samboradford

Regardless of whether it was or wasn't used in the past, I wouldn't recommend experimenting with lead nitrate. Being soluble, it is all too easy for it to be absorbed by into the body. Even small quantities can, over time, be quite harmful.

 

I haven't made touch paper for years, but I recall finding that a fairly dilute solution of potassium nitrate worked better for me than a more concentrated one. With a dilute solution, it doesn't form visible crystals on drying.

Crikey, the world has gone mad.  Better go and have one more sniff of my Paris Green before the fun police come along and lock it away. 

personally, I wouldn't reccommend experimenting with oxidisers like potassium nitrate as you might get blown up.

Nobody knows for sure : http://www.fireworks...uchpaper.23872/

My understanding is in fact that the original blue touch paper containd lead nitrate in the soaking solution to counteract the crytsal fomation from the potassium nitrate.  I suspect that is where you're solution ( excuse the pun ) lies rather than with the strontium nitrate.

Sam

Rek,

Safety fuse ( UN0105 )

is in Schedule 2 Part I ( EXPLOSIVES NOT REQUIRING AN EXPLOSIVES CERTIFICATE )

see :

http://www.legislati...schedule/2/made

HI Bart,

APC Pure should help you with that one.  You will need to email them direct and explain your usage, fill out a declaration of usage and send them copies of your EPP. 

Sam.

No problem, Phil has been around for a long time I think the OP might want to rethink that request, Phil has been great in his products and input, not blowing smoke up your arse Phil but fairs fair.    

I certainly have no designs on running a "shop".  Yes Phil runs an excellent shop and has done for sometime as you point out.

If the society chose to, membership funds could be used to procure items and have these stored at a premises.  It might make sense for these premises to be already in use for pyrotechnic sales or it may not.  The point of this would be for society members, not for private commercial gain.  This would be a clear and immediate benefit to being a member of the society.  For example, if a business can procure Potassium Perchlorate at £5 - £6 per Kilogram including shipping then members could access this at cost, as has in fact been suggested in the past.

Cohesion is needed, clarity of posting and information and not making posts that are overtly critical of one-another or otherwise derogatory of the society or it's committee.  Constructive feedback is a different entity entirely and a useful one.

There is no harm re-iterating the legal standpoint as many times as necessary, given it's importance - accepted it can be frustrating.  Wayne has often unfairly been shot as the messenger in my book.

A magazine might be useful if it contained some meat - a focus on a different legislative topic each issue, new techniques or processes, adverts from pyrotechnic companies and discounts, etc etc - there is no reason why it couldn't be mailed as a pdf rather than hard copy if required.

More suggestions I think would be useful.

Top 5 things you would do or have the society do if someone had a magic wand, could fix all the problems / make them go away and we could all, miraculously, work together again.  Sorry, sounds like I've lost it but currently cohesion needs to start somewhere.  For my two-pence :

1. Liase with members / ELOs to help them gain their A+Ks

2. Produce a monthly magazine - both to communicate what the society is doing and as a drawcard for membership

3. Investigate alternative ways of expanding the options available within hobby experimental pyrotechnics - I mean looking to extend the 100g rule (contentious I know)

4. Provide a shop / supply of fuse, chemicals, building materials, books, tools etc. Perhaps take on a member to provide this.

5. Work on building the forum - assign people to generate posts and contents to garner discussion

Meetups are not on my list because at the moment there isn't the footfall to make it effectively work ( as was tried ) I'd do options 1 - 5 first.

Maybe we need an interactive map of where we all are ?

Shimizu makes reference to a 75:25 mix of amorphous boron ( note the crystalline form is not suitable) and potassium nitrate in Fireworks, the art, science and technique. 

He goes onto to state :

boron has a specific gravity of 2.35, melts at 2l60°C, boils at 3650°C..... A mixture of amorphous boron and potassium nitrate in a ratio 75:25 burns rapidly with a brilliant green flame at very high temperature.The green colour comes from BO2 band spectrum. The boron mixture is used as an ignition composition in place of thermit, and the difference between the two lies in that the former ignites other compositions with its high temperature flame but the latter mainly with its high temperature liquid cinder. The boron mixture ignites very well from a relatively weak heat source such as a black powder flame.

That may help you get started ?

Phil is spot on - the CATO occurs when the pressure exceeds the containment strength of the tube which, broadly speaking, can only be solved by 1 of 5 ways :

1. Increasing the strength of the tube

2. Reducing the power of the mix

3. Increasing the size of the nozzle

4. reducing the length of the core

5. Improving the stability of the mix during burning so that oscillations in pressure don't exceed that which is containable by the vessel

1.

Wood hardener in my experience makes little difference.  Most UK parallel wound tubes are fairly comparable in strength. I have some NEPT tubes I have yet to test.

2.

Can be done with charcoal or other additives. For a really hot mix sometimes quite a large amount of charcoal needs to be added and can be tedious as you need to mix, rice and dry each time.  My preference is vaseline or mineral oil dissolved in naptha add 1 - 3% ( I can't tell much difference between vaseline vs baby oil personally )

3.

not feasible with O.B. tooling unless you go nozzless

4.

not feasible with O.B. tooling

5.

Only really relevant if your fuel is on the edge, you will only know this from starting slow and titrating up.  Greater burn stability is achieved by :

a) better compaction - ie a press or using a wooden mallet on a wooden post to reduce bounce and whacking it really hard, you can tell if it's bouncing on your O.B. tooling as you will find it tedious to switch to your final rammer after the spindle is passed as it will keep flaking at you and seem to take ages to switch up rammers - add mineral oil ( baby oil ) or vaseline as above and you won't look back

igniting the core in one single go - ie BM up to the tip of the core

c) good mixing of your ingredients - Ball mill, add mineral oil and rice.

d) preventing cracking of the grain during storage which allows the flame front momentary access to a greater surface area which causes a pressure spike and CATO - mineral oil helps reduce this, as does having completely dry KNO3 and charcoal ( yep, check your charcoal is dry )

e) there is a relatively new wave of tube waxers - it does work, you have to dissolve paraffin wax in naphtha and coat the inside of your tube, this is believed by LLoyd S. over the pond and others to lubricate the wall which prevents distortions in the grain due to binding with it and also to prevent the flame front leaching up between the grain and the tube.  Again, only relevant if aiming for super hot fuels.

I have your tooling and this will work for you for that tooling.

ball mill 4 hours 60:30:10 pine or willow.

Make 3 batches, + 3% mineral oil, + 2% mineral oil and + 1% mineral oil, all dissolved in naphtha then riced with acetone or IPA to dilute and dried.  Start with your +3% mix and test that rocket, then gradually test +2%, then +1% until CATO.

In fact, if I press my motors I can easily run 60:30:10 + 1% mineral oil on the O.B. Set.

This should work.

Let me know.

Hi Sparky,

I'm sure I can help you.  Can you just confirm where you got your tubes from, you said they are concentric ( do you mean parallel wound and not spiral ) - it's usually quite difficult to properly buckle a good tube with hand ramming, they will flare at the bottom though.  Can you also confirm the following :

a) how are you ricing ?  with alcohol / water and NO binder

what are you using to ram them - what is the mallet made from, does it bounce ?

c) are you using a ramming post

d) is your fuel completely dry ( how long after making them do you fire them )

e) how are you fusing them

f) do they CATO immediately or after a short delay

+1% mineral oil reduces thrust by around 6 - 8% but it also significantly aids compaction which if your rammers are bouncing will reduce grain flaking and cracking and lower your CATO incidence. I dissolve 1% mineral oil in coleman naphtha fuel ( others use zippo fuel ) - add to pre-milled mix until tomato soup consistency, stir until comes together in a ball then rice as is through 4-mesh screen and dry.

This company is excellent and who I use for all my lab ware :

http://www.betterequipped.co.uk/

for reagents and chemicals I find this company is the best, although they do glassware too :

https://www.apcpure.com/

Hope that helps.

Sam.