Urgent question !

[50AE]

I have a problem to solve guys. I decided to test one of my 3" shells for New year, it was C6 stars with BBQ charcoal, using 20 mesh granulated pulverone as burst, 18-20 layers of pasting. Only some of the stars ignited.

However, I tried a second 3" shell, which had spider stars using very reactive charcoal, burst BP on rice hulls and had the same pasting. It broke very well.

 

I need to know fast what could be the reason that the most of the first stars blew blind? The BBQ charcoal of the C6 stars, or the finer break charge making an unburnt barrier between the stars?

The second thing I worry about is: I don't have rice hulls anymore.

 

Thanks and Merry Christmass!

[Zmuro]

You pasted your shell with to many layers, for 3in shell 8 layers is enough.

[aa92td]

1st , as Zmuro said , you pase your shell with to many layers and all the start became dust.

2nd , instead of ricehulls you can use sawdust , i'm using it and its giving me great results.

[50AE]

If I don't paste enough layers, the shell doesn't fit well in the mortar.

And I've shot 3 more heavy pasted shells like that without blind blown stars.

 

Thanks, I'll try the sawdust thing.

Edited December 25, 2009 by 50AE

[Mumbles]

You might want to mix 4 or 5 parts of the saw dust into some BP, and dust the TT stars with it, if you have time.

 

I have to agree with you though, if the 3" hemis you have are commercial, they tend to come small.

[Arthur]

Rice Krispies (breakfast cereal) is an expensive but very good break carrier, in the UK it's retail so it wins on grounds of availability. It also crushes well so when you close a shell the Krispies crush down to allow the hemis to close easily.

 

Some sorts of sawdust with thin curls work well too.

 

If your shells fit too loosely in your mortars, either look for some smaller mortars, or add a small sabot of corrugated card round the correctly pasted ball. Smaller mortars tend to come from the HDPE pipe ranges that gas and water utilities use. My HDPE mortars are about 3 - 5 mm smaller than the usual pyro tube sizes, sometime it helps sometimes it doesn't!

 

One of the worst causes of malfunction is dampness! If the BP contains too much moisture (1.5% is normal!) it will perform badly. Are your stars truly dry to the middle. Fireworks made in haste often perform less well simply because the moisture in the paper and gum affects the active components if it hasn't had time to migrate out.

[50AE]

The problem is that I have another unpasted 2 shells with BP pulverone. Could the pulverone blow the stars blind? Or I should paste them with less layers (14-16) or disassemble the shells and put BP on filler?

 

I remember my first shell. It was pasted with 14 layers of 35lb virgin craft. It was broken with granulated golden powder. It worked very well.

I pasted two more shells with the same paper with 14 layers using granulated BP for the first shell and granulated H3 for the second. Both worked well.

 

 

So yesterday the first shell that didn't work well had BP pulverone with chryzanthemum 6 stars and 10 layers of 60lb kraft, which must be around 18 layers of 35 lb kraft

The second shell had BP on hulls as break and had the same pasting, it was awesome. The stars were spider that had the most reactive charcoal I've had.

 

And how does it come you guys achieve big breaks using boosters without having your stars blown blind ? Should I use a booster and paste the shell with less layers than the other way out ?

 

Arthur, I'm sure my BP was very good and not damp. The C6 stars could've been damp though, even if they were hard as a rock.

Edited December 26, 2009 by 50AE

[FREAKYDUTCHMEN]

Prime every star, even C6, with 1mm hot BP.

[JamesH]

50AE, I've been having exactly the same problem with my 2" shells, the primed 1/4" round D1 glitter stars keep blowing blind.

The thing is, i'm only using 0.4g of nitrate flash with 4:1 bp on grass seed pasted with 8 layers of potato sack kraft paper.

I find it difficult to believe thats its too much, but it's probably down to, the same reason as yours - too many layers!

I've got another shell ready to go, but this time it's pasted with 4 layers.

I'll post a vid of it when i fire it in the next few days. I have a vid of the last one too if anyone wants to see it - maybe they can tell whats wrong? The stars seem to light in the first few frames of the burst, then they go out.

 

50AE, do you have a video of the shells?

[Swede]

Has anyone tried vermiculite as a burst carrier, or is it avoided due to health reasons? It is VERY light and absorbent, and should coat well.

[50AE]

Sorry, I'm at work. Thanks for the info. Here's my channel with videos of shells http://www.youtube.com/user/extrasonic. But I didn't film the last two.

[a_bab]

Vermiculite makes a great "hulls replacement".

 

I personally don't like wood shavings as they tend to create glowing embers down to the ground.

 

I've seen in in some petshops from France ground corn cob for rodents (as a wood shaving replacement) in large bags; maybe it's available elsewhere too. Thjat is known to work perfectly.

 

Rice crispies are good, but they shrink and the leftovers are some empty fragile "BP shells" with the shrunk rice grain inside.

 

For me the best to use would be grass seed.

[50AE]

Ok guys, thanks. I have one question.

 

Do you think that my shells would work well if I use BP 15-20 mesh pulverone as burst, easy to ignite stars (chlorate based) and less layers (14-16).

[Mumbles]

If you can't light C6, chances are poor for chlorate.

[50AE]

Yes, but someone mentioned that charcoal streamers using unreactive charcoal are harder to light and I've already broken two successfuly shells using granulated H3 and golden powder the same mesh size. The shells had emerald green and tigertail stars. I'd like to know if someone had success breaking 3" shells with granulated BP.

[a_bab]

Unless you try it, you never know for sure, but I see no reason why it wouldn't work. Tipically, chlorate stars are much easier to ignite than BP based ones, which in turn are very easy to get going. Think spider web shell: an enormous break, spiced up with lots of flash, and yet the stars ignite.

 

As stated before your problem seems to be the excessive pasting that crushes the (poorly made) stars. The break must have been strong and loud too. I understand you need to get the shell larger due to the hemis size; a good way to cheat is to use string. Just string it up and you'll get the correspondant string thickness (x2 due to the crossings). Do this after some 8 layers, and finish with 2 layers of whell pasted paper (use PVA).

Edited December 26, 2009 by a_bab

[Gunzway]

50AE, I've been having exactly the same problem with my 2" shells, the primed 1/4" round D1 glitter stars keep blowing blind.

The thing is, i'm only using 0.4g of nitrate flash with 4:1 bp on grass seed pasted with 8 layers of potato sack kraft paper.

I find it difficult to believe thats its too much, but it's probably down to, the same reason as yours - too many layers!

I've got another shell ready to go, but this time it's pasted with 4 layers.

I'll post a vid of it when i fire it in the next few days. I have a vid of the last one too if anyone wants to see it - maybe they can tell whats wrong? The stars seem to light in the first few frames of the burst, then they go out.

 

50AE, do you have a video of the shells?

 

Does it ignite and light the glitter or just the prime? I'll be highly surprised if they all ignite (the stars themselves, not the prime) and then blow blind. I would like to take a look at the video.

[dagabu]

Has anyone tried vermiculite as a burst carrier, or is it avoided due to health reasons? It is VERY light and absorbent, and should coat well.

 

Yup,

 

I have a bag right here, want it? I have about 20# left. I did some rice hulls and some vermiculite the same day and let them dry to their original weight and I can launch a ball shell with the rice hulls but the vermiculite fizzles, makes smoke, sputters. Nada.

 

I am using the 5# I made for filling space, nothing more, I say pass.

 

D

[psyco_1322]

The polverone is not going to cause your stars to blow blind. You're only talking an inch or some of powder to burn through, it's not blocking any fire.

 

Your layers are a little excessive. I use about 6 layers (3 overlapping layers) of gummed craft, which is about 30-35lb. Its plenty enough to break them wide using 3g of whistle for booster. I like whistle because it seems to be a bit softer breaking than flash and I think it gives a longer duration flame when it burns, possibly yielding better ignition. Plus it tends to cling to things better, as flash might settle to the bottom of the shell wall. Yes, the undersized shell issue is a PITA. You can do as mentioned and wrapped some paper/cardboard around the shell until you get a good fit. It makes for an unsightly shell but it works for taking up the room, so take pics of your shells before strapping on the ugly.

 

If I had to take a guess, its the BBQ charcoal that you use to make the stars. Spider stars are made to light easy with really hard breaks. BBQ charcoal contains a fair amount of clay...yes, unburnable clay. That might make the stars pretty difficult to light, and maybe not even burn well with lots of fall out. Use some good charcoal next time, doesn't need to be hot, just pure.

 

A note on the sawdust ideas. The sawdust Mumbles suggested to use in with some BP for a prime is fine and powdery, like a sanding byproduct, know as wood meal. The sawdust people are suggesting to use as carrier is more like what would come off a table saw. It might work well for a carrier, but it's going to suck when the black powder turns all those piece of wood into glowing fall out. The ultimate goal of shells is to not have anything burning coming back to the ground. Huge clouds of glowing embers that aren't part of an effect are not very pretty and make your shells look noobish. BBQ charcoal is not going to be helping this, and probably makes for some really nasty looking charcoal streamers.

 

So all in all: Cut back your pasting by about a third, get rid of that BBQ charcoal and use some good cooked wood, give your stars a nice prime of bp and maybe some wood meal and see if they even burn, beef up your shells with some thick paper and tape, and try for round 2.

[50AE]

Thank you a lot! I now made 4 shells using very hot pulverone, it makes a POMP sound when lit. The stars are chlorate based and the final shell has emerald green stars. I'm going to cut the pasting a little. Let's say 8-9 layers of recycled 60lb paper. Edited December 27, 2009 by 50AE

[firetech]

Thats still a lot of pasting but whatever works for you works.

[50AE]

It's 4 layer less than previously.

Later I may go outside and fire another of the heavy pasted shell that had some NA glitter. I'll tell you if it has worked. If it does, I will suspect more the C6 stars in the first shell.

[JamesH]

I fired a second 2" round shell tonight. Everything kept exactly the same as the last one but pasted with 4 layers instead of the 8 I used last time.

Well, it was hardly any better, 2 stars ignited out of ~85!! I'll upload the videos tommorrow.

I can't believe that 4 layers of paper is too much, it's getting very frustrating!!

I supose I'll have to try 2 layers next! But 2 layers!!?? I know the potato sack kraft paper i'm using is pretty strong (J value = 25) but 2 layers just seems ridiculous!

By the way the very same stars ignite just fine when fired fron a mine!

If i don't get to the bottom of it soon I won't have any hair left!

 

50AE, did you fire that test shell yet?

[psyco_1322]

James,

 

If you have some whistle, sub that in for your slow flash and try another one. If you have none, just leave out the flash, and see how it works with out.

[50AE]

I guess that video proves that the pasting is a lot :

Ah, and one thing: after pasting 20 layers, I've put 3 layers of gummed tape on each shell.

Now it will be 14-16 layers and hopefully, they will light. I may test one of the new shells before the NYE.

 

http://pyrobin.com/files/clip0042.mp4

 

Also, could the glue play in this problem? I'm using wallpaper glue (CMC) instead of wheat paste.

 

Edit2 : My shells are done . To be honest, I pasted them with 7 layers of 60lbs paper, which is equal to 14 layers of 30lbs paper. The clearance between the shells and the mortar is 2.5-3mm

Edited December 28, 2009 by 50AE