db5086 Posted August 24, 2014 Posted August 24, 2014 I have some 30 mesh flake that I want to incorporate into a bright white streamer(Davis) cut star for a flitter effect. I know it's not the ideal metal but I have it and want to use it up. What would be the most efficient way to treat the aluminum so the nitrate leaves it alone. I have dichromate and boric acid and I'm not totally sure of the treatment process or which one to use. Will it mess with the antimony. DAVIS White StreamerPotassium Nitrate. 62Antimony 111. 17Sulfur. 17Dextrin 0330 mesh aluminum. 05
pex Posted August 24, 2014 Posted August 24, 2014 Use boric acid. I use it in a lot aluminum nitrate based stars.
db5086 Posted August 24, 2014 Author Posted August 24, 2014 Ok. So does the boric acid powder go into the binding solution (water/alc)or dry mixed into the compound or is it directly misted onto the aluminum and allowed to dry to be diaper into the mix later. I really want to get this right and appreciate the knowledge that comes from all of you.
Carbon796 Posted August 24, 2014 Posted August 24, 2014 (edited) You just add 1-2% to your comp before screening and wetting. Though you really shouldn't need it for that comp. But, if it makes you feel more comfortable, then by all means, add it. You will not notice any difference in how the comp preforms once dry, between with or without. No it will not affect the antimony trisulphide. Dichromate is for treating magnesium only-as far as metals are concerned. I would also raise the dex up to .05 - .03 might be a little weak. Edited August 24, 2014 by Carbon796
db5086 Posted August 24, 2014 Author Posted August 24, 2014 I'm just concerned of the surface area of the aluminum and will use the boric acid sifted into the comp. Thanks for the head's up on the dex. I already bumped it to 5% since that's what I have had the best performance with as far as hard stars go.
Carbon796 Posted August 24, 2014 Posted August 24, 2014 (edited) The 30 mesh flake will be less likely to react, than something like 10890 where it would be more intimately mixed into the comp. Because of its much smaller particle size. Edited August 24, 2014 by Carbon796
BurritoBandito Posted August 24, 2014 Posted August 24, 2014 Personally, I use boric acid any time I mix aluminum with a nitrate. I feel that it's best to err on the side of caution.
db5086 Posted August 24, 2014 Author Posted August 24, 2014 Alright, I mixed a 100g batch and added the aluminum flake. I took a tea spoon sample and mixed with the water/alcohol solution no boric acid and after a while the drying compound felt quite warm so I washed it out. The balance of the mix has been treated. The stars are now drying well away from anything combustible. I will keep an eye on them but feel like there shouldn't be an issue. Thanks for sharing the wisdom fellas.
pex Posted August 24, 2014 Posted August 24, 2014 I use boric acid always to. I al so used it in a few magal glitters. It just feels more safe
Carbon796 Posted August 24, 2014 Posted August 24, 2014 (edited) Boric acid has been known to possibly attack MG/AL. Aluminum doesn't like being in a caustic environment, Magnesium and MG/AL doesn't like being in an acidic environment. Edited August 24, 2014 by Carbon796
Carbon796 Posted August 24, 2014 Posted August 24, 2014 Same here, but the opposite, I've never had a problem without it. Though the difference in everyone's methods and supplies will/can affect weather, one person may have a reaction. While another may not.
uncrichie Posted August 24, 2014 Posted August 24, 2014 Is it necessary to add Boric Acid with slow flash booster (KNO3, S, Alu,) being no water is involved?
db5086 Posted August 24, 2014 Author Posted August 24, 2014 I think it's the h20 that starts the problem between aluminum and the nitrate. I'm just learning so someone else more knowledgeable than me can chime in and correct me. I did a search and got some good information on the reaction.
BurritoBandito Posted August 24, 2014 Posted August 24, 2014 Personally, I use boric acid any time I mix aluminum with a nitrate. I feel that it's best to err on the side of caution.
nater Posted August 24, 2014 Posted August 24, 2014 I don't use boric acid with slow flash. The H2O is part of the reaction. Also, most recommend to mix the boric acid in the water before dampening.
Mumbles Posted August 25, 2014 Posted August 25, 2014 Both mixed try or dissolved can work. I usually use a solution personally. I feel it is more effective being more intimately mixed, even though you end up with very little actually added to the composition. Water is cheap, so I just kept a gallon of boric acid solution around. It lasts essentially forever, and is one less thing to weigh out. You need water for the reaction to go forward. It's also accelerated by bases, such as sodium bicarbonate or sodium oxalate. I wouldn't worry about it in things like slow flash. It wont hurt if you want to add any for peace of mind though. I have had issues with MgAl glitters being affected by boric acid for what it's worth.
uncrichie Posted August 26, 2014 Posted August 26, 2014 Thanks Mumbles, Kurt I wouldn't worry about it in things like slow flash. It wont hurt if you want to add any for peace of mind though.
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