PCB repair: Super glue and baking soda?

[Intripped]

Trying to figure out if this is a good glueing/recostructing material.
It certainly looks promising but I'm not sure about its electrical insulation characteristics, dealing with hi-voltage tube amps.

Does anyone here have already used it or know something more?
Thanks.

[Chuck H]

So are you attempting structural repairs? As far as I know niether baking soda or CA glue is conductive. I'm not a chemist but I don't figure combining them to make a difference in that regard. As to insulation, if it's not conductive and forces a gap then it'll probably be fine. I'd be more concerned about structural stability. I would think think the CA/BS paste is going to be a good bit less flexible than most circuit board materials. I don't know your circumstances. I'd be inclined to just cut away any charred or conductive board material and either handwire across/around the problem or add/install a small board to carry components in that location. Flying leads as needed.

JM2c

[The Dude]

......I'd be inclined to just cut away any charred or conductive board material and either handwire across/around the problem......

^^^^^^That.

[Greg Robinson]

Epoxy is the standard repair adhesive for typical PCB's, which are made of FR4 epoxy fiberglass.

[glebert]

I wouldn't do it. Baking soda in solution is conductive. I would be concerned with some traces of unreacted baking soda getting encapsulated and then absorbing moisture.

Here is a thread I found of a model builder who described CA+baking soda failing after several decades. I would want my repairs to last longer than that.
https://www.modelcarsmag.com/forums/...d-baking-soda/

CA + baking soda is great to fill overcut guitar nuts, though. Maybe for something like a cracked knob or whatnot.

[Chuck H]

I wouldn't do it. Baking soda in solution is conductive. I would be concerned with some traces of unreacted baking soda getting encapsulated and then absorbing moisture.

Ah!! Chemical salts from reaction. Baking soda is a base (as opposed to acid) so it's reactive. And saline solutions are semiconductive. Good catch. Great report and thank you.

[Jon Snell]

What's wrong with epoxy resin?
Non conductive and strong.

[tedmich]

I'd be hesitant to use CA/bicarb in HV applications, while cyanoacrylate is used in low voltage circuits often.

Like most plastics, solidified CA is an excellent dielectric, and the catalytic/structural sodium bicarb shouldnt conduct very well, but a nice inert epoxy would probably be a better choice for PCB repair IMO.

[Mick Bailey]

+1 on epoxy. I've used this for decades without problems, though if it's a high temperature area you have to consider that regular epoxies have a fairly low temperature limit and choose something more specific.

As far as baking soda and superglue go, I've never seen any tests of how it holds up under the voltages found in tube amps. Given that Marshall and Blackstar amps had problems with conductive boards in HT areas even with glass fibre boards, I'd want certainty that the time and effort put into a board repair wasn't going to be a problem later on.

[Delta362]

I haven't repaired cracks in boards, but have used the Dremel to cut out any carbon impregnated from a thermal event. Then I fill it with an MG Chemicals Overcoat Pen.

[Tom Phillips]

For the times that I have needed to dremel out small areas of carbonized PCB, I have just left the resulting open hole when the location doesn't need to support components or traces. I actually think it looks fine and certainly performs well. No one has ever complained. Just my method - not a criticism of work done by others.

[Intripped]

Thanks to everyone for the interesting posts.
(... i've reconsidered the idea of using superglue+baking soda for PCB repairs!)