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Copper PCBs

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patroclus

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I've using perforated circuit boards along with cable for some months, since I started with practical electronics. Now I'm thinking of using copper PCBs, the ones you draw the lines on it, and then put it in some acid liquid (not the photo-sensitive boards).

what things do I need, like, for example, to make the holes?
Any permanent pen would do the job?
Is there any "not-expensive" acid solution?

As I never used this before, Any clue or advice?
Thanks a lot
 
Some folks say that the "Sharpie" brand markers work the best (Black). I've heard of some people complaining about the other brands of markers. Sharpies are very common AND they make them in several different tips that you can use. I use the Fine point for small traces, and the normal point for filling in large areas etc.

Of course, you'll probably want to get some sort of template for drawing the traces and pads (Hole solder points). If you can't find a good template at an electronics store, stop by your local drafting store, or art supplies store. They should have something you'll need. I'm sure some online folks sell some templates. One major point, if you use a template, make sure to raise the template off of the surface, or the ink will bleed underneith the template. Then your traces will look like a drunk man did the job. About 1/16 inch is good. You can use a couple of popsicle sticks, a triangle pad made of tape. Basically, anything that you can put between the template and the copper to raise the template off of the copper about 1/16 or so.

I like to draw the traces and pads out on paper, before I start marking up the copper. It just gives me practice, and another opportunity to find a better way of organizing the circuit. It also provides an opportunity to get your scaling down, make sure components will fit in the area provided. Of course, if you make a mistake on the copper, you can wipe it off using the solvent, but you'll probably end up smearing something that you didn't want to, and end up starting from scratch, or might as well have.

Check google.com and search for "making PCB". There are dozens of sites dedicated to teaching people how to make their own PCB.
 
thanks.
I already looked in google, of course, but almost all things reffer to the photo-sensitive boards, and that is not for me :)
I like the template method, specially when drawing many lines close to each other.

One more thing, what kind of tool should I buy to make the holes?
 
Well, I have a Dremmel tool with a normal drill bit. In case you're not familiar with a dremmel tool, it's a hand held rotary tool, similar to a drill, but it turns at a greater RPM, and can be used for grinding, sanding, drilling, cutting, polishing etc. I use the dremmel for many items that surround a circuit, such as: Grinding holes in cases, cutting excess metal away, trimming PCB etc. I use a 1/16" drill bit for most of the holes for the pads. You can go smaller, for the smaller gauge lead wires, or larger for the larger gauge lead wires. Generally, 1/16" does the job for most applications.

Of course, you don't need to use a dremmel tool. You can use a power drill, hand drill (crank style drill, or push pull drill). I've even got away with drilling holes using a twisting motion with a drill bit and my fingers, but drilling many holes this way is a waste of time.

One point to consider, make sure that your drill bit wont drill out the entire pad that you've made, otherwise, soldering the component to the trace will be quite a pain in the neck.

Another point to consider, always drill from the copper side through to the uncopper side. If you do it the other way around, you'll have a rough hole where your solder joint will be. Sometimes the phenolic or epoxy glass burrs will get in the way, and provide for a crappy solder joint. Also, if you drill the other way around (through the uncopper to the copper) you may lift the copper from the board and potentially crack a trace, or your pad.

Also, drill nice and easy. Let the drill bit do the work. Applying excess pressure will set you up to slam the board when you break through, thus potentially cracking the board, or make a crappy hole.

Also, you'll probably want to clean the board, once you're done drilling, just to get all of the fragments and finger prints off of the board before you solder. Those fragments can really screw up a solder joint.

Also, if you're having trouble keeping the drill bit centered on the area that you want to drill, try using a small screw driver to indent your center point before drilling. Just hand pressure will normally do the job. Don't pound on the screw driver, or you might crack the board. The small indentation (Center punch) will keep your drill bit in that zone, while you start to drill.

Finally, try to design so that your holes will be away from the edge of the board. Sometimes, you can crack the board by drilling near the edge, or provide for a weak point in your structure. This isn't a big issue, but a point to consider when designing your layout. A good 1/4 inch from the edge is pretty good. Of course, you can get away with drilling near the edge, but sooner or later, you're bound to crack a board.


I'll post a link to a site that gives a tutorial on this subject. I have to find it first.
 
:D LOL. Final point, I swear!

You may need to check the size of your traces, depending on the voltage and amperage that you are using. Obviously, a 1/32 inch trace wont hold up very well when it is subjected to a few amps of current.

I'm not sure of a reference site, which would give you the size of trace you need for a given power, but I'm sure they have it posted somewhere. I know most books on making PCB will have a similar reference, but that costs $.

Good luck
 
PCBs

There are some prior threads on the subject in this forum and in the design/ideas/reviews forum:

https://www.electro-tech-online.com/threads/0-24ma-current-source.6284/
https://www.electro-tech-online.com/threads/digital-odometer-anybody-can-help-me.4614/
https://www.electro-tech-online.com/threads/fm-receiver.3715/

Second the good comments on using a dremel tool. Small drill bits and the cut-off wheels are the two accessories I find the most use for. They sell a nice drill press stand (model 212) that's ideal for drilling pc boards.
 
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Thanks for all the tips.
Now I'm just wondering which way to draw lines and pads. I started thinking on manual drawing, maybe aided by templates, rulers, etc..
As I've not many equipment or monetary resources, this is what really suits me, but maybe toner transfer?? I don't know..
 
A dremmel hand tool with a set of drills would do the job? (15000 RPM or so)
I mean, I don't need to get something like the dremmel model 212 for good result, do I?
**broken link removed**
Or is it necesary?

Because I'm a little sort of money and space. thanks
 
You may be able to do without a press, if you're working on a 0.1" grid. A drill press stand just makes the work a lot easier, and ensures 90 deg holes (nice for double-sided boards)
 
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