Veroboard alternatives for high voltage

[PsychMan]

Happy New Year Everyone, I hope 2016 brings you all lovely vintage acquisitions and lots of electrical fun!

As I have several chassis waiting to be worked on, I thought it best I finally built the capacitor reformer, as seen on this site (Paul Stennings design). It states vero board is not suitable due to the higher voltages. Any alternatives you can reccommend? I looked for "plain matrix board" in maplin but couldn't see any, is this essentially veroboard minus the copper?

One other method that occurred to me was to use a block of wood, hammer nails in at various points, and make a little point to point build. I remember my old man doing this when I was a boy To show me behaviours of various components. Only trouble with this I guess is the solder probably won't take to the nails.

[TrevorG3VLF]

I presume the circuit is not complicated. One technique I have used is to cut some PCB in small pieces and to glue them to an insulating substrate. The insulation will depend on the material and the spacing between lands.

I made a kit radio about 60 years ago using metal eyelets set in a plastic sheet. GRP would be good for this.

Solder will take very well to steel nails. Wood is only a good insulator when dry.

[mhennessy]

Maplin still have some, but it looks like they are discontinuing it, so grab it if you can: http://www.maplin.co.uk/p/3962-srbp-...rd-plain-jp53h

ESR have some. I've used ESR, and recommend them. First on this page: https://www.esr.co.uk/electronics/pcb-stripboard.htm

I've built a lot with this over the years, and like it for simple jobs. Compared to Veroboard, you can mount the components exactly where you want them - just like a PCB - and because the components might not have to stretch over great distances (as they might on a Verboard layout), it's easier to recycle used components that have had their leads cropped. As a kid, nearly all of my "stocks" were salvaged, so this was a big deal for me.

A tip: you can get solder pins that fit the holes nicely. If I was developing a circuit, I used the pins for components that I expected to have to change, and this made things much easier. But then, that's because I was a bit "OTT" underneath; the copper wire used to join up components underneath was always wrapped around the component lead (or pin) at least one complete turn, so the joint was good before the solder was added. Good for reliability, but less good for repair...

I can't immediately find them now, but the pins I liked had something like a V shape to the top half, which meant that component leads sat in them neatly. Can anyone else remember what these were called?

Doubt I'd have the patience, dexterity or eyesight to work this pedantically now. For simple one-offs, I just use Veroboard most of the time. I would make PCBs, but with small kids and cats in the house, I prefer to not use the chemicals... Obviously for "real" jobs, getting a prototype PCB is just part of the R&D budget.

Another tip: you can use regular Veroboard for low-current mains stuff. But you have to be careful. Firstly, you can remove copper strips really, really easily from Veroboard - just with the heat from your soldering iron. Once you've done it a few times, it becomes really quick. Getting it started is a bit tricky, but removing a few inches of track at a time is very straightforward.

Next, take great care over the construction. Joints should be mechanically secure before the application of solder - this might mean folding wires down so that the contact area is increased. Watch for components that are heavy or run hot - these might cause the soldering to go bad later. Make sure you use a metal box that is firmly earthed: attach a ring connection to the box using a screw and nut and locking washers - and ensure that this screw/nut is not responsible for securing anything else. Ensure there is a mains fuse - my preference is for a fused IEC mains inlet, but cutting the rectangular opening is a pain! Include an over-sized sheet of insulating material beneath the circuit board. The board should be spaced away from the box by at least 5mm - preferably 10mm (yes, people sometimes forget about that, believe it or not!). Use heat-shrink or similar sleeving where possible. PTFE sleeving looks nice on component leads.

Sorry for any "sucking eggs" moments above

Good luck,

Mark

[Tractorfan]

Hi,
I've built a few projects on Veroboard which included PCB mounted relays that switched mains. I removed two rows of copper strip between mains and control circuitry and the equivalent width of gap in strips running the other way which works very well.
Cheers, Pete.

[Bazz4CQJ]

I've built a number of units using Veroboard type material running up to around 300V HT (~100mA) and not had any problems so far. To be honest, I never looked to see if there was any data restricting its use at those sort of voltages; there's obviously a limit.

B

Veroboard starts to fizz a bit over a kilovolt twixt tracks, found this out working on the Sinclair Pandora computer prototype EHT stage. All I did was to squirt on some varnish, it was all too compact and had to work!

Lifting adjacent tracks is much better and gives over 3mm creepage, which I think is good enough for earthed devices.

[Andrew B]

I think they were called "Dalo" or "Vero" pins.

You pushed the pin thru the hole in the board (green plastic with 0.25" pitch) and "staked" it on the bottom with a centre punch.

The problem being the board they were staked to was a cheapo thermo-plastic, so as you heated the pins while soldering components, the plastic melted!!! AND it was that sort of plastic that gave off eye-watering smoke

[mhennessy]

These are the nearest I can find:

http://www.verotl.com/en/product/dou...o-part-18-0226

The ones I used weren't wire-wrap types, so were much shorter. But these could be cut down, of course.

I used these with standard SRBP 0.1" matrix board, so no melted plastic for me

[Diabolical Artificer]

A tag board is one way to go for this project, I used it for my cap reformer. It's very simple and uses a variac to vary the voltage and consists of a voltage doubler, resistor to limit current and a neon to indicate leakage/state of cap.

Andy.

['LIVEWIRE?']

I haven't checked lately, but vintage-parts.com stock both tagboards and tag strips, both of which were, of course, the standard way of building projects back in the 1960s. PW even published designs for a transistor amplifier and, IIRC, a transistor radio buit on tagboards early in that decade.