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Home made PCB's

QuantumCheese

Apr 27, 2012
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Hi all,

I've been at this for a while now and with reasonable results (single sided only obviously). I would like to try DS but among the many pitfalls I have encountered along the way, i discovered that my HP laser output isn't to scale - it changes from the top of a sheet to the bottom!

Anyway, back to the point. I started with the traditional approach, printing acetates, uv exposure, various chemical baths etc, finished job. but then i came across the "press and peel" method which cuts out the need for a couple of the chemical stages and gets straight into the etching bit and i was wondering if anyone else on here uses it? (and if so, what degree of success have you been having?)

It seems to come in two flavors, Blue & Yellow, these numbers are ebay item numbers in case you have no idea what i'm on about! Yellow - 251426505370, Blue - 111279259955

With the Blue type I have had pretty good repeatable results, however with the yellow it's been a total disaster! I bought the yellow because it's a fraction of the price of the Blue, but if it's rubbish its not exactly saving me money is it!

Please chime in with your stories - good or bad, maybe we can help each other out

Below is an example of a few simple boards i made today with the Blue sheets.....The ones I tried to make with the Yellow got scrubbed they were so bad!
 

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shumifan50

Jan 16, 2014
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This is just a variation of printing on paper and ironing onto PCB. I have found this to be disastrously bad, spending waaaay to much time touching up hte transfer with the result looking decidedly poor.

I will stick with the good old photo-resist boards and UV exposure.
 

QuantumCheese

Apr 27, 2012
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This is just a variation of printing on paper and ironing onto PCB. .

That's exactly what it is! I didn't mention the iron, though thinking about it i should have as there are 'press & peel' stickers too, forgot about them.

Apologies. "Iron-on toner-transfer method" would probably be it's best description.
 

shumifan50

Jan 16, 2014
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It also does not eliminate 'a couple' of chemical processes. It only eliminates the exposure and development of the photoresist( one chemical process). This is at the expense of only being able to etch wide tracks and big pads very poorly. This process only works for very simple boards with very few very simple components.

The only problem with using pre-coated photoresist boards is that you need a UV exposure unit to do it well, but you will be rewarded with good looking boards supporting VERY thin tracks and surface mount pads for processors and the like.
 

QuantumCheese

Apr 27, 2012
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I would call Developing a chemical process, and i would also call removing of the photo-resist after etching a chemical process, but that's just me i guess.

The whole point to this is 'home made'. not double sided with through plating. not covered with high freq tracking and uProc buses. So think, a PIC and some mainly through-hole components and definitely single sided. Anything more complex & the drilling becomes tedious.

" etch wide tracks and big pads very poorly" - did you look at the picture? wide tracks yes, gap between track & flood fill pretty good i would say. As for your VERY thin tracks, i seem to be able to manage to go down to 0.3mm tolerances with reasonable results, though i ve found it's best to stick to about 0.5mm, and surface mount yes, though only large-ish stuff. if i need a complex board, i'll get one made.

Can we stick to discussing the iron-methods here please, i'm more interested in peoples experiences with that. i've been using the UV method or >25yrs and am looking at simpler alternatives, and how (or if) the process can be made to work as close to as well as

If you use or have used this method, please stick some pics of your creations up here for all to see :)
 
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davenn

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and i would also call removing of the photo-resist after etching a chemical process, but that's just me i guess.

naaa more of a mechanical process... Steel wool is the usual way to rub it off and buff up the copper ready to be tinned

Dave
 

QuantumCheese

Apr 27, 2012
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naaa more of a mechanical process... Steel wool is the usual way to rub it off and buff up the copper ready to be tinned

Dave

Mmm, never done it that way.... I have a bottle of "600-019, Processing Chemical for Photoresist Stripping" (that's an RS part no. btw)
.....and i haven't even got on to tinning yet, that's definitely in the 'nasty chemical' bracket
I use a Flux pen, also from RS i think. I find it a lot easier and quicker than tinning, and results-wise it seals the copper nicely and solders very well.

tried that one Dave?
 

shumifan50

Jan 16, 2014
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OK totally on topic.

I have tried to make PCBs using this mechanism with very limited success. Some very simple boards actually worked(tracks connected) while many required subsequent patching with wire jumpers to ensure track continuity. None were such that I would show them to anybody.
Many boards were destroyed with the heat from the iron causing the copper to delaminate from the resin board in the attempt to get better transfer.
Each board involved multiple transfers in an attempt to get the best transfer before etching. This improved the final result, but not by much.

I had better succes with the pens that you draw directly on the PCB.
The only worse solution than toner transfer is using rub-off transfers.

Unless you will only do one or two PCBs ever, I would strongly recommend setting up a photoresist/UV etching system.

I strongly recommend against using the toner trnsfer mechnism based on my experience with it.

Sorry I can't post any images of PCBs done with toner trabsfer, they are all in the rubbish.
 

jpanhalt

Nov 12, 2013
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I have used positive resist (Injectorall brand) exclusively since the mid to late 90's. After etching, I leave the photoresist on the board until after drilling, and I am just ready to use it. Some people have claimed to be able to solder right through it. I have never tried that. I use mostly 805-sized SMD and am more comfortable with a little flux.

Now, for removing the resist, you can you can grind it off, sand it off, or whatever. For me the easiest way is simply to put the board back into the development bath, which for my boards is just 0.4 molar NaOH or KOH, with an added teaspoon or so of lye per 400 mL.

The remaining resist turns purple and most of it flakes off under the surface. Any that remains just washes off to give me a smooth, chemically clean copper surface ready for solder.

Remember, it is a positive resist. You could probably set the whole board in the sun for a little while and just use the original developer, but I have never tried that. I end up making most of my boards at night.


John
 
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QuantumCheese

Apr 27, 2012
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Sorry I can't post any images of PCBs done with toner trabsfer, they are all in the rubbish.

He he, that's kind of why i started this thread! I was hoping someone had had better luck than me with this method. I've never had copper de-lamination how hot was the iron :eek:
I can't say i have had 100% success, but it close enough to make it a goer. I'll post some more pics of boards i've made with this method later
 

QuantumCheese

Apr 27, 2012
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Look at this thread for a DIY board done with toner transfer:

https://www.electronicspoint.com/build-device-schematic-diy-pc-board-t257052.html

Bob

that looks pretty good bob! I only very recently discovered the 'just print it onto paper & then Iron it to transfer' method (not tried it myself though).... from the descriptions i've read, it does take a bit of cleaning to get the paper off. and i have to say the tracks do look a bit wibbly! but at the end of the day it's cheaper than the transfer-sheets i have been using

thanks for chiming in, it what it's all about :)
 

BobK

Jan 5, 2010
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I actually have modified a laminator now to make the process more reliable and I got very good results the first couple of times, but it seems to have degraded for some reason. With the laminator, blue transfer sheets made the best images.

Bob
 

QuantumCheese

Apr 27, 2012
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I had wondered about modifying a laminator, at the present I've stolen a roller from the other-half's art things & use a combo of Iron + Rollering, which is bit of faff but seems to get reasonable results.

I've attached a photo of one of the earliest boards i did using the blue transfer method, i made a couple of boo boo's (before you all start poking fun). first i forgot to print the holes, so drilling was a nightmare doh, but i also didn't flood fill so it damn near used up all my etchant. hay ho, you live and learn.
What you are looking at is one 6 boards and the blue transfer stuff post transfering, all etched 100% OK and a track width of 0.3mm. For anyone curious, it was for one of my many LED bike lights.
I actually find thick tracks harder than thin ones with this stuff!

Carl
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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I'm going to try a method tonight using a laser cutter, painted PCB and ferric chloride.

Maybe not quite a home method, but I'm interested in how well it will work.

I'll post the results in a different thread so as not to hijack this one.
 

jpanhalt

Nov 12, 2013
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OT

Steve, Please start that thread. I am really interested in a DIY laser cutter and almost bit on one last year. It is still CNC vs. laser in my mind, maybe both?

John
 
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