Photo Resist Board

[Digital]

Hello,

Back In the day Maplin used to sell Photoresist Boards and they were clear (no green tint) fibreglass boards. Does anyone have any alternatives as I cant stand that green tint on these new boards.

Thanks,

Digital.

[eddie_ce]

I don't know what you mean by clear, but for decades now I have used boards made by a company called Bungard and always had good results. The board colour is what I would call "normal". These should be available from the usual suspects.

Hope this is of some use to you.

[Scimitar]

When I had some boards made commercially, There was a wide choice of FR4 colours, so they must be fairly easy to buy. I hade some nice yellow ones and some white ones made...

[Digital]

Originally Posted by eddie_ce

I don't know what you mean by clear, but for decades now I have used boards made by a company called Bungard and always had good results. The board colour is what I would call "normal". These should be available from the usual suspects.

Hope this is of some use to you.

Hello,

What colour are the bungard boards, do you have a photo ?

Thanks !

[David G4EBT]

Originally Posted by Digital

Hello,

Back In the day Maplin used to sell Photoresist Boards and they were clear (no green tint) fibreglass boards. Does anyone have any alternatives as I cant stand that green tint on these new boards.

Thanks,

Digital.

Welcome to the forum.

Presumably you mean the colour of the UV lacquer coating rather than the FR4 fibreglass laminate itself?

I can't answer that as abandoned pre-coated boards many years ago as I found the exposure time too critical.

Either under exposed so the developer didn't wash off all the exposed areas, or over exposed in which case all the lacquer washed off and I was left with plain piece of laminate. I started to use self-spray positive UV lacquer from Maplin for a while, so if the exposed board didn't turn out quite right, at least I could remove the lacquer with meths or acetone, respray the board again and have another go.

However, about four years ago I discovered the negative resist UV dry film technique which is cheap and gives consistently good results, the only problem being to ensure that all air bubbles are excluded before passing the board through the laminator to seal the film to the board. The developer (soda ash) is cheap too. The technique has been widely covered in forum threads and on internet. E.G.:

https://www.vintage-radio.net/forum/...ts+UV+dry+film

Of course, nowadays, for anyone who is competent at converting artwork to Gerber files (which excludes me as I'm not far enough up the food chain to be able to do that!), making ones own PCBs makes no sense financially, as many forum members will attest. JLPCB in China will make PCBs for a fraction of what you could buy plain FR4 laminate for and will give an instant quote.

https://jlcpcb.com/?gclid=CjwKCAjw19...BoChQ0QAvD_BwE

A forum chum recently ordered ten PCBs from JLPCB about 5cm x 7cm. Total cost inc post: £7.50. Yes, 75p each.

If I'd have spent a fraction of the time I've spent over the years developing, etching, drilling and tinning homebrew PCBs on learning how to create Gerber files instead, I'd have save hundreds of hours. But as a hobbyist, I derive perverse satisfaction from engaging in activities which are low tech - high skill, and can make a board the same day that I design it. There's also some truth in the adage that you can't teach old dogs new tricks and I'm stuck in a rut as deep as a grave.

Enjoy your PCB making.

[eddie_ce]

Here are a couple of photos of a small board I made recently with Bungard FR4 material. The quality of pictures is not too good but should give you some idea.

[Digital]

Originally Posted by David G4EBT

Welcome to the forum.

Presumably you mean the colour of the UV lacquer coating rather than the FR4 fibreglass laminate itself?

I can't answer that as abandoned pre-coated boards many years ago as I found the exposure time too critical.

Either under exposed so the developer didn't wash off all the exposed areas, or over exposed in which case all the lacquer washed off and I was left with plain piece of laminate. I started to use self-spray positive UV lacquer from Maplin for a while, so if the exposed board didn't turn out quite right, at least I could remove the lacquer with meths or acetone, respray the board again and have another go.

However, about four years ago I discovered the negative resist UV dry film technique which is cheap and gives consistently good results, the only problem being to ensure that all air bubbles are excluded before passing the board through the laminator to seal the film to the board. The developer (soda ash) is cheap too. The technique has been widely covered in forum threads and on internet. E.G.:

https://www.vintage-radio.net/forum/...ts+UV+dry+film

Of course, nowadays, for anyone who is competent at converting artwork to Gerber files (which excludes me as I'm not far enough up the food chain to be able to do that!), making ones own PCBs makes no sense financially, as many forum members will attest. JLPCB in China will make PCBs for a fraction of what you could buy plain FR4 laminate for and will give an instant quote.

https://jlcpcb.com/?gclid=CjwKCAjw19...BoChQ0QAvD_BwE

A forum chum recently ordered ten PCBs from JLPCB about 5cm x 7cm. Total cost inc post: £7.50. Yes, 75p each.

If I'd have spent a fraction of the time I've spent over the years developing, etching, drilling and tinning homebrew PCBs on learning how to create Gerber files instead, I'd have save hundreds of hours. But as a hobbyist, I derive perverse satisfaction from engaging in activities which are low tech - high skill, and can make a board the same day that I design it. There's also some truth in the adage that you can't teach old dogs new tricks and I'm stuck in a rut as deep as a grave.

Enjoy your PCB making.

Hello David and Eddie,

Thank you. I agree, However I am stuck In my old ways I like making things myself because then I can say I made that circuit and It works. Please see the photos of what I mean by "clear". The bungard boards still have a green tint If you know what I mean please see the photos attached. Photo on the right Is the component side.

[David G4EBT]

Originally Posted by Digital

Hello David and Eddie,

Thank you. I agree, However I am stuck In my old ways I like making things myself because then I can say I made that circuit and It works. Please see the photos of what I mean by "clear". The bungard boards still have a green tint If you know what I mean please see the photos attached. Photo on the right Is the component side.

Thanks for the clarification - I thought you meant the colour of the UV photo-resist coating on the board - not the colour of the fibreglass laminate substrate when etched. As I mentioned, I've not use pre-sensitised boards for many years, but almost invariably the FR4 single-side PCB laminate I've bought was from Maplin, both for convenience, and that it was reasonably priced. When they were about to close, I did a round trip of their branches in Hull, York, Bradford, Huddersfield, Wakefield, and Scunthorpe. I was only after two things - genuine Veropins which no-one else seems to sell, and PCB laminate. I bought what they had.

I've never thought much about variations in colour of the fibreglass, but looking at pics of boards I've made in recent years, they do seem to have varied markedly from a light straw colour, to greenish, sometimes with greater transparency. Particularly marked in the first pic below of two boards for one project.

Your sentiments about sticking to your old ways very much chimes with my own outlook. For some years now, most of my PCBs are from my own designs, and I find it convenient to be able to design and make a PCB the same day. I don't use any CAD programs - I find them too constraining and irksome to use. I just use MS Paint.

I've been making my own PCBs since the early 1960s - in the early days by photocopying magazine artwork, sticking in over the laminate, drilling through all the hole positions, removing the paper, then 'joining the dots' with rub-down transfers. Sometimes designed my own PCBs and used the same rub-down transfer technique.

In the mid 1980s, I built a UV light box and started using pre-sensitised UV boards, with varying degrees of success. Back then, the only way to create a DIY mask was to get a photocopy of the artwork onto OHP film and tape together two or even three images to get sufficient opacity for a useable mask. The drawback of that is that with more than one copy, the opacity of the 'clear' areas also increased. When developed, I often ended up with an under or over exposed board. That's when I started spraying my own plain laminate with positive UV lacquer, which Maplin sold at quite a keen price. I tried printing onto tracing paper (known outside the UK as 'vegetal' paper), sprayed with 'transparentiser' (some said WD40 was OK too). Didn't work for me. Modern ink jet/laser printers tend not to be very good at printing solid colours onto OHP film, but about three years ago I discovered 'micro-porous' film which is far better.

Back on topic - the pics below are of PCBs I've designed and made for some of my homebrew projects showing the variations in colour of the etched boards.

As far as I can say, all the laminate came from Maplin at various times.

The second and last ones look markedly greenish. Incidentally, the colour variations aren't due to staining from ferric chloride etchant as I've not used that for many years. Instead, I use sodium persulphate crystals, which make a colourless etchant, which even after several uses, turns pale blue, with no residue 'sludge'.

Hope you find some laminate to your liking.

[eddie_ce]

I seem to recall that earlier batches of Bungard boards had less of a greenish tint to them. Possibly it's a case of which supplier of base material they chose. As a finished board is usually not on display the colour is not too important to me.

I like the Bungard boards because they are fairly tolerant regarding exposure times. I have no connection with the company.

Years ago, to save money I tried using spray on photo resist from an aerosol, I think it was called "Positiv 20" the results were not very good, unevenness in the coating and little specs of dust being the major problems.

Unfortunately, I don't have anything further to suggest, it will probably come down to trial and error to see which, if any supplier's material fits the bill.

[Digital]

Hello David,

I dont use any computer software I have always used Decadry Rub On Transfers as thats the way I learnt to make back In the late 80s, I used to put the rub down transfers on a clear sheet or even plastic and I would always have amazing results. However It's a shame Maplin Is no more I used to like the Velleman Pins (Double Sided I Think). I'm really liking the look of the 3rd photo as that's the board Velleman used to use.

Hello Eddie,

Really appreciate the help, However I just bought some Positiv 20 spray a few days ago ! Whoops, I'll let you know how I get On.

Kind Regards,

Digital.

[Digital]

Hello David,

I haven't had a chance to use the Positiv 20 spray however I should get some time soon are you willing to sell me some copper clad board If I ask for one of the following manufacturer markings : MAS, i , then the 3rd photo or IGAV if you have any of the following give me a shout.

Thanks !

[David G4EBT]

Sorry that I'm unable to help - I haven't made any PCBs for a little while now and don't have anything suitable. I've used up the stocks that I bought from Maplin just as they were closing down. I made the mistake of buying some supposedly FR4 laminate from an eBay supplier, but I found that when I came to drill the pads for ICs etc, the copper had very poor adherence to the substrate and lifted off, so I scrapped the board. If/when I need any laminate, I'll buy it from a trusted supplier such as RS or Rapid Electronics, who state the thickness of the copper film, which is generally 35 microns thick.

For example:

https://uk.rs-online.com/web/p/plain...B&gclsrc=aw.ds

https://www.rapidonline.com/RVFM-Cop...4aAqkxEALw_wcB

For anyone able to create Gerber files from PCB layouts, (which doesn't include me!) nowadays it makes little sense making ones own, when JLPCB will make several small high quality drilled, tinned and screen printed PCBs for under £10.00 post free - less than the cost of raw materials for DIY PCBs. On the few occasions that I'm likely to need a PCB, as I'm an old timer in a rut as deep as a grave, I'll stick to my old ways.

Good luck with your PCB making activities.

[bikerhifinut]

David,
That strikes a chord with me!
However I was unfortunately not blessed with good (or even fairly mediocre) art and graphics skills and all my efforts at DIY PCB making over the years has been at best scrappy.
I was introduced only last weekend to the Kicad software by a local radio Amateur accquaintance. He is sure I will get the hang of it, but so far its a struggle with the graphics package and I guess I will need to burn a lot of midnight oil practising Computer CAD skills. This package will produce a gerber file and I can confirm what David has said about getting boards made as most of the local crowd I know do this.
https://kicad-pcb.org/ it's freeware apparently developed at CERN and its completely free at point of use.
Apparently there are also libraries of symbols etc online to draw with if the library in the freeware isnt enough.

If I had Davids amazing craft talents I doubt I would go down this route either, your projects are a work of art sir.

Regards.

Andy.

[Digital]

Hello David,

No worries really appreciate the response. That's very unfortunate there were quite a lot of cheap boards going around and still are. I love making my own PCB's and love It because I can say "I made that board and I put It together and It works !" Have a good day.

Thanks.

[Digital]

Hello Again,

I don't suppose anyone knows If MAS the copper clad manufacturers are still trading ? I've been repairing a few PCBs during the week and noticed that some of the boards are of very high quality. Would be Interested If anyone has any copper clad from them that they are willing to part with. I recently opened up my old radio alarm clock from 1991 which I got for free with the Embassy Cigarette Vouchers and the IC's used are the KA22427 which I've gathered Is the AM/FM radio IC and the TMS3450NL for the alarm clock section does anyone know If the board for these chips could be dug out the radio alarm clock was manufactured by Parsons however I can find any sort of history on them.

Thanks.

[Radio Wrangler]

The greeny-grey tinge comes from the resin that the glassfibre may is set in. It comes down to which company made the base substrate that the copper foils were applied to.
Nelco was renowned for good quality material and I first met the green tinge on their stuff. It is likely that modern substrate manufacturers opt for a greenish resin because their customers associate that with a known good material. It may even be associated with the choice of fire retardant chemicals in the FR-4 (hence the prefix!)

If you don't want to see the raw board and you do go the Gerbers route, you can just specify a soldermask layer (one for each side) and most PCB firms will give you a choice of colour of the overcoat. I've had bright red and deep blue in the past to mark out certain special boards. The only things showing were the copper pads for the components.

David

[Digital]

Hello David,

I have managed to source some laminate that doesn't have a green tinge and also no copper laminate on It however I need to apply that copper laminate with a bonding press however I don't own one nor do the company that Is willing to sell me the laminate do you know anyone that could help me out here ? I was also told the green stuff also serves as a UV block.

Thanks.

[Radio Wrangler]

That's an awful lot of work to do just to be rid of a tinge of colour. The press to get it to adhere and the acid etch probably needed to prepare the surfaces will likely cost you more than having a board professionally made with a solder mask overcoat in a colour you prefer.

How many boards do you want to make? Single sided, double sided, multilayer?

I keep coming across SRBP based PCB material at radio rallies (remember when we had those... Eeee luxury!) and some oriental products still appear with paper-based board in its usual light browny beige colour.

David