Making ejection charges ahead of time?

[icyclops]

Do you ride along inside of your rockets so that you can untwist the wires at apogee?

What’s wrong with you guys? Geeeezzzzz

 

[Sooner Boomer]

But can I make them (ejection charges) and keep them in an ammo can or similar for use at the launch? With the leads either still insulated or twisted together?

Yes. If you're concerned about static, you can keep the built/wired charges inside a silver static protection bag, like are used for circuit board. They are easily/readily available. If you can't find one, PM me and I will mail you a large one.

Static in general - use fabric softener. That's one thing it is supposed to do - reduce "static cling". You can even dilute it and put it in a spray bottle to spray on odd surfaces. In material handling, I've had to deal a LOT with static electricity (did you know it only develops on insulating materials?). I can tell you horror stories about stuff clinging where it is not wanted (but no earth-shattering ka-booms...).

 

[hball55]

Do you ride along inside of your rockets so that you can untwist the wires at apogee?

Don’t install ejection charges in your rocket until you get to the launch. Before going to the LCO/RSO table, you will want to double check everything, connections, etc. If your charges are already inside your rocket, it’d be a pain in the butt opening the rocket up to check. Remember, wires can come loose while driving down the road to the launch, so why invite disaster just to save a little time.

 

[tbonerocketeer]

I used to be a professional pyrotechnician who fired display fireworks shows. We had a strict policy of NOT "squibbing" (e-matching) any live fireworks until they are set up on-site. This was due to their sensitivity to shock. That said, if you protect them from shock (like you said by carrying them in an ammo can), and twist the ends together (ALWAYS) to prevent a static charge, it is perfectly safe.

FYI:

I've seen a string of 3 6" shells fire during the fireworks squibbing process due to static charge. Remember, wind builds up static electricity on your clothes.

A crew on another company's shoot were all killed when pre-loaded and squibbed mortar racks that were being unloaded from a semi trailer suddenly fired. It just takes a good pinch between hard surfaces to fire an e match.

2 totally different animals. The crew killed in a truck in NC was matching during lightning in the back of a box truck is what I have been told. I shoot shows as well and we have prematched devices all the time. A shunted match is safe for travel. Preloaded ejection charges are normal in my opinion, have done so for over 15 years.

 

[OverTheTop]

Don’t install ejection charges in your rocket until you get to the launch. Before going to the LCO/RSO table, you will want to double check everything, connections, etc. If your charges are already inside your rocket, it’d be a pain in the butt opening the rocket up to check. Remember, wires can come loose while driving down the road to the launch, so why invite disaster just to save a little time.

I always prepare before launch. The rocket is treated like a loaded gun and not pointed at anyone from that point, until launch. All launches successful so far .

 

[gary7]

This is what I am getting out of this:

1) It seems that from the personal experience of a few that unwanted firing of an e-match does happen thus more caution is warranted. Always better to error on the side of safety. I like Crazy Jim's advice to wear protective glasses as well.

2) It is ok to install or tape your e-match or igniter in the electronics bay, minus the battery connection and 4F in my hotel room or at home prior to a launch.

3) Installation completion just prior to launch made easier by loading a premeasured amount of 4F in a container of some sort to save a few minutes at best, but to also help reduce effect of wind while trying to do so.

I personally use a well of some type most often, taping the igniter to the outside and bending it over into the well then pouring my 4F into it. (Hmm, isn't this the way most of us do it?) Other times however I do use a rubber glove finger tip. It is not that difficult to load an e-match in either but it does save a bit of time and means I have one less step to do at a launch site. Especially for very busy launches like MWP or during a very cold, windy day, like at MWP.

The real concern for me is an e-match lighting while in a pod or finger tip with any amount of 4F.

As side note, does a small bottle like this pose a static problem?
The small tip is useful for pouring 4F into a measuring tube like an ejection charge container.

My 2¢

 

[Steve Shannon]

I measure mine at my table using a Lee powder measure scoop. Someday I’ll get one of these:
https://www.midwayusa.com/product/1002220681?pid=431413

 

[Ez2cDave]

What’s wrong with you guys? Geeeezzzzz

Agreed . . . The issue of safety is not a joking matter.

Dave F.

 

[mtnmanak]

I measure mine at my table using a Lee powder measure scoop. Someday I’ll get one of these:
https://www.midwayusa.com/product/1002220681?pid=431413

One of these kills two birds with one stone: carries powder and measures out variable amounts all in one tool:

https://www.midwayusa.com/product/1023140946?pid=637942

 

[Sooner Boomer]

This is what I am getting out of this:

1) It seems that from the personal experience of a few that unwanted firing of an e-match does happen thus more caution is warranted. Always better to error on the side of safety. I like Crazy Jim's advice to wear protective glasses as well.

2) It is ok to install or tape your e-match or igniter in the electronics bay, minus the battery connection and 4F in my hotel room or at home prior to a launch.

3) Installation completion just prior to launch made easier by loading a premeasured amount of 4F in a container of some sort to save a few minutes at best, but to also help reduce effect of wind while trying to do so.

I personally use a well of some type most often, taping the igniter to the outside and bending it over into the well then pouring my 4F into it. (Hmm, isn't this the way most of us do it?) Other times however I do use a rubber glove finger tip. It is not that difficult to load an e-match in either but it does save a bit of time and means I have one less step to do at a launch site. Especially for very busy launches like MWP or during a very cold, windy day, like at MWP.

The real concern for me is an e-match lighting while in a pod or finger tip with any amount of 4F.

As side note, does a small bottle like this pose a static problem?
The small tip is useful for pouring 4F into a measuring tube like an ejection charge container. View attachment 458048

My 2¢

You *can* use one, but you may experience grains sticking to the inside from static. There are MANY measuring tools for shooting black powder that might work better, if you can find/afford one. Almost all are made from metal.

 

[davdue]

I've been saving them for that reason, though I'll need to 3D print a skinnier funnel! I think if I try to pour it even on a fold of paper, I'll end up covering my desktop with BP!

I have always used the cardboard top from an AeroTech reload (when they came with it stapled on the bag). I keep it in my range box and it is always available whether I am prepping charges at home or at the pasture. Yes I fly with the Kloudbusters. Thankfully if it is AirFest I have my trailer and it is just like prepping at home. I measure by weight pour it from the scale top to the cardboard and then put it in a saved centrifuge tube that gets marked with the amount. I the case of big rockets several tubes taped together and marked.

 

[BSNW]

I agree that measuring at the field is not easy. I compromise by pre-measuring a lot of charges in centrifuge vials and installing the e-matches in the rockets at home (so, e-matches installed, charges separate until I get to the field). At the field, I pour the charges in the wells or in the pre-constructed vial/e-matches, stuff with dog barf and tape or cap. Easy to do at the field and no worrying about measuring.

I realize everyone has their own method and we all have to make our own decisions about what level of risk vs. time we are willing to accept. For me, this method gives me the comfort level vs. time-to-prep at the field that I am comfortable with.

In the photo below, the charge vials range from 0.5g in the upper left corner to 2.7g in the lower right, incrementing by 0.1g. I re-use the vials.

View attachment 457737

View attachment 457738

I can always tell if a person in rocketry works in a lab by certain items seen at the field or in their range box. -80 freezer boxes and old tips boxes are great for storing rocketry items! I use old tip boxes to store my altimeters...and all kinds of other goodies. Never seen cell-cryo vials used for charges, maybe 2ml tubes. Great idea.

Andrew

 

[mtnmanak]

I can always tell if a person in rocketry works in a lab by certain items seen at the field or in their range box. -80 freezer boxes and old tips boxes are great for storing rocketry items! I use old tip boxes to store my altimeters...and all kinds of other goodies. Never seen cell-cryo vials used for charges, maybe 2ml tubes. Great idea.

Andrew

As other people have noted in this thread, FFFFg powder is roughly the same by weight or volume, so 1g of powder is roughly 1ml of powder. The cryo vials can perform a double duty in the field for quick reference and approximate measuring. When I go to the field, I carry most charges up to and including 5g, but over the summer, I went to a launch, but forgot all my freezer boxes at home. I had a bunch of empty vials and a can of BP with me, though, and had long since taught my kids how to measure out charges, so my daughter setup a BP station and would pour out vials for me as I called out the charges I needed. Also, after we get home from launches, my kids know one of their "recovery" duties is to refill all the BP vials and put the boxes back in order.

I hadn't seen anyone else use the cryo vials and freezer boxes before, but I had them on-hand and realized they would work great for BP. Mother of invention, and all that...