Fly swatters for static grass...problems? variations

[bertiedog]

I must admit I have advised the use of converted fly swatters for making a static grass applicator, and they work fine for me and others, but it seems a lot of converted ones do not work well, if at all,

 

The simplest answer seemed to be....are the leads connected the right way around, positive to the sieve, and negative to the ground. This seems to be the answer in a lot of cases.

 

But further research has show that there is also another major issue that is hidden at first glance, that the makers use several circuits and the later types do no generate a high enouth voltage to work with static grass.

 

The "classic" tpe around for several years uses an oscillator to feed a circuit called a Cockcroft multiplier, which jacks up the voltage to about 2 thousand volts. It has a chain of diodes and capacitors to do this.

 

However it seems the designers have decided that the circuit is excessive, and the later fly swatters use the oscillator to feed a transformer, thats feeds only one stage of a multiplier, resulting in a high voltage, but much lower at about 800 volts. This type charges a large capacitor on the output to provide the power surge to operate as a swatter.

 

So only the first can really be used for static grass, the second version is too low an output to work, and would need to feed a further Cockcroft circuit to increase the output. The large capacitor is removed and the chain of diodes and capacitors added across the output. This, with the changes should reach about 4k to 5k with four stages added.

 

So the situation is that there are at least two types, or more, of the circuits used in these swatters, and explains why some will not work with static grass.

 

It is impossible to see what is used from the outside, but the boards are identifiable as the new has only one big output capacitor, whilst the old ones have a whole bunch gathered together on the end of the boards, with cross connect diodes.

 

All is not lost if you are into electronics, the Cockcroft ladder can be added to the new ones, and the output would be quite beefy to say the least!

 

Hopes this clears up the mysteries surrounding these units, lots on Youtube about them, but bear in mind some people on there do not know there are different versions made.

 

Stephen

Edited July 31, 2017 by bertiedog

[lyneux]

No need to disassemble a fly swat. I have had good results using a negative ion generator from Oakley Electronics which can give an even higher voltage (12kv) when fed by 12v DC.

 

http://oatleyelectronics.com//product_info.php?products_id=915

 

No doubt these are available from other suppliers too?

 

Guy

[bertiedog]

These circuits work very well, but can be a little bit of overkill as they can be a bit more dangerous with the output higher. They can give you a nasty jolt if you touch the leads whilst active. 

 

If you use them the leads must be high voltage rated such as scope leads, and sleeved at joints with heat shrink. The earthing spike or clip should be well insulated as well, far more than the swatter circuits demand.

 

I built one of them but found it frankly too powerful, as it ejects the flock rapidly from the sieve, great for vast pastures but swamping for detailed grass. When the mass comes out it also does not stand as erect as usual due to the larger amount dumped.

It is best with  small sieve or a sieve with only a small area exposed, when it can handle long grass much better than the smaller units.

 

I feel the more experienced electronics enthusiast will get on with them fine, but you have to know what your doing with the high voltage these generate, albeit at a low current. Lots of the ion units are on Ebay as well.

Stephen.

[bertiedog]

http://www.ebay.co.uk/itm/12V-Anion-Air-Purifier-Negative-Ion-Generator-Module-Air-Vitamins-/201918234355?hash=item2f0343bef3:g:1IwAAOSwn-tZDX-U

 

This is the same type of unit at £2.99 Ebay from China. This has the 12 volt input, and ONE lead to the seive, earth from the negative wire.

However some units come with !2 volts in on red and black and Two output white leads, one of which will be the earth, the other the EHT.

They are not marked for polarity, so you will have to test the unit with the leads both ways round to find the position that raises the flock upright.

One word of caution, take the Chinese estimate of outputs with a pinch of salt, they all produce about the same, but some sellers claim falsely high outputs. Most give 6kv at minimum, which is more than enough anyway. Some claim 12 Kv or even 20Kv

Don't forget that you have to fit a decent Plastic box around the whole thing, and budget for the EHT leads. Most multimeter leads will do fine.

 

Stephen

[corneliuslundie]

Our club made a successful version by putting the electronics from two swatters in series inside one handle. Also, we have arranged it so it can be connected to a tea strainer type applicator (but bigger) or to a metal topped jar with a mesh. The voltage is high enough for most of the applications we have tried. And the things are so cheap to buy that we bought a batch from China.

One problem has been finding sieves of the right mesh. That seems important o getting good results.

Jonathan

[bertiedog]

Our club made a successful version by putting the electronics from two swatters in series inside one handle. Also, we have arranged it so it can be connected to a tea strainer type applicator (but bigger) or to a metal topped jar with a mesh. The voltage is high enough for most of the applications we have tried. And the things are so cheap to buy that we bought a batch from China.

One problem has been finding sieves of the right mesh. That seems important o getting good results.

Jonathan

Oach! two in series? this is very odd as in theory it reduces the power because the output caps are in series, and how on earth are the pulses of DC synchronised. Much better to add to the Cockcroft ladder string with extra stages of diodes and caps....you can quickly get 40KV or more.

I doubt the series is doubling anything, but it filing in the gaps in the pulsing DC output.

By the way it has a practical top limit of about 60 KV, any more and it's really out of control, see the Old Frankenstein films which used genuine EHT sparks on Jacobs ladders.

[corneliuslundie]

I don't know why or how putting two in series worked but in practice it did. I rely on the expertise in electronics matters of the two ex BT engineers belonging to the club . When measured the output was about 2 kV, enough for effective use.

Jonathan

[bertiedog]

Putting in series depends on the versions I have found, the single stage ones will wok in series, but do no double the voltage, but double the power, so beware!

The earlier type with multi stage output are mind numbing in complexity when put in series, but appear to give the same result.

 

However, working on a suggestion on youtube, All the devices can also be used to add foilage to trees, and not by shaking it over the tree, but picking up tree scatter from a metal plate connected to the earth lead.

 

The positive lead instead of going to the hopper goes to a clip on the stem of a loose tree, in say seafoam, which is damped with water, them adhesive spray, and whilst the machine is running is passed over a pile of dry scatter material on the metal plate.

 

The branches will attract the scatter foliage up from the open metal plate. It works with even the simle flyswater powered ones.

.

It works with scatters, fine foam, wool flock, polyester flock, dry herd dust, and tea leaves, etc., and seems to leave a more realistic "lay" to the scatter leaves than shaking over the top of the tree.

 

Today producing a load of sawdust dyed with acrylic paint, various grades from pinewood to MDF fine dust, plus drying out tea leaves completly, along with some old crushed herbs, all treated in the microwave. If you use a micro for the drying, addd a covered cup of water to load the machine, the herbs etc will still heat and dry correctly.

[bertiedog]

removed, see next post

Edited August 1, 2017 by bertiedog

[bertiedog]

Disregarding using a coil, and working with only a swatter, ion generator, or any existing Static grass generator:

 

The Static grass head shown here is the result of a few tests of various swatter circuits and ion HT generators, and could be applied to any unit with modifications. It is safe, very safe for the operator, and has a easy to make plastic mesh, which you can make at home in a full set of sizes to suit up to 1cm for most swatters and 2cmm for most ion circuits or commercial units.

 

 

It may be already used in some designs but I am unaware of any design infringement and offer it as open source design.

The head is about 5cm thick, a PVC plumbing pipe with commercial screw capped ends. One end has the rod through it to run along the centre line to about 20 mm from the front plate. Diameter of the pipe is up to you, and availability of end caps that screw on/off leaving a flange on the pipe.

The front plate is a disk of 20hou plasticard with a simple drilled pattern of holes in a set of sizes from 1mm to about 6mm ( for very long grasses). the end cap has the end cut out and the disk drops on to the end flange before the cap is re-screwed on.

You can make the electrode out of a steel or brass washer, mounted on washers and nuts on the thread. The connection is made to the back via an HT lead and the whole connection covered with hot glue to insulate it. If made as a unit the lead can go direct to the power. A commercial rubber shroud HT cover could be used rather than the glue. The lead should be a multimeter type at minimum, as should the negative earthing cable.

Any PVC pipe size will do as long as screw endcaps are made for it, and the key to working is the "floating electrode", which upon switching on and giving a shake is surrounded by the flock, and it comes through the mesh in a most controlled way.

Be it a maxi size or a tiny half inch , the washer position is the vital key to operating. As there is no metal to touch it is very safe indeed.

In all the trials on sizes the one vital point is that the electrode is about 20 to 25mm from the mesh, 20 seems the best for general length flock and a normal generator. The feed is not fast, it is very controllable indeed.

Stephen

 

Edited August 1, 2017 by bertiedog

[bertiedog]

In passing, I have often used tea leaves as foliage, with airbrushing to add colour to the leaves, bit I tried pre bleaching them and dying, which gives a pre coloured version. Peroxide bleach solution or simple domestic bleach will turn the leaves a very light tan, rinse and add dye or acrylic paint, well thinned down, to taste, for tones. The leaves are then fluffed up and ready to go as scatter or tree leaves.

 

If a plate based device is built, a pile on the plate will be attracted upwards to a seafoam or other basic tree connected via a clip to the Static generator  The effect is excellent for most deciduous trees, and easier than then airbrushing the colour on afterwards.

 

Stephen

[bertiedog]

Also mention was made of the conductivity of the glue, I have always added domestic washing liquid to the glue, (PVA), plus a pinch of salt, as the washing liquid already contains salts.

 

I checked up on this and salt does not harm PVA in setting, and It seems from a chemist friend that Epsom salt, Bicarbonate of Soda , or domestic table Salt will all work, just add a pinch to the mix.

 

Straight from the bottle PVA is too thick for static grass, add about 30% water to get it more runny. Several makers offer special glues, I tried some out and they make little difference for most work.

 

Titebond Woodworking glue also works, but dries a bit glossy, as it is a type of resin. A mix of 30% Titebond and PVA works though and remains "Tacky" for longer than pure PVA.

 

An interesting addition are spray on second stage glues to add layers or special effects and these are difficult to replicate. But heavy duty hair spray does work almost as well, although a final spray with matt varnish should be used to stabilise the finish.

 

The extra spray works with both grass and foliage scatters, etc. It can get a bit messy if to much is used at once though, do it in layers rather than one hit.

 

Also one point is that glue is not needed if your covering a painted surface with thick acrylic paint or a paint and PVA mix, the flock will still stick.  Coloured wet plaster will also attract flock and scatters to it, like rock faces with grass clumps.

 

Stephen.

[bertiedog]

As of Saturday, Poundland have the swatters back in stock, at one pound!

[bertiedog]

Modified one of the new stock Poundland Swatters to static grass, and it works perfectly. despite a slightly lower output. I am rapidly coming to the conclusion that it is operator technique that is the main issue with the swatters, to much flock in the mesh container, too great a distance from the mesh to the glue, glue that does not conduct. ( add salt), and generally working too fast, and dumping too much flock in one go.

The new one is powering a tray to hold trees and bushes over, to raise the flock purely by the static to the branches, and powering a metal tip to the Noch or Gaugemaster puffer bottles.

 

It is just a brass tube 2.5 mm diameter, about 3cm long pushed into the bottle and connected to the power. Each puff sends out the flock in a controlled burst, could not be simpler. It also handles long grass much better than meshes.

[bertiedog]

Tried the WWS/Peco basing glue for static grass and textures today, which despite it's higher price does work well. It is thinner than a standard PVA Glue, but seems a bit tackier, and longer drying than standard PVA glue types like Unibond etc.

The one thing I have not tried is the add on spray glue, as it seems only suited to large areas, useless for fine detail, when it is used with masking, as it would over spray on to nearby objects and put the grass where it is not wanted at all.

The Peco glue dries matt and does not seem to alter the colour of most scatters and it does not affect flock for static grass.

 

Stephen

 

On further testing the WWS/PECO Glue does dry with a satin sheen, if the base surface is gloss or very smooth, so it may need a coat of scattered fine earth to get a dead matt edge, or sprayed with a matt medium. The effect is very slight and only shows on the edges really.

Edited August 16, 2017 by bertiedog

[bertiedog]

One thought, and it is quite safe to do, connect the Ion 12 volt unit to a standard flyswatter, it may need a lead from external batteries or a battery pack added to the handle. Remove all the other electronics and connect to the grids......meet super flyswatter! if works even better than standard, with resounding pops as the flies are swatted. Just as safe as usual, as the outer grid is connected to the negative.

 

Stephen