Some infos about Winokur 39J

[MinamotoKobayashi]

Hello forum, finally I'm back

I just prepared Winokur 39J glitter stars in a good way.

First of all I milled all the chems together (without atomized aluminum and Magnalium) in my ballmill

soaked in bioethanol 95%, I have dried it and finely granulated with the help of a 60 mesh sieve.

I added the metals ad mixed together very well.

Then I have slightly wetted the mix and created small 10mm cylindrical stars with my star plate and the help of an hydraulic press.

I putted the cylindrical stars in my star roller and I started to make near-rounded stars slowly flouring the slightly wetted mix

over and sprayng demineralized water with a very small percentage of alcohol to break the water surface tension.

Using a mix slightly wetted for the star roller is a great advantage because do not generate any kind of dust.

No need to use protective mask.

The stars now looks like a chickpea

I tried them as soon as they are dried.

 

I have two important questions for the forum experts about these kind of stars:

 

1. Milling the chems soaked in alcohol is a safe operation but lengthen the whole procedure a lot,

so my idea is to mill together some chems is a total safe manner and add the remaining chems later.

There are many variants of Winokur 39j formula .. I used this:

 

49,8 Potassium Nitrate

18,5 Charcoal (Airfloat)

11,7 Antimony Trisulfide

4,9 Barium Carbonate

8,8 Aluminium (atomized, 325 mesh)

2.4 Magnalium (Granular, 60 mesh)

3,9 Dextrin

So, Magnalium apart, which of these components should I exclude from dry milling to work in total safety?

2. In many formulas containing aluminum atomized and magnalium I see also a small percentage of boric acid to avoid

metal oxydation, especially in presence of sulphur.

In Winokur 39J I see both the metals and the presence of sulphur, but not the boric acid.

There is no risk of oxydation in this formula?

 

 

 

Edited July 8, 2020 by MinamotoKobayashi

[NeighborJ]

The boric acid is very effective at protecting Al but ineffective at providing any protection to the MgAl. It may accelerate the degredation of MgAl so I would personally omit boric acid from the process.

 

W39j was a modification by Tom R. of the original Winokur #39 formula for use as a rocket delay. It burns quite slowly by design. I would use a reactive, finely milled charcoal and mill it well with all but the metals and oxidizer then screen mix all the components. Ofcourse the nitrate will also require seperate milling beforehand.

 

Tom R is not known for taking short cuts and this formula reflects his patience of manufacturing by not working as good if the process is altered for expedition. Tom recommends using 6% water for pumping stars, this small ammount of moisture ensures the best chance of the stars drying before any significant amount of oxidation occurs. Your rolling process presents a large degree of unknown variable which can potentially negatively effect the desired outcome. They were intended for use in Italian cylinder shells and not rolled stars.

Edited July 8, 2020 by NeighborJ

[MinamotoKobayashi]

Thanks Jason.

I will try!

Actually I'm driyng the stars in my handmade dehidratator with three fans that create a strong airflow to accelerate the drying process.

I suppose that I cannot use electric dehydratator at 70 *C otherwise I will ruin the effect, right?

Edited July 8, 2020 by MinamotoKobayashi

[NeighborJ]

Yes, It's not a good idea to force dry any glitter with heat. Room temperature or lower until the stars have given up most of their moisture, it is generally safe to heat them a bit at the end to drive off the last bit of water.