Model Rocket Building Blog

Model Rocket Building Posts

Sport Rocketry / Components / Recovery / Shock Cords

    Simple Shock Cord Install Tool (2010-08-01)
    This tool is so simple it almost seems ridiculous to post it. Over the past few months I've been burning through a surplus of Micro Maxx engines. Some MMX rockets have minimum diameter tubing, too ... [Read More]

    Estes Shock Cord Mounts TIP (2010-10-31)
    I'm not a big fan of the Estes "Tea Bag" shock cord mounts. I never had any pull out at ejection, they just tend to be too bulky in a smaller diameter tube. Years ago, Estes would pre -print the ... [Read More]

    More Shock Cord Mount Ideas Part 1 (2011-04-04)
    In a recent YORF post, James Jason Wentworth ( Blackshire ) came up with a great variation of the G. Harry Stine "Shock Lock" shock cord mount. Anytime there is a post by Jason, I always read it ... [Read More]

    More Shock Cord Mount Ideas Part 2 (2011-04-16)
    While Jason Wentworth (Blackshire) used standard copy paper, I wanted to try some Tyvek. This is used in strong envelopes, you can't tear through it every easily. THE TYVEK DID NOT WORK! I had an ... [Read More]

    More Shock Cord Ideas Part 3 (2011-04-18)
    Continuing on with Jason's shock cord design, Here's what it looks made with 24 lb. paper. The shock cord was laced through the three holes. The lower half was folded over and glued over the shock ... [Read More]

    Harry Stine Shock Lock Patent (2011-06-18)
    This is the approved patent for G. Harry Stine's Shock Lock or shock cord retainer. This one goes back to 1970 when he was with MPC. I remember seeing these first in the old Minijet kits. It's a ... [Read More]

    Old Shock Cord Mounts - Before Kevlar (2012-03-04)
    A while back I got an email from a Mr. Hamblin asking how to install a shock cord in a smaller diameter body tube. Here's the response I sent him: Old School: You could always cut two slits in the ... [Read More]

    Old Centuri Shock Cord Mount (2012-04-03)
    Here's another way to do a shock cord mount, this time from the old Centuri SR-71 Blackbird kit. The "two identical shock cord fasteners" could easily be cut from 110 lb. cardstock. On the JimZ ... [Read More]

    Kevlar Zipper Protector (2012-09-08)
    Chuck Haislip (CWBullet on TRF) is working on a new style of  "bumper" to prevent Kevlar zippers at ejection. "If you are worried about a zipper, take a Nerf Dart and remove the end. Feed ... [Read More]

    Braided Kevlar - CHEAP! (2012-11-06)
    I\'d seen a post about the Kevlar Store on TRF. http://kevlarstore.webs.com/ I finally ordered some 100 lb. and samples of the 135 lb. Kevlar.! Here\'s how the 100 lb. spool arrives. This is ... [Read More]

    Kevlar Unraveling? TIP (2013-02-10)
    I was tying off some three strand Kevlar. Three strand Kevlar (not the braided type) has a tendency to unravel on the ends. In the picture on the right you can see it starting to separate. Before ... [Read More]

    Replaceable Kevlar Article in Apogee Peak Of Flight Newsletter (2013-05-08)
      My article on Replaceable Kevlar Shock Cords was published in the Apogee Peak Of Flight newsletter yesterday: You can download issue 338 HERE This is a simple new way to install a ... [Read More]

    Cutting Kevlar? Tip (2013-07-11)
    I've read that Kevlar is 5X stronger than steel. Why not cut Kevlar the same way you would cut steel wire? I've cut Kevlar with scissors, but was concerned it could ruin the edge. A knife could ... [Read More]

    Apogee Peak Of Flight Article - Minimum Diameter Replaceable Kevlar (2013-07-17)
    I've written a new article for the latest issue of the Apogee Peak Of Flight Newsletter, # 343. This method shows how to install a Replaceable Kevlar Line in Minimum Diameter (BT-20 and BT-50) ... [Read More]

    Tri-Fold Shock Cord Mounts, Part 1 (2013-09-08)
    Here's how I remember shock cord mounts in the first kits I built: Cut two slits, collapse the middle, insert the shock cord and glue shut. How did we ever insert the cord from the top and ... [Read More]

    Tri-Fold Shock Cord Mounts, Part 2 (2013-09-10)
    The tri-fold was first shown first in the 1968 catalog and on the AeroFin model, DOM Plan 53. This illustration is from the 1969 Estes Catalog "Yellow Pages" showing the Alpha construction - HERE ... [Read More]

    Another Kevlar Resource (2014-05-10)
    Here's another source for Kevlar shock cords: EMMA KITES http://www.emmakites.com/Wholesale-kite-line_c365 1,000 feet of 150 lb. twisted Kevlar for $16.50? WOW!!! Braided Kevlar is also ... [Read More]

    Checking The Kevlar Line (2014-06-14)
    I got a Email question on how to check the condition of the Kevlar line: After the third flight of the Quest X-15, I pulled the Kevlar loop off the rear of the engine mount tube. This model ... [Read More]

    Kevlar Inventor Dies (2014-06-21)
    WILMINGTON, Del. (AP) -- Stephanie Kwolek, a pioneering female chemist at DuPont who invented the exceedingly tough fibers widely used in Kevlar body armor, has died, colleagues said Friday. She ... [Read More]

    New Estes Shock Cord Mount (2014-08-09)
      John Boren mentioned a new Estes shock cord anchor used in the Pro Series II E2X kits at the NARAM Manufacturers Forum. I went to the Estes Website to check it out - CLICK HERE These ... [Read More]

    Kevlar Loop Knot (2014-11-30)
    When you put a tight loop to make a knot in three strand Kevlar it tends to unravel. (On left) Before tying the overhand knot, over twist to tighten the line to overcompensate where the line ... [Read More]

    Public Missiles Shock Cord Knot (2014-12-04)
      From the Public Missiles Tiny Pterodactyl instructions: https://publicmissiles.com/pml/images/TinyPteroinstructionbooklet.pdf Here's another knot to think about. I still prefer the ... [Read More]

    Better Kevlar / Shock Cord Knot? (2015-05-28)
    Quest kit instructions show a very simple overhand knot to join the Kevlar and Elastic ends of the shock cord. It works fine but I never cared for this knot. I always look for something cleaner. ... [Read More]

    Real Shock Cord Rubber Supplier (2015-09-25)
    On TRF, Caveduck referred a website with the old style shock cord rubber:   "The white rubber has additives and colorants in it that reduce the life. For a longer lasting shock cord, ... [Read More]

    Tri-Fold with Kevlar - TIP (2015-10-14)
    Here's a smart variation on the Estes tri-fold mount. If the shock cord breaks at the mount, simply tie on a new one, onto the Kevlar loop.  Lonnie Joe Buchanon Jr. ‎ Model Rocketry ... [Read More]

    Estes and Kevlar? (2015-10-19)
    Here's the top centering ring on the new Estes Honest John. There is a laser cut hole into the centering ring. Many builder's have asked why Estes doesn't drop the tri-fold mount and switch over to ... [Read More]

    A Better Shock Cord Knot? Tips, Part 1 (2016-06-23)
    Here's how Quest shows to tie the Kevlar to an elastic shock cord. We've all tied shock cords on this way. I was concerned that the tight knot might weaken the tightly cinched elastic. For years ... [Read More]

    A Better Shock Cord Knot? Tips, Part 2 (2016-06-24)
    Tie an over hand loop knot in both the Kevlar and elastic cords. The loops should be about 3/4" long. (Left side picture) Pass the Elastic loop over the Kevlar loop. The elastic loop can pass over ... [Read More]

    Model Rocket News Idea Box - Shock Cord Attachment (2016-09-23)
    From the Estes Model Rocket News, Vol. 3, #1, Feb/March, 1963. Here's an early shock cord retention using an engine block. It's similar to using just a segment of body tube used in the Enerjet ... [Read More]

    New Kevlar Supplier? Part 1 (2017-05-23)
    NOTE: Before you order any Kevlar line from this supplier - Emma Kites,  PLEASE WAIT and read the third post in this series. There is a concern with this Kevlar  that some might have ... [Read More]

    New Kevlar Supplier, Part 2 (2017-05-24)
    For a while, FlisKits included braided Kevlar in their MicroMax kits. Braided Kevlar is made up of smaller lines, is softer and more flexible. The braided Kevlar will burn through and break quicker ... [Read More]

    New Kevlar Supplier, Part 3 (2017-05-25)
    This softer Emma Kites Kevlar can fray at the end. Tie an overhand knot close to the end. Here's the weird thing about the Emma Kites Kevlar. Normally a square knot stays tightly together after ... [Read More]

    Everything I've Posted About Shock Cord Mounts (2018-06-09)
    On TRF, somebody found a listing of all my shock cord mount posts on rocktreviews.com - https://www.rocketreviews.com/shock-cords-2720.html Did you ever get that feeling that maybe rocketry has ... [Read More]

    Shock Cord and Glue TIP (2018-06-13)
    An email TIP from Bruce Levison, "I prefer to use white glue to fasten shock cord mounts into my rockets, that way if they get stuck in a tree they come down after a few rains."  "I also use ... [Read More]

    Unraveling Kevlar? TIPS (2019-03-08)
    When tying an overhand loop knot in Kevlar, the strands can start to unravel. This is shown on the left. The picture on the right shows the knot with the strands still tight. In the top ... [Read More]

    Ed Mitton Snap Swivel Connection TIP (2019-06-23)
    For the longest time I've been tying the parachute shroud lines to the small loop on a snap swivel. It's not the easiest way to attach them. You've got to tie the line ends onto the small loop ... [Read More]

    Free Tri-Fold Mounts PDF (2019-09-07)
    Most build as directed by the instructions - including the tri-fold shock cord mounts. I've never been a big fan of the tri-fold mounts. The mount is usually printed on the instruction sheets, on ... [Read More]

    New Shock Cord Knot? (2020-01-24)
    On Y.O.R.F., Bernomatic found a good knot for attaching a shock cord to a nose cone screw eye or plastic eye on a nose cone shoulder. Imagine a screw eye in place of the fish hook. To learn how to ... [Read More]

    Exocet / Tomahawk Shock Cord Anchor? (2020-05-17)
    On the Facebook Model Rocketry USA page, Robert Spillane posted a picture of his Estes Mini Scale Combo Pack. These were sport scale mini engine rockets, two models in on kit package. Follow up ... [Read More]