19 replies to this topic

[martyn]

What with my wild optimism, back to work on nights, and now this - I'm really fed up!
Just failed miserably, again! - with some senko hannabi. (skylighter formula)
Funny thing is - I felt much naughtier buying the king size rizzla to roll them in than I did mixing the stuff.

[Deano 1]

'martyn', on 29 Jun 2010 - 9:48 PM, said:

What with my wild optimism, back to work on nights, and now this - I'm really fed up!
Just failed miserably, again! - with some senko hannabi. (skylighter formula)
Funny thing is - I felt much naughtier buying the king size rizzla to roll them in than I did mixing the stuff.

send us a link to the skylighter project and I'll ha a look, it takes an age to find owt on the site and I'm up at 6

[martyn]

'Deano 1', on 29 Jun 2010 - 9:59 PM, said:

send us a link to the skylighter project and I'll ha a look, it takes an age to find owt on the site and I'm up at 6

Here you go

http://blog.skylight...-sparklers.html

nite nite

[Deano 1]

Kinell Martyn thats a bit long winded for a poxy little sparkler that'll burn yer fingers I'd throw that one to the dogs mate, soz, nite nite

[martyn]

morning - it's just nice to make something you can use there and then at home sometimes.
I believe if you can get the 'blob' right, the effect is actually very nice, it's just that I can't, so it isn't!
It's also something my 13 year old son can help with as it is relatively safe in terms of quantity and chemicals - certainly safer than filling the mower with petrol.
The only good thing about it was the smell - ah

Edited by martyn, 30 June 2010 - 07:35 AM.

[Creepin_pyro]

I've found the SL formula needed more oxidiser. It can also help to add some bicarb to the mis to slow things down even further.

And you don't need big rizla - they work best when they're small. Small silver rizla works wonders.

[alany]

I find something closer to this is a good starting point:

60.00% Potassium Nitrate
24.00% Sulfur
16.00% Charcoal (pine, airfloat)

The charcoal is the most critical component, and the paper can make a big difference to how well the dross ball sticks too. Pine charcoal is a good thing to try first, other charcoals may not work at all, pine has never failed to give me at least a few branching sparks. You may need to tweak the ratios a bit though.

To test a number of charcoals quickly you can make some Liver of Sulfur (Potassium Polysulfides) by fusing Sulfur and Potassium Carbonate in a crucible, then mixing a little of each test charcoal into a droplet of the liver of sulfur on a nichrome wire loop. Use a Bunsen or similar torch to melt the polysulfides and start the reaction. Alternative if you don't mind wasting a bit more chemicals you can just prepare small amounts in a mortar and pestle, helps if you have an sensitive and accurate balance.

I use kitchen wrap paper, specifically Tiger brand, but that may not be available in your neck of the woods. Tissue paper if tough enough to withstand the twisting can be very good. I cut strips about 12-15 mm wide with a paper cutter straight from the roll of kitchen paper and then sit down and watch TV while I twist up a batch. I use an adjustable measuring spoon built from a soda straw and a bamboo BBQ skewer to ensure consistency in loading. I fold the strip into a vee for about the first 30 mm, put the composition in about 8 mm from the end, close the eve and start twisting up the paper until the composition is well contained. The remaining paper can be twisted with a bit less care and a touch of paste on your fingers if desired (I generally don't bother) to form the handle.

I should probably do an article with a video on the process. It isn't too hard to master, but dialing in the composition can be very frustrating. Over all the years I have been making senko hanabi I am still not completely happy with my results.

[a_bab]

Oh boy, this is exactly what I tried yesterday with the SL formula. Besides an ugly blister I did't get anything. It's becoming an obsession now.

[rocketpro]

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Edited by rocketpro, 06 August 2010 - 09:15 AM.

[alany]

How is it behaving when you burn it?

[martyn]

'alany', on 12 Jul 2010 - 10:18 PM, said:

How is it behaving when you burn it?

In my case - if I twist a pinch up in a rizzla and light it - if acts as a sort of mini rocket, ejecting fire / sparks about 2-3 inches.
I think it is burning far too fiercely, I can't see a blob of dross forming to produce the delicate sparks.

[phildunford]

There are obviously similarities between this and the 'Old English Flowerpot'.

The formula I use for this is:

Potassium Nitrate 50%
Sulphur 25%
Lampblack 10%
Antimony Trisulphide 5%
Green Powder 10%

Green powder being the usual 75 15 10 blackpowder mix, screened, but not ball milled.

From an old Pyrotechnica article.

A lot of sulphur & some lampblack as well as the charcoal in the 'Green Powder'.

Don't know if this might help with the Senko Hanabi...

[Arthur Brown]

I'm wondering about particle size too! Molten blobs that sparkle sounds like a poorly milled attempt at BP too!

[Creepin_pyro]

'martyn', on 13 Jul 2010 - 9:22 PM, said:

In my case - if I twist a pinch up in a rizzla and light it - if acts as a sort of mini rocket, ejecting fire / sparks about 2-3 inches.
I think it is burning far too fiercely, I can't see a blob of dross forming to produce the delicate sparks.

This is exactly how the un-tweaked skylighter formula performed at first...

Adding more Nitrate and a pinch of bicarb soon slowed it down enough to work for me.

[alany]

'phildunford', on 14 Jul 2010 - 08:48 AM, said:

Don't know if this might help with the Senko Hanabi...

I wonder, as the reaction is basically identical, just the flowerpot throws balls of dross to react in flight where the senko hanabi dross ball is held in place.

I tried to duplicate your rather nice flowerpot gerb using that composition, but was not able to get many of the nice "flowers". I suspect the lampblack I am using is the problem. Where did you source yours?

OT but: Making good old English flowerpot has been an ambition of mine for a long time. I've tried using the same charcoal I use in senko hanabi with poor results, even when using compositions rich in sulfur (to the point where the gerb explodes from choking up on dross). High exhaust velocities seem to help fling the dross out into the air, but I've found it hard to simultaneously keep the composition gassy and drossy enough. I tried grain powder as propellant, which worked to some degree, but again I blew up a fair few with that approach.