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sodium vs. potassium benzoate for whistle mix


MadMat

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I have seen formulas for both sodium and potassium benzoate for making whistle mix. Is, as with some other formulations, the potassium salt slightly more reactive? Is there a difference, as with some other salts, in the hygroscopic nature of sodium vs. potassium? I have yet to make whistle and have noticed that the sodium salt is relatively cheaper than the potassium salt. Just looking for some experienced information.

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Lots of guys use the sodium and say you just need to keep your rockets sealed from moisture. It performs the same as potassium but like you said, it's cheaper. I've only used KBenz so far because I have about 10 lbs that was given to me. Edited by OldMarine
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For pretty-much everything 'commercial', we had to use the K-based salt. Our product WAS sealed in heat-sealed baggies, and with desiccant packs, and it still would pull moisture in through the polyethylene (which is permeable). The only way we could keep product 'on the shelf' was with the potassium version.

 

Lloyd

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do the different benzo salts not have a different "tone" to the whistle effect?

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opps started a post without entirely reading an answer :wacko:

Edited by MadMat
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What are you using it for? I pressed a 1/2" ID whistle today using 7:3 perc:Kbenz +1 mineral oil +1 CuO that had been stored in a snap-top plastic container (not a "seal" by any means). Conditions have been cold and rainy, with RH around 90% for months now. That thing howled.

Edited by Wiley
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Well, I've never made whistle before (as good an excuse for making it as any). I was going to experiment with making some rockets and also try using it to spike my burst charge for my smaller shells; and I guess whatever else I could think of for it :)

Edited by MadMat
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I love it for boosting the burst in my 1.75"-3" rocket headings.
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  • 2 weeks later...

I love it for boosting the burst in my 1.75"-3" rocket headings.

OldMarine,

How much whistle do you use in your 1.75" shells to boost them?

Thanks!

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They're so tiny I only need about a ½ gram to get it right. Any more than that pulverizes my charcoal stars. I use the same in canisters and balls though I could probably go a little higher in the cans without destroying my stars. With small stars they look pretty nice according to my only judge who happens to be my granddaughter!

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Well, I've never made whistle before (as good an excuse for making it as any). I was going to experiment with making some rockets and also try using it to spike my burst charge for my smaller shells; and I guess whatever else I could think of for it :)

Make sure you use good pure Potassium Perchlorate or it will quit whistling over time, if you expect that out of it.

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Two things for you to chew on, the first is Danny Creagan's site from way back, wichita buggy whip where Dan offers a crap load of experiments, trial and testing of components and more. Second is his whistle fuel testing. This was done ad nauseum with several oxidizers and catalysts.

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Make sure you use good pure Potassium Perchlorate or it will quit whistling over time, if you expect that out of it.

 

 

Do you know of any good vs. bad sources or suppliers? You always hear people praise things like Swedish, Taiwainese, and Spanish Perc. Domestic is a mixed bag depending on source. Chinese comes with standard chinese quality. For me the chinese has always been fine and the most cost effective, but my uses tend to not be very audible whistle heavy.

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I made two batches of whistle with so called domestic potassium perchlorate (WECCO), both sucked BAD. The perc was noticeably fine, but perhaps not "dust" like the Chinese stuff is, I was new and didn't think to mill it (it was sold as fine enough for whistle).

 

The Chinese stuff has worked great for me, fast burning, loud whistles and deep blue color comets alike.

 

When I was at PGI, one of the suppliers was bragging about how "his" perc (Chinese green drum) was winning competitions.

Edited by Maserface
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  • 3 weeks later...

Hi folks, I am new here, and I am from India, although I have lived in us(washington), where I first tried some pyro mixtures related to whistles. I do it just as a hobby that has some chem background. Originally I was interested in the phenomena of oscilating burning, and whistles are a product of it. Can anyone point me to the actual details of this oscillating burning ? ( I tried to search online , but no luck).

My question is somewhat related to this topic, and since I cannot create new topics, I am posting my question(s) here. (If this is wrong , sorry about it)

Originally I tried the electrolysis method and got the chlorate as I expected. A 70/30 mix of this chlorate I produced and food grade sodium benzoate I purchased caused a whistle that was pretty strong. This was when the climate was relatively cold (therefore absolute humidity was low, I think it was 5-10 C during that time). I typically produced 1grams of whistle mix for use at a time. Since I am primarily interested in testing the results rather than creating a proper rocket or anything of that sort. I use hand pressure and a tube of paper with inner diameter of ~ 3mm to 5mm, and I was able to consistently produce whistling sound. I tried various mixes but exactly 70/30 is what worked. Maybe more like 70 to 72 and 30-31.

I went to India for vacation. I tried to reproduce my results there.THEY DID NOT WORK as expected ! :wacko:
Temp there was around 40.C (104F), and Relative humidity was 70. I highly suspect it was due to temprature and humidity. Sodium benzoate was the same one that I used in US.

  1. The electrolysis resulted into very small crystals like maybe around 0.1mm as compared to around 3mm when I was in US. ( i suspect this was due to impurities in the water, anyone have any clue, or observed this result ?)
  2. The whistle mix would not work, it worked for some random ratios for example 75/25 or 80/20 and sometimes for 70/30. This was very confusing for me, I did about 30 tries, and it looked like the temp and time of day affected the result significantly. (Most successful tries were in the morning, least successful towards evening).
  3. Using a RO filter for water, slightly improved the wet chlorate yield, but drying them turned the crystals into whitish substance and not the same shiny crystals I would get when I was in us ? Was this KCLo3 decomposing at room temp (41 C ) ? I suspect my KCLO3 decomposed rapidly into KCL and KCLO4 at room temp since the ambient temp itself was quite hot , plus the humidity. Does anyone have any experimental data about the decomposition of KCLO3 at room temp ?
  4. Another suspect I have is sodium benzoate and its water absorbing abilities, I had a high def weighing machine, and saw that for every ~10 minutes the weight of the powdered benzo went up by about 0.001 gms . Has anyone tried this, or observed this ?

 

Finally I want to ask everyone here, what is the hot + humid place anyone has tried to make a working whistle mix ? If so, what was the way to prevent decomposition of oxidizer at high tempratures (assuming that is what happened to me), and how to stop the hygroscopic nature of benzoate ?

Thanks & Regards,

Nikhil.

 

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  • 2 weeks later...

Dear Friend:

 

Both work quite well.

The sodium salt may be somehow cheaper.

The Potassium salt is less hygroscopic.

And it is sold as a very fine poder, like meal, whereas the sodium salt generally is comercialized as a more coarse powder.

With the fine poder you can press whistles with less pressure, whereas the coarse product needs a quite higher pressure in order your whistles not to explode when lighted.

How much pressure ? You will have to try it.

 

Yours truly: Toivo

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  • 2 weeks later...

 

 

Do you know of any good vs. bad sources or suppliers? You always hear people praise things like Swedish, Taiwainese, and Spanish Perc. Domestic is a mixed bag depending on source. Chinese comes with standard chinese quality. For me the chinese has always been fine and the most cost effective, but my uses tend to not be very audible whistle heavy.

In the past i have always bought the cheaper Chinese stuff. Since then i got some from Tim and havent had any problems yet.

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Use dry and well ball milled and well mixed powders. All compositions are usable.

 

Test was done for Potassium perchlorate/Sodium benzoate/SB/ or Sodium salicylate/SS/ = 70-75/25-30 mixtures. Tubes L=60-100 mm. Dia Ф=15 mm.

 

1. L = 60 mm. SB70/30. 5. L = 60 mm. SS70/30.

2. L = 60 mm. SB75/25. 6. L = 60 mm. SS75/25.

3. L = 80 mm. SB70/30. 7. L = 80 mm. SS70/30.

4. L = 80 mm. SB75/25. 8. L = 100 mm. SS70/30.

https://youtu.be/9z1gtFhvCB8

Edited by Yus
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