Faster way to tape Z-folds?

My last build was a testbed for how I could engineer the 4-5 lb airframe for extremely fast servicing for multiple flights. I 3D printed a screw-on tailcone for motor retention and used speaker terminals to connect ejection charges. The most elaborate part was the bolt-action retention of the e-bay/coupler to the payload section. I have a detent mechanism to keep the bolt-action locked.

Servicing is entirely tool-less, which leads me to my next problem. It took me maybe 10-15 minutes to make up the taped Z-folds of the shock cord. My first thought was just get a tape dispenser to use in the field, second was to make up a jig to hold all 4-5-6 Z-folds while I tape them...then 3d printing a dispenser and holder all in one...

Finally I came to the realization that there's probably a machine out there in the local bakery to tape that bag of fresh bagles shut in my kitchen. That machine is below, what's everyone's thoughts on using something like this to cut out some of the more tedious parts of flight prep?


excell 7605K/BLU05 Excell 7605K Bag Sealing Tape Dispenser: 1/2" Wide, Blue https://www.amazon.com/dp/B00Z3N453M/ref=cm_sw_r_sms_apa_i_SH1sEb1A0NJ2D

I might be a little nuts for thinking of using something like this, but this is some of what I do for a living.

I don’t find taping the z-folds that labor intensive, so this isn’t something I’d be interested in. I just tear off a few strips in advance, stick them to the edge of my prep table, do a series of z-folds, grab a strip and wrap the folds, then move on to the next section. I takes no time.

Save your money and do like Thirsty.

Or save money and time and don't z fold. Just feed the shock cord nicely into the tube and fly it.

When I do Z-folds, I use a rubber band around each end of the bundle. When deployed, the rubber bands stay wrapped around the shock cord, so resetting the band on the ground doesn't take long at all. I just do my folds, roll the band down and stretch over the end of the folded section, and that's it.

Another fast method I've seen but not actually done myself is to lay out two strips of masking tape on a table a bit more than the length necessary to go around the folded cord. One end of each strip is folded over to stick to the table so the rest of the sticky side is facing up, and the strips are spaced far enough apart to accommodate the whole bundle. The cord is then laid across the bottom half of the strips of tape back and forth to form the bundle, and then the whole bundle is rolled like a rolling pin to take up the last of the tape which naturally wraps itself around. When I saw this done, it was for a mid-power rocket with a six foot shock cord bundled up to be only one foot from the nose to the top of the body tube. The deployment was perfect, and I could actually see the bundle break open and unfurl.

Yup. Hair bands for me. No gummy, sticky tape.

I don't think those bag sealers are available in sizes large enough for most shock cords. You might be able to make something that uses masking tape.

But, I think the best solution is probably just to get someone to help you. If the helper just cuts off pieces of tape to the right length for you, it would probably cut the time in half.

Eric said:

Or save money and time and don't z fold. Just feed the shock cord nicely into the tube and fly it.

Click to expand...

I mostly only do the taping step for large diameter rockets or when the cord needs to be more organized. Also, the tape can absorb some shock as each piece breaks. For most rockets I do what you said and just feed it in. And for some, I do a z-fold and just place the bundle in the tube without tape.

Most of my rockets I use kevlar from MMT or to CR eye bolt. Than go with tubular nylon. Z fold nylon and just use masking tape to hold folds. I also protect nylon strap with Nomex. Keeps strap from getting charred. You just do what you like to do. There is no right or wrong to a lot of this hobby.

An alternative method may be to crochet the shock cord, Tim Van Milligan shows hows its done. You don't need the crochet hook though.

https://www.apogeerockets.com/Advanced_Construction_Videos/Rocketry_Video_31

Also, do you have any more info on your tool-less bay you talked about? Sounds pretty interesting!