terryg
Well-Known Member
How do you pack your charge wells? I have been using glove tips up to this point but I need to use charge wells on my latest project.
Charge wells
- Thread starter terryg
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Glove tip snugged down into the charge well would work fine. So would dog barf, taped. Or a foam earplug depending on the well size.
Spoon in the BP, insert the e-matches on the top, jam pack with wadding (I use crepe party streamers from a reputable party supplier as they have fire retardant in them), tamp down with a wooden dowel and keep packing till it is level with the top of the well. Tape over with Kapton tape, partly down the sides of the well. One wrap of tape around the outside to make sure it doesn't unpeel from the surface. This sticking problem gets worse as the rocket gets more use.
FYI if you put a shallow groove around the outside of the well you can fit an undersized o-ring over the tape to hold it in place during flight. I do this now and find it much more reliable than just tape.
FYI if you put a shallow groove around the outside of the well you can fit an undersized o-ring over the tape to hold it in place during flight. I do this now and find it much more reliable than just tape.
Crazyrocket
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This is what I do. Glove tip filled with BP, ematch inserted and then electrical tape to seal and surround the latex. This then goes into a charge well with dog barf on top to pack it in and then masking tape across the top and around the side.
I use the copper water pipe caps, 1/2" or 3/4" depending on the rocket size. Nothing fancy or exotic, just pour the powder in, ematch on top and the wire taped to the outside to hold it in place while putting some dog barf in, not packed too tight, but full. I use two pieced of yellow masking tape at 90 deg. across the top. I've never had the tape let loose, no matter how many flight or the profile (up to 50 flights and 80G) or how dirty the cups got.
It's actually hard to peel the tape off the outside when cleaning up.
It's actually hard to peel the tape off the outside when cleaning up.
bobbyg23
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Yup. Done!
I’ve been using these 2ml vials. They work great for 3” and 4” rockets. I use 5ml vials on big rockets (8” airframes). I drill I tiny hole in them for the e-match leads.
https://www.amazon.com/dp/B00NIBG62...abc_QX228H7PXGK9H8GXPDQW?_encoding=UTF8&psc=1
https://www.amazon.com/dp/B00NIBG62...abc_QX228H7PXGK9H8GXPDQW?_encoding=UTF8&psc=1
I've been using centrifuge tubes, with a snap cap; I pierce the bottom, and run the ematch wires thru, and seal it with a dab of hotmelt or rtv, I bought two sizes, in bags of 100, the large ones have screw caps, useful if you have to travel, but you have to remember to remove it, or risk ventilating your rocket.
I've used cartridge cases before. But the same drill as above. BP, match, dog barf and tape.
caveduck
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Be sure to pack consistently and ground test, since you are changing from glove fingers with almost no confinement to packed charge wells with a fair amount of confinement - it affects the energy output quite a bit. I find myself using maybe 40% less BP with wells, of course YMMV depending on how tightly you pack and seal the well. For high altitude (5km+), adding 30-40mm of bonus length on the well helps get much more complete BP burn.
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This is what I use....pvc and cpvc end caps to hold my pvc and cpvc charge wells. Yes, I use two sizes on each. One for the primary and the other for the backup (redundant) charge. I drill holes in the end caps to secure to the bulkhead with bolts and to feed the Firewire through for the large charge well in this example as it's wired directly to the altimeter to minimize other connections. The charge wells are pieces of pvc or cpvc pipe with an epoxy end. I pour a little epoxy into the tube which is sitting on a piece of wax paper. Note the hole for the Firewire. I bend the Firewire head down in a "u" so it rests on the bottom of the well and thread the leads thru the well and out the hole (see actual prepped one.) I weigh my BP out on a small jewelers balance. I then fill well with pieces of recovery wadding and tape over. I also write the weight on the tape and whether it's for the D, M, or in this case, the booster of a two stager. I keep a spreadsheet of ground test results for each rocket which I check before preparing. These wells have been very rugged, reliable and cheap.
