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First time BP problem


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#1 dodge586

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Posted 15 July 2010 - 02:54 PM

Hi guys,
After years of wanting to get into pyro I've finally pulled my finger out and ordered the various bits I need to have a go at making my own BP as a first step.

I ordered all my chems from hobbychemicals.co.uk

For the first go I thought I'd make a very small amount, keeping it simple I measured out 7.5Gm of Potassium Nitrate, 1.5Gm Airfloat Willow Charcoal and 1Gm Sulphur. The chemicals are already very fine and not wanting to invest in a mill just yet I thought I'd give them a quick grind in a wooden pestle and mortar.

In hot anticipation I marched outside with my concoction formed a small little pile (not contained) and lit at arms length.
Then nothing.
Kept the flame close for a long time and had several reattempts still nothing.

Even if it were poorly mixed or not 100% accurate I was expecting a little whoosh or at least for it to combust!!

Very disappointed I was really hoping to get off to a better start.

What on earth am I doing wrong please?

Thanks muchly

#2 phildunford

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Posted 15 July 2010 - 03:02 PM

You could only expect a slow burn, but if you get nothing, I suspect that one of the chemicals is not what it says it is - most likely the KNO3.
Teaching moft plainly, and withall moft exactly, the composing of all manner of fire-works for tryumph and recreation (John Bate 1635)
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#3 pyrotechnist

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Posted 15 July 2010 - 03:06 PM

Dont use hobbychem even ebay is better than that.
fireworks is my aim setting of is the game

#4 Atom Fireworks

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Posted 15 July 2010 - 03:44 PM

Whe i first started i did exactly the same as you, mixed a bit in a mortar and pestle and ground it for around 10 minutes, you should have atleast got a burn if it has not taken flame then something is wrong with you chemicals ide say 100% that its something wrong with the chems. I take it you live in the uk, if you do then their are some people on this forum who sell the neccasary chemicals howere you may find it a little hard to find the oxidisers as no body sells them too youunless they know you. Get your feet under the table and the doors will open.

Jay

#5 Atom Fireworks

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Posted 15 July 2010 - 04:49 PM

To add to my comment i just thought, i used a Stone Morar and Pestle, ive never seen a wooden one but maybe because its wooden it isnt grinding as good as mine was. The way to overcome this is to build a basic ball mill, it really isnt a hard task and wont be costly if you build it yourself.

#6 dodge586

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Posted 15 July 2010 - 06:40 PM

Thanks guys. Perhaps something is up with the potassium nitrate...
Would anyone care to test a small amount if I were to post some?
Or perhaps I should just order a fresh batch from Gardens direct and see if it makes a difference?
Thanks

#7 The Lizard

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Posted 15 July 2010 - 07:36 PM

Hi mate

I tend to get my KNO3 of inoxia in coarse and that is fine.

Hope that helps,

#8 plastics

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Posted 15 July 2010 - 07:54 PM

I too am fairly new - started last summer. Doors do open after a bit of looking around on the net and lots of background reading. There is a thread on this forum about obtaining materials. I read every post and that started me off. Obviously perfecting and understanding your own BP is a critical step. I quickly went from grinding and screening to a ball mill. Nothing too fancy - cast all the lead media myself (not recommended it stinks and kills your neurons). Now, as the real experienced guys will tell you, I need to build something myself a bit more durable that can handle larger quantities.

It does sound like your oxidiser is a bit suspect although green BP is not necessarily the easiest to light - so don't expect miracles. It does matter what sulphur and especially what charcoal you use

If you are in any doubt about the usefulness of a ball here is a little compilation I made a couple of weeks ago comparing milling times. I started with KNO3 that resembled table salt, sulphur and willow charcoal (all from forum members). I think the results speak for themselves. In the last sequence my hand is shaking because a 'test' just before had taken the hairs off my forearm. Another critical piece of advice - play safe



#9 PyroSkitz

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Posted 15 July 2010 - 08:10 PM

hi, i have no problem to accept 10grams of materials if you send them in a small envelope, will test them in a small ball mill i got, as 10grams of composition will get lost in my big ball mill haha :D
i will then give you my verdict on the stuff you have, if you want to do this PM me i will send you the required details as i obviously aint posting my info on a live forum haha :)

#10 Guido Fawkes

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Posted 15 July 2010 - 11:18 PM

Hi I've used H,cs stuff (only the Kn03) with no problems. Green meal can be hard to light. my absolutely base test is to put a bit on a fag paper and light that. you could do a simple test by dissolving as much KN03 as you can in a small (say a tablespoonfull) quantity of water. soak a bit of cotton string or paper in the solution and let dry. light it then blow out the flame.
it should glow red with a slow slightly fizzing progress. good luck. by the way well milled/ ground B.P looks very like fresh cement. very fine absolutely flat and almost the same colour.

#11 dodge586

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Posted 24 July 2010 - 12:38 PM

Hi all! I am pleased to report success!!!!!! Thanks to everyone that helped both in the thread and via PM!!
This time I spent about 20 mins with the pestle and mortar! I was surprised to find my right arm hurting when usually it's very good at such prolonged action!!!

Was a little slow to light but then went up no problem! Feel really pleased!

Interestingly, I left the small piles of BP on the patio from my failed first batch. They have been out in the elements since my first post about 10 days ago. Given that they point blank refused to light I was amazed that a pile went up very spectacularly from the heat of my new batch next to it!

Probably more flames and heat from the old pile than my new freshly mixed batch! Was very surprised but also pleased. It left behind some red blobs which resembled melted plastic - any ideas?

I then lit one further pile of 'old stuff' that had been sat out in the rain and sun for 10 days or more and it went up even more spectacularly!

Feel very pleased and looking forward to taking my new hobby further.
Def going to invest in a ball mill!

Thanks!

#12 alany

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Posted 24 July 2010 - 01:18 PM

Dampen your 10 g batch with about 1.5 g of water, knead it a bit, force through a sieve and dry before testing (while you wait for your mill parts to arrive), should make it a bit easer to ignite. Also a glowing splint or a jet/blue flame butane torch is a much better ignition source for composition testing than a match or lighter. Lighter flames are fairly cool, easily blown out and just plain frustrating, a good piezo ignition torch is an investment you will not regret.

You may find compacted comps easier to ignite also, try rolling a 5 mm or so paper tube, about 20-50 mm long from a few turns of paper, then press or funnel and wire load comp into it until you have a filled it solidly. Stand it upright, say with a little blutack or by pressing it into a sand bucket, then cautiously light the powder surface at the tube end. By timing burns of identically loaded tubes you can make meaningful comparisons of your composition burn rates as your techniques improve. Burning piles is instructive to a point, but frequently misleading once sufficiently good incorporation is achieved (goes "poof", but you can no longer judge which poof is better).

Being able to make black match makes this a relatively safe and easy test, you can stand back and observe, video/time with stopwatch, etc. You should try to make good quality delay elements like black match or Chinese fuse ASAP, they do not require spectacular quality BP but milling will help. Of course if you can get commercial fuse, use that.

BTW: leaving piles of failed test comps around is a bad habit, at the very least wash them away with some water.

#13 PyroSkitz

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Posted 13 August 2010 - 08:20 PM

heh nice to hear dodge, and im no expert quite the opposite im still an amateur :) but when i was starting out i had the same sort of problems as most people do i believe ( apart from the people who invest in a ball mill without even a pestle and mortar) hehe :P but the red slag left behind is the potassium nitrate that was not fully incorperated into the charcoal/sulfur or another theory, because your making such small batches, a few extra 0.1grams of potassium nitrate that might of been added to the mix, will actually mess up the ratios by a considerable amount of course :) think of it like 7.5:1.5:1.0 or 750:150:100, the 2nd ratio is the same, but 1gram added to the second ratio will not make much of a diffrence yet added to the first they it throws it way off.., this could be your problem, please contact me of your progress in the near future would love to hear :)




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