Repair of pads on pcb, how to effectively leave tin on silicon.

I have a problem, so I would like to fix the PCB, namely the copper (I think) fields have broken off. Nevertheless, copper wires (paths) still lead to these fields.

If it wasn't for the fact that SMD elements are attached to these fields, I would use some glue with the addition of silver or something, and so I probably have to come up with something else. The fields are small, namely about 1mm per 1mm.

Ultimately, I want the entire field to be filled with tin and then solder the elements using hot-air. The problem, however, is that the tin does not really want to peel off the soldering iron tip and stick (total) to the silicon. There is a copper track at the corner of the field so the connection should be fine.

I plan to buy rosin tomorrow, maybe it will help. I was thinking about putting a piece of tin on this field and heating it with hot-air, but I'm afraid it won't do anything.

Can anyone advise on this? I tried using flux, but to no avail. Should I use some kind of agent or maybe some special tin? I am currently using SN60Pb40.
Has anyone had this problem and somehow managed to solve it?

Either the pad is cut out of a thin copper foil and glued to a high-temperature resin, or soldered to what is left ... It is normal that tin does not "stick" to silicon ...

Micchaleq wrote:

There is a copper track at the corner of the field so the connection should be fine.

It is not covered with a solder mask? The surface has probably oxidized. Take a needle or something very small and very gently scrape the surfaces (get rid of oxides on the surface). If you don't feel up to it, take it to someone who specializes in it.

Micchaleq wrote:

I have a problem, so I would like to fix the PCB, namely the copper (I think) fields have broken off. Nevertheless, copper wires (paths) still lead to these fields.

If it wasn't for the fact that SMD elements are attached to these fields, I would use some glue with the addition of silver or something, and so I probably have to come up with something else. The fields are small, namely about 1mm per 1mm.

Ultimately, I want the entire field to be filled with tin and then solder the elements using hot-air. The problem, however, is that the tin does not really want to peel off the soldering iron tip and stick (total) to the silicon. There is a copper track at the corner of the field so the connection should be fine.

I plan to buy rosin tomorrow, maybe it will help. I was thinking about putting a piece of tin on this field and heating it with hot-air, but I'm afraid it won't do anything.

Can anyone advise on this? I tried using flux, but to no avail. Should I use some kind of agent or maybe some special tin? I am currently using SN60Pb40.
Has anyone had this problem and somehow managed to solve it?

Hello,
As broken pads, I use a thin wire from, for example, a copper cable, from the broken path to the element that was supposed to be soldered to the pad, I solder such a wire, tinning it beforehand, sometimes I additionally strengthen such a wire with cyanoacrylate glue.

cpavlo wrote:

Hello,
As broken pads, I use a thin wire from, for example, a copper cable, from the broken path to the element that was supposed to be soldered to the pad, I solder such a wire, tinning it beforehand, sometimes I additionally strengthen such a wire with cyanoacrylate glue.

Thanks for the information, but I rather have to restore this field because, as I mentioned, I have to solder the SMD element there. Only I did not mention that the size is 0402 or 1005 (1mm by 0.5mm). The difficult thing is that I have several of these fields, and what's worse for this element, the fields on both sides have been broken ... I'll try some high-temperature glue and a piece of copper foil.

Micchaleq wrote:

cpavlo wrote:

Hello,
As broken pads, I use a thin wire from, for example, a copper cable, from the broken path to the element that was supposed to be soldered to the pad, I solder such a wire, tinning it beforehand, sometimes I additionally strengthen such a wire with cyanoacrylate glue.

Thanks for the information, but I rather have to restore this field because, as I mentioned, I have to solder the SMD element there. Only I did not mention that the size is 0402 or 1005 (1mm by 0.5mm). The difficult thing is that I have several of these fields, and what's worse for this element, the fields on both sides have been broken ... I'll try some high-temperature glue and a piece of copper foil.

I added such "wires" to the "ene" KBC Literally wires like human hair
First, I put the system as it should be, and then I soldered a wire to the pins of the system and then soldered the other end of the wire to the appropriate path, precise work. To make it easier, I slightly whitened the lead on the circuit with tin, the wires as well, so with tweezers it was enough to put the wire on the lead and touch it with a thin soldering iron tip for two seconds.
At the end, after the work, I checked with the meter set to the diode if there are transitions and if there are no short circuits....

The idea with the wires seems very cool. However, I have a problem with attaching this smd element because the device can be in motion, so I would like it to hold firmly, and I can't imagine it without soldering. When I solder it to the track, I get the impression that in case of any movements, the entire track will come off.

Micchaleq wrote:

The idea with the wires seems very cool. However, I have a problem with attaching this smd element because the device can be in motion, so I would like it to hold firmly, and I can't imagine it without soldering. When I solder it to the track, I get the impression that in case of any movements, the entire track will come off.

In such cases, these "wires" can be flooded with cyanoacrylate glue, I did so and everything was stiff and held quite firmly, the downside of this is (I know from my own experience) that if something goes wrong, it is difficult to wash off the cyanoacrylate glue, but I have a way already, in the form of acetone, but you have to be careful not to wash too much, for example, inscriptions....

I would solder this SMD element to the track that sticks to the laminate (it is not silicon by any means!). Maybe you're heating too much that the paths go away??
And connect the second lead with a wire. The wire and the element "glue" with some varnish as it is supposed to be in motion, although without it, if the path holds well, it should be fine.

Thanks for any comments.

So to speak, I have already received such an element, so I am not the cause of their lack. My job is to restore them somehow, and I won't rest until I do.
Yesterday I managed to cut out the appropriate element from copper foil, which I had previously tinned on one side and glued on some tesa glue (instant). Nevertheless, as soon as I touched this field with a hot tip, it peeled off.

I need these pads so that they can be used again, for example, when the element that is soldered to them burns. Therefore, it needs a solution that will last longer and not just for art.

It looks cool in this video: https://www.youtube.com/watch?v=dwrnWasLYUc but I'm very curious what kind of binder it is. It's about that transparent foil that goes under the pad later. It looks like some kind of heat activated glue.

I watched these high temperature resins but they cost over PLN 200 for large bottles and I need something 1-2g (certainly not more).
Can anyone tell me what this binder is and possibly how to look for it?

I have the pad itself and the kapon tape and sticking the pad on the tape is very simple and it is easier to fold it later. I just don't have a binder solution yet.

Micchaleq wrote:

It looks cool in this video: https://www.youtube.com/watch?v=dwrnWasLYUc but I'm very curious what kind of binder it is. It's about that transparent foil that goes under the pad later. It looks like some kind of heat activated glue.

Title, description plus in the film itself there is an explanation of "what is it" - search under the name "dry film"

Thanks for the info, I thought it was about something else.
I understand that this is some kind of dry film (I assume photographic).
Can anyone give me more guidance on how to look for such foil and what it is called exactly in Polish?

Also, has anyone tried this method? Will the use of this under the pad withstand further processing, i.e. soldering the element etc? Is it better to give it a rest and get interested in some resin?

I found something else like OCA glue? Isn't it just the same?

Micchaleq wrote:

I understand that this is some kind of dry film (I assume photographic).

No photographic film (Where did this idea come from?). This is laminate film.

Micchaleq wrote:

Also, has anyone tried this method? Will the use of this under the pad withstand further processing, i.e. soldering the element etc? Is it better to give it a rest and get interested in some resin?

You will glue the pad to the laminate. You'll solder to it (provided you don't overheat).

In general, I ordered this foil, but it is probably more for PCB lamination than ordinary lamination.
I found it on the website under the heading "photosensitive film". Besides, I also ordered this CW2500. I'm just wondering if the CW2500 alone is enough or do you need to buy the CW3300 for it? It seems to me that this whole pen only adds color (although I'm not sure).

Micchaleq wrote:

I found it on the website under the heading "photosensitive film".

You don't solder anything to the photosensitive foil.
The simplest solution is to glue the element and solder thin wires from the element to the tracks.
You can also try conductive paint, e.g. SUCH You can also look for conductive paste used in screen printing

It's not about soldering something to the foil, it's about using it as a binder connecting the pcb board with a piece of copper foil (specifically, the element cut out of it). Summing up, I concluded from the film that they put the foil under the pad and then they weld it.

In general, I'm going to test both options and if I manage to solve my problem with one of them, I will share and close the topic.

Micchaleq wrote:

only to use it as a binder connecting the pcb board with a piece of copper foil

I, on the other hand, have the impression that this polyamide was used as a mask to apply glue in the right place.

kj1 wrote:

Micchaleq wrote:

only to use it as a binder connecting the pcb board with a piece of copper foil

I, on the other hand, have the impression that this polyamide was used as a mask to apply glue in the right place.

For a moment, I thought that copper pads were applied to this foil (in a chemical process), just like home-made tiles. Nevertheless, in the film I quoted, there are words that, in my opinion, suggest that they put the foil underneath and weld it. I'm not sure so I'll check it out.

To sum up, for me, the foil will only serve as a binder between the plate and the copper foil.

On the other hand, it would be easier for a piece of foil to be covered with copper and then, after cutting, to weld only this foil to the pcb board. Nevertheless, I read somewhere that this is not the best solution.

My comment is for this video: https://youtube.com/watch?v=vx50YtEC2S8
There it is clearly visible that it is a mask.
This second video actually shows as if the pad was glued through the foil. But the foil is on top.

The foil is just a binder. A pad is applied to the foil, a polyimide tape is glued and heated. It can be an ordinary laminating foil or a photoresist (it's a waste of money for it).