Technical Articles

Rubber Bands Break for a Reason

6/15/2004

Rubber Stow Bands Break For A Reason

by John Sherman

December 26, 2000

It has become apparent to me that despite the problems in the past with out-of-sequence openings among other things, that people haven't learned that rubber bands break for a reason. The U.S. Government spent a lot of money developing a specification for parachute stow bands. In my 35 years in the sport I have never found an acceptable substitute.

You might find a product which will work most of the time and which might seem to solve your breakage problem. But don't count on it working every time in every situation. If you think about it, you might ask why someone hasn't previously come up with a more durable product. It's such a simple matter, a stronger rubber band, and there are a lot of smart people who have come before us….

I remember the “Red” rubber band that was popular for a while in the 70's. They ended up melting and sticking to the grommets. I remember the Buna "N"  "O" rings. They “spit” lines. I remember the Type 17 riser problem that was traced to a non-Mil. Spec Stow band. If you haven’t had a bag lock due to one of these “unbreakable” stow bands – you probably will. I have witnessed three bag lock/cutaways that are directly attributable to “bands that would not break.”

Consider this; Parachute "system" designers develop components based upon the characteristics of the stow band. This is a fact. I know, as that is what I do for a living, and have been doing it for over 30 years. I strongly advise all parachutists to use only Mil Spec. Rubber Stow Bands. To use anything else can and will compromise your system.

The really good aspect of all of this is that Mil. Spec. Rubber Bands cost considerably less than all of the new-fangled substitutes.