How to solder Thru-hole components on top layer

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Hello all, maybe the dumbest question of today… For the first time I designed a 2 layer pcb.
(I make the pcb’s at home with dry film) But how do I solder a IC socket or capacitor on the pads at the top layer?

Greetings, and thanks in advanced.
Cees.

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Have you tried using a soldering iron?

You probably will have trouble getting to the pins to solder them on the top side. One DIY method is to stick a thin wire from the down side up through the PCB, bend it and solder it to a track (I assume your DIY PCB’s do not have a solder mask). There are also PCB rivets being sold, but you’ll need some experience and the right tools to make this work reliably.

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Thanks for the tip with the wire. yep I don’t have/use solder mask
Unfortunately I can’t order pcb’s from China (Blocked by government were I live)

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A comment on PCB rivets. They are widely used on single sided, wave soldered, PCBs; to support large and/or heavy components with large heat variations. eg. 5 watt resistors and transformers in SMPS’s.

Their principal use is to prevent solder joint cracking and thereby improving reliability of the PCB, especially in commercially wave soldered products.

The small diameter ones do work well as vias. There is usually no need to flare the second end if you solder the already flared end first.

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There are specialized tools for flaring PCB rivets. I never used PCB rivets myself, but I guess you can easily make such a tool by putting a centerpunch in a drillpress (don’t rotate the drill)

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Thank you all for the tips.
Also the rivets I can’t buy here, so back to the drawing table and go for an 1 layer pcb.

Cees.

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That (and inability to buy Chinese pcbs) seems like one heck of a restriction. Is there no other low cost place from which you can order pcbs? Maybe Mexico?

I think the unspoken technical issue is that your home-fabricated pcbs do not have plated-through holes. THAT is a real pain. When I worked at an employer which had a pcb mill (mechanical milling of the pcb) we put wires through the holes to interconnect layers. This often requires more board area, and it does not add strength to the mounting of any heavier through-hole components.

Even though USA and China are not having a love fest at the moment, I can order from JLCPCB to USA when I want to do so.

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It seems that it’s a more general question, how to use the top layer when you don’t have PTHs. Without access to rivets you would have to take advantage of THT components as PTHs and solder those on both pads. Naturally as you said some can’t like IC sockets. If your design isn’t complex maybe stick to 1 layer fabrication and a few jumpers, using the top Cu layer as a guide?

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Several answers to this one. Been there, done that back in the 90s.
1: think about it in your PCB design. Radial caps, relays etc. where you can’t get under them for soldring: revise your routing.
2: use sockets like PreciDip or other machined-pin types. Or even better: don’t use sockets.

Cheers.

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In 80s I was assembling 2 side PCBs without PTH. Our technology of making vias:

  • squeeze the tip of the silver wire tightly (to make it being flat) with flat pliers, approximately 0.7 mm length, and bend it at a 90° angle,
  • cut the wire about 5mm from the bend,
  • make lot such hooks,
  • place the PCB on the 4 matchboxes in the corners,
  • insert a hook wire in each via,
  • put a metal sheet on the PCB,
  • turn the PCB over with this sheet,
  • cut all standing wires at about 0.7mm height over PCB,
  • pressing with the tip of flat pliers, bend all the standing wires,
  • solder the wires at both sides making nice, round soles.
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I live in Indonesia, I made an account by JLC and some others, the ordering is no problem, but the Indonesian government raised the tax a lot for electronics.
I have to pay 40 Dollar extra per pcb !!!
Also AliExpress and others stopped sending to Indonesia because the high tax…

Thanks or the replay.
Cees

12

Back when I used to do such things, I would stand the hard-to-solder parts up off the board enough to get a fine-tipped iron under them. Also, I would use IC sockets that had a metal post at the bottom that I could solder to.

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I have done what you describe for many years using small wires or intentionally setting THTs as vias.

Whats more you can actually solder classic IC sockets from both sides if you chose the better ones with open pins and enlarge the pads (that s especially easy with KiCad). This means you have to carefully plan IC placing to reach the pins from all sides !

It is not a professional solution but for single circuits/prototyping it can be acceptable.

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In 80s Poland was a communist country. I could order locally only PCBs without plated holes.
But in 90s even we have just liberated ourselves from Russian domination the PCB manufacturers started to offer PCBs with PTH. I think they were not very far behind world technology.
I order PCBs only locally.
Don’t you have local manufacturers with reasonable (quality/price) offer?

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15

Years ago I used rivets for prototypes, but they are not as reliable as you might think. In the end, every rivet had soldered manually and PTH for THT was avoided.

My recommendation:

  • Keep your limitations in mind while the PCB design.
  • Use THT pins to connect both sied, if you can reach both sides when the componend is places.
  • Avoid connections on the assembly side if you can’t reach the pad when the componend is placed. Instead of this, place additional VIAs around the THT-Pad (see below).
  • Use SMD components, if possible.
  • Use a large annual rest ring for vias and put a wire through the hole. Solder the wire on both sides and then cut off the wire.
  • If you need a connection on both sides of a THT pad, you maybe enlarge the hole size and place one or more wire around the THT pad. Put a wire through the THT hole and then through the VIA hole and then solder the wire at the VIA hole. That avoides that you lose connection while soldering on the oder side.