Printed Circuit Board Holes

The industry standard for commercially made PCBs is plated through holes. There are a number of alternatives:

Dwayne Reid of Trinity Electronics Systems Ltd Edmonton, AB, CANADA says:

I have used the Multicore 'Coperset' system. They extrude solder in rods of the appropriate diameter and electroplate copper onto those rods. Then they score the copper at intervals somewhat more than 1/16th inches (longer than a PCB thickness). To use the system, you drill the holes EXACTLY the right diameter, place the board over an anvil and stick one of the rods into the hole. You break off a section by bending the rod back and forth so that you are left with a little cylinder sticking above the board. A sping-loaded punch is used to flatten that cyclinder - when you squash it length-wise, it gets fatter and the copper plating 'grips' the inside of the hole. Think of an old fashioned thermos bottle with the lever-type rubber stopper. Anyways, when you have done all the holes, you flood both sides of each loaction with solder, then heat up and remove the solder. Multicore suggests using solder-wick but I get better results with my vacuum desoldering system. Voila! Plated thru holes! Downsides: the orignal rods that I got weren't scored at the right distances (too short) and the little cylinders didn't grip the holes reliably. I understand that has been fixed. Also - its expensive and its time-consuming. But it does work.

You can save a lot of money by not buying the kit - only the rod refils. you can use an automatic pencil to dispense them  see

Tony says:

What you could do is use a PC Board repair kit. They have small, metal, funnel shaped things that are hollow inside, actually like a real funnel:

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You drop these into your thru holes. Then you take two pointy headed tools, and you press one into the top of the 'funnel' and one into the 'tube' end of the funnel. You expand the bottom of the tube and have a thing that looks like an empty thread spool thru your hole.

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     |          |          PC Board
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We used them in the USAF to repair boards that a via or pad disintegrated due to heat.

Alan King says:

Don't forget you have another option, that may be viable since you described it as a lot of address/data lines. Old useless chips (or maybe even the blank test ones some places sell for soldering practice) make good via makers if you have a bit of flexibility in layout and can align your holes. Put them on .1" centers, bend the leads straight out from the chip so they'll be easier to cut, and solder in. Solder both sides and cut off the rest of the leads and chip. Is a heck of a lot faster than placing single wires by hand. Can use header etc what ever you have on hand, I just usually have junk chips. 50 is a bit much, but if you can lay it out so you have 2 rows of 20 and use an old 40 pin chip it can be managed..

See also:

• http://www.thinktink.com/frstpage.htm
  http://www.thinktink.com/stack/volumes/voli/store/catalog.htm They have an interesting conductive ink
• http://www.ping.be/~ping0751/pcbzone.htm
• http://www.jlc.net/~preid/pcbpro/indexpcb.htm

Comments:

• Your local fabric store carries "sequin pins". These are small (0.018" diam by 1/2" long) pins with small heads. $3 or so for about 400. Drill a 0.022-0.024" hole, push the pin thru, and solder in place. Cut off the sharp end, and you've got a FAST, CHEAP, and EASY feedthru.+

Questions:

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