Do sew stiffeners or not to sew?

[alexey 6]

Some manufacturers makes stiffers the same as flaps, and place binding over stiffeners, so when you binding, you actially sew thry plastic (Mirage).

Some tend to make stiffenrs a little smaller, to place them near bindings. So - you dont sew plastic, and can use lighter machine (Javelin).

What is pro and cons in each case?

Sorry for bad English

Lexa

[masterrigger1 2]

Alexy,

The stifferners that are sewn tends to break in the sewn areas over time. The use of MDS plastic has somewhat lessened that problem though.

The stiffeners that are captured, not sewn, sometimes break/tear out of the surrounding fabric over time.


MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[alexey 6]

And - what is the best?

Lexa

[riggerrob 558]

That is a matter of opinion.
Al Macdonald at Flying High insists that when he catches stiffeners in the stitching that holds binding tape, that they are much stronger.
On the other hand, many manufacturers avoid binding stiffeners because it is really hard on (quickly wears out) the sewing machines used for binding.
Also remember that sewing binding tape on over top of stiffeners requires a highly experienced sewing machine operator.
Also consider that some manufacturers just leave the inboard edges of their stiffeners loose (inside an inner layer of fabric, while others catch them in an inner binding tape, while still others sew through the stiffeners once or twice.
There is more than one way to skin a cat/ install stiffeners.
Personally, I prefer to bind most of the edges before installing stiffeners and reserve bound stiffeners for the last one or two visible flaps (i.e. pin covers).

[FrogNog 1]

I would prefer the free stiffeners, unless someone could show me they had less durability, or unless there were places where they wouldn't work.

It seems to me that repairs could be done by more people due to the lighter machine requirements. It also seems to me that where breaking out is a real concern, the breakout location(s) could be reinforced with wide tape on the inside before closing the piece to contain the stiffener.

-=-=-=-=-
Pull.

[masterrigger1 2]

Quote

On the other hand, many manufacturers avoid binding stiffeners because it is really hard on (quickly wears out) the sewing machines used for binding.
Also remember that sewing binding tape on over top of stiffeners requires a highly experienced sewing machine operator.

Rob,
We here at Skyworks use a small oven to preheat the plastic for 30 minutes @115-125 degrees.
it is then removed and sewn into place.

The plastic then sews like butter and the plastic seems to last longer.

The lack of generated stress during needle penetrations when it is cold would be my guess.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[CrazyL 0]

(Also remember that sewing binding tape on over top of stiffeners requires a highly experienced sewing machine operator.) Thanks for the compliment. Just did several stiffener/binding/grommet jobs this past week. I get hired by people to do that particular job often.

[alexey 6]

Quote

We here at Skyworks use a small oven to preheat the plastic for 30 minutes @115-125 degrees.
it is then removed and sewn into place.
The plastic then sews like butter and the plastic seems to last longer.
The lack of generated stress during needle penetrations when it is cold would be my guess.

Smart idea.
I hope 115 deg - its Fa, not C :)
How long did you do like that? Did you find any cons of such method?

Lexa

[CrazyL 0]

overcooking. I'd suggest working with scrap first.

[riggerrob 558]

I also know a few riggers who like to pre-heat grommets in the kitchen oven before pounding them into place.

[crazydiver 0]

These are all great ideas!

Cheers,
Travis

[aironscott 3]

Mel-
Thanks for passing that info on. It only makes sense that making the nylotron more plyable would make it easier to sew through. I'll be trying that on the next rig I build. My double needle doesn't seem to care what it goes through but I have often tried to find a better way to sew through the plastic.
Thanks!
Aaron

“God Damn Mountain Dew MotherFuckers!”

[johnny1488 1]

Quote

Some tend to make stiffenrs a little smaller, to place them near bindings. So - you dont sew plastic, and can use lighter machine (Javelin).

If you are talking about the main flaps SunPath now sews the stiffener. I think it is a huge improvement. Look at an older Javelin and fold the tuck tab under the flaps. The binding tape almost always rolls under. I have seen a lot of flaps come open this way and a lot of unnecessary wear. Not to mention its really ugly.

Johnny
--"This ain't no book club, we're all gonna die!"
Mike Rome

[alexey 6]

Just found...

Some manufacters do not sew thry plastic at all - just put them in pocket, made of type 12, that sewed to the inside part of flap (something like RI - Voodoo...)
So, the only fixation for plastic - its a grommet.
What is disadwantages of such method?
May be - loose ends can damage flaps (but, type 12???)

Lexa