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I've made my first ever pcb myself and the etching and drilling all look pretty good at this point. I am still not sure, however, what to do about the vias. I have about 15 holes that I need to make sure a connection is made from one side to another. On a professionally fabricated board they would have copper running through, but I am not that awesome.

Should I just fill it with a glob of solder, or should I actually put some wire in it or something?

Also, some of my holes for components have wires on the top and some have wires on the bottom. How can I be sure that a solid contact is made with both sides of the hole? It seems like it would be difficult to get right under an ic to solder it to the board on both sides. It looks like the thick part of the leads make a pretty good contact, but I would like to be sure. For resistors and other smaller parts it is not so obvious that it touches both pads.

I'm hoping that if I just make sure my iron is hot and make good joints it should flow through and contact both sides. Any tricks for making sure I get good contact on both sides?

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    \$\begingroup\$ I was told to use resistor legs(cut them off) and solder them for vias. \$\endgroup\$ – Dean Jul 28 '11 at 16:03
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    \$\begingroup\$ Thats a great idea. I have tons of clipped legs already. \$\endgroup\$ – captncraig Jul 28 '11 at 17:25
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Congratulations. Welcome to the club.

You MUST have through wires in vias.

  • Solder "glops" will not work. If they work sometimes they will not work always, and one which do happen to work will die during rework/touchup/alterations.

  • Threading some single strand wire through the holes and then soldering it and then cutting it off is advised. Do not use multi-strand wire - tends to make larger ends, harder to deal with overall - no better result.

  • Wire can be left vertical in hole and soldered and clipped as above. this "tends" to stay in place when resoldered for many values of tend, but an enthusiastic hot irom may draw it out. For extra safety bend wire at right angle on each side before soldering. enter image description here Clipping before soldering leaves a smaller solder blob than otherwise.

  • You can buy special pins made for this purpose but they tend to be ugly, cost money and work no better.

  • You can use dressmaking pins for this but make sure they they solder OK. Nickel plated brass ones solder well (or, the one that I used long ago did). Solid steel pins are often very very very hard to solder). Small head sizes are desirable - large head sizes take up more room than needed.

  • I've seen people suggest running a wire through the same hole as an IC pin and using that to gain access to the connection on the top side. I've not tried that and it sounds messy but I mention it as a possibility.

With tracks that go to the top of IC leads you must either

  • Solder to track on top of PCB or

  • Provide an alternative link from top to bottom as well (via a "via" or other.)

Some devices are easy to top solder to, some aren't. If wires come to IC pads from under the IC, having enough pad on the outside to solder to is wise (at least).

If using sockets (and they are often a good idea as long as not rubbish) then choose a type that allows iron top access to the top of the pin when inserted. "Machine screw" round pin sockets are generally well spoken of and work well enough for this purpose. I've had good results from them over the years.

Whatever socket you use, choose an acceptable quality one. this need not be the dearest but will probably also not be the cheapest. Here brand name often counts. Cheap and no-name is often no-quality.

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  • \$\begingroup\$ I like the idea to make an extra via for components that are hard to solder on top. I will try to route signals on the bottom when possible, but when I can't I could probably usually come out another 1/4 inch and add a via. I guess I just need some more eagle practice. \$\endgroup\$ – captncraig Jul 28 '11 at 4:47
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    \$\begingroup\$ Extra vias like that solves a lot of problems, especially with headers. I often do it. \$\endgroup\$ – Leon Heller Jul 28 '11 at 9:01
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Just put wire through the vias and solder it on both sides, I use 28 swg tinned Cu wire. You need to solder component leads on both sides. IC leads can usually be soldered on both sides, but it can be difficult if sockets are used. My home-made PCBs are usually single-sided with a few wire links, I find that easier than making double-sided boards. I can manage 8 mil tracks without any problems, so I can generally do most of the routing on the bottom layer. Using surface mount devices solves a lot of problems.

Join the Yahoo Homebrew PCB group.

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  • \$\begingroup\$ That is good advice, but I found my design was complicated enough, and the ic pins were laid out such that I would have needed way too many wires with only a single layer. Getting it lined up on both sides took several tries, and soldering may yet prove difficult. Maybe I will end up giving in and having more wires than I would like though. \$\endgroup\$ – captncraig Jul 28 '11 at 3:46
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A tip for those componens where you have traces coming from them on the component layer:

Don't.

Instead, (assuming there is space) take the trace a short way from the component on the underside of the board, then put a via in to bring the trace to the top layer. That way you don't have to be worrying about soldering both sides of the component, and it makes it a lot easier to replace a component should you need to.

On a side note - surface mount devices don't suffer from this problem - they're not as scary as they seem - honest. All you need is a steady hand and a good iron (or even a blower).

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  • \$\begingroup\$ Is there any good way to get eagle's autorouter to do this? I tried having it only route the bottom, and then seeing what connections can't be made. I then try to make a via near the component and route it by hand, but it is a bit difficult. I feel like maybe it can be done with design rules, but I am a noob. \$\endgroup\$ – captncraig Jul 28 '11 at 15:59
  • \$\begingroup\$ Ok, I think I got it. AutoRoute on bottom only. Run AutoRoute again with top layer. Anytime a component is connected on top, put a via nearby and run a trace on both sides to the hole. Looks pretty good. \$\endgroup\$ – captncraig Jul 28 '11 at 17:19
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I have found a great and easy solution, #20 Brass Escutcheon Pins available online from eBay or other sources. The pins are slightly larger than sewing pins and not as hard. The ones I got are about 0.25 inches long. (.035" diam shaft .063" head) Cost about a 0.10 cents per pin.

Drill holes (#60 drill bit) through the board insert all the pins on one side, solder the the head (like a nail head) then turn the board over solder the other side cut off excess length. Being made of brass soldering is easy.

Just recently tried this, it was taking considerable time to do using any other process with wire. This can be done in minutes for the whole board, the head keeps the pin from falling through.

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  • \$\begingroup\$ #20 Brass Escutcheon Pins ( Cost Error )about a penny per pin. Should be about 0.10 cents per pin. \$\endgroup\$ – Bob Brandt Feb 9 '15 at 20:05
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Like the OP, I am a noob and trying to weigh up the pros and cons between copper-plating the holes and making vias with wire a short distance from the component instead. As mentioned by another poster, I thought about using the legs of components for vias, though some component legs are thicker than others and I am concerned that current limits may be inadvertently exceeded. I may have found a universal solution today in Hobby Lobby, which is 0.010 and 0.016 brass wire (music wire was also available). All I need now is to know how many amps it can handle.

In response to the OP's later message about accurately aligning both layers, I recommend watching a 32 minute video on YouTube from Euro Circuits. It is very educational and takes the viewer through a complete commercial-scale production of a multilayer PCB and references the alignment issue in several places. This method can be easily accomplished with dowel pegs, a drill and a hole punch, if you don't have a commercial-scale wallet! Check out https://www.youtube.com/watch?v=sIV0icM_Ujo for the video.

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    \$\begingroup\$ I am not sure if this answer also contains a question or was juts a follow up to the other answers. Please ask a new/separate question if you actually have one (regarding the current capability maybe). \$\endgroup\$ – Rev1.0 Jun 17 '15 at 6:56

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