Daveyfire e-matches and others ...

To all,

Planning to dabble with electronics and dual-deployment and such in 2008 so have been scouting around for a local source of e-matches to use principally for igniting BP charges for deployment purposes.

A local fireworks place carries ...

1) Mystical e-matches. What have folks heard about them?

2) MJG J-Tek (https://www.electricmatch.com/product.html)

3) He is also willing to sell off his remaining stock of Daveyfires. From the packaging I believe them to be 28BR's.

Questions...

Does anyone recommend any of the above over another? Should I particularly avoid anyone of these? I read on the Net that the J-Tek's are basically a clone of the Daveyfire F's and because of their higher current draw are not the optimum for BP use (using a 9V as a combined power source for both the altimeter and e-matches could cause a significant voltage drop on the altimeter when using the J-Teks that may lead to brown-outs or other anamolies with the altimeter). Thoughts on this?

Also, there is also some question about the Daveyfires he has. While the Daveyfire packaging says "A/N 28 BR" they are all black leads (1 foot long). While I trust the guy knows his product and is confident they are indeed Daveyfires, I'm wondering if they are some other Daveyfire that he just threw into this particular box I looked at (it was not a full box). The only stuff I could find online says Davefire F's are black leads and the white leads are B's and orange leads are BR's. But I don't know if this is a hard and fast rule. Anybody know?

Finally, if they are Daveyfires (those seemed to be one of the chosen ones amongst rocketeers before Daveyfire ceased production) they are undoubtedly a number of years old. Does one have to worry about a shelf life with these things?

Thanks in advance.

... Bill

The Daveyfire BR's will work great for you.

J-Teks are becoming increasingly popular now. I am going to be acquiring a few for testing on my MAWD and ARTS2 and will report back with what I learn.

J-Teks work fine with MAWD, RRC2 and Adept RAS2 altimeters. They have an all-fire current of .75 amp.

BKROSNEY said:

To all,

Planning to dabble with electronics and dual-deployment and such in 2008 so have been scouting around for a local source of e-matches to use principally for igniting BP charges for deployment purposes.

A local fireworks place carries ...

1) Mystical e-matches. What have folks heard about them?

2) MJG J-Tek (https://www.electricmatch.com/product.html)

3) He is also willing to sell off his remaining stock of Daveyfires. From the packaging I believe them to be 28BR's.

Questions...

Does anyone recommend any of the above over another? Should I particularly avoid anyone of these? I read on the Net that the J-Tek's are basically a clone of the Daveyfire F's and because of their higher current draw are not the optimum for BP use (using a 9V as a combined power source for both the altimeter and e-matches could cause a significant voltage drop on the altimeter when using the J-Teks that may lead to brown-outs or other anamolies with the altimeter). Thoughts on this?

Also, there is also some question about the Daveyfires he has. While the Daveyfire packaging says "A/N 28 BR" they are all black leads (1 foot long). While I trust the guy knows his product and is confident they are indeed Daveyfires, I'm wondering if they are some other Daveyfire that he just threw into this particular box I looked at (it was not a full box). The only stuff I could find online says Davefire F's are black leads and the white leads are B's and orange leads are BR's. But I don't know if this is a hard and fast rule. Anybody know?

Finally, if they are Daveyfires (those seemed to be one of the chosen ones amongst rocketeers before Daveyfire ceased production) they are undoubtedly a number of years old. Does one have to worry about a shelf life with these things?

Thanks in advance.

... Bill

Click to expand...

To answer the questions you first need to know what the electronics you are using are capable of and or need to have for ematch values of current used to fire. Not all Altimeters are created equal nor are all ematches low current.

Davey Fires used to be the hot ticket. BUT I have heard rumor that the pyrogen has a shelf life. So it may be they are well past their time. BUT also the most common Davey Fire ematches used did not have black leads. They were orange dual wire solid core made and the leads were normally somewhere in the 36 to 48 inch long range.

Personally I haven't heard of Mystical ematches

The Jteks I have and heard good things but again see my first comments on Altimeter capability and Ematch Needs to make sure it will work with what you have.

constevens said:

Davey Fires used to be the hot ticket. BUT I have heard rumor that the pyrogen has a shelf life.

Click to expand...

Daveyfire used a lead based low explosive. As long as the seal on the fusehead is not damaged the ematches should last a long, long time. I've had some for about 10 years and they work fine. Others have tested some that were 20 years old at the time and they worked fine.

Rocketjunkie said:

J-Teks work fine with MAWD, RRC2 and Adept RAS2 altimeters. They have an all-fire current of .75 amp.

Click to expand...

While this is true and I myself have used the J-tek's with an RRC2x the all fire current is not the recommendation from the manufacturer. They recommend 1.5 amps as the nominal firing circuit. So some care must be taken with certain low output altimeters.

As indicated by others - check the manuals and supply specifics if you know what electronics you have access to - that will go a long way towards making sure that the right info comes your way.

https://www.electricmatch.com/product.html

BKROSNEY said:

Planning to dabble with electronics and dual-deployment and such in 2008 so have been scouting around for a local source of e-matches to use principally for igniting BP charges for deployment purposes.

Click to expand...

This year I started using Pyrodex "P" and christmas tree lightbulbs. It avoids all of the entanblements and works just as well. Doug Pratt has a web page describing how to wrap a centerfuge vial with black tape to contain it so it fully burns.

I bought 100 lightbulbs for $2 at the start of christmas mania.

Glen

overby said:

This year I started using Pyrodex "P" and christmas tree lightbulbs. It avoids all of the entanblements and works just as well. Doug Pratt has a web page describing how to wrap a centerfuge vial with black tape to contain it so it fully burns.

I bought 100 lightbulbs for $2 at the start of christmas mania.

Glen

Click to expand...

I have used light bulbs like that before and don't anymore. I find them not nearly as reliable, especially with high G load flights. The elements can break while under the high G's and then leave you with no recovery.

constevens said:

I have used light bulbs like that before and don't anymore. I find them not nearly as reliable, especially with high G load flights. The elements can break while under the high G's and then leave you with no recovery.

Click to expand...

My technique with the xmass bulbs has been very reliable in the few launches an a lot of ground testing i've done with them so far, about 40-50 bulbs total- including a couple of very high-G K1250 and H400 powered flights, at 30-50G. The 'secret' is i used gelcap pill casings: Put a small hole in one end, glue the filament in it then fill both halves of the casing with BP (or Pyrodex) and close, while gently tapping the sides to tamp the powder tightly around the filament. a little scotch tape to keep it closed, then seal that in one end of a piece of latex hose. The pill holds about 1/2-3/4G of BP, so you add whatever additional BP you need in the latex hose and seal the other end. Voila! works like a charm. The one failure i've had was due to crossed wires in redundant charges - DOH!- at the altimeter end, nothing to do with the 'ignition end',which tested fine on the ground later.
I find the loose but packed BP around the filament lights quicker and much more easily (at lower current) than when the filament is dipped in pyrogen, because the pyrogen acts as a heatsink delaying and reducing the temperature rise of the filament. My way, the filament is mostly in air, so it can heat up just as quick and easy as when it was in its glass envellope. The Pill casing serves to keep the BP around the filament 'packed' and immobilized with enough grains of powder in direct contact with the filament to assure ignition under any circumstances- withouth putting any strain on the filament and risking damaging it. Its also pretty quick to whip up a batch this way, no messy pyrogen dip and drying period. I use hot glue for the filaments, and can do about 1/ 2-3minutes while watching TV, including prepping & soldering extention wires to the filament tails. I fill the pill casings only when prepping the rocket at the field, of course.
I've been able to get reliable ignition with a 3V lithium coin cell this way, though i've not tried that in an actual flight. yet.

FROB- Have pics of your setup?

constevens said:

I have used light bulbs like that before and don't anymore. I find them not nearly as reliable, especially with high G load flights. The elements can break while under the high G's and then leave you with no recovery.

Click to expand...

I doubt the problem is high G's. It probably has more to do with vibration.

Arnold Roquerre said:

I doubt the problem is high G's. It probably has more to do with vibration.

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If it was Just vibration it would do it more so on all flights as I am sure there is plenty vibration anytime a rocket is under flight. But put that same bulb filament under a 50G pull and it can break. Have tested this myself. I'm sure if you check with many of the folks that fly high G force (as well as high altitude) they will give you much of the same info. Not nearly as reliable as ematches are.

constevens said:

If it was Just vibration it would do it more so on all flights as I am sure there is plenty vibration anytime a rocket is under flight. But put that same bulb filament under a 50G pull and it can break. Have tested this myself. I'm sure if you check with many of the folks that fly high G force (as well as high altitude) they will give you much of the same info. Not nearly as reliable as ematches are.

Click to expand...

How did you test them, other than in flight?

I agree ematches or wire with a nichrome bridge are more reliable. I have never used them in flights, but I do used them instead of ematches for ground testing.

Arnold Roquerre said:

How did you test them, other than in flight?

I agree ematches or wire with a nichrome bridge are more reliable. I have never used them in flights, but I do used them instead of ematches for ground testing.

Click to expand...

Well, Unless you have a way to simulate a 40-50G pull (or better) its near impossible. But ive had it happen on flight, as well as have had it advised to me(after my own personal experience of course, couldn't have been before.. ) by others with the same knowledge/experience. With that lesson learned and behind me I NEVER fly with bulbs. Recovery is the most important part. Why risk a possible failure. As for ground testing. Sure I can see the use for bulbs so you can save the matches for flights.

Speaking of High G flights..

Conway, I finally saw the Full Throttle flight. My LDRS DVD came in today. All I gotta say is AWESOME!!!

OK, back to the debate!

SpartaChris said:

Speaking of High G flights..

Conway, I finally saw the Full Throttle flight. My LDRS DVD came in today. All I gotta say is AWESOME!!!

OK, back to the debate!

Click to expand...

So you like that lil red N motor I built eh? (only 11,580ns N2400) LOL.. It ended up flying to 13,996ft. The ARTS showed right at 42G's max.. Glad you liked it Bro. I will be flying it at Xprize Cup this year.. and maybe a new high altitude project at LDRS.

Thanks Chris.

Gee now I need to get my DVD ordered..

But yes.. Back on to the topic.

constevens said:

Well, Unless you have a way to simulate a 40-50G pull (or better) its near impossible. But ive had it happen on flight, as well as have had it advised to me(after my own personal experience of course, couldn't have been before.. ) by others with the same knowledge/experience. With that lesson learned and behind me I NEVER fly with bulbs. Recovery is the most important part. Why risk a possible failure. As for ground testing. Sure I can see the use for bulbs so you can save the matches for flights.

Click to expand...

I think a non-BATF solution is important since so many people have difficulty securing a license, especially if they live in cities or areas that do not meet the BATF requirements for storage. Nitrous is great, ematch alternatives are still needed for deployment. Even the Rouse-Tech system needs an ematch which, now, requires a BATF license to purchase.

If one could get their hands on a research centrifugal machine, one could run a test. Simpler, just glue a bulb already broken to board and then hit the board with a hammer (after calibrating the force first).

I have had good sucess with x-mas tree bulbs so far. That includes my L2 Cert flight of my Binder Design ExelPlus on a J350. I do use 2 bulbs so if one does fail there is another one to fire the BP.

https://s45.photobucket.com/albums/f77/BAR0051/?action=view&current=DualXmastreebulbs.jpg

I am thinking of going to e-matches in my 3 in. dual deploy rocket because of the size of my x-mas tree bulb setup, it would be tighter fit. Also, I got started with them because I thought it would be hard to get e-matches but I am finding that it is not that hard to get them (I have a LEUP).

Arnold Roquerre said:

I think a non-BATF solution is important since so many people have difficulty securing a license, especially if they live in cities or areas that do not meet the BATF requirements for storage. Nitrous is great, ematch alternatives are still needed for deployment. Even the Rouse-Tech system needs an ematch which, now, requires a BATF license to purchase.

If one could get their hands on a research centrifugal machine, one could run a test. Simpler, just glue a bulb already broken to board and then hit the board with a hammer (after calibrating the force first).

Click to expand...

What I find interesting is that Ematches are not an actually regulated item by the BATFE (if you think they are ask them or look at the explosives list they go off of. I asked my agents and they said they were not regulated) but because of whatever fear issues or whatever it is manufactures and dealers have seemed to self impose this regulation upon themselfs..

But if you also read the fine print of the explosives list you will also notice it says they can regualte anything they deem so.. So really even the stuff you mention could be regulated depending on their use. Same with ematches I guess.. Kind of like BP up to 50lbs is legit without any permit. BUT only for use in antique firearms. Not for our use. So regulated again.. Pretty hard to get regulation free. Thats why I decided to get a permit as well. Then im good. I know that not all can do that. But there are ways around that. Shring storage, Club storage, On site vendors and more.. Not that I wish it but regulation may be something we have to live with.