Guitar string shock cord anchors

[DynaSoar]

Anyone ever tried a guitar string for an anchor?
Definitely burn proof. Thin enough to wrap around the engine block and slide between it and the body. Got that nifty little nut on one end for a ready-made self-tightening loop. "Normal" tension is around 20 to 40 pounds. Kevlar or nylon tube or cord above that with a bungee loop in it for shock absorbtion, and it should last as long as the rocket.

 

[Planet Andy]

DS

That's a cool idea, I've got lots of those hangin around. You thinking unwound? maybe a .10 or .12? I wonder about the (lack of) flexibility or maybe stretchiness is a better word and if the body tube could possibly get sliced if things aren't pointed in the optimal direction on ejection. More experiments in order.

Andy

 

[Micromeister]

Interesting Idea Dyna:
Haven't tried guitar strings, and i've got a ton of old ernie ball super slinkie's laying around I'll have to give it a try.
I have had very good luck on Model Rockets & LMR's with 1/32" #3458T21 185lb 1x19strand Stainless Steel wire rope @.09ft, 3/64" #3458T22 375lb 1x19 strand st stl. wire rope @ .12ft, and 1/16" #3458T23 500lb 1x19 strand st stl wire rope @ .19ft. from McMaster-Carr. Either mechanicak crimp sleeves or twiest and solder a loop have worked very well. These cables are almost as limp as new rope. very nice to work with

 

[DynaSoar]

Originally posted by Planet Andy
DS

That's a cool idea, I've got lots of those hangin around. You thinking unwound? maybe a .10 or .12? I wonder about the (lack of) flexibility or maybe stretchiness is a better word and if the body tube could possibly get sliced if things aren't pointed in the optimal direction on ejection. More experiments in order.

Andy

Something high E or B. It'd be a zipper risk if it went past the end of the tube. I was thinking of just running it to the end, tying a loop there, and running kevlar or nylon through the loop. Tube wouldn't need any additional spreading to prevent zipping, but kevlar might. Stick a small strip of duct tape at the right height to meet the end of the tube, slap another small strip face to face with it, with the cord between. To pack it, wrap it around the finger in a helix, slide that in, and pack everything on top. Shouldn't be enough spring in it to pop out.

 

[DynaSoar]

Originally posted by Micromeister
Interesting Idea Dyna:
Haven't tried guitar strings, and i've got a ton of old ernie ball super slinkie's laying around I'll have to give it a try.
I have had very good luck on Model Rockets & LMR's with 1/32" #3458T21 185lb 1x19strand Stainless Steel wire rope @.09ft, 3/64" #3458T22 375lb 1x19 strand st stl. wire rope @ .12ft, and 1/16" #3458T23 500lb 1x19 strand st stl wire rope @ .19ft. from McMaster-Carr. Either mechanicak crimp sleeves or twiest and solder a loop have worked very well. These cables are almost as limp as new rope. very nice to work with

I was thinking of wire rope, and of fishing leaders, when I thought of this. You're right, a crimp sleeve would be good. Poking yourself with the end while trying to tie one is not fun, often for several days.

And you can't beat the price. Either you've got them lying around, or will, like we do, or if you don't play you probably know someone who does. And, there's always music stores to go beg throw-aways from.

Those cheap, brass wound rock hard Black Diamonds are still around. I bet I can find the steel .013 and 0.17s for less than a buck each.

 

[rstaff3]

I other flexible wire works, I'd assume guitar strings would also. Would they be cost effective? Or only if you play and generate your own leftovers?

 

[DynaSoar]

Originally posted by rstaff3
I other flexible wire works, I'd assume guitar strings would also. Would they be cost effective? Or only if you play and generate your own leftovers?

Or someone else's leftovers..... as I said there's always music stores.

I'd check out a music store and find out what their cheapest high E or B string goes for and compare it to, say, uncoated steel fishing leader in both price and the hardware it comes with. A guitar string has a hollow nut twisted into one end.

The traditional "cheap" guitar strings, "Black Diamond" are going for just over $5 a set on the web, so probably $6 a set or so in the stores. The plain (that is, not wound) higher stringers (B and high E) will be cheaper than the others, so singly you could possibily find them for less than a dollar. How does that compare with fishing leaders?

 

[cls]

if you don't already have guitar strings in the house... for about $3 at the hardware store you can get a really big roll of "music wire", spring steel.

I've heard reports of the braided wire fishing leader burning through, so I never tried it, just used kevlar instead.

 

[DynaSoar]

Originally posted by cls
if you don't already have guitar strings in the house... for about $3 at the hardware store you can get a really big roll of "music wire", spring steel.

I've heard reports of the braided wire fishing leader burning through, so I never tried it, just used kevlar instead.

That's be the stuff if it's steel. Probably best to us e.01 to 0.2" dia.

It kinks and then breaks if folded, so when bending it for loops etc., bend it smoothly. And be careful of the ends. When they poke you it hurts like boogers for days.

 

[Manwithbeers]

I tried braided steel fishing leaders and braided steel picture framing wire. Neither worked well. The picture framing wire didn't last even 1 launch. It Kinked stuffing the tube and then broke or burned through on ejection. ( I was using an anti zipper device which slowed the release of the hot gasses) The fishing wire lasted 4 or 5 launches and broke. I've had much better luck with nice flexible kevlar thread combined with rubber cord.
Just FYI

Layne

 

[rstaff3]

Where wire works well in my experience is in a short leader that serves as an attachment point for the main shock tether. Like the NCR Gorilla mount.

 

[GL-P]

I use light steel leaders on my CAR L2 cert rocket. The leaders were used to pull the pin on the beeper. No problems so far.

 

[urbanek]

I wouldn't use steel. One of the compounds produced by black powder is sulfuric acid. It's very corrosive. If you have a large mass of steel (like you would in a Level 2 or Level 3 sized bird) you may only notice the that the surface of the wire leader gets rougher and rougher over time. In a small wire (like a quitar string) I think it would just unexpectedly break, sooner or later.

urbanek

 

[Bowhunter]

Well Im a Bass player and I play a 5 string That low B string I could use to pull a truck out of a ditch LOL

 

[Micromeister]

Personally I like the 1/32" braded stainless cable I posted earlier, It can be knotted (once) at the anchor end and embedded in epxoy inside the MMT or single wrapped around a cardstock motor block than epoxied in place. 303 and 304 alloy withstand the exhaust by-product problem while remaining nearly as limp as a piece of stiff kevlar. Tiny Hipress sleeves make crimping an attachment loop simple, while edges of the sleeves can be filed and sanded very smooth.
I looked at my batch of old strings, I think they well be way to stiff for anything smaller then BT-80's. Dyna, sounded good at first