Author Topic: Bonetti Generator  (Read 786 times)

Offline Bluechip

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Bonetti Generator
« on: August 06, 2021, 03:27:05 PM »
Hi Troops

A few pics. of progress so far.

Lots to do yet.

Next bit is the other acrylic disc and  get them to size ... the one on the RT is just roughed out and ONLY JUST FITS ....  ::)

Goon ... !!!

Not doing a build log 'cos this forum ain't really the place for it is it.  :headscratch:



Dave

https://www.coe.ufrj.br/~acmq/bonetti.html


« Last Edit: August 06, 2021, 03:33:45 PM by Bluechip »

Offline Jo

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Re: Bonetti Generator
« Reply #1 on: August 06, 2021, 03:53:15 PM »
Love the brass spindle, it gives it that traditional feel ;)

Looking forward to seeing this come together  :)

Jo
Enjoyment is more important than achievement.

Offline Roger B

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Re: Bonetti Generator
« Reply #2 on: August 06, 2021, 05:11:06 PM »
Looks fun  :)  :)  :)

I'm sure it could find a place in Vehicles and Models. I would like to follow the build  :ThumbsUp:
Best regards

Roger

Offline Alyn Foundry

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Re: Bonetti Generator
« Reply #3 on: August 06, 2021, 05:43:40 PM »
Hi Dave.

I'm  "  ecstatic  "   :)

Few know of the immense power that an electrostatic field can generate. The following videos were made a few Christmases ago for the grandchildren.

Let me know if you need any Polycarbonate sheet, I have Kg's of it.

Cheers Graham.
 




Offline Bearcar1

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Re: Bonetti Generator
« Reply #4 on: August 22, 2021, 08:39:21 PM »
Heck yeah! put that build log up here..... I know I would like to see it all in progress.  :stir: :Director: :DrinkPint:


BC1
Jim

Offline Bluechip

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Re: Bonetti Generator
« Reply #5 on: August 23, 2021, 12:02:48 PM »
I'm on the case.   :ThumbsUp:

Had to correct a load of stuff I did 2 years ago when I started it.  :headscratch:

Forgot what I'd done and what was only sort of 'roughed' out but not to size or concentric.   :-[   :facepalm:   :old:

Just about sorted it. Loads of pics. done.  :D

Dave


Offline Jo

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Re: Bonetti Generator
« Reply #6 on: August 23, 2021, 12:34:47 PM »
Just about sorted it. Loads of pics. done.  :D


Looking forward to seeing them  :)

Jo
Enjoyment is more important than achievement.

Offline Bluechip

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Re: Bonetti Generator
« Reply #7 on: August 25, 2021, 11:14:17 AM »
Hi Troops

Ok I will carry on with this rather marginal topic ...   :headscratch:

Graham:  Fascinating videos.  :ThumbsUp: ... What sort of polycarbonate sheet.  Dimensions ?? 

.................

Bit of background. This is not the first Bonetti I've built. I made one some 25 years ago with 20" discs cut from some 6mm polycarbonate ( PC ) sheet. Now PC sheet is somewhat softer than Perspex and I found it easier to deal with. At the time I had access to ( the late ) Wilf's Harrison woodturning lathe with a bowl / platter turning facility on the blunt end of the headstock.  :)  I made the discs with wood-turning tools quite easily.

A Bonetti generator is, to all intents, a Wimshurst Machine minus the sectors. The sectors act as 'charge concentrators' and a Wimshurst will almost invariably 'self-start' . A Bonetti almost invariably won't! You need to induce a charge on one of the discs by means of a Perspex rod rubbed with a 'furry' fabric, or, in my case, one of those velvet pads intended to get dust off vinyl LP's.

The Atmosphere: ie. that tenous stuff wafting around your head ( and other bits ). For most purposes it can be regarded as an insulator. When you start dealing with 'Influence Machines' it's anything but. It's well known that warm air will hold more water vapour than colder air. I remember one cold and very dry April day my Bonetti DID self-start. Just the once! That was the day I get some 7"- 8" sparks  :cartwheel:  Usually about 6" or so.

Sharp Edges and Spiky bits:  ( Including dust paricles ). These tend to initiate Corona Dioscharge, Silent discharge, St. Elmo's Fire etc. Call it what you like. THEY ARE NOT BENEFICIAL. Get rid of them. They will leak your precious charge away. Bit like trying to make a ballon from sponge rubber.

Bonetti I, It's demise: I didn't use it for some years and I kept it in the garage. Decided to get it going again and found it was covered in dust and condensation   :'(   So, shytte-for-brains here put a fan heater on it to dry it out.  It did dry it but also warped one of the discs  :Doh:  Never worked again.

Delivery due. Will continue later. 

D.

Offline Jo

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Re: Bonetti Generator
« Reply #8 on: August 25, 2021, 12:00:58 PM »
Two days later and...

 :pics:

Jo
Enjoyment is more important than achievement.

Offline Bluechip

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Re: Bonetti Generator
« Reply #9 on: August 25, 2021, 12:07:00 PM »
Two days later and...

 :pics:

Jo

Pics later today .... Give me a chance   ..... Shouldn't you be washing tee-shirts or some thing .....    :lolb:
« Last Edit: August 25, 2021, 12:11:11 PM by Bluechip »

Offline Bluechip

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Re: Bonetti Generator
« Reply #10 on: August 25, 2021, 03:41:37 PM »
As Henry V never said ' Once more unto the Bonetti, dear friends '    ::)

Pic 1 shows a disc I made about 18 months ago. It has several 'features' I had just about forgotten about:

[1] It's too big to get in the WM18.

[2] The edges are chipped in several places.

[3] Centre hole. I found out too late a 15mm twist drill bit ( with a 5mm pilot ) is no damn good at all on 5mm Perpex sheet. It broke the Perspex on exit.  So, I found out that a 25mm Forstner bit would open it out and make an accepable finish.
 
( Not sure that is a real Forstner type cutter. I'm sure I had some ( CLICO ? ) that had sawtooth type periphery ).

Another 'discovery'  ::) was that using a 5mm slot drill to reduce the OD was OK until about 2mm of the side edges were in contact then it tried to jerk the Perspex up and down. Which is damned noisy and tends to chip bits out of it. ...
At this point I concluded that I needed to have the sheet effectively clamped between two fairly hefty bits of 'some thing' with only a bit of the Perspex sticking out. I also concluded I'd better devise some method of stopping the 2MT centre being pulled out of the RT by the clamping bolt.  ( I came close to concluding an even better strategy would be to sling the whole damn thing under the bench and pretend it never happened ! ).

Anyway, I got two bits of 11mm OSB glued together, 4 holes put in to suit the slots and a PVC 'hub' thingy made to suit the 15mm arbor, and set about chewing it circular.   ( PIC 2 ).

Then made the securing bits to stop the arbor pulling out of the RT centre. ( PIC 3, 4, 4A, 5 ).

More ....

D.
« Last Edit: August 25, 2021, 04:12:39 PM by Bluechip »

Offline Bluechip

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Re: Bonetti Generator
« Reply #11 on: August 25, 2021, 04:03:42 PM »
Back again ...  :)

We are now at the position in PIC 6. 2MT arbor fixed in the RT.

Then made a 15mm ID to 25mm OD spacer to suit the existing arbor and disc centre hole.

A second Perpex disc was roughed out, a 25mm hole poked in it and loaded up on the RT.

The top 'clamping sheet' or whatever is fitted with some of those sticky pad rubber feet ( PIC 8 ).

PICs 7 & 9 show the discs being reduced to a common diameter. ... which leaves me to the last. PIC 10.

I did not like the 6 M4 CSK screws holding the disc to the PVC flange by means of holes tapped in the PVC. I had visions of them coming out, so I replaced the M4 Pozidrives with M5 Socket CSK screws and long enough to have a washer and Nyloc nut on the back.

D.

A certain Forum Administratrix domiciled not a million miles from Hampshire observed how easy it would be to make these discs on a
Colchester Lathe with a 18" faceplate.

Alas, I have neither an 18" faceplate nor a Colchester lathe to screw it to .....
  :'(  :'(  :'(


 



« Last Edit: August 25, 2021, 04:09:48 PM by Bluechip »

Offline Bluechip

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Re: Bonetti Generator
« Reply #12 on: August 25, 2021, 04:05:23 PM »
Two days later and...

 :pics:

Jo

Happy Now ??

 :wine1:

Dave

Offline Alyn Foundry

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Re: Bonetti Generator
« Reply #13 on: August 25, 2021, 04:13:47 PM »
Hi Dave.

Iím pleased you found the videos interesting.

I have many sizes and thicknessís here, number 2 son worked for a Plastics company. We were allowed to have the off cuts for my many and varied projects. Just ask and Iíll see what Iíve got left.

Hereís just one made from 10 mm Polycarbonate wasteÖ.


Cheers Graham.