Ejection Canisters

[cwbullet]

You use blue tape. I thought that was a sin or something. Just kidding.

[llickteig1]

Lance,

Does this work with "black powder alternatives" like pyrodex? Obviously, I'd have to test regardless, but if anyone has done tests to see if the tubing provides enough containment I'd appreciate the feedback. Surgical tubing looks like a low-cost, easy way to get a system in place.

I am starting to plan out my dual deploy plan of attack and this thread on ejection canisters is very timely and informative. Thanks to all who contributed thus far!

I don't know. BP works great and I haven't personally felt the need to try the alternatives. It wouldn't surprise if it would, though. Someone should do some extensive testing and post the results.

--Lance.

[cwbullet]

I will test pyrogens with it and get back to you.

[RadManCF]

I don't know. BP works great and I haven't personally felt the need to try the alternatives. It wouldn't surprise if it would, though. Someone should do some extensive testing and post the results.

--Lance.

Along those lines, has anyone ever done tests to compare the performance of rigid canisters (blackiron pipe, aluminum, copper pipe, PVC etc.) vs. non rigid canisters? (surgical tubing, cardboard, tape etc.) I would suspect that the rigid canisters would work better with pyrodex, as the container will not expand upon ignition, containing the gasses more effectively, and allowing the powder to burn more completley.

[cwbullet]

Along those lines, has anyone ever done tests to compare the performance of rigid canisters (blackiron pipe, aluminum, copper pipe, PVC etc.) vs. non rigid canisters? (surgical tubing, cardboard, tape etc.) I would suspect that the rigid canisters would work better with pyrodex, as the container will not expand upon ignition, containing the gasses more effectively, and allowing the powder to burn more completley.

I suspect the same of surgical tubing.

[cwbullet]

Something else I have used successfully with both pyrodex and black powder.



Pill canister do use. I just use tape as a lid and throw the metal lid away.

[cwbullet]

In searching today, I found another option that are pre made and do not require an e-match.

Pratt Hobbies: http://www.pratthobbies.com/products.asp?cat=38

[cwbullet]

Here is a picture of Newton's 3rd:



It appears they have closed shop. Their domain is no longer active and will be auctioned if they do not renew.

[glenbo]

I use Blastcaps although I dont know if its the best choice for Pyrodex due to containment issues. Bp is hard to find where I live
but when I find some I plan on switcihing to BP.

[cwbullet]

I did test Pyrodex today with straws, gloves, and latex tubing. I did not get as energetic of a response. It took about 1.3 times as much to separate and it still was not as strong. I will try to get video in the future.

[cwbullet]

Straws:

I tool medium size drinking straws and put an match in one end. I closed that ends with hot glue. After it dried, I filled them and closed the other end with masking tape. It works well. Good idea, Jon.

Similar image:

The only difference is I taped mine shut.

[GaryT]

Pyrodex I just don't get it?? Why would anyone want to use an inferior product to 4F BP? Can't find it locally? Then just order it on line, There are a multitude of places that ship it right to your door, Yes you'll pay a hazmat fee but even at that and depending on how much you buy you can get it for like 25-45.00 a pound and a pound should last the average flier a few years.

For my flights it's 4F BP and nothing else.

[dixontj93060]

I would be very doubtful based on my experience. To get an equivalent response from smokeless powder (I use Hodgdon Triple 7) in a centrifuge tube I have to pack the powder in with a piece of metal tape, fill any gap with dog barf, close and then wrap the whole assembly with another layer or two of metal tape. Smokeless powder works much better in copper tubing. It seems that it the centrifuge plastic container alone does give enough firm containment. The plastic either expands or melts (or both) under heat before you get the smokeless powder to vigorously react. My guess is that you would get a similar effect with a straw, latex glove, etc. as they provide even less rigid containment than a hard plastic centrifuge tube.

I did test Pyrodex today with straws, gloves, and latex tubing. I did not get as energetic of a response. It took about 1.3 times as much to separate and it still was not as strong. I will try to get video in the future.

[jd2cylman]

RE: Ejection Canisters




1) SafeEject by Spacetec



What is the capacity of these? 3 or 4 grams? More? There is nothing on the website about capacity. Kinda odd that they don't list it.

Adrian

[cwbullet]

Safe Eject I and II will fill with about 3-4 grams.
SafeEject EX will take about 6-8 grams.

BlackSky Ejector will take about 4-6 grams.

Pyrodex I just don't get it?? Why would anyone want to use an inferior product to 4F BP? Can't find it locally? Then just order it on line, There are a multitude of places that ship it right to your door, Yes you'll pay a hazmat fee but even at that and depending on how much you buy you can get it for like 25-45.00 a pound and a pound should last the average flier a few years.

Gary: I agree with you. Someone asked the question and I confirmed it would not work.

[Rocketjunkie]

$109 for 5 lb. including hazmat at powder.com

[cwbullet]

I personally have no issue buying it online. I suggest http://www.powderinc.com/

[iter]

I have this in another thread, but it seems relevant to repost here.

I use Pyrodex in paper tubes (coat hanger tubes) with wood dowel plugs that glue in with yellow carpenter's glue.

1 gram opens a 3" tube quite decisively. 2 grams blows out the engine mount. Video below is 1 gram ground test.

I use tantalum capacitors for initiation--cheap as dirt, no hazmat issues, etc.

Ari.

[Rocketjunkie]

I use tantalum capacitors for initiation--cheap as dirt, no hazmat issues, etc.

Do you overvolt them so they explode? What value do you use (uF and voltage) and battery voltage?

[cwbullet]

What type and strength of tantalum capacitors?

[GaryT]

I personally have no issue buying it online. I suggest http://www.powderinc.com/

Yup great service.

[cwbullet]

Yup great service.

I bought some form them for my black powder rifle got it with 2 weeks.

[iter]

I use 10uF, 35V caps. The trick is reverse polarity. 12 volts the wrong way and they explode every time.

I encourage you to experiment with just the cap first, without any powder. One word of warning: you may want to do the experiment outside. The burn produces a nasty smell that can linger in your workshop for hours.

Also, in my experience, axial caps are immune to explosion. There may be something about their construction that contains the heat more evenly. Radial caps like the one in my picture explode reliably for me (haven't had a failure yet).

Ari.

[chadrog]

I use 10uF, 35V caps. The trick is reverse polarity. 12 volts the wrong way and they explode every time.

I encourage you to experiment with just the cap first, without any powder. One word of warning: you may want to do the experiment outside. The burn produces a nasty smell that can linger in your workshop for hours.

Also, in my experience, axial caps are immune to explosion. There may be something about their construction that contains the heat more evenly. Radial caps like the one in my picture explode reliably for me (haven't had a failure yet).

Ari.

I'll never forget that smell - hooked one up backwards by mistake in electronics class, the stink hung around for what seemed like forever!

[iter]

Interestingly enough, with powder, I don't notice the electric burn smell. Maybe it burns up with Pyrodex, or maybe the Pyrodex just has a stronger smell, or maybe it scatters farther, but when I test complete cartridges, all I can smell is the Pyrodex, and even that only faintly.

Ari.

[cwbullet]

I'll never forget that smell - hooked one up backwards by mistake in electronics class, the stink hung around for what seemed like forever!

The only thing worse is hair burning. I will give the capacitor a try.

[RadManCF]

Pyrodex I just don't get it?? Why would anyone want to use an inferior product to 4F BP? Can't find it locally? Then just order it on line, There are a multitude of places that ship it right to your door, Yes you'll pay a hazmat fee but even at that and depending on how much you buy you can get it for like 25-45.00 a pound and a pound should last the average flier a few years.

For my flights it's 4F BP and nothing else.

So, in your opinion, how is pyrodex inferior? I would argue that from logistical and value engineering standpoints, pyrodex is far superior.

[cwbullet]

Added thread for Pyrodex vs. Black Powder.

http://www.rocketryforum.com/showthr...622#post352622

[stealth6]

I too was "forced" to buy black powder online. There are a few, but not many, sources. The problem is that most of them, including the oft mentioned powderinc, won't sell anything less than 5 pounds. Now, I know that buying a larger amount is more cost effective because the hazmat fee is spread out more, but 5 pounds is A LOT of bp in my world. It would take many years for me to use anywhere near that amount. I'm also the only flyer for many miles around, and I don't regularly attend club events, so splitting up a bulk purchase with other folks is not an option.

So, consequently I tried to find a source that would sell in smaller lots. I found only two. One of them - Graf & Sons - sells in quantities of 2 pounds. They also seem to be "good folk" and they offer a lot of choices. So, I purchased from them and have been so far entirely happy with my purchase. Yes, it was pretty expensive in the short term. But over the long time this will last me, in the end it's not all that bad.

So, if your situation is similiar to mine, check them at www.grafs.com.

be safe, s6

[GaryT]

So, in your opinion, how is pyrodex inferior? I would argue that from logistical and value engineering standpoints, pyrodex is far superior.

For use in "Rocketry" 4F BP is superior to pyrodex, Burns quicker, Provides much more energy and requires much less attention to containment, Dirtier yes but when I have 2000.00 dollars invested into a rocket I'm not about to use anything but 4F BP.

Now I'm NOT saying pyrodex dosen't work as well all know people do use it succesfully but not me.