19 replies to this topic

[GuiltyCol]

I've finally decided to make some BP for the first time ever and could do with a little guidance please. I've read Introductory Practical Pyrotechnics by Tom Perigrin and read many of the relevant topics on these fora and believe I have enough knowledge to take my first practical step, but would appreciate a guiding hand of a few points.

I won't bore you with my motivations, but I've decided to try to buy the requisite BP components locally, rather than over the internet e.g. from eBay or specialist chemical suppliers. I know I need Potassium Nitrate, Charcoal and Sulphur. So today I went looking round the local shops:

I got some Artists Charcoal (Willow) from Hobby Craft, so that's ok. Then I went to B&Q, Homebase and a dedicated local garden centre looking for Potassium Nitrate and Sulphur. Sulphur has completely eluded me so far, I was looking for Sulphur powder or Sulphur Chips in the Gardening sections but couldn't find anything like it. Any tips welcome?

I've had some partial success sourcing Potassium Nitrate. Sure there's loads of fertilisers, but they all have different ratios. Looking at the "NPK" ratios, the highest I found was Westland Feed-All Soluble Plant Food which has a NPK of 15:5:30. However I'm a little worried about the extra ingredients, details are:

Nitrogen (N) Total = 15.0%
Phosphorous Pentoxide (P2O5) = 5.0%
Potassium Oxide (K2O) = 30%
Magnesium Oxide (MgO) = 3.0%
Sulphur Trioxide (SO3) = 5.0%

There's a few other bits, Boron, Copper, Iron etc but all below 0.025%.

So the first question is, are there any issues with that Potassium Nitrate? Second question is: Whilst I haven't got any Sulphur, there is Sulphur Trioxide already in the mix, is that of any help or should I ignore it and keep on searching for a separate Sulphur source?

Many thanks for your help.

[x-Ammo-Nx-x]

I've finally decided to make some BP for the first time ever and could do with a little guidance please. I've read Introductory Practical Pyrotechnics by Tom Perigrin and read many of the relevant topics on these fora and believe I have enough knowledge to take my first practical step, but would appreciate a guiding hand of a few points.

I won't bore you with my motivations, but I've decided to try to buy the requisite BP components locally, rather than over the internet e.g. from eBay or specialist chemical suppliers. I know I need Potassium Nitrate, Charcoal and Sulphur. So today I went looking round the local shops:

I got some Artists Charcoal (Willow) from Hobby Craft, so that's ok. Then I went to B&Q, Homebase and a dedicated local garden centre looking for Potassium Nitrate and Sulphur. Sulphur has completely eluded me so far, I was looking for Sulphur powder or Sulphur Chips in the Gardening sections but couldn't find anything like it. Any tips welcome?

I've had some partial success sourcing Potassium Nitrate. Sure there's loads of fertilisers, but they all have different ratios. Looking at the "NPK" ratios, the highest I found was Westland Feed-All Soluble Plant Food which has a NPK of 15:5:30. However I'm a little worried about the extra ingredients, details are:

Nitrogen (N) Total = 15.0%
Phosphorous Pentoxide (P2O5) = 5.0%
Potassium Oxide (K2O) = 30%
Magnesium Oxide (MgO) = 3.0%
Sulphur Trioxide (SO3) = 5.0%

There's a few other bits, Boron, Copper, Iron etc but all below 0.025%.

So the first question is, are there any issues with that Potassium Nitrate? Second question is: Whilst I haven't got any Sulphur, there is Sulphur Trioxide already in the mix, is that of any help or should I ignore it and keep on searching for a separate Sulphur source?

Many thanks for your help.

Just from a few days of chatting to people here I`d advise you stay away from any fertilizer based KNO3. There are too many other chemicals that are contaminating the BP which will greatly affect its burn rate, if it ignites at all. You can buy KNO3 off ebay cheap enough or if you ask here you may find someone willing to supply you some for a good price.

[alex000]

Just from a few days of chatting to people here I`d advise you stay away from any fertilizer based KNO3. There are too many other chemicals that are contaminating the BP which will greatly affect its burn rate, if it ignites at all. You can buy KNO3 off ebay cheap enough or if you ask here you may find someone willing to supply you some for a good price.

Kn03 off ebay is a ripp off, use GD like many I use their kn03 Fertilizer based and it works a treat

[TheExplosionist]

There are only 2 fertilisers I know of that contain a decent amount of nitre: Westland which is pink and 60% yield KNO3, and better is a Wilko brand growmore or something which is light blue. Obviously these must be refined but it won't attract as much attention as buying pure chemicals.

[GuiltyCol]

Thanks for the quick replies. Are we basically saying that it's not possible to buy the ingredients over the counter then? That's a shame.

> Kn03 off ebay is a ripp off, use GD

By GD, do you mean GardensDirect? I've had a look and they do:

Potassium Nitrate
Sulphur

I note their KNO3 has this NPK ratio: 13-0-46. Is that what you'd recommended, no Phosphorous Pentoxide (I assume that's what the P in NPK stands for)?

> Westland which is pink and 60% yield KNO3

How do you calculate KNO3? Take the label I posted originally, there is no "KNO3" listed there, or are you combining ingredients somehow?

Edited by GuiltyCol, 21 October 2007 - 07:36 PM.

[pyromaniac303]

How do you calculate KNO3? Take the label I posted originally, there is no "KNO3" listed there, or are you combining ingredients somehow?

Its the breakdown of products when burnt I think, not the actual ingredients used. You want to be buying single chemical fertilisers, not just guessing at one with a similar NPK ratio. I have no problem going to the garden centre in Doncaster and buying 500g KNO3 for £3.50. Unfortunately they dont sell in larger amounts...

Look for a plain box with Chempak written on it, about the only company that does garden grade KNO3 I have come across in garden centres.

[Asteroid]

Since it is supposed to be fertiliser, the NPK represents the ratios by weight of Nitrogen, Phosphorus and Potassium when in the ground, not when burnt. Gardendirect accepts postal orders also, which I suspect may be of use to you. Potassium nitrate will often be labeled Nitrate of potash and will always be 13-0-46.

Edited by Asteroid, 21 October 2007 - 08:00 PM.

[pyromaniac303]

Since it is supposed to be fertiliser, the NPK represents the ratios by weight of Nitrogen, Phosphorus and Potassium when in the ground, not when burnt.

Why are the products all oxides then?

Nitrogen (N) Total = 15.0%
Phosphorous Pentoxide (P2O5) = 5.0%
Potassium Oxide (K2O) = 30%
Magnesium Oxide (MgO) = 3.0%
Sulphur Trioxide (SO3) = 5.0%

[icarus]

kno3 in the garden centre is quite rare but you can often find sodium nitrate no one likes using it as it absorbs water pyro devices turn to slush if stored etc i use it for same day use projects

[Asteroid]

Why are the products all oxides then?

That's not an NPK ratio, and as to why they are all oxides TBH I don't know.

In general, the mass fraction (percentage) of elemental phosphorus, [P] = 0.436 x [P2O5]

and the mass fraction (percentage) of elemental potassium, [K] = 0.83 x [K2O]

(These conversion factors are mandatory under the UK fertilizer-labelling regulations if elemental values are declared in addition to the N-P-K declaration.[5])

An 18−51−20 fertilizer therefore contains, by weight, 18% elemental nitrogen (N), 22% elemental phosphorus (P) and 16% elemental potassium (K).

They are, according to wikipedia, labeled like that because of UK law

[marble]

The whole fertilizer things is confusing

Don't touch that fertilizer seeing as it contains sulfur trioxide which is highly toxic and is used to make sulfuric acid!

Sulfur should be in most garden centers, try a smaller one or a larger one.

[Asteroid]

It won't actually contain Sulphur trioxide in that form, but will be 5% 1 molecule of slphur and 3 of oxygen. I agree though, it is confusing!

[Andrew]

Here are some definitive Answers.

1. Basically, using NPK values is absolutely pointless. DON'T do it, it will not get you anywhere, forget those numbers even exist. They mean nothing to Pyro. NEVER NEVER NEVER buy a branded/blended fertiliser and expect good results in anything other than plants. Only buy chemicals that are on their own, i.e. not had anything added.

2. Potassium Nitrate bought from GD or other fertiliser Potassium Nitrate is perfectly fine for BP. If your on a purity quest the improvements you'll get are slim and you'll need a fat wallet.

3. Sulphur is a big thing and you need to get it right. This is where Garden centres are a bad thing. The link to Sulphur posted by GuiltyCol is for the WRONG type of Sulphur, this is the RIGHT type of Sulphur at GD. Dusting Sulphur is a big NO NO. It is what is commonly known as "Flowers of Sulphur". This is made in such a way that gives rise to high acidity levels. This in turn makes your BP more sensitive and thus more dangerous. You need to buy "Rhombic Sulphur", commonly known as "Roll Sulphur". It is a little more expensive in a powdered form but it is far safer (and cheaper than flowers when in chip form). Rhombic Sulphur is available in chips or powder. Don't buy Flowers for Pyro.

4. eBay is a rip off. However there are a few reputable suppliers (and I mean only a few), that are also cheap. The biggest Problem with eBay sellers is that most of them are breaking several laws. It's best to stay clear unless you are sure they are legally trading.




What you really need to do is search the forum, there are thousands of posts regarding good suppliers. Look in the "Buying Chemicals" thread for a start. If you need to find reputable suppliers PM a few people that have lots of posts and ask nicely. You'll probably be told to search but some people will tell you good Pyro suppliers. There really is no need to go round garden centres in a clandestine fashion drawing attention to yourselves (if you ask for Potassium Nitrate in a garden centre you better be feeling lucky, and hope no police turn up. Not likely but you only have to be of the wrong appearance and ask an overzealous assistant to draw the wrong kind of attention). There are dedicated Pyro suppliers who you can get pretty much anything you need from, in the UK.

[Anders Greenman]

When it comes to agricultural grade KNO3, nothing beats Yara's Krista K Plus! It's 98% Potassium Nitrate. I'm not sure if they sell it in Britain though.

[Andrew]

When it comes to agricultural grade KNO3, nothing beats Yara's Krista K Plus! It's 98% Potassium Nitrate. I'm not sure if they sell it in Britain though.

They do, at about £10/25kg if you know where to get it from.