633 replies to this topic

[pudi.dk]

Anyone tried this one, Kosanke Green MgAl?

Barium Nitrate.........................................56
Parlon.....................................................14
Aluminum, atomized, 400 mesh.................9
Sulfur.......................................................9
Magnalium, granular, -200 mesh................4
Dextrin....................................................4
Red Gum.................................................3
Boric Acid...............................................1

Since there is parlon and red gum, could I just leave out boric acid
and dextrin and then bind with acetone:alcohol 50/50, then make cut
stars? If doing so, should I dry the acetone with CaCl2 to prevent
corrosion of MgAl from the water in the acetone?

Edited by pudi.dk, 26 May 2008 - 10:55 PM.

[Mumbles]

Boric Acid wont protect MgAl anyway, so it wouldn't make any difference if you removed it. You could probably replace the dextrin with RG and be able to cut it just fine with straight alcohol, or an alcohol acetone mix.

[pyrotrev]

As long as your stars aren't too big I would suspect that with the alcohol/acetone mix they will dry quickly enough not to cause any problems with a little bit of damp in the solvents.

Edited by pyrotrev, 27 May 2008 - 12:09 PM.

[cooperman435]

howcome if everyone is claiming Boric acid wont protect MgAl that without it my Win20# stars puff up within 2 days of pumping but with it they are fine?

[digger]

howcome if everyone is claiming Boric acid wont protect MgAl that without it my Win20# stars puff up within 2 days of pumping but with it they are fine?

Interesting, I assume that the notion is that magnesium reacts strongly with pretty much any acid and hence acids are to be avoided.

I don't know how alloying affects the acid reaction though, but from you experiment it would appear to bode well unless magnesium borate does not produce a visible bloom.

P.S. I rolled up some win16 the other day and dried them in my drying cab, I did not use any boric acid and there are a couple of white dots on the surface of the stars (which I put down to them being force dried / over a ruby red core).

[maxman]

Digger, I see you're at the ruby reds again!? I hope they work ok this time. I read a post on rec.pyro that suggested no alcohol to be used in the water. He claimed that with alcohol they crumbled and with water only they were rock hard. I thought it was more to do with hydroscopic strontium nitrate though. Anyone any experience on that one?

[BrightStar]

howcome if everyone is claiming Boric acid wont protect MgAl that without it my Win20# stars puff up within 2 days of pumping but with it they are fine?

Interesting indeed... I usually cut my Win20 (200 mesh granular MgAl) and it's quite thoroughly dampened with water+IPA (no boric acid). It's quick and easy in this respect with no adverse reactions so far. I usually though have it almost dry within a day.

Edited by BrightStar, 04 June 2008 - 02:12 PM.

[digger]

Digger, I see you're at the ruby reds again!? I hope they work ok this time. I read a post on rec.pyro that suggested no alcohol to be used in the water. He claimed that with alcohol they crumbled and with water only they were rock hard. I thought it was more to do with hydroscopic strontium nitrate though. Anyone any experience on that one?

Not quite I had quite a number of 8mm ruby reds from last time so I decided to chuck em in the star roller and roll something that would go hard over the top. It seems to have worked, I fired a couple last night from a star gun, good ignition, and nice change from glitter to red. I just hate to have to waste any comp.

If I do decide to do ruby reds or similar again I will be looking to bind them with something other than water/dex. Maybe use parlon/red gum with a dried acetone/alcohol mixture. I faffed around and wasted far too much comp the last time I tried making them.

[Bonny]

Digger, I see you're at the ruby reds again!? I hope they work ok this time. I read a post on rec.pyro that suggested no alcohol to be used in the water. He claimed that with alcohol they crumbled and with water only they were rock hard. I thought it was more to do with hydroscopic strontium nitrate though. Anyone any experience on that one?

I've made a few batches of ruby red using 70/30 water IPA and they dried nice and hard.

[pyrotrev]

2 points about the boric acid argument.... firstly that Kosanke mix had some 400 mesh ali in it that the boric acid will protect, and secondly, since boric acid protects against alkaline reactions such as occur with nitrates & Al, it might help with MgAl in some circumstances I guess. Magnesium self protects against alkaline corrosion to some extent, but is attacked by acid, whereas aluminium is resistant to acid, but attacked by alkali. Exactly what happens with MgAl is unclear to me, but Cooperman's experience would seem to suggest it's useful to some extent.

Edited by pyrotrev, 29 May 2008 - 07:03 PM.

[Mumbles]

I don't know what is happening with copperman's experience. No matter how I've prepared win 20, I have never had a problem with any sort of reaction.

As for the Kosanke MgAl. Barium Nitrate does not react with aluminum the same way potassium does. I don't know why exactly, but I have never seen or heard reports of any reactions between barium nitrate and aluminum. Might have to do with the great insolubility of barium hydroxide. It would act as it's own buffer eating up any hydroxide ions present, and subsequently killing the reaction under normal conditions.

Boric acid isn't really an acid in a traditional sense. It accepts hydroxide ions, rather than donating protons. For that matter, it doesn't even really dissociate water(accepting OH- from the water). A 1M solution of boric acid would contribute a negligible amount of H+ compared to the water itself that it was dissolved in.

[kelly]

Been reading forum for months, lots of very interesting information! Am presently attempting to collect chems to make a few of the colored stars, have most that the formulas require, exception being a chlorine donor. Dechlorane, Lindane, HCB, and HCE are all prohibited substances in Oz, and PVC and Saran are unobtainable. Am current evaporating some Sodium Hypochlorite (common household bleach) obtaining clean white crystals, and have available pool chem containing TRICHLORISOCYANURIC Acid but not purchased as it is called an oxidiser and I have enough of that already. Am I even close to getting something that will work as a donor? Or is there something else I should try (like perhaps knitting)? I ask because I haven't seen the info I'm after, am I in the wrong forum?

Thanks, Kelly.

[BrightStar]

Kelly, suggest you contact Steve at Inoxia - he should be able to send you some Parlon (66% chlorine) by airmail. Even 500g goes a long way when you're starting out.

Edited by BrightStar, 04 June 2008 - 02:26 PM.

[Bonny]

Been reading forum for months, lots of very interesting information! Am presently attempting to collect chems to make a few of the colored stars, have most that the formulas require, exception being a chlorine donor. Dechlorane, Lindane, HCB, and HCE are all prohibited substances in Oz, and PVC and Saran are unobtainable. Am current evaporating some Sodium Hypochlorite (common household bleach) obtaining clean white crystals, and have available pool chem containing TRICHLORISOCYANURIC Acid but not purchased as it is called an oxidiser and I have enough of that already. Am I even close to getting something that will work as a donor? Or is there something else I should try (like perhaps knitting)? I ask because I haven't seen the info I'm after, am I in the wrong forum?

Thanks, Kelly.

As Brightstar suggested try Inoxia or someone else for chlorine donors such as parlon,pvc or saran. As for evaporating the bleach, best to leave that one alone, (as well as the other pool chems). Sodium salts will destroy any colours you are trying to make, unless it is yellow of course.

[kelly]

As Brightstar suggested try Inoxia or someone else for chlorine donors such as parlon,pvc or saran. As for evaporating the bleach, best to leave that one alone, (as well as the other pool chems). Sodium salts will destroy any colours you are trying to make, unless it is yellow of course.

Thanks Bonny & Brightstar, as far as pyro as a hobbie, it would appear that I'm in the Twilight zone, everything is possible but nothing is available. Thanks again!