Black Powder question

Discussion in 'High Power Rocketry (HPR)' started by Joe Rocket 97, Dec 23, 2018.

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  1. Jan 5, 2019 #61

    David Schwantz

    David Schwantz

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    So lets say that when you set off a charge and it does not blow the shear pins has any one ever ruptured a tube?
     
  2. Jan 6, 2019 #62

    timbucktoo

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    Not me personally but have heard of others doing so.
     
  3. Jan 6, 2019 #63

    blackjack2564

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    Never in a fiberglass rocket of any size.
    Yes in a cardboard 6in cluster rocket.
    Had 2 8gram charges and both were wired to fire at same time [not intentionally] 16 gram was a bit much...lol
    First...last...only time I EVER let someone else prep my rocket!

    Supposed to have been 4 gr charges x 2 but idiot head was fool'n with his phone at had peanut butter in his ears. Totally messed up in every way.
    Blew off/cratered the top 6in of fincan at apogee, but everything deployed Ok....well kinda, the dead guy in the rocket was vaporized.

    I have a strict sizing for all my rockets from 29mm to 12inch diameter, when followed, it never has failed.
    You are more likely to strip out the shear pins with an over zealous load, than blow up the tube. Unless you really overdo the charge.
     
  4. Jan 6, 2019 #64

    TimothyG

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    I don't see what all the fuss is about. You can order Black powder online by the pound easily with no other major information required. I've been ordering from the same website for over a decade for most of my reloading needs. They just updated their site so I'm a little lost on it but I believe this is the link for 4fg. https://www.powdervalleyinc.com/product/goex-black-powder-ffffg-1/
    Great company but really slow on shipping things and they charge the full hazmat rate.
     
  5. Jan 6, 2019 #65

    seth_cooper

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    Could you elaborate on this?
     
  6. Jan 6, 2019 #66

    blackjack2564

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    What I do may/may not apply to you.
    Everyone builds a bit different than each other. How tight you want couplers/tubes/nose cones, to fit.
    I keep track of every rocket built and how much BP is used for charges.
    Often overlooked is...in fincan you may fit a small 2 grain motor or a full 6xl motor. Obviously [to me] I need much less when flying motor that fills the fincan & I cut down more than half the amount used for a short motor.
    BP charge remains same for main. That area being pressurized is always the same.

    Look at acceleration graphs from flight to see how much negative acceleration happens, when charges fire. For me around 15-20 seems to work. When you see -50 or -75..time to cut back on charge size or amount of pins.

    I use fewer shear pins than most, so I need less BP
    1 for 38 [the urban legend about always use 2 or more so tube won't jam...is just that legend.At least if parts are fitted correctly]
    2 for 54 and 3inch
    3 for minimum 3in .{L&M motors] going higher where things get wonky, no risk early main. Not needed for sport flying.
    3 for 4in ...unless nose weight added..then 4 pins
    From here I go up to 4-40 or 6-60 for 5-6-7.5-8-12 inch tubes.
    when building new project, refer to my records and go with what worked in past.
    Rarely use pins for fincan to av-bay...only on 2-stagers
    When using head end deploy [main in NC] add 1 more pin..up the charge.

    There are way too many more criteria I use to keep going here,I could write a book, but you get the idea .
    Experience,keep records, see what others with same kit use, how many shear pins and their break point [2-256 shear at 22-24lb @] etc.

    So I can't say for every 38mm rocket use "X" amount. even if 3 of us had the same rocket, we probably built it different as far as fit.
    If we did [build exactly same] then "X" would work for all.
     
    Last edited: Jan 6, 2019
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  7. Jan 6, 2019 #67

    Steve Shannon

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    Gee, that sounds a lot like what a scientist does.
     
  8. Jan 8, 2019 #68

    Don Allen

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  9. Jan 9, 2019 #69

    Buckeye

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    You answered your own question. People on this forum go bonkers and twist themselves in knots over hazmat charges. After spending thousands of dollars on rockets and motors that go boom, another $35 is apparently an indignity too great to bear. If and when I need another can of BP (currently going on 20 years), I will probably pay the fee and sleep easy, rather than driving to every BassPro in a 5 state radius with some cockemamy story about my uncle's flintlock muzzleloader.

    But, I can complain with the best of them, also. Powdervalley charges $19.95 hazmat for 49 lbs of powder. $10 hazmat was mentioned in another post. So, I will ask again. Why are we paying $35 for a single wimpy G motor?
     
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  10. Jan 9, 2019 #70

    Steve Shannon

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    Hazmat charges are set by the freight company. I suspect the company that charges $10 has an arrangement with their freight company. They do a lot more business than our rocket motor vendors. All their business will go through them in exchange for a special rate.
    FedEx charges $27.50. A Hazmat shipment must go in a special box. Together they probably add up to about $35. Personally I try to arrange or get in on club orders, which are usually a few thousand dollars worth of motors. The shipping gets prorated so it’s very little.
     
  11. Jan 9, 2019 #71

    Buckeye

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    Good info. Thanks.

    Given the propellant tonnage that Wildman ships out, he should qualify for a special rate, too!
     
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  12. Jan 9, 2019 #72

    Banzai88

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    Don't rule out that some places might be subsidizing or absorbing part or all of the hazmat charges.

    I order a LOT of smokeless powder, in excess of 50lbs a year. Quite often I'll order in bulk when they offer special deals, places like Midway and Midsouth offer reduced or no hazmat charges throughout the year, often for as little an order as 4 pounds (about $80ish worth of product). But places like that have HUNDREDS of orders a day to spread the loss across, and believe me, the margin on a LOT of outdoors/gun items is astronomical.

    Rocket motor dealers probably don't have the volume or margin with which to do the same.
     
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  13. Feb 11, 2019 at 4:03 PM #73

    Crayok

    Crayok

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    Hey Midpower, You can use BP here in Canada, is it more of an issue getting BP where you are?

    David
     
  14. Feb 11, 2019 at 6:03 PM #74

    dr wogz

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    David,

    From what I've been told, understood, and experienced (here in QC & in ON) you need your PAL / FAC card. We have some friends who have bought it for us. But we've asked, they (the store) produce the can, then ask for our FAC. We say sorry, they say sorry.. Canadian Tire, Gun shops.. all ask.. I've even been asked for my FAC to buy lead shot...

    Maybe it's the few stores we've gone into, their policy, or that the clerks are being overly "safe" / not fully knowing eh rules. We just resort to our friends with guns to buy it..
     
  15. Feb 11, 2019 at 6:13 PM #75

    Crayok

    Crayok

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    Well that is interesting. We can buy BP with no licence here in Alberta, it must be a provincial thing. CAR/ACF even has a letter from ERD allowing the use in rockets as an EC.

    http://canadianrocketry.org/files/ERD_BP_letter.jpg

    This letter does not give us a licence, if required to purchase BP. Something more to look into.

    David
     
  16. Feb 11, 2019 at 6:55 PM #76

    dr wogz

    dr wogz

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    Quebec is 'gunning' for a gun registry of its own. So, we seem to be a little touchy with things that go 'bang'.. Albertans are "cowboys" who like their guns! :D We're city folk!

    The letter states that NRC will allow you (CAR only) to assemble the ejection charges on site. No mention of obtaining or use by other affiliations. And, that that transporting must be by approved methods (obviously!).. Would NAR or TRA clubs have to ask NRC for a similar letter?
     
    Last edited: Feb 11, 2019 at 7:20 PM
  17. Feb 11, 2019 at 11:44 PM #77

    Crayok

    Crayok

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    Well that will be annoying if it keeps getting more and more regulated.

    I really don't know, I believe it was done because of the safety code or the issue we are putting "explosives" beside the motors in our rockets and this was done for clarification. If I recall it was no "explosive warheads" in some wording somewhere. This was the result. I am reaching here on information from the past.

    David
     
  18. Feb 13, 2019 at 1:33 AM #78

    midpower_madness

    midpower_madness

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    I have a letter from NRCan which would explain the use of BP for dual deployment which I showed to my local gun store. No problems - easy as 1 2 3. I know there is a similar letter from the ATFE as well.... which allows for BP use this way.
     
  19. Feb 13, 2019 at 2:07 AM #79

    Steve Shannon

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    I would love to see such a letter from ATF.
     
  20. Feb 13, 2019 at 5:04 AM #80

    Sabrina

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    Well... this one time at band camp... :p

    "Uncle" Gus helped me make sure the laundry would fully eject by augmenting the ejection charge with a *little extra black power.

    This is an acceptable practice - but this time I think he used -too much :eek::eek::eek::eek::eek::eek::eek::eek:

    That's the Aerotech "cooling mesh" coming out of the side of the rocket in the third picture. Maybe one of these days I'll get around to editing the video - it's pretty interesting...:D:cool::confused:


    vlcsnap-2019-02-12-22h44m25s443.png vlcsnap-2019-02-12-22h39m58s876.png vlcsnap-2019-02-12-22h40m21s421.png
     
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  21. Feb 13, 2019 at 1:15 PM #81

    David Schwantz

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  22. Feb 13, 2019 at 1:28 PM #82

    Onebadhawk

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    Woooooooooo
    What a pic Sabrina...
    I take it that pic was taken from a video..
    The chances of a still at that moment are pretty slim..

    Great shot Sabrina..

    Teddy
     
  23. Feb 13, 2019 at 3:32 PM #83

    BayouRat

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    If you don't pin your fincan to av-bay. Beware of drag separation at Mach 3 and MECO. ;)

     
  24. Feb 13, 2019 at 7:34 PM #84

    blackjack2564

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    "Rarely" key word here...I do pin for high mach flights, but that's occasionally. Most of my flights are "sport" flying.
     

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