135 replies to this topic

[RegimentalPyro]

Measured out 45cm of my BP and lit one end. It took about 3-4 seconds to burn through so I reckon I have a slow burning comp here.

OK - Nothing worthwhile is ever easy. Back to the drawing board. I'll try and score some willow charcoal for my next milling. I'll keep you posted guys...

I guess there are a few circumstances when I'll want slow burning BP [although I can't think of any off the top of my head] so I won't chuck the stuff yet.

[OxCid]

why not make some black match with it,

[BigG]

Keep this black powder for black match (fuse). In most applications you will want your black fuse to be slow so you can retire to a safe distance.

B.T.W your small yellow/white balls that are left behind are Sulphur. This suggest not enough ball milling which is very strange as three hours should give you better results. It might also suggest wrong quantities. Can you let us know how you measure the materials, by volume or weight?

BigG

[RegimentalPyro]

By weight.

I measured 150g KNO3, then made up to 180g with charcoal, and finally added Sulphur up to 200g.

Thanks for the suggestion about the black match. I'll do that.

Edited by RegimentalPyro, 11 August 2003 - 06:07 PM.

[Rhodri]

You could also use this powder as a fountain too if you were to add 10% Al / Fe.

[RegimentalPyro]

Another good suggestion there Rhodri. Must remember the following fact

Keep the comp, even if you think it's no good. - You'll find a use if you think hard enough.....

Being a keen cyclist, I have a few spare bits of bike around that are made of Al / Fe. Can I just file these down to get Al / Fe powder?

I've heard that Fe powder needs to be coated in Linseed unless it's going to be used immedietely. Would any oil barrier work - [3in1, Lithiumgrease etc].

[BigG]

If you plan on storing your fountain for more then a week ? your Iron should be coated before using. 3 in 1 and other quick improvement oils will protect the metal for a short period of time ? about 2 to three weeks. Better protection can be obtained with linseed oil (which is what commercial manufacturers use and is easily obtainable). Use about 5 gram of linseed oil for 100 grams iron. The iron needs to be impregnated with the oil. Put them in a pan and mix above a low temperature hot plate slowly. Keep on going until the all iron is uniformed in colour and all signs of liquid will disappear from the pan (which means some of oil was observed into the iron and some evaporated). Such coating survives amazing humidity. I laid a batch in 80% humidity for a month and no signed of rusting were shown. (A sample in the lab showed a small degree of rusting in the microscopic level ? but still very expectable.)

Stay Green!!! BigG

[bernie]

This is rather obvious but....you will want to cook that linseed oil outside.

[Rhodri]

You could file down Al/Fe but it will take ages to get some and then 'boomph' it's gone.

Use this link to get your Al from Tiranti: METAL POWDERS



Metal Fillers.

Description: A series of fine metal powders (200-325 mesh) specially for use with resins in the Cold Cast Resin Metal Process originally developed by Alec Tiranti Ltd in the late fifties. The powders are pure metals, not colours, and are unsuitable for painting. Please note that we cannot guarantee colours, and that enough should be in hand of the same shade for the whole job in hand.
The metal powder is mixed with GP or Multi-Purpose Resin, and hardener. This mixture is then painted into the mould as a first layer or gel coat. It is then either filled solid with resin and filler or laminated with glass fibre. When polished to reveal the metal, the castings are almost identical in appearance to a cast piece in the chosen metal. The metal content of the metal / resin mix should be as high as possible; too little metal filler is as bad as none at all. Cold Cast Resin Metal pieces in bronze, brass or copper can be patinated using Antiquing Fluids or Cupra.

Quantities of Fillers:
In general, a rule of thumb is equal parts by volume plus a little more filler (based on GP or Multi-Purpose resin at room temperature). A guide to weight ratios of metal fillers to one part of Multi-Purpose resin is:
Aluminium: 1?
Bronze: 6 or 7
Brass: 5 or 6
Copper: 4 or 5
Iron: 6 or 7

[RegimentalPyro]

OK - Some good news. Last night I set off my first ever homemade fireworks. Taking into account the advice of this forum I made a couple of fountains.

These were made using tubes gleaned from a friend who works at Asda - The carrier bags there come on a roll with these at the centre. They're quite sturdy and you can get about 3 fountains to a tube.

I didn't measure the ID, but to give you some idea of size a broom handle fit inside fairly snugly. I decided to use the broom handle as a rammer.

I used CatSan [clumping variety] rammed *HARD* as my end plugs and my slow burning crappy BP as comp. After some inginuity ending up with a plug at one end, some BP tapped firm in the middle and a plug with a 2/3mm hole/nozzle at the other. Filled this hole with BP to prime it and stuck in some screwed up touch-paper [my touch paper turned out to be much more reliable than my blackmatch which has yet to be perfected]

Erring on the side of caution, my first fountain didn't have much comp [2xID tamped down gently], and had a 3mm nozzle. This gave about a 7-10 sec fountain of golden sparks with a height of 5-6 feet. Much elation and a manic grin on my face. My first DIY pyro device - hooray

The second had about half agian more BP [3xID tamped down gently] and a smaller 1-1.5mm nozzle. This was far more spectacular. 15 sec of golden sparks shooting about 12-15 feet in the air. My grin widened!

Two points I noted.

On both the fountains the tube burnt through at the sides [about 3/4 of the way through the burn] leading to a secondary fountain out the side. As the fountain was securely fixed, this was no real problem, but I am assuming I need to do one of the following [I'm guessing on a.]
a. Use thicker walled tubes.
b. Line the inside of the tubes with some sort of inert fire retardant chemical. Maybe a saturated solution of tablesalt painted on the interior of the tube and left to dry?

When burning my crappy BP confined in this manner I noticed that I didn't get the glowing "slag" [Sulphur?] that was exhibited when the BP is burnt "unconfined". Wonder what this says about this batch of slowburning BP - any suggestions?.

[Rhodri]

Hi

Well done! It's a great thrill is it not!

#1 - You need to use a much thicker walled tube. BP and metals burn exceptionally hot - hence the rupturing of your tube and 'two' fountains.

#2 - There may have been less 'slag' because of the more effiecient 'clean burn' brought about by compacting the powder. The temperatues would be higher and volatilise the solids more efficiently.

Rhod

[RegimentalPyro]

I was literally jumping up and down with delight! Mondo good time! Picture below...



Where do you get your tubes from? Thick walled tubes seem to be a rare breed.

Whilst I'm asking about supplies, where can I get willow charcoal cheaply. I milled ?4 of artists charcoal and only got 15g or so. My next step [of course] is to make my own but that would involve going down to the riverbank with a handaxe and an acquisitive approach to forestry.

Edited by RegimentalPyro, 07 September 2003 - 08:27 PM.

[Stuart]

Dont get your hopes up but my dad owns a Waterproof Clothing company. Now, he gets his fabric on big roles right. The center of the rolls are cardboard tubes, thick cardboard tubes. They vary in ID but I think it could be anything from2/3 cm to 2 inches (which is 5 cm). The walls are anything from 2/3 mm thick to 5mm thick. Now, if I can get him to remember, I might be able to get him to bring them home (he throws them out anyway) and I would then be able to cut them to the right sizes (unless you want to pay the postage for sending a 1.5m tube). I wouldn't charge anything except P&P. Pyromaster and Matt have seen a pcture of one and they send their blessing. He has just ordered a few rolls of fabric 2 days ago and has had a big order too so hopes up people. He orders new fabric every 1 or 2 week methinks.


Stuart

[RegimentalPyro]

That's a really generous offer there Stuart - I'm gonna take you up on that. Let me know when when you have the rolls, and how much P&P you want and I'll shower you with cash accordingly.

[RegimentalPyro]

I've added a picture of the second fountain to the original post above so you can see the results of this forum - pretty......Thanks guys!

I've also milled up another batch of BP, using willow charcoal this time and a digital scale [120gx0.1g] to measure instead of an old slimmers scale[Thanx ebay!]. Initial tests seem to indicate that this is a mite more frisky, but then it started raining so I have to postpone further testing. Any danger in making fast BP into another fountain so I can run a side-by-side comparison?