Isolating Crazy Jim's fingertip bp charges

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Crash-n-Burn

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Hi folks,

I've had success with CJ's bp charges discussed in the 3in Darkstar build, where he uses bp in the fingertip of a latex glove taped to an e-match. I'm switching up a couple of rockets to use redundant altimeters with backup charges. It has occurred to me that the heat from the first bp charge may ignite the backup since it is only insulated by the dog barf in the payload or booster.

I'd prefer not to switch to charge wells, so I'm interested if y'all have come up with a way to protect the backup charge. Seems like a few wraps of masking tape to encapsulate the backup charge would do the trick, is it that simple?
 

cwbullet

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You can also use finger cots. They are basically just small rubber sleeves for your finger tips.
 

Ravenex

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We use glove tips and wrap them with blue tape after filling. We did ground tests to try seeing if the main charge would blow the backup. It's a non issue.
 

cwbullet

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We use glove tips and wrap them with blue tape after filling. We did ground tests to try seeing if the main charge would blow the backup. It's a non issue.
I would concur. I have head of back up charges going off but suspect it had very little to do with the type of charge container.
 

blackjack2564

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I've been using them for over 12 yrs. & never had an issue with one setting the other off.
Even when putting 7 grams in them. The larger the rocket, farther apart they are on the bulk plate & think this helps a great deal. I always have them on opposite sides of the BP eye bolt.

Lately I run 2 charges out the same hole on BP, but space them on opposite side of eyebolt & tape to BP to hold in place.
I always have run a strip of tape around the glove tip & label it, this also helps isolate the charge.

DSCN1479.jpg
 

ep29030

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I've never had it happen in my dual altimeter setup.I also use the latex glove tips, but I separate the charges -- one on each side of the bay cap, and I put a layer of dog barf over everything. If you want extra safety, just wrap the last charge with a small piece of nomex cloth. Absent that, heavy cotton fabric would also protect the charge. it is hot but it only lasts a fraction of a second.
 
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