Homemade pcb with Photoresist method

Boardburner2:
Sounds like through hole rivets , Farnell used to do them.

Csn be found on ebay.

Hot diggity, Farnell has them....but what's a pound???

As for Ebay..... I've not bought anything from there for a long long time. Too much junk being peddled there

I have a million of these.
When it comes to a home made PCBs, I would walk over a bed of hot coals to avoid it.

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Good old dayshttps://www.google.ca/search?q=pcb+rivets&espv=2&biw=1360&bih=643&tbm=isch&tbo=u&source=univ&sa=X&ved=0CCcQsARqFQoTCOLsx7O06MgCFZGliAodvyQGkg

Edit:

FYI
http://www.electricstuff.co.uk/pcbs.html

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Good for giving a heavy item like a small transformer/inductor some extra support on a single side board.
I also still have bags of them in the bottom of the drawer.
leo..

FYI
http://www.circuitmedic.com/products/201-3140G.shtml

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I just put a phillips head screwdriver on the thin end of the rivet, and hit it with a hammer.
Leo..

I will try a cheap transparent/tracing paper and see if it works with my laser printer

About the spray i will use the positiv 20, everyone suggest it and looks like no one had tried any alternatives

When i would need more than 2 boards i will go for sure for seed, pcbway or similar but for now i d rather to waste some time and as someone have smartly said i will double check my design doing manually the boards

I use the negative pre sensitized board, less ink from the ink jet printer.

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larryd:
I use the negative pre sensitized board, less ink from the ink jet printer.

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Depends on your circuit design on the amount of ink that is used

With a ground plain.

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Using the negative method i find that most printers cannot do large areas of dense black weather they are inkjet or laser.

I had that problem years ago with a laser printer on acetate, giving ‘whiskering’ which had to be cleaned up.

My through hole plating was a bit of 22swg tcw.

I generally used pre-coated boards from eg Farnell.

double sided by drilling marker holes through the acetate and board to align. Ferric chloride etch in an agitated bath.

Long time ago.

And no good for fancy stuff. But quick. Well, quicker than the slow boat or the local specialist. And cheaper . Back in the 90’s I paid about £200 for a batch of 10 smallish double sided plated-thru boards with a 7-day turnaround.

Allan

Boardburner2:
Using the negative method i find that most printers cannot do large areas of dense black weather they are inkjet or laser.

i agree, i tried to do it on a simple paper and my printer wasn't able to do it all black

The link I made in post #1 mentions my method using an 8600 ink jet printer with clear overhead material.

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Another important question:

Which do you consider to be safe values for the width of the traces and the isolation? Obviously talking about homemade pcb

I use 16mil for the traces and 24mil of isolation,, you?

I like 25mil traces 50 and 75 for power and grounds.
15 mil in tight places.
Use ground/power plains.
Thermal relief vias as needed.

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Ground vias also to connect the top & bottom ground planes.

More ground plane area also equals less copper to be removed for faster etching.

A trace width to current carrying capability calculator will show that 10 mil wide trace of 1 oz thick copper can carry 1A current with minimal temperature rise over the length of the trace.
http://www.pcbco.com.au/tracecalc.html
For example, I entered 1A, 10C rise 1 oz copper, 20C ambient, 20mm trace length (2cm, getting close to an inch).
A 10 mil trace is all that is needed.
So 10 mil for mA or uA signals is all you need, and nearly 2A supply current can be met with a 25mil wide trace.

Use ground planes, don't snake ground traces all over the place.

I'm pretty sure there are other calculators which use the latest IPC model where you can enter width, length, thickness, etc. and get a current capacity out of it, but I'm having trouble finding one. Most seem to go other way, start with current etc and get the needed trace width.

Old eyes and shaky hands like 80 mil pads for PTH components.

@cross I used the same calculator once. i needed to make a bench power supply, and since i doesn t have any idea about these formulas i found it very helpful. Anyway i use 16mil instead of the 10 because i am scared to "lost" a trace with the homemade process

@larryd you use very big traces! Is it due to the current of your pcb or for the method you use to make them?

'Old eyes and shaky hands' is why MrsCrossRoads puts parts on the boards we build.
I can handle solder paste with a stencil, and sometimes have to do a board a couple of times when the stencil alignment is a little off, or I was a little uneven with squeegee pressure, or the paste got too thin over some pads while I squeegied, lots of ways to mess that up.

IMO larger width traces have very little drawback.
Larger traces gives: more surface contact to the substrate, less resistance which can help in less noisy signals and more heat tolerance.

I am not a fan of widths 10mils or less, especially if there is room for say 25mils.

Narrow widths have their place especially with high density designs.
However, it doesn't seem reasonable to have a 60-80mil pad and then an exiting 10mil trace especially if a wider trace can be accommodated.

Do not forget to incorporate good path way layout and proper power supply decoupling.

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