static produced by hdpe bottles ?

[dave321]

in the uk we dont tend to use binary flash powder mixtures for use in concussion mortars,

the practice is usually to buy pre-manufactured items.

 

it seems this is not true for the usa, where it appears usuall to shake the fuel and oxidiser together

in one of the bottles provided, and use a capfull of mix in the mortar.

 

QUESTION:- i can only assume that the risk of static generation during shaking in the bottle

is negligable or the practice would not be adopted ?

 

i always thought plastics generated static (depends on which plastic) some worse than others.

 

i assume the mixing bottles are hdpe or ldpe ?

 

any comments on this risk / practice

 

dave

[dave321]

no comments from our americans colleagues ?

 

i dont intend to adopt the practice myself, just curious as it seems standard practice by the suppliers providing the "a" "b" binary powders

 

dave

Edited March 27, 2013 by dave321

[Poindexter]

It seems HDPE is the best possible polymer for BP compositions, BP substitutes and smokeless gun powders. All of my commercial containers of those are HDPE.

 

I haven't fooled with binary compositions at all.

 

However, I was about to start a new thread asking if PET or PETE is safe to use for short term (less than 90day) storage of BP comps.

 

I figure someone with enough chemistry background to answer your question can answer mine too...

[mikeee]

A cardboard/paper container would be the best choice for mixing FP in.

I also have a couple of wood bowls that I turned on a lathe that I use to mix some materials in.

I have talked to other hobbiest that have used plastic bowls, bottles, baggies to mix FP in.

I try to stay away from any materials that will generate static charges.

[Peret]

In a closed system, ie an HDPE bottle, nothing will happen no matter how much static is generated, because everything inside is at an equal potential. It's the discharge of static electricity that you wish to avoid. However, in this situation no static will be generated, because there's no mechanism for charge separation. In order to build up a static charge you need some way of removing charge carriers, such as by scuffing your rubber-clad feet as you walk across across a nylon carpet. If you just stand still or shuffle on the spot, as many charges will jump back as are rubbed off and the net result is neutrality. In the same way, an equal number of positive and negative ions will be present inside the bottle after shaking as were in it before.

 

The danger comes when you open the bottle, after carrying it around the room scuffing your Nikes on the nylon rug. The spark won't jump into the jar, but it may jump from you onto the nearest surface and ignite the dust on the way.

[dave321]

 

hmm,

 

some interesting points there peret,

I will have to give it a bit more thinking time

 

dave

[pdfbq]

Read about the Faraday cage.

When you build up charge it will always go to the outside of the object.

This is because same potential repels same potential.

[AirCowPeacock]

I've never noticed the HDPE bottles I use to carry any static charge, but I have seen Ziplocks, which apparently are a PE too. I have seen PETE/PET containers carry small charge though, I don't use 'em for that very reason.

[Bobosan]

Bumping this old thread. Has anyone confirmed if PETE containers are really static safe for mixed comps?