Hey, new here!

[FiroweWorks]

Hey everybody, just joined and hopeful that people still post on here.

Edit: First question, what is the best way to make a bp slurry (no NC lacquer) and how long should it dry for, etc. Any info welcome!

Edited October 27 by FiroweWorks

[Zumber]

You need to add binder in it and add solvent and make paste.

Consistency of paste depends on what purpose you need BP slurry for.

Sometimes it is necessary to dry primed things quickly for instance time fuse, spolette....

Solvent depends on what binder is used.

It may be dextrin water, parlon acetone, red gum-shellac alcohol,nitrocellulose likewise.

You must mention what are you trying to do so that member may give right suggestions.

 

 

[MadMat]

What is the purpose for making this BP slurry? Right off the top of my head I can think of three or four reasons and some would be made slightly different. One thing to remember, any time you are adding a considerable amount of water to BP, it is a good idea to add alcohol to the water. Any where from 10% to 50% depending on why you are making the slurry. There are two good reasons for adding alcohol; first it will speed up the drying and secondly, it will significantly lower the solubility of the potassium nitrate in the BP. Why would you want these two things? Simple, when the potassium nitrate is dissolved in water, it will re-crystallize when drying. The crystals that form can grow rather large and the longer it takes to dry the larger those crystals will grow. Growing large crystals of potassium nitrate in your BP will do exactly the opposite of all that ball milling you did when making the BP in the first place, making it very slow burning garbage!

Edited October 28 by MadMat
correction

[FiroweWorks]

To both replies: my intention is to either prime cake inserts and or make a tail.

Madmat, what % alcohol would be best for the reasons above? Also what kind alcohol? does 70% isopropyl work?

Zumber: Can alcohol be a solvent? Im just using water and dextrin.

Also any recommendations for drying environment?

Thanks for both helpful responses.

 

Edited October 28 by FiroweWorks

[ThrownBiscuit]

Myself, I use ethanol as a solvent for shellac in the form of denatured alcohol from the hardware store. 

For using fencepost prime I usually use 40% denatured alcohol to 60% water to moisten. 

I have included a link to a fencepost prime discussion from the archives. Myself I alter the recipe a bit by using cedar charcoal for both the airfloat and the spruce part and add 3 parts dextrin by weight, but it works fine for me.

As far as drying time that varies on a lot of conditions: temperature, relative humidity, airflow, moisture content of star, hygroscopicity of star components, size of star, etc. 

Since I mostly do small batches, I use an old food dehydrator turned to the lowest temperature setting. The dehydrator being outside and away from any combustible structures and run on a long extension cable. (This is because of some interesting things I have seen D1 glitter do when it was over moistened. It can get rather warm and give off bad odors and possibly self-ignite) Depending on the type of star and earlier mentioned conditions it can take anywhere from a few hours to over a week to dry. I have had some charcoal stars take a week and a half to properly dry but at that time relative humidity was hovering around the 90% mark for most of that month.

[MadMat]

If you are working with dextrin as a binder you should keep the percentage of alcohol on the low side, too much with hinder the binding action of the dextrin. 10% should be enough. Yes, isopropyl alcohol will work just fine. If you are priming, you don't need to add so much water you make a slurry. It should be simply wet enough to make it sticky. I have primed stars (completely dry) by simply spritzing them with alcohol/water+ 20% dextrin dissolved in it and then rolling the stars around in a pan of mill dust. If this gives you any ideas...

Edited October 29 by MadMat