Sr(NO3)2 question..

[braddsn]

I have read a lot of information on this forum, and other sites about Strontium Nit. based stars. It seems that it is best for the stars to be dried at temps above 80F. I rolled some Ruby Red stars 3 days ago.. they are 8,9, and 10mm un-primed. I checked them today and just picking them up gently, they crumble between my fingers. Now, to be fair the temp has not been above 55F since I rolled them. They are drying on a screen with a fan blowing up through the screen. The perc stars I rolled the same day are almost rock hard. I realize this is part of rolling nitrate stars. but my question is... 1) Should I just dry these stars in the dehydrator instead of air drying them? And 2) Would it be easier to find a formula that doesn't use Strontium Nit? When I test burned the dry comp, it was the most brilliant red I had ever seen.. much better than any carbonate star I have ever tried. I really want to use Strontium Nitrate based reds, but it it worth the extra pain? Looking for some opinions/advice. If I have to ditch Strontium Nitrate, I will go with Buell Red probably.

Edited March 16, 2015 by braddsn

[pyrojig]

I prefer to roll with the alcohol sys or acetone . Using binders like parlon , and or phenolic may prove their worth here .

[db5086]

Wait em out Brad. I too had a similar problem with a strontium based batch of stars that just would not dry last fall. I put a handful to save in a coffee can and burned off the rest. The stars I saved are hard as rocks now and are the inner petal of a 4" shell that I'm gonna shoot on memorial day.

[braddsn]

ok db, I will. My only option for salvaging them would be to throw em in the dehydrator, so I will. If they were to take 3 months to dry, that wouldn't work for me, I test fire and build a lot of shells, so I need a relatively quick turnaround. Thanks for the advice.

[nater]

If you need stars to dry fast, I cannot say enough good things about using phenolic resin as the binder with denatured alcohol to activate it.

[braddsn]

Nater, I would be willing to try that but I have no idea where to get it. I did some google searching to no avail. And if I had it, how much do I use? Everything else in star formula stay the same? I use dex for everything because of the information available about it. I know the japanese roll with phenolic...do you have a good source for the stuff?

[nater]

Jim at ctpyro.com is the source for it. Phenolic Resin is a fuel, so you replace any red gum with it and eliminate dextrin. Some say 7% in the comp is the best for binding. So if a comp has 5% Red Gum, eliminate the red gum and add 7 of phenolic. However if a comp has 9% red gum, use 9% phenolic.

 

You can also make a solution of red gum dissolved in alcohol (try 10%) and use that to wet the comp. It works well for color stars but tends to ruin a glitter.

Edited March 15, 2015 by nater

[Sparx88]

I use ruby red pretty much exclusively other than mgnal red and I wet them with 70% alcohol and dry them in a dehydrator at 110f for a week. The first few days will seem like they are not going to make it but they will.

[pyrojig]

As Nater said, I like the laq. sys ( dissolving the resin into the alcohol) Usually I do 6% , but it is a matter of opinion , and experimenting is a wonderful thing. There is really no wrong way here , it is just a matter of what works for ya. I like to get it thin enough to use a spray bottle to apply it.

[bajadudes]

Definitely takes longer to dry. When I was working production we also never mixed strontium nitrate red comp or rolled them on rainy or damp days. The red would appear somewhat washed out if we did. It does make a beautiful deep red.