Wondered if anyone has ever used the spray on Photo-Resist coating for PCB's and had good consistent results with it. I've never tried it but keep wondering.
Thanks Karl
Thanks Karl
Yep it works fine, but sure you will have a few mishaps the first couple of tries...
Avoid the Cramolin brand, Positiv20 works quite well.
You need to cover the board in as thin a coat as you can consistantly apply without any uncovered pinpricks left...
I prefer spraying mine at night, in sunlight it always looks like I applied less than I did, it is painfull dealing with too thick a coat during the development stage...
I use outdoors UV exposure, I would say about 5 minutes would be right for the UK, 4:30 for bright sunny days.
Avoid the Cramolin brand, Positiv20 works quite well.
You need to cover the board in as thin a coat as you can consistantly apply without any uncovered pinpricks left...
I prefer spraying mine at night, in sunlight it always looks like I applied less than I did, it is painfull dealing with too thick a coat during the development stage...
I use outdoors UV exposure, I would say about 5 minutes would be right for the UK, 4:30 for bright sunny days.
Hi Nordic,
Good to know it works O.K. I was worried about not getting it "thin and even". The one I have in mind is by Electrolube, which is about 11 GBP here. So it could work out cheaper as well.
One thing I have only just thought of, once sprayed you'll have to use it straight away so it does not get contaminated or "exposed". Worth a try I think 🙂 Thanks for that,
Regards Karl
Good to know it works O.K. I was worried about not getting it "thin and even". The one I have in mind is by Electrolube, which is about 11 GBP here. So it could work out cheaper as well.
One thing I have only just thought of, once sprayed you'll have to use it straight away so it does not get contaminated or "exposed". Worth a try I think 🙂 Thanks for that,
Regards Karl
I dry mine overnight in a light tight biscuit tin.
It works OK, but not perfectly. For all the effort involved, I prefer to laser onto glossy paper & iron that onto the copper. WAY cheaper, and much less work.
It works OK, but not perfectly. For all the effort involved, I prefer to laser onto glossy paper & iron that onto the copper. WAY cheaper, and much less work.
Getting CONSISTENT results is hard. Some work well, some not. I think it is very dependeant on the spay uniformity, and the quality of the artwork.
Generally the uniformity of the resist varies over a board, unless its a very small board. Some areas over expose, other dont.
Maybe true photographic artwork would help, but it costs too much for once offs.
Generally the uniformity of the resist varies over a board, unless its a very small board. Some areas over expose, other dont.
Maybe true photographic artwork would help, but it costs too much for once offs.
Once sprayed and dried it just needs to be kept out of light, I just turn mine over and put it face down in a drawer on some cloth to avoid scratching.
Twikki sad, Twikki leaves....If I could have anything I chose as a child, It would have been Twikki...
With some pointers from Nordic I've done quite a few boards, including some double sided boards down to 12mil resolution without breaking a sweat. Works fine everytime, although it took some practice in the beginning to get the process right. I must admit that I'm using the missus' imagesetter at work to do the artwork, so that helps.
Hallo Gert, I have the memory of a goldfish, did you test that tinnig stuff eventualy...? We kind of lost contact in the wait.
Hahaha Mooly
Hahaha Mooly
Hi,
I use an inkjet and some special film (specially for this ) and find it works amazingly well( like you after some practice with print settings etc). Problem is that local suppliers have stopped stocking the precoated fibre glass board, they do an "economy" one which is O.K. ish for prototyping. I can always mail order but thought this worth a try. Thanks
I use an inkjet and some special film (specially for this ) and find it works amazingly well( like you after some practice with print settings etc). Problem is that local suppliers have stopped stocking the precoated fibre glass board, they do an "economy" one which is O.K. ish for prototyping. I can always mail order but thought this worth a try. Thanks
Yep it is important, when you buy transparencies to make sure you get the right type.... Lazer or bubblejet...
Bublejet ink will not dry on lazer transparencies....
And I'm not sure if bubblejet transparencies can take the heat cycle in a lazer printer...
Bublejet ink will not dry on lazer transparencies....
And I'm not sure if bubblejet transparencies can take the heat cycle in a lazer printer...
I never used spray, but just a bottle of the liquid. I built a spinner for small boards, a motor with adjustable speed and a flat plate. The board was stuck to the plate with double stick tape, some resist applied, then the board was spun to remove the excess and insure a thin layer. It worked great, but what a PITA. Now I use the wonderful laser printer method, or if too lazy, just order the board from one of the quick turn prototype houses.
One thing you've got to watch with this stuff is as it takes a long time to dry - keep it covered while its drying otherwise it gets covered in dust hair and anything else floating in the air. 😱
Tony
Tony
While spraying boards........ let the oven heat up at the lowest setting... I think it is about 70 degrees... When finished spraying pop board into oven, after about 10 minutes, switch the oven off, at 15 minutes remove boards... if there are small uncovered pinpricks... now is the time to give it another quick spray... (it will dry almost instantly because of the heated board...
The heating ensures good bonding between the copper and the sprayed on layer.
The heating ensures good bonding between the copper and the sprayed on layer.
Probably a daft question but what do you clean your boards with prior to spraying. When I used to hand draw and use transfers I used those green kitchen pad things ( a bit like a rough mat ) and then used iso to wipe it down. The pads leave swirl marks in the copper, though whether this would affect the result I don't know.
The swirling, or texturising gives toner and press and peel transfers something to bite into... can't imagine it being bad for spray either...
Remember to get tinning solution or at least flux so you can tin your boards with solder...
Remember to get tinning solution or at least flux so you can tin your boards with solder...
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