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jimlongley wrote:

WildBill wrote:I am new to this discussion, but I have a couple of thoughts.

My experience has been trying to eliminate static rather that generate it.

First, you want to lower the humidity so that the static doesn't disippate.

Grounding the drum would drain the static so I think that isolating the drum would be better.

Agreed, I used to do the same thing, and the lowest humidity possible along with isolating the drum from ground are necessities.

Charles L. Cotton wrote:

george wrote:The option of the Van de Graaf would get you all the potential you need.

You generate static forces by physically rubbing electrons off of one material onto another. That is how the Van de Graaf works.

If you are going to make a 5 gallon roller, then you just have to try several different "wipers" on the bucket. I would start with a piece of carpet first. Just allow it to lay across the bucket, so it makes contact. Probably would be best to have a ground wire to the carpet.

I have gathered the materials to begin the same process, sans the mass production scale you are proposing.

I thought you gave away all of your casting stuff 10 years ago.

I thought about the carpet wiper also and that would be easy to implement. I'm not sure how to use a Van de Graff generator and have the static charge in the 5 gallon bucket. The ones I've seen have a spark gap of no more than an one or two inches. Perhaps the lid for the bucket would have a lip that could be used to roll inside the spark gap, but that would require precise control of the bucket placement.

I gave away (actually an long-term lend) my casting equipment, but the guys with quit casting or decided not to do it. However, I plan to build something like the old Ballisti-Cast Mark II, or perhaps a Mark X except it would be motorized, so the gear I have now will probably be used for a relatively short time. We'll use a Star Lube/Sizer with an autofeed and it too will be motorized. (It's a good thing my buddy is good at designing equipment!)

If you're interested, search http://castboolits.gunloads.com/" onclick="window.open(this.href);return false; for posts by JMorris and look at some of the equipment he designed and built. It's absolutely amazing what he has done.

Chas.

Chas, the spark gap is there to show that a potential is being created. "Static Electricity" is just that, static, with no flow, the spark gap is flow, generated by many thousands of volts potential. If that JMorris is who I think it is, I used to shoot with him, and he is that brilliant.

With any static generator what you would do is tie one of the electrodes to the drum and the other to ground, and it wouldn't even matter if the drum was metal as long as it wasn't connected in any way to ground. You would want to wear, at a minimum, an anti-static bracelet and probably more, these anti-static devices dissipate a static charge "quiescently" to ground to reduce shock hazard.

And you probably don't want to do this anywhere near your ham radio equipment or other electronics.

The Annoyed Man wrote:Have you tried rubbing an inflated balloon against your hair?

Charles L. Cotton wrote:This has a lot of potential. I could use a Van de Graaf generator and just lay one electrode over the plastic barrel as it turns (like the carpet idea) and the other to ground. It would probably be better to use a wide ground strap or something like an aircraft static wick for the electrode on the barrel, rather than just a wire. I sure hope this works!

That probably is the same JMorris. He shot the IDPA State Championships when we ran them at PSC in 2001 through 2006. I didn't realize it was him until he mentioned it in a PM on Castboolits. You're right, he's brilliant.

Thanks for the input guys,
Chas.

george wrote:The point of the carpet/silk scarf wiper is to make the drum apparatus itself into a Van de Graaf generator.

It will not build up much potential, because of the slow speed, but it shouldn't take much emf to adhere atomized paint to the bullets.

With out a ground wire to the carpet, the effect would eventually stop, since there would not be a consistent flow of electrons into the carpet, through the wire.

Someone smarter, help me out here.

george wrote:The point of the carpet/silk scarf wiper is to make the drum apparatus itself into a Van de Graaf generator.

It will not build up much potential, because of the slow speed, but it shouldn't take much emf to adhere atomized paint to the bullets.

With out a ground wire to the carpet, the effect would eventually stop, since there would not be a consistent flow of electrons into the carpet, through the wire.

Someone smarter, help me out here.

Charles L. Cotton wrote:

george wrote:The point of the carpet/silk scarf wiper is to make the drum apparatus itself into a Van de Graaf generator.

It will not build up much potential, because of the slow speed, but it shouldn't take much emf to adhere atomized paint to the bullets.

With out a ground wire to the carpet, the effect would eventually stop, since there would not be a consistent flow of electrons into the carpet, through the wire.

Someone smarter, help me out here.

Since swirling the powder, plastic BBs and bullets in a #5 plastic tub works well, I'll try this method first. It's certainly easier. I should be able to spin the bucket at pretty much any reasonable speed by selecting the appropriate motor and gearing. If I use an AC motor, I'll either need to get a geared motor or a VFD to control speed. I'd prefer a DC motor, but I'm not at all sure what torque I'll need when the thing is in production with a 40% load of mixture. I've read conflicting information about speed v. powder adherence to the bullets.

Chas.

One of the most significant drawbacks of nylon fibers is their inability to dissipate static electricity. In normal use, particularly under low humidity conditions, static charges can easily be generated in excess of 12,000 volts. Static charges of this level are well above the recommended maximum value for sensitive electronic equipment. To reduce the impact of static charges, manufacturers add carbonized fiber to the nylon yarn or put a conductive coating on the surface of the nylon fibers that helps dissipate static charges before they reach a level where they can damage electronic equipment.

Olefin fibers do not generate static electricity, making them particularly well suited for applications with installations of sensitive electronic equipment, such as telecommunications equipment or computers.

WildBill wrote:Depending on the size of the drum, I would try around 5-10 RPM for starters and adjust up or down for optimum coating.

A faster speed may generate more static, but I don't think the coating would be as uniform.

The speed should be such that the spheres and bullets roll to coat them.

Rotating the drum too fast will cause them to get too high on the wall and then fall.

Also if you have a way to introduce the powder uniformly from the front to the back of the drum while it is rotating, the coating will be more uniform.

This would require a door or latch on the end of the tumbler.

As far as generating the static - you may try different types of carpet material: Nylon seems a great choice.

One of the most significant drawbacks of nylon fibers is their inability to dissipate static electricity. In normal use, particularly under low humidity conditions, static charges can easily be generated in excess of 12,000 volts. Static charges of this level are well above the recommended maximum value for sensitive electronic equipment. To reduce the impact of static charges, manufacturers add carbonized fiber to the nylon yarn or put a conductive coating on the surface of the nylon fibers that helps dissipate static charges before they reach a level where they can damage electronic equipment.

Olefin fibers do not generate static electricity, making them particularly well suited for applications with installations of sensitive electronic equipment, such as telecommunications equipment or computers.

Rifleman55 wrote:Charles
Not to hijack your thread, where are you getting sufficient quantities of alloy, I have been having trouble getting used wheel weights, which I used for years, I have been buying coated bullets from a guy up near Dallas and they are not too bad a price.