I wanted to thank all who responded.I'll look into this,again very good advice and ideas.cjp.

By coincidence I had to remove the old shock cord from my 80's Estes Icarus this last Sunday.

What I do is use a small flat screw driver and carefully remove the shock cord mount. This will tear the inside layer of the body tube as well. After that I smear white glue inside the body tube, let dry completely and then use a round file to clean the inside and make everything smooth.

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My rocket fleet and more @ Leo's Leisure Site and on YouTube - My latest project: ALTDuino

What method are you going to use installing new one?cjp.

Earlier this year, I designed a removable shock cord anchor that can be made of either thin sheet steel or resin-impregnated beveridge board (the material that Centuri/Estes fiber fins are made of). For 13 mm rockets, it can be made of steel wire. All of them can be retro-fitted into existing rockets, and they allow the anchor and shock cord to be easily removed for inspection (and to replace the shock cord, if necessary). For tandem Kevlar/elastic shock cords, they make it easy to tie the elastic to the Kevlar *below* the top edge of the body tube, which prevents the abrasive Kevlar from "zippering" the body tube.

Dr. Roy F. Houchin built prototypes of the sheet steel version, and he also wrote an article (illustrated with photographs taken by his wife) that Tim Van Milligan published in his "Peak of Flight" newsletter. The article is in one of the issues between #224 and #244. (I apologize for not being specific, but I forget which issue it's in, my computer with a link to the exact issue died a few days ago, and I have a *slow* internet connection.) The "Peak of Flight" newsletter archive is here: http://www.apogeerockets.com/educat...ter_archive.asp

I hope this information will be helpful.

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I'll be using the same Estes paper shock cord mount however instead of using a rubber shock cord I'm going to be using a Kevlar string (aprox. 8 inches long). At the end of it I will be attacking a long shock cord so I can easily replace it if needed.

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Leo

My rocket fleet and more @ Leo's Leisure Site and on YouTube - My latest project: ALTDuino

I'm still looking thru the newsletters,I have plenty of time,Leo I don't have kevlar thread,the braid kevlar would be to thick to make a loop.I bought some hemp cord at the hobbylobby a while back,and read somewhere if you put a light coat of white glue on it that it would hold up to the heat of ejection,thought I might give that a try.I hope to use this imput from everyone on future fixes with other rockets. I've learned alot today.The first rocket that I'm going to try this on is a Estes Viking(small Dia.tube),then my Custom Redliner. All the rest have kevlar shockcords that are 2 to 3 times the length of the rocket.As I stated these are attached with clay epoxy.But I don't know if I'll continue this practice.The clay is expensive and it use can be appiled elsewhere.

I found a spool(50 yards) of kevlar thread on ebay,I'll use the thread to form a loop short of the end of the tube and use braided elastic.The thread is used for kevlar vests.Looks to be the same size as a regular spool of thread.Should I use two pieces in the loop or would one do? I'll use 5 min. epoxy to attatch things.

Found and bought 100ft of med. kevlar that looked heavier than kevlar thread.This should do it.Got old mount out with out any trouble or damage to the tube.Thanks to everyone who responded.So much to learn from the members of De Olde Rocket Forum.

Hemp cord and hemp rope have a reputation for developing interior rot where you can't see it. You don't know that the rot exists until the line parts. Sailing ships of yore eventually replaced their hemp lines with sisal rope because of this. Just so you know.

Another good option is to make a shock cord anchor out of nylon coated stainless steel fishing leader. It will not burn, will not rot, and will not corrode. Attach it deep in the tube, and make it just long enough to reach the lip of the tube. Then tie elastic or another shock cord material that you prefer to it. The stainless steel leader will be permanent, while the shock cord attached to it will be replaceable. If you make the leader long enough, and bury it deep in the tube, you can easily reach it to attach the shock cord by pushing the free end out through the motor tube. Then you can tie on your shock cord and push the combination back through the motor tube and up and out of the top of the tube. As long as you make the steel leader more than half as long as the distance from the top of the motor mount to the top of the tube, and anchor it more than halfway down in the tube, this arrangement will work.

MarkII

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I took some hemp string and put a light coat of white glue on it and it did just what I thought it would.It became stiff,so that's when I found some med. kevlar string.It's thicker than the thread and not as thick as the braided 700lb. that I have and use on my larger rockets.I'll make a loop and attatch elastic as replacements on my smaller rockets.Thank you for the information,yet another great idea.cjp.