16 replies to this topic

[Yugen-biki]

spykke

Thumping a pile with a hammer will at best tell you nothing and at worst injure you.

I don't agree wtih you.
At best you'll get a id?a how sensitive the mixture is to shock. If you rubb the hammer in the comp you'll get a id?a how friction sensitiver it is.
But this says nothing really about the compability with other compositons and if there are some chemical instabilities in one or more och the chemiclas in the comp..
Regarding chemical stability and compabilities you have to trust the litterature and experts.
But makeing a not very scientiffic "drop hammer test" at home, useing very small ammounts of the comp can't hurt in my oppinion.

But it is no secret that chlorates are sensitive. Use them as little as possible.

[BigG]

spykke
I don't agree wtih you.
At best you'll get a id?a how sensitive the mixture is to shock. If you rubb the hammer in the comp you'll get a id?a how friction sensitiver it is.
But this says nothing really about the compability with other compositons and if there are some chemical instabilities in one or more och the chemiclas in the comp..
Regarding chemical stability and compabilities you have to trust the litterature and experts.
But makeing a not very scientiffic "drop hammer test" at home, useing very small ammounts of the comp can't hurt in my oppinion.

But it is no secret that chlorates are sensitive. Use them as little as possible.

Yugen-biki - I have to disagree with you on this one. Hammer drop tests are not done by a person holding the hammer. Even small amounts can create an unfortunate accident. I'm sure it's possible to create some device that will allow you to drop a hammer without holding it.

I think spyyke is trying to suggest that this is not a very scientific way to go about things. Hammering something without measuring the strength of the hit or the height of the fall will really prove nothing and can get you hurt. The fact that something did not detonate does not mean it's not sensitive - it just means that under the specific strange you apply - the material does not detonate. It requires a repetitive quantity of tests - increasing the height/strange before reaching a valid conclusion about sensitivity.

One must remember that the fireworks chemistry world is very well defined. The list of chemicals is almost a closed one. The compositions used are very similar to one each other and one can tell in great confidence if a composition is sensitive/not sensitive by reading the right material in the first place. This is why most hobbyists are not chemistry experts and still have high level of confidence at what they mix and do. The accident levels amount hobbyists is very low - and when an accidents do happened, it usually because people rush forward without paying regard to the knowledge that is required or obtained.

New members should handle only non-sensitive formula to start with - those are the BP type formulas. Not flash, Not whistle, not Chlorate based. I am very concern with the original post of this thread. Suggesting using chlorate because it's available. That's plain wrong. Also the idea of testing the composition yourself is nonsense. First READ about the composition - then you gain a knowledge level that allow you to conduct tests of it in a safe manner. The forums are a good place for information - but people here are hobbyist like you and can make unfounded mistakes. READ the material and you are on your way. References for good books already exist on the forum - Use them.

[spykke]

Hitting a pile with a hammer tells you nothing new - you should already be aware that the composition is sensitive - if you have studied the literature or have some basic knowledge. It won't tell you how sensitive - something you need to know for safe handling.

Regarding chemical stability and compabilities you have to trust the litterature and experts.

Not a chance - when it comes to specific compositions I may handle I would only trust specific tests done on that material.

Edited by spykke, 22 March 2005 - 01:24 PM.

[BigG]

Hitting a pile with a hammer tells you nothing new - you should already be aware that the composition is sensitive - if you have studied the literature or have some basic knowledge. It won't tell you how sensitive - something you need to know for safe handling.
Not a chance - when it comes to specific compositions I may handle I would only trust specific tests done on that material.

Of course now I'll have to disagree with you?.

While it will be very nice to test EVERYTHING - it?s not likely to be possible. Nor does the statement that you cannot base knowledge of reaction on known properties of other compositions. The whole idea that hobbyist cannot operate because they have no means to test like commercial operations do - is at best strange.

As mentioned before - fireworks are a very closed world when it comes to chemistry. We are not trying new materials very often and the changes to quantities in most existing formulas will not change their properties by much.

For example, all "firedust" compositions (BP with differest KNO3/S/C ratios) are not going to become more reactive or explosive then BP regardless of the tests you will run on them.

It is worth mentioning that fireworks evolved with time. Publications from the 50's and 60's are now considered outdated, and even recent formulation are found do be more reactive then one might think (some surprise findings are emerged regarding the usage of MG/AL in formulations compare to MG or AL alone) - yet, in the quantities that hobbyist look at, the main attention needs to be practiced on separation rather then commercial style testing that is not visible.

[spykke]

I will only speak for myself - others have to make their own choices. There is no way, ever, that I would handle a composition unless I knew it's characteristics. It is a stance which was drummed into me when I started work and I've always stuck with it, even when it has upset others who wanted me to cut corners. In my opinion it is not a case of "it will be very nice to test EVERYTHING", it is an absolute necessity. I value my health and life too much to work in any other way.

Whilst, on the face of it, compositions may be expected to have similar behaviours, many factors such as sources of ingredients, grist, crystal structure, purity can effect the sensitiveness of the composition. Look, for example, at the difference that flake titanium versus turnings has on friction sensitiveness. Or consider the problem of using a poor quality perchlorate (with high chlorate content) with sulphur as opposed to a high purity perchlorate. There's lots of useful data on these issues in the open literature.

The same maxim is never to take things for granted.

Edited by spykke, 22 March 2005 - 03:04 PM.

[Yugen-biki]

BigG

One must remember that the fireworks chemistry world is very well defined. The list of chemicals is almost a closed one. The compositions used are very similar to one each other and...

I agree 100%.
When I first made some flash I did a lot of reserch. I found out quite fast that it is a sensitive compositon. But the numbers in the books how the compositions behaved in a dropp hammer machine said nothing to. OK, it's more sensitive that BP, but I had no id?a how sensitive the BP was either.
And a good way is to simulate a situation that you and the composition may some day be in. For example ramming a rocket with BP. I firt hammer a little BP on the ground before I hammer a spoon full in a confined paper tube.
Not that i usually hammer my flash, but a friction test might be a good indicator on how things are. When I load a salute the flash comes in contact with the paper container and the spoon. Why not rub the spoon on some paper and se what happends with a very small ammount of the composition.

In the end I know that all of us are just trying to be as safe as possible.

spykke

Not a chance - when it comes to specific compositions I may handle I would only trust specific tests done on that material.

Does this mean that you don't trust any compositions found in Lancaster or Shimizu?
I for one just hate the compositon data bases out there where the comps are taken out of context and you don't know s**t about it. But my copy of Shimizu is like a bible to me. That book is made for the industry and why would he print dangerous compositions in his book?


I'll let this thing go. In the end we are only trying our best to be safe in the best way we find fit. Some methods are better that others and I don't say mine is best.
But I don't think I can be convinsed why a non scientific test whith a small ammount of composition is of no value.

[spykke]

Does this mean that you don't trust any compositions found in Lancaster or Shimizu?

No!!! What I said was I would not handle any composition without knowing it's properties first. I'm sure the compositions quoted in those books do what they intend. (give a red light or crackle or whatever) What they don't do is specify the purity, form or grist of the ingredients. (see my earlier post) These of course affect the behaviour of the composition. That is why I would want to establish the sensitiveness of the actual composition using the actual sourced ingredients before undertaking batch sizes more than a gramme or two. This is standard practice in Research and Development in the explosives industry - that was my work for 12 years.

You don't walk into a dark room without turning on the light. So why handle a composition without knowing how it behaves?

[BigG]

No!!! What I said was I would not handle any composition without knowing it's properties first. I'm sure the compositions quoted in those books do what they intend. (give a red light or crackle or whatever) What they don't do is  specify the purity, form or grist of the ingredients. (see my earlier post) These of course affect the behaviour of the composition. That is why I would want to establish the sensitiveness of the actual composition using the actual sourced ingredients before undertaking batch sizes more than a gramme or two. This is standard practice in Research and Development in the explosives industry - that was my work for 12 years.

You don't walk into a dark room without turning on the light. So why handle a composition without knowing how it behaves?

Well, I would walk into a dark room if I know what's in it and I don't want to turn on the lights and wake up the kids

I see your point - but again, I don't agree that every manufacture in the fireworks industry (and I am very careful in saying the fireworks industry. I have no idea how the general explosive industry operates) makes batches of 1 or 2 grams before mixing larger batches. Since our resources (skylighter, firefox or other chemical suppliers) usually well define what they sell (Aluminium, flake, 3 micron or aluminium, atomised, 300 mesh) then you do have a general idea about the grit, size and acceptability of the material. Lancaster mention the problem of "lampblack" in a formula can mean 1 of 100 things - but his point is that smaller batches need to be made to test the effect is proper - not the sensitivity.

Again - I do really need to emphasis that the fireworks industry does differ from the general explosive industry in what it does. The energy invested in fireworks compositions is by far less energetic then military or scientific one. The act of generalizing this industry together with the one of general explosives is convenient, but the need to include so many clauses that specifically talk about fireworks does indicate the unique statue of that industry.

As such, the industry does make sure it source its chemicals from suppliers that can supply the right information - with the right material information and safety notes, but it does not go into the extent of making 1 to 2 gram batches of EVERYTHING it mixes.

On a personal note, my view was always is that there must be a logical path between safety and sanity. If our view is that safety comes at all costs, then we have no option but to live as a nanny state. Possible, but I don't see how many people will stay in a country that force you to check for gas leaks before lighting the stove. My personal view is the solution in this case to encourage separation between the operator and the mixture as much as possible. Together with the knowledge of the properties of your chemicals, you can get to a level of safety that is acceptable. It will mean that accidents will happen, but they will be isolated cases, and with proper separation, will mean a minimal damage and lost of life.

[spykke]

To a large degree this debate isn't really relevant in the UK because we no longer have a fireworks manufacturing industry as such. Looking back at the days when we did, the firework industry wasn't as good as a performer in terms of health and safety as the rest of the explosives industry. Possibly because they did consider themselves to be different. Certainly their routine testing and characterisation of compositions was poor. I don't think the fireworks industry is any different to other explosives manufacturers. They are faced with the same issues. In many cases the hazards may be lower but in many cases the risks are higher. People may not get blown to pieces in fireworks accidents but they do tend to get burned badly.


I tend to react badly when people start talking about the nanny state and the balance between safety and sanity. Personal safety, which I am talking about here, has nothing to do with the state or law enforcers. Its all about the risks an individual is prepared to take. I'm no risk taker and I have no desire to be burned or lose a limb or worse because of something I could have done but didn't. I can't prevent the unexpected accident but I can and will do something about the foreseeable.

[Yugen-biki]

spykke

This is standard practice in Research and Development in the explosives industry - that was my work for 12 years.

BigG

Again - I do really need to emphasis that the fireworks industry does differ from the general explosive industry in what it does. The energy invested in fireworks compositions is by far less energetic then military or scientific one. The act of generalizing this industry together...

Yes, this is important to note.

spykke

What they don't do is specify the purity, form or grist of the ingredients...

I get my chemicals from a person who has a lot of knowlidge from the pyrotechnical industry. I asked him about chemical properties and if I had to worry about that. His respons was something similar to that his chemicals are not very likely at all to cause any problem.
For some one buying their chemicals from garden centers and pottery supplies need to pay extra attention to what purity they have gotten their hands on.


In the end. Don't make dangerous mixtures you know are dangerous and repetedly times are reported dangerous in forums and most important in the updated pyrotechnical litterature, like Shimuzu and Lancatser.
Wich moderatly pyrotechnicaly interested person does not know the basic dangers about some chemicals when mixed, like chlorate and sulfur?
And mixtures that are stated safe, like BP, is very unlikely to cause any problem.

[BigG]

I tend to react badly when people start talking about the nanny state and the balance between safety and sanity. Personal safety, which I am talking about here, has nothing to do with the state or law enforcers. Its all about the risks an individual is prepared to take. I'm no risk taker and I have no desire to be burned or lose a limb or worse because of something I could have done but didn't. I can't prevent the unexpected accident but I can and will do something about the foreseeable.

You Tend to react badly?!?! What does that means?

We don't argue about the fact that your views on safety are in the extreme end of this industry - and I'm happy you made it very clear that they are your own personal views. We also don't argue that the few manufacturers (5 Isn't it? - only one full time) left in this country have an excellent safety records (of no accidents) and that they do not mix a single gram or two every time they bring in a new version of a known chemical.

Now, your views are important - just like any other members view on this forum. They are not there to upset, or make people react badly - but they are open to discussion and hopefully, before deciding on a path, members will take to the point that safety is very important and they have to act in a legal manner with a minimal level of risk. At the end of the day, everyone needs to understand that pyrotechnic is dangerous, and you are taking a risk when applying it - a risk that can be significantly reduced by cleanliness, separation, chemical understanding and good working procedures.

Edited by BigG, 23 March 2005 - 09:47 AM.

[Phoenix]

In more direct response to the topic of this thread, I would not be too quick to condemn a hammer test, provided it is carried out safely - outside, wearing eye protection, and using a very small quantity of composition. Bill Ofca points out that whilst it won't tell you anything specific, it will give you an idea of how sensitive a composition is.

For example, black powder and variations thereon will be difficult or impossible to ignite by hitting or scraping them, perchlorate colours may ignite from a strong blow, chlorate colours from a lighter blow, and incompatible mixtures such as chlorate and sulphur will ignite with very little effort. This doesn't tell you anything in the way that a laboratory hammer drop test would, but it does give you a feel for how sensitive each composition is.

If you performed this test on a composition that you had not used before and found that it ignited with very little effort, then you would know that it was unsafe to use. If you found that it could be ignited with a very hard blow, then that would not guarantee the mixture as being safe, but it would provide some grounds for you to believe that the mixture could be used with care, provided it was not subjected to any severe shocks.

For example, one might want to substitute chlorate for perchlorate in a published colour composition. Obviously, the first thing to consider would be chemical compatibilities. Suppose that these were all OK. The chlorate composition will be more sensitive to impact and friction that the original perchlorate composition was. If a hammer test showed that the new composition ignited very easily, then one could deduce that the substitution was unacceptable. However, if the impact sensitivity was found to be similar to that of other "safe" chlorate compositions, then one could probably use the new mixture, with due caution.

Obviously, such a test is not proof that a new mixture is safe, and by saying what I have I am not advising anyone to go mixing up new compositions and using them if they don't ignite from being struck. Rather I am saying that a hammer test on small quantity of composition can be a useful means in familiarising yourself with its friction and impact sensitivity, and there is no reason why it should be dangerous if common sense is used.

[BigG]

The main problem with this approach is to quantify what is a "big blow" and what is a "small blow", and how you can be sure that you tried the same "Big blow" twice....

I think this might have some value as a demonstration, but it's not really very scientific. I do think you can probably make a drop test that is more realistic even in home environment.

[spykke]

We don't argue about the fact that your views on safety are in the extreme end of this industry

A disappointing view which speaks volumes. You might not argue but I would certainly disagree. However, I think this debate has run it's course and I won't comment any further.

[adamw]

Please dont think of BigG as ignorant. Maybe it was misworded:

Spykke, your views are based on being in the industry 12 years, and it it is not difficult to see how you think an amatuer's idea of testing and safety is less sophisticated than yours. In practice, we all have the same goal: to carry out what we are doing as safely as possible and to commit fully to enhancing our own and others knowledge in the field.

May I ask... why did you join the forum? Surely now that you have left the industry?? you wish to take part in experimentation on an 'amatuer' level?