34 replies to this topic

[pyromaniac303]

Did you compact it thoroughly? The way it leapt into the air makes me think that perhaps there were cracks in the composition or loose powder, causing it to burn quite violently.

A Bengal composition of mine:
Grass Green

Barium Nitrate 65%
Parlon 20%
Magnalium 8%
Sulfur 7%

Due to the relatively cool fuels it is not as bright as some others, but seems to be deeper and less washed out than other barium nitrate greens. Still not quite as good as the barium chlorate greens, but much cheaper and less hazardous to work with. Also it can be parlon bound with acetone, but it does suffer from shrinkage above about 15mm ID causing the flame to burn down the side of the tube.

On the subject of tubes, I find that spirometer tubes from local doctors surgeries are perfect. I picked up a box of several hundred that were being thrown away as they had ordered the wrong ones for their equipment. They are spiral wound with a waxy outer coating, and approximately 1mm wall thickness. They also come in a range of diameters.

[sagoraMundy]

Did you compact it thoroughly? The way it leapt into the air makes me think that perhaps there were cracks in the composition or loose powder, causing it to burn quite violently.

Like PC's stated process, it was a slurry which I just poured into the tube.

My suspicion is that it shrank during drying and because the walls of my tube were too thick they trapped a pocket of burning gas and made it go off like that.

Will try it again with a thinner-walled paper tube as RFD suggests.

Also must try your Grass Green formula; sounds yummy.

The way my wipe-up towel burned with such a glorious shade of green I'm wondering if I couldn't just pour the slurry out onto a long slab of cardboard and fuse one end and just let it burn in the open.

[Potassium chlorate]

OK after letting my first bengal fire project dry for three days I lit it off. Pretty sure this AIN'T what's s'posed to happen:

http://tinyurl.com/4hojqvr

It's your suggested formula PC: 90% Barium Chlorate and 10% Shellac dissolved in alcohol.

Reading back, I notice you poured yours into a thin-walled paper tube; my tube was pretty stout. Wonder if that's why it went off instead of just burning?

I told you that barium chlorate is sensitive, didn't I?

It's very probable that the thick tube made it go off, yes. I use toilet paper tubes or household paper tubes. Not that fancy, but it works.

[sagoraMundy]

Amen to that (sensitive!). Just grateful when it decided to go ballistic that it didn't land on me or the camera!

Thanx for the follow-up on paper tubes. I've just made a run of new ones, 20lb bond paper wrapped two or three times round a 1/2" wooden dowel. Maybe stick to short one- or two-inch loads till I see how this stuff burns.

Appreciate your advice PC,
s

[RFD]

I have seen on different pyro sites that a few people feel that the type of paper for the tubes is important,mainly how the paper burns may effect the colour of the bengal,to honest Ive tried all sorts from post it notes,cheap A4 copier paper,newspaper and everything in between and havnt been able to discern the difference,only thing i did notice is the type of glue used to roll the tubes can create a slight orange tint,but barium chlorate is such a good "traffic light green" i dont think its worth worrying about.