Save $ and make our own static flocker


Tygrr

Member
Hi, I am not sure if this is the correct forum for this. If it isn't, will the moderator please move it to the correct one. (Oops .. this prob should be in "Scenery" .. sorry)

I have been "drooling" over the new static flockers, but they want soooo much money for one. I came across a reference to a homemade one in a yahoo HO group, but no plans or hint as to where to find them. Soooo, after much searching I finally found the plans, AND ... where the cheapest place to get the most important part .. the negative ion generator.

Plans:

http://model-railroad-hobbyist.com/magazine/mrh-2010-MarApr/static_grass_applicators

Ion Generator:

http://www.allelectronics.com/make-a-store/item/SW-750/IONIZER/1.html
(this is the 120 volt one, no one seems to have the 12 volt ones any more. So, since this is full household current * BE CAREFUL !! *)

I bought 2, just in case I screw up my first attempt :D. If this works as well as I hope, I may just buy a few dozen, assemble, and then sell them at a fraction of what Noch charges. :D
 
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.Ion Generator:

http://www.allelectronics.com/make-a-store/item/SW-750/IONIZER/1.html
(this is the 120 volt one, no one seems to have the 12 volt ones any more. So, since this is full household current

It looks like you picked a device designed for ozone production, which can be AC. Ozone is from corona, and as such AC works just fine.

A **negative** ion generator, electrostatic spray, or powdering gun has to be dc voltage. It cannot be AC or it will not work. The keyword is static, or standing, representing the non-moving charges. AC would have repeated charge and discharge and have no effect on the materials.

note: Some negative ion generators are NOT negative ion generators, they are ripping people off. They are really just corona ozone generators that randomly produce a balance of positive and negative ions.

So if the catalog is correct and you are ordering a 60 Hz output transformer, you can scare cats and make ozone and blow up your DCC controls and knock yourself on your butt, but the grass would not come through charged.

What you need is a DC supply.

The good news is since you are only dealing with several thousand volts, you could series a bunch of HV rectifier diodes like 1N4007 diodes (each is 1 kilovolt) and get DC from your AC transformer.

I would include a small fuse in or near the plug on the small pin side of the power line, and use a polarized plug. I would use a leak resistor of about 1 meg ohm or so (1/2 watt) to the UNFUSED neutral side of the power cord. This resistor would connect to the "ground" terminal of the HV supply. This would prevent the output "ground" from charging above earth potential.

I'd also be careful around solid state electronics with such a device. :)

If you use DC output on the supply and take reasonable precautions, I think it will work fine. Many years ago I built my own electrostatic paint gun system, and was able to paint the inner surface of things quite well. I used a 25 kV supply based on a supply for a CRT.

Most recently I built a cat control device using similar techniques. The cat charges to earth potential, and the bird feeder to high DC potential. When the neighbor's big fat cat leaps from the earth to the birdhouse it gets a momentary shock, like shuffling feet and touching a doorknob. I used 40-45 kV from a voltage quadrupler and a similar transformer.

My wife just has to remember to turn the supply off before re-filling the bird feeder.
 
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Hmmmmmmmmmm .... what you say makes sense ... but ..

Isn't this the same as the one in the plans? That seems to work for a whole bunch of ppl that have built one.
 
Hmmmmmmmmmm .... what you say makes sense ... but ..

Isn't this the same as the one in the plans? That seems to work for a whole bunch of ppl that have built one.

I don't know what is in the plans people have used, but I know for sure how charges actually work. :)

The unit you linked to, according to the specs, has 60 Hz output. (Power line frequency AC)

Edit:

Now it always is possible their specs are wrong, and it is really DC and the output is not 7.5 kV 60 Hz like they claim.

In order to make things "stand up" from static, the things all have to be charged the same polarity. If you try to charge with AC things passing out of the screen will have a different polarity and charge level varying continuously over time.

There isn't a spray gun in the world that works with AC.

Every one of them used DC, not AC. Almost always the stuff being coated is positive, and the coating is negative.

If people are using AC, they might just as well unplug the power.

I've bought little supplies like you linked to, and I've bought DC supplies. What the text said on the one you linked to was "output 60 Hz". That's AC.

Tom
 
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I know how to wire a house, but I know almost nothing about electronics; so I will defer to your knowledge in that field. However, since I have already paid for the parts, I am gonna try to build one and see if .. maybe, just maybe .. the part description is incomplete and it will work as planned. If not, well .. then I learned something and got some practice soldering .. LOL
( I once used a train transformer to teach the dog to stop cocking his leg on the old fridge in the basement, hung a screen in front of it, he peed on that for ummmm maybe 1/2 second .. he learned REEEAL fast .. lol)
 
I know how to wire a house, but I know almost nothing about electronics; so I will defer to your knowledge in that field. However, since I have already paid for the parts, I am gonna try to build one and see if .. maybe, just maybe .. the part description is incomplete and it will work as planned. If not, well .. then I learned something and got some practice soldering .. LOL
( I once used a train transformer to teach the dog to stop cocking his leg on the old fridge in the basement, hung a screen in front of it, he peed on that for ummmm maybe 1/2 second .. he learned REEEAL fast .. lol)

Either the wording of the specs for that unit in the catalog is wrong, or it won't work. It isn't unheard of for specs to be wrong in a surplus parts source, so it might be DC despite what the text says.

If you want the grass to repel against other grass, it absolutely must be DC. The polarity does not matter. Same charges repel.

You can make ions and ozone from either AC or DC.
 
I agree w/ your statement of "has to be DC". Do the following reviews mean that the add copy is wrong?

"A customer from Upper Midwest, USA
Excellent!
I used one of these to make a static grass

applicator for model railroads and dioramas.

I had previously built a static grass

applicator using an electronic flyswatter.

That unit worked and I was happy with it but

decided to give it a try with this unit. The

difference is amazing, especially with longer

fibers (6mm-8mm).

A customer from Huntington Beach California
Output is a -4kVDC output
From the website www.seawiseion.com these are

DC output devices at around 4kVDC. From

tearing down the device it uses a SBS

(K1199E70) to drive a transformer and diode

based voltage doubler. The output has two 2.3

Meg resistors in series. There are two 4K7

resistors on both the white and black leads.

The black lead is negative to the HV output

A customer from Huntington Beach California
Voltage multiplier
I checked this with a strong magnet, there is

no core. So I assume this is a doubler ladder

using diodes and capacitors. If no one can

find a schematic for this I might just buy on

an depot it.

william beaty from Seattle, WA USA
Making measurements
For testing, use an old-style analog microamp

meter with a 1Meg resistor in series to

measure the short-circuit output current.

(The 1M resistor will have little effect on a

working device.)

These devices measure 7KV using a standard

1gigohm HV probe with DMM. Also they measure

45uA DC when shorted (DON'T MEASURE uA WITH A

STANDARD DMM METER unless you know how to

avoid zapping it with HV!) The internal

impedance may be around 150 to 200megs, so

the unloaded Vout would actually be higher,

around -8000Vdc. It also measures -380Vdc

when loaded down by a voltmeter with a Zin of

10M (again, you risk destroying your DMM if

you don't know the tricks.)

For safety you might wish to wire a couple of

470K resistors in series. This won't affect

the HV output, but it removes possible

hazards in malfunctioning units if 120VAC

should somehow internally connect to the

output wire.
 
Yep, if the customer reviews are correct the ad copy is wrong. The output is not 7.5 kV 60 Hz. It is DC. From the reviews it might not be 7.5 kV or the fellow who measured it as 4 kV didn't have a high enough impedance meter. My bet is the voltage is much higher than that customer measured, because his meter was too low of an impedance.

There is always a logical answer why something that cannot possibly work according to good science or physics actually works, and it is always some form of human error. :) :)

BTW, that last bit of advice is very good. Isolate any external connections through at least a 100k ohm resistor. If it were mine, I would:

1.) Isolate any connections to the outside from the output through a series resistor.

2.) Use a polarized cord with a small fuse on the hot side.

3.) Keep it away from any solid state electronics.


Tom
 
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