Problem with stars (BP/Al mix)

[Pretty green flame]

Greets

 

Wel my problem is that my stars do not give the desired effect. I mix up a batch of shimizus fountain formula (BP + 20% Al), this works very well as a powder giving off a lot of white spark but as soon as i turn them into stars things start to go wrong. The stars take fire very easily but instead of throwing out white spark it just burns with and orange light and leaves behind a glowing pile of crap, upon closer inspection it was revealed that the aluminium doesn't even burn.

 

What could be wrong? Could the reason be too much water when i am pumping them (I used gum arabic solution for wetting them), crappy aluminium or what?

 

The same happened to my other comps containing aluminium, as a powder it burns beautifully but when i turn them into stars they just get all crappy like.

 

Thanks

[Mardec]

I have had the exact same problem

 

Mill you bp first, that helps

 

Coat the stars so they burn hotter (bp wil do)

 

Do you put some H3BO3 in them? Al could be oxidised.

 

 

& btw, if you make those stars big (if they only burn orange, you do get some cool effect).

 

This is what happened with me:

 

I shot the star

It got to break altitude

Bam, louzy orange balls..

Kept burning orange

 

And al of the sudden they exploded with hell lots of fire light and burning al

 

My gues is that they burned to cool and then reached critical temperature and it just worked as a flash powder inside..

 

Conclusion, your stars burn to cool for the al to burn, coat them with bp (+ 5% al for hotter fire).

 

And if that didn't help your al might bad for this kind of stars

And that would suck

[fredjr]

and leaves behind a glowing pile of crap

Does this mean you are just burning the star on the ground? A static test on the ground doesn't show you true performance of a star. My glitter stars look like that when burned on the ground but when moving though the air they throw off globs of molten material and make excellent glitter. What do they look like when shot from a stargun?

[Pretty green flame]

and leaves behind a glowing pile of crap

Does this mean you are just burning the star on the ground? A static test on the ground doesn't show you true performance of a star. My glitter stars look like that when burned on the ground but when moving though the air they throw off globs of molten material and make excellent glitter. What do they look like when shot from a stargun?

I see, i will shoot one from a star gun later today and see it if works.

[Mumbles]

You may also want to try different formulas. Perhaps 10%. Some gerb compositions need the pressure and lack of atmospheric air to function properly. There is a thread in the composition section entitled "Meal and metal" or "metal and meal" that will fit your purposes here. Also another one is the "reeper silver" I don't remember if we still have that one, but it was meal with 10 or 15% -325 mesh atomised Al.

[Mephistos Minion]

Reeper silver looks gold on the ground, but as soon as it comes flying from a starmine at high speed it is a really nice bright comp. Definetly do a stargun test on them, or a starmine one if you have lots Also your gum arabic may be a problem. I think I remember draco aster having some troubles with TT stars bound with GA. Apparently the burn was way too slow/not at all. Perhaps they are not burning fast/hot enough to light the Al propperly. Perhaps use dextrine next batch, that is if they fail the stargun tests.

[Pretty green flame]

I have done a star gun test and although it was better it did not produce many white sparks. Could it be that i am not produceing a hot enough flame so the Al doesn't burn?

[Draco_Aster]

Yah, gum arabic is OK aslong as you change the comp to suite as it is a fuel. Totally wrecks good BP and rich fuel comps.

[al93535]

Pretty Green Flame:

 

You nailed it. Especially with larger meshes of al you need a hotter oxidizer! I had this problem. You can easily fix it though! Add a bit of perc, or barium nitrate! Also, it helps to use a small % of fine aluminum to get the comp burning really hot.

[Pretty green flame]

Cheers!

 

I will try some Ba-nitrate as i have plenty of it .

Thanks for that Al

[Pretty green flame]

Al, i'd like to thank you for the tip (about the Ba-nitrate), my stars are working as they should.

 

Thanks again.