PCB trace repair - super glue, hot glue ?

Thread Starter

DarthVolta

Joined Jan 27, 2015
447
Until I get a trace repair kit or whatever, with epoxy, I have an old board here with some traces I ripped up, removing a chip. If heat is not an issue either in repair or operation, is there anything wrong with just plain super glue or hot-glue? I already have that.

I learned that to get really fine wire for traces, just un-strand some fine wire. Last time I tried this repair, I was using cheap flux, cheap iron, and 30-some odd gauge wire, and I failed.
 

Papabravo

Joined Feb 24, 2006
13,712
If they are cyanoacrylates you could be exposed to dangerous fumes. Anything sounding like cyanide would scare me without more reliable information. Find it, read it, and pay attention
 

Thread Starter

DarthVolta

Joined Jan 27, 2015
447
For the traces, I figured I'd try the tiniest bit, just paint it underneath, not like a conformal coating. I'm not used to super glue at all tho, I hope iso-alcohol will clean the mess I might make,m and not react and do anything bad.
 
Heat typically de-bonds Superglue and the process gives off nasty fumes. Epoxy has a much better chance in working. Tinned wire has a better chance than copper.

Kynar insulated wire wrap wire is a choice. Tinned buss bar wire and teflon sleaveing better and easier to work with.

You need to watch out for multilayer boards and plated through holes.

Don't forget to remove the solder mask.

Some pretty decent repairs can be made with epoxy including chips and chunks missing.

Then there is copper and tinned copper shielding tape. The adhesive may not be conductive.
 

jpanhalt

Joined Jan 18, 2008
9,389
Cyanoacrylics (CA's) do not release cyanide at the sort of temperatures to which they will be exposed. They are in fact used for tissue glues and have relatively low toxicity. Under pyrolysis conditions (e.g., burning), a lot of things without cyanide in the name produce cyanide. The biggest problem with CA's is that they are not very heat stable and under soldering temperatures, they decompose and/or depolymerize back to the monomers. In fact, that is how they can be made.

I find their heat instability to be an advantage when assembling SMD's on a PCB. A micro spot of CA will hold a component well enough to get it soldered. But if the component needs to be removed, it will come off easily. It is also used commercially as in the manufacture of PCB's with components on both sides.

If you try it, you may find that it sets up much more slowly on copper/PCB than when gluing other materials (like balsa wood) together. Polymerization of CA's is catalyzed by bases (Lewis type). You can use hardener available in most hobby supply stores. A very inexpensive substitute is to rub a little baking soda on one of the parts to be joined. Add the adhesive to the other part and press together. You do not need a visible amount of baking soda residue. You are just treating the surface. So, wipe on, wipe off. Household ammonia may also work, but I haven't tried that intentionally.
 

dl324

Joined Mar 30, 2015
10,722
Pictures would be helpful.

Have you considered point to point wiring and using hot glue to secure the wire if it's too long to lay flat? That's how HP used to repair PCBs in the HP3000 computer. They allowed up to a half dozen or so jumpers before the board had to be scrapped.
 

Audioguru again

Joined Oct 21, 2019
1,473
You are learning that a cheap soldering iron has no control of its temperature, so sitting there it gets way too hot and destroys a pcb. Also its tip does not last long.
Then you will learn that its very high temperature incinerates the important cleaning rosin in solder making poor solder joints.
Then you will learn that it gets too cool if you use it which causes bad "cold" solder joints.

My Weller temperature controlled soldering iron is about 55 years old and still works perfectly. It is still made today. It does not use a cheap light dimmer circuit like many new soldering irons use for poor control. Mine is always at the correct temperature with nothing to fiddle with.

Then you will learn to use a solder sucker. It slurps away melted solder making parts easy to remove. Mine has a plunger to set it and a trigger button to activate it. A cheap soldering iron will also quickly destroy it.
 

Thread Starter

DarthVolta

Joined Jan 27, 2015
447
Pictures would be helpful.

Have you considered point to point wiring and using hot glue to secure the wire if it's too long to lay flat? That's how HP used to repair PCBs in the HP3000 computer. They allowed up to a half dozen or so jumpers before the board had to be scrapped.
My microscope can take pic's but I need a little flash card. Well I have to remove a few things and do it right this time, so I could try point to point.

But I think if I cleared the area, and with blue-tak, or hot glue, I should do better. I have good flux and soldering iron this time too.

But next month, I want to get the real expoxy or glue that they use for repair, and for gluing parts down 1st.
 
Top