly effects pull strength) and pull them through with a wire. On the other end I guess one could do the same to attach around the fork, where I would probly put a small diameter metal ringso the latex could rotate without any great amount of friction.

I've seen where Flatband has done this for years, but never thought about tying the tubes instead of punching holes in it to attach pouche. Thanx for the photo's.

The funny thing tho, is that presumably the same company made the thinner wall and thicker wall from the same batch measurements so both should have the same terminal velcity potential. The only diff. should be the thinner wall will have to use a much smaller ball bearing by weight to match the velocity produced by the thicker one.

So even though all I have to work with is the thinner wall stuff for now as I bought a big length, I should be able to coax the same speed from them, but not the same KE by using the heavier weight. Most latex from what I've read has a terminal velocity of about 270fps. So the very best one should be able to hope for is 255 to 265 given some energy is always lost.

Your pouch is kinda small but 1/2 nuts weighing about 14-15 grams make some dandy ammo for that strength band. I cut my own from some pretty heavy duty leather thats needed for these strength bands. Yours looks pretty fast, the nice long bands a smooth strong pull. I dont think you will wear those out very soon, and should have a lot of fun with them.
 

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Both of you guys need to read the info I posted on tapered bands. It will tell you why using bands like this is going the wrong direction. If you want to make tubes faster taper them or use multiple thin tubes. Tapering tubes is no big deal just insert the smaller tube into the larger one. Many dankung shooters including myself use this method for extra speed.
 

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Both of you guys need to read the info I posted on tapered bands. It will tell you why using bands like this is going the wrong direction. If you want to make tubes faster taper them or use multiple thin tubes. Tapering tubes is no big deal just insert the smaller tube into the larger one. Many dankung shooters including myself use this method for extra speed.
Most of my slingshots have tapered bands. I wanted to leave this one with tubes for durability and to experiment. You say this is going the wrong direction, but in my cardboard tests I got better penetration with this then I did with the extended fork Falcon 2 with Tex-shooter's fastest bands. Speed? This thing has it.

PS, I do think that Flat Bands will be faster than tubes, that has been proven. However, it is my belief that you can get very close with the right tubes (dipped, natural, low durometer, Latex).
 

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With all do respect, if you think this is fast your in for a big surprise. If you had a proper thera-band setup you would know what I mean.

Have you tried the Trumark RRT bands?
I have a Theraband setup on the way now, although I understand that the Tex-shooter Express bands are faster. They use Hygenic continuously dipped latex, which is supposed to be faster than Theraband. We will see.

Nope, I have not. I have tried red tapered tubes previously though, and was unimpressed. The flat bands were much faster.
 

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Resident Nutcase
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TruckLee Local: for me anyway, the less stretch and the stronger the pull, the faster it will be. In-swinger ballista's using non-stretch material projectile speeds are well over 300fps. Putting a stretchy powerband on it slows it down robbing it of energy.
That is why I seek to exceed 300fps using latex tube.

Im working on getting an independent source to verify performance results, while keeping design secret (for now). I need to get a chronograph because the springs make noise and the powerband "snaps" at the end of the stroke. The audacity digital sound recorder picks that up and makes reading results somewhat questionable. So I have to wait on my chrony to do accurate testing. I'll keep folks informed of any solid results or tests I can manage in the future, and preferably from someone other than me. Thanx for your input.

Take care aim high shoot straight.

W.

With all do respect, if you think this is fast your in for a big surprise. If you had a proper thera-band setup you would know what I mean.

Have you tried the Trumark RRT bands?
I have a Theraband setup on the way now, although I understand that the Tex-shooter Express bands are faster. They use Hygenic continuously dipped latex, which is supposed to be faster than Theraband. We will see.

Nope, I have not. I have tried red tapered tubes previously though, and was unimpressed. The flat bands were much faster.
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Thanks for the update on these, Aaron. Looks like this tubing turned out to be the great deal I was hoping it would.


Btw, I've taken to tying tubes at the pouch also. It works very well and seems to last longer than the "loop-in" method (i.e., poking a hole in the tube and feeding it through itself). I just use some cotton string that's about 1/16" diameter.
 

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I'm sure the tex bands are fast for their size, but wide flatbands are a different level of power. Buy some thera-band (or other good latex) and experiment. Aaron, if your getting the sling I think your getting that will be a great start. You will still need to optimize the band to your draw length and also match the bands to the ammo being used. After a while you'll get used to the feel and the sharp snap of the bands and then you'll really notice how slow thick tubes really are. Tubes will make a dull thump and your can feel the lack of power in your hands. I still shoot tubes every day, but only the thin skinny ones on my dankung.

Good Luck
 

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Discussion Starter · #10 ·
Btw, I've taken to tying tubes at the pouch also. It works very well and seems to last longer than the "loop-in" method (i.e., poking a hole in the tube and feeding it through itself). I just use some cotton string that's about 1/16" diameter.
I used some of this stuff:
http://www.esticker.com/zoomprod.cf...h&productid=389552&search_name=389552&stype=1
Waxed thread does not like to slip, which I figured was the most important issue in this case. I did this to tie it;
1. I tied a single constrictor knot with plenty of cord left over
2. I pulled the ends to the other side of the tube
3. I tied a "right-over-left half knot" similar to the first step in tying shoes
4. Repeated Steps 2 and 3
4. Repeated Steps 2 and 3 again
6. I tied a standard square knot
7. I cut off the ends of the thread.
 

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Discussion Starter · #12 ·
Have you guys ever used this tubing force calculator?

http://www.primeline....com/tools.html
Nope, I hadnt seen it. Honestly though, I don't know how accurate it is. It does not take into the fact that different rubber types will have different specifications. A lower durometer, like the Kent tubes at 35, will be easier to pull then a tube with a higher durometer.
 

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Discussion Starter · #14 ·
Did you check the specs of the Primeline tubing?
I have! The Primeline rubber is slightly more dense, with a .97 specific gravity vs .95 with the Kent. The difference is observed in the modulus difference between the two. The primeline's modulus is 125PSI at 100% vs 190PSI at 300% for the Kent. Modulus is a rating of elasticity, or to put it more simply... stiffness. The lower the number the easier it will be to pull, and the more quickly it will retract. According to the sheet you linked to, the Primeline tube would have a pull weight of 11.8lbs at 100% whereas the Kent would have a pull weight of 17.9lbs at 300% elongation. My math says that the Primeline rubber would probably have a pull weight of around 20lbs at 300% but there is no way to validate that, that I know of anyway.
 

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You know a few years ago I did a number of tests on all types of rubber. Of course 4-5 years later Gary can't find all his written down statistics.(Idiot!) I don't know what happened to them. Anyway, I do remember shooting a bunch of different tubes through the Chrony. The one I remember specifically was the Blue tapered tubes from Crosman as being the fastest tubes that I tested. I think I got around a 270fps with a 8mm or 9mm steel ball at maximium extension-maybe 38-40 inches. The fastest set of rubbers of all was a custom tapered single folded cut of .020" flat med latex which did over 400fps.(also with an 8-9mm steel ball) I didn't test any small diameter (Chinese style tubes). They would probably do well. I never did hear of anyone getting over 300 fps using tubes (Except in the old magazine ads-don't believe them). I tried with standard lengths. I think it could be done on a custom length cut with a big extended fork.Very high speeds in slingshots(375-425fps) invariably translates into very short band life though ( 2-10 shots maybe?). Flatband
 

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Aaron, was this the magical K3876 synthetic rubber? What model/ spec did you order (I want to place an order). Alternately, if you have spare, I'd like to buy some from you.
 

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I use reguler store bought thin rubber bands about an 1 and 1/2 inches long to attach my tubes to my pouch,you just loop it over the short pinched end wrap it around untill you run out of rubber band and then loop it over the short pinched end again and its done,been using this method for ever.It would work for attaching flat bands or tubes to the fork also but you would have to put the pouch on after the fork attachment was done.
 

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I use reguler store bought thin rubber bands about an 1 and 1/2 inches long to attach my tubes to my pouch,you just loop it over the short pinched end wrap it around untill you run out of rubber band and then loop it over the short pinched end again and its done,been using this method for ever.It would work for attaching flat bands or tubes to the fork also but you would have to put the pouch on after the fork attachment was done.
can you make a video of that?im not getting how to end it.
 

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I use reguler store bought thin rubber bands about an 1 and 1/2 inches long to attach my tubes to my pouch,you just loop it over the short pinched end wrap it around untill you run out of rubber band and then loop it over the short pinched end again and its done,been using this method for ever.It would work for attaching flat bands or tubes to the fork also but you would have to put the pouch on after the fork attachment was done.
can you make a video of that?im not getting how to end it.
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Me neither... even pictures would help me to understand.
 

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No picks or vids but you put the tube or flat band thru the hole in the pouch now you pinch the tube or flat band over like you were going to tie it with string or whatever but instead you take a rubber band put it over the short piece of band or tube stretch it and keep wrapping untill you almost run out of rubberband and just loop it over the short piece or tube or band and its done!!!
 
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