Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Hi
Thought I would share my way of making cheap DIY PCBs to you folk, been doing it this way since the early 70s after endless experiments.
1ST Design your layout, I normally use Sprint because of its ease of use, you can covert your circuit diagram to BMP then use it as a transparency under lay for your track pcb layout.
Once you have accomplished that you can print direct from your lay files.
2nd Paper types, In the early days I used same as allot of you on here old glossy mags, the draw back is to hit and miss and hassle of cleaning paper off.
The best most effective way is to use wax based paper, by using this you
just peel it off the copper and job done, you will find all plastic ink is where you want it on the copper laminate, the paper you originally printed on will be spotless as if it had never been printed on in the first place.
The next best paper if you have no wax paper is ordinary thin old Fax paper, the type that was on rolls, you will need to run under water to get paper off but where its so thin it only takes a few minutes.

Procedure : Print your lay file to paper with laser printer set at best settings, then print to your wax based paper.
Sand your pre cut copper laminate with very fine wet and dry under running warm/hot tap water with circular motion making sure all copper clad is spotless with a nice shinny surface, At this point Its paramount you do not touch copper clad, wipe with kitchen towel to dry.
Now cut your lay file from the paper leaving a extra half inch all round.
Lay the laminate carefully holding by edges as you would a dvd or ic, copper side down on top of your printed lay file.
Use the half inch extra to fold tightly round back end of laminate creating lips which you need to tape down with paper tape.
Once that done run through ordinary Laminator 10 times.
I used to use ordinary house hold iron but there are to many hit and misses, temperatures variants from one iron to the next the thermostats in them are very primitive which can easily damage the PCB surface due to amount of heat.
Using a Laminator as described will give enough heat to easily melt the laser compound but enough to damage copper clad surface.
Now this part is also very important, once you have run the laminate through for the 10th time you need to cool it off quickly so just put it in the freezer for 30 mins which fits the bill nicely.
After the 30 minutes take out of freezer, unwrap, providing you have followed my procedure the paper will just fall away leaving a nice covering on the copper and nothing on the paper.
Now clean with warm water, nothing abrasive
The whole job from start to finish including etching if your organised should take about 1 hour for a board say 95x100mm.
While the board is in the freezer if using granules as I do you can mix with water in piyrex dish heat with gun which i normally direct onto the surface of the mix, not the dish because you only need it warm.
The etching procedure should take no longer than 15 minutes, if it takes much longer by getting the wrong mix you will end up with a pitted surface.

You will always get 100% success providing you follow my instructions to the book, remember copper surface needs to be totally clean of grease which includes your finger prints throughout procedure, Temperature of transferring lay files, to much heat or not enough heat will give same symptoms, Etching, get the right mix keep warm,Glide PCB through solution keeping it on the move, it needs to be in and out of solution fast as possible otherwise you loose print or at best get pitting on track surface.
Actually the most boring and time consuming part of making a successful PCB is drilling the holes, even though I have a pillar drill its still a pain, worse if your getting on in the years like me, and eyes not as good as they used to be.
Anyway hope this is of some help
Regards
Dave