Tubular nylon vs nylon webbing for recovery harness

[kjkcolorado]

I'm shopping for recovery harness material for a HPR scratch build using 4" blue tube. The tensile strength of the 1" tubular nylon I have seen on Amazon is 4000 lbs, compared to 4200 lbs for 1" heavy nylon webbing (non-tubular). With similar tensile strength ratings, what are the advantages/disadvantages of each? Or, more simply, what do you use and why?

 

[Nessalco]

Tubular nylon has several specific characteristics that some folks like. It has significant 'give' when placed under load, it is resistant to abrasion, and it ties easily. There are also some special knots that can only be tied in tubular product.

I use kevlar.

Kevin

 

[Handeman]

If you are building a 4" rocket, why are you looking at 1"?. It seems like a lot more then what you need unless they are going to be much heavier then most 4" rockets.

I've had 9/16" tubular Nylon, 1/4" tubular Kevlar, and 1/2" Kevlar mule tape as shock cords in my 4" rockets up to 15 lbs and never had an issue.

I would prefer the tubular Nylon or Kevlar over almost anything else no matter what size you decide on.

 

[kjkcolorado]

Handeman, I was only using the 1" as a reference for the similar tensile strengths of tubular nylon vs nylon webbing. I found those numbers quickly in my online search. Reading my original post, it does seem like I was deciding between the 1" versions of each for my 4" blue tube project. Sorry for the poor wording. I will be using a smaller size strap (probably 9/16", since that seems relatively easy to find).

Just thought of another question regarding the two nylon strap choices. I am planning to sew my own loops per the tutorial on John Cocker's website (using a sewing awl, the Speedy Stitch, using crossing lock stitches). Coker demonstrates the technique on nylon strap, not tubular nylon. Can the tubular nylon be stitched the same way?

 

[o1d_dude]

I prefer the red 1/2" tubular nylon from Sports Chalet for about 25 cents a foot. It's very soft which makes it easy to stow in the body tubes, etc.

Don't know if Sports Chalet is local to you but if it is, check them out. The cordage is usually in the camping/climbing section of the store.

REI also sells a 9/16" tubular nylon but it's a bit heavier and stiffer than the Sports Chalet stuff. I've never tried washing it to see if it softens the material but recall having heard that somewhere.

 

[kjkcolorado]

Anyone who hand stitches their own loops in tubular nylon? Looking for any feedback/experience there....

 

[o1d_dude]

Anyone who hand stitches their own loops in tubular nylon? Looking for any feedback/experience there....

Yes, I do.

You'll need a sewing awl like this (https://www.speedystitcher.com/) for ease of sewing through the double/triple thickness of the tubular nylon. I bought mine from Amazon but you can probably find it locally at Walmart, Tandy Leather, etc.

Member John Coker has a video tutorial that I followed and the results were pretty good. Here's the link to John's website... www.jcrocket.com

John's many tutorials are an excellent resource as is his www.Thrustcurve.org online motor sim.

Edit: I forgot to mention member OneBadHawk who sells finished kevlar and tubular nylon shockcords. www.onebadhawk.com

 

[kjkcolorado]

Sewing awl is already on the way from Amazon. Found one local, but was over 2x the cost for the same thing. I've seen Coker's tutorial (thanks John!). He uses nylon strap/webbing in his tutorial video. I'm assuming it works the same on tubular nylon.

 

[Handeman]

You might want to look into the stitch pattern for the loops. I've always seen the box patterns, but from what I've seen on some of the parachute sites, the z pattern is better. The box pattern has a line of stitching across the web and that is a weak point.

 

[o1d_dude]

When I sew loops in my tubular nylon shockcords I use a Z pattern.

The OneBadHawk shockcords also use a Z pattern.

 

[bobkrech]

Tubular nylon should be more flexible than nylon webbing of the same strength and most likely will be easier to stuff in the rocket. It also does not have sharp edges like webbing, and has more shock absorbing capability than webbing.

Bob

 

[jlnel]

Would tubular tend to zipper more? I have not made any for larger rockets yet but i like the info in this post so far and dont think ill worry to much about it.