Cylindrical Salute Inserts in Cylindrical Shells

[AirCowPeacock]

I keep putting 1/4" ID x 2.5" salutes into my 1.5" cylindrical shells, but they only occasionally work. Are they getting ripped apart inside the shell as it breaks? Would shorter, wider salutes prevent this?

[dan999ification]

are they lighting, can you find some debris? My only problem with insert shells that size is spreading them evenly the confinement and spiking needs to be just right.

Is the shell breaking before they light up?

 

Dan.

[Seymour]

 

Posted Today, 07:53 AM

I keep putting 1/4" ID x 2.5" salutes into my 1.5" cylindrical shells, but they only occasionally work. Are they getting ripped apart inside the shell as it breaks? Would shorter, wider salutes prevent this?

 

Either they are blowiing blind or they are getting ripped apart. You will know if they get ripped up since they will all go off when the shell/bombette explodes... in one explosion.

 

Your shape is not a problem, though maybe the way you have made them is.

 

However I'm pretty confident you are having priming problems. How have you primed the timefuse (assuming you're using it). Cross matched? cut at an angle, dipped in slurrey then grain?

[AirCowPeacock]

I'm not using timefuse for the salutes, I'm using visco. But if I use time fuse then there will be no room for plug in the salute, the time-fuse itself will act as the end-plug. I have found ripped apart salute casing (its red and easy to spot,) but i've never found a whole one. The shells break itself also seems to be exceptionally strong and bright--perhaps from the flash powder in the salutes. The non-fused end of the salute is rather weak. I don't know how I should be plugging the end to avoid putting pressure on the flash. I have been using a (~5/8" long) cylinder of crumpled up paper stuffed in the salute and a layer of Al tape over the end. On the ground they work fine..but in the shell--maybe they don't withstand. So their length doesn't temp them to break in-half with the pressure coming on their sides? The salute casing are just 1/4" ID bottle rocket/firecracker tubes from pyrocreations. about 1/8" walls, quite strong.

[Seymour]

I'm not using timefuse for the salutes, I'm using visco.

 

That's all good. Visco can work very well.

 

But if I use time fuse then there will be no room for plug in the salute, the time-fuse itself will act as the end-plug.

 

That sounds ideal.

 

The shells break itself also seems to be exceptionally strong and bright--perhaps from the flash powder in the salutes.

 

That is a good indicator. How are you sealing around the fuse end?

 

Traditionally one would cap such a salute with a fairly thick card disk, a few layers thick of serial box card can substitute in a pinch. This is held on, and the unit is sealed from lift gasses with two turns of paste soaked kraft paper, folding it down neatly over both ends. Ultimately tape can work instead of pasting, but pasting usually ends up cheaper, easier and more effective.

 

Ramming a clay plug, filling the salute, and then dealing with sealing the fuse end last is another good one. Possibly most common is hot glue, low temp ideally.

 

Regardless of how you do it, particular attention needs to be made to ensuring that it is going to be sealed from the high pressure inferno of the shell burst. Any pin hole in the glue around the fuse, or under a wrinkle in tape could be a failure.

 

 

I don't know how I should be plugging the end to avoid putting pressure on the flash.

 

While It pays not to treat all flash powders equally, for the standard 70/30 KP/Al, I'm fairly comfortable pressing on it with my weight in to a casing, though I would pay attention to the materials I'm using, and would hesitate to use significant mechanical force. Ultimately this is not a requirement, as the case should be sufficient to provide the strength in insert size salutes.

 

As for your particular casings, if it's strong enough for a rocket tube, I'm sure it will do fine. It's long shape should not cause problems unless you are using a very, very fierce burst.

Edited September 4, 2012 by Seymour

[AirCowPeacock]

Okay thank you. I will try pasting next time. For the fuse end I'm putting it on my rocket spindle and ramming clay as I would for a nozzle, then I put a ring of hot glue around my fuse and stick it in. I then load my flash after the fuse is in so I can avoid mixing hot-glue and flash (It also makes it easier to get the fuse well into the flash.) I'll have another shell this weekend hopefully. I'll tell you how it goes, thanks.

[AirCowPeacock]

By the way, I'm using Shimizu Thunder #3: KP 64, Al 23, S8 13

[psyco_1322]

Buy some of the little plugs they sell for the tubes. A little white glue around them and push them in, then fill the outside with hot glue. I used hot glue on the insides of my plugs but they are 3/4" and bigger, and it's just not workable in smaller tubes. I'd really advise you switching to time fuse, I never get good repeatable results with visco on inserts. If your time fuse fits loosely in the tubes, run a bead of hot glue around it close to the end and twist it into the tube. Make sure to get a good fillet on the outside, around the fuse. I'd also suggest to smear a little prime paste across the surface of the fuse that goes into the flash, that will insure no duds from failure to transfer fire. Then cross match the outside end of the fuse, it's almost sure to take fire that way. Timings on a shell that small probably should not exceed 1/2" from the primed end to your cross match mark, an addition 1/4" will be needed for the cross matching.

[AirCowPeacock]

Okay I'll try your advice. I am concerned about transfer of fire, I switched from 70:30 KP:Al to Shimizu's Thunder #3 was because of transfer of fire issues--and I swear, its alot louder. I'll make sure to thoroughly prime both ends. I don't have time fuse at this moment. I'm going to buy some refills on pretty much all my fuses soon, I'm almost out of most and all the say out of others. I'm actually going to try use 3/4" of my 10 sec/ft fuse for the salutes (that's 0.625 seconds,) prime both ends.

[eb11]

i had a problem with the fuse ends on my canister shells and used gorrila glue around the fuse to seal it have not had a problem since

[psyco_1322]

Different flash formulas have different tones. I use 7:3:1 for anything small, the sulfur helps with ignition and makes the mix cheaper, but does add to sensitivity.

 

If you are timing with visco, you really should put a few wraps of tape around the length that is being timed. Also make the cut on the igniting end at an angle.

 

Hot glue works wonders when it comes to fusing shells.

[AirCowPeacock]

I always cut visco at a 45* angle; and for timing I put a few wraps of gummed tape around the time portion of the fuse and measure that length for time, with a mm or two for fire transfer--it's never failed me. Speaking of flash tones. What would you suggest for a really deep flash in a 1.5" or 2" cylindrical aerial salute. I want to be able to feel it in my chest from 100 m; (will that be big enough anyways?)

[dagabu]

Pyrocreation's 1/16" walled tubes are just not made to withstand the break of a cylinder shell.

 

http://pi.b5z.net/i/u/2001189/i/quarter_tubes_BULK_ezr.jpg

 

 

Pyrodirect has the ones with a double wall wrap that seem to handle the break just fine, I have been using them for years.

 

http://www.pyrodirect.com/images/tubewithfuse.jpg

The tube has to be able to bend without splitting (that's what they are probably doing) or you need to press the flash into the tube to keep the tube rigid enough to resist the break. The paste wrapping may help with keeping them rigid too.

 

-dag

[Col]

I use 400mm of 30lb pure kraft to roll 1/4" id x 1/16" wall insert tubes. They`re impossible to crush with your fingers and handle.a fairly hard break. Epoxy is good for sealing the non fused end.

[AirCowPeacock]

But won't pressing the flash slow the burn potentially to the point where it won't *bang* but instead blow out the nozzle like some overpowered rocket? And on top of that the three or so grams of flash I normally make for 4 of these salutes will probably just be enough for just one or two. Okay, thanks for the advise on the tubes. Next time I buy from pyrodirect (which should be in 2 or 3 weeks) I'll make sure to get some of those thicker walled tubes.

[dan999ification]

roll them i found they are the easiest size to get right just fiddly, i think there is a couple of pics in my gallery of finished inserts made with cheap kraft and a chop stick, i cant view on my phone.

 

Dan.

[Mumbles]

I've gotten these 1/4" ID x 2 or 2.5" long spiral tubes from a couple of sources now. Cannonfuse, Pyro Direct, and a now defunct reseller. The ones from the defunct reseller were the best, which is a shame. The ones from cannonfuse and Pyro Direct were about the same quality. If I really tried I could at least deform the ends of the tube from cannonfuse/Pyro Direct. They still appeared to be strong enough to handle a shell burst though. I've used them for spolettes, and to anchor time fuse into shells and never had a problem with either of those uses.

 

To me it sounds like 1 of 2 things. You're either having priming issues or your bottom plug isn't strong enough. I'd lean toward the plug being the problem from what I've read. There are plenty of good suggestions in this thread. I've used clay before with good success for the bottom plug, as well as something similar to Psyco's suggestion.

 

There used to be a perfect solution to your problem, but I can't find the particular end plugs anymore. Cannonfuse (I think) used to sell plastic end plugs that fit into these 1/4" tubes. They still carry the ones for the larger tubes, but not 1/4" anymore from the looks of it, which is a shame because the larger ones really aren't good for as much. There are other sources. The one I found below only sells in bags of 1000 for around $37 for 5000 for around $92. They can actually be used on both ends. The small size seemed to seal out fire fairly well on the bottom, and the top can be pierced with an awl or something to allow room for the visco. Gorilla glue was the best for sealing these things. I'd look at T-15 or T-17, though others may have additional opinions.

 

http://www.stockcap.com/store/Product/ProductInfo.aspx?id=490

 

The same thing could be done with paper end plugs sold by a variety of the suppliers too of course.

[dan999ification]

speaking of plugs you can make them from a smalll disc of card or cereal box, i put one disc in my mouth form it over a 4mm dowell push it in a tube and keep going until they come out the other end, dry them bag them, if they deform mist them and reform.

I have also used a strip of card rolled up this expands inside the tube and provides a block for when you hot glue or seal it another way this is also good for timing visco in top plugs, now i tend to ram tissue plugs only to block contact between the f and the glue and i always use time fuse for the top plug since my first timed salute going untimed mine still blow with time fuse and eigth inch walls (convolute wound) with bp.

 

Dan.

[dagabu]

I use 400mm of 30lb pure kraft to roll 1/4" id x 1/16" wall insert tubes. They`re impossible to crush with your fingers and handle.a fairly hard break. Epoxy is good for sealing the non fused end.

 

Col, I had forgotten about rolling them. How cheap would that be anyway?

 

-dag

[dan999ification]

depends how many you need i use recycled kraft free from ikea, a few square meters is plenty for the year, but you can buy 5m rolls of kraft for a quid, bit more than a dollar, like col's youd have a hard time crushing the small ones if you stood on them, cheaper than buying them, better quality, time and patience is the thing.

 

Dan.

[AirCowPeacock]

I have no issue making tubes for shells fountaIns and mortars tubs, but for bottle rockets and tIny salutes--it already seems like a lot of work for something you will probably use by the tens without making your own tubes--time and patience has to be plentiful I imagine. Probably want to make them by the tens too.

[dan999ification]

fifty is about all i can do in one sitting, the hands wrinkle and need drying, the patience is for when you screw a few up and take it out on the next ones, seriously though it takes no time once you get the nack, makes you not want to blow them all on one timed salute, if i could find them cheap enough or get cap plugs ( what the op needs ) i would but until then 8 in a 40mm is good for me.

 

Dan.

[Col]

Col, I had forgotten about rolling them. How cheap would that be anyway?

 

-dag

 

Using pure kraft about 4p for 10, which converts to around 6 us cents A polished 1/4" brass rod makes the best former..glue doesnt stick to it.

Edited September 7, 2012 by Col

[cogbarry]

Is the sole purpose of the cylinder shell to carry these inserts or are these star shells with the inserts acting as a secondary effect (sort of like bottom shot)? I ask this because I experimented with 2" plastic cylinder shells when I first started in pyro. I used the same tubes you are using with visco fuse, the end of the visco fuse dipped in BP slurry. I also used the paper plugs that I purchased with the tubes. The shell was not burst hard, it simply burst the top cover off the shell and ejected the contents much like a mine. All of the small salutes worked every time. I never had an ignition failure or see the salutes blown apart from the burst charge.

[dagabu]

Using pure kraft about 4p for 10, which converts to around 6 us cents A polished 1/4" brass rod makes the best former..glue doesnt stick to it.

 

Nice, thanks for the tips. I have been using gummed kraft tape for tubes too and love the way they turn out.

 

-dag