I don't think I've ever seen conductive putty. Closest thing I can think of is conductive paint.

edited to add:

It looks like MG Chemicals has a conductive paste and conductive grease:

https://mgchemicals.com/products/grease-for-e … nductive-paste/
https://mgchemicals.com/products/grease-for-e … contact-grease/

Nexxen wrote on 2024-11-25, 15:11:

Or maybe how to do some? Adding some modelling paste to graphite powder?

Best guess, not all that wild as I am considering material properties here, bentonite clay (commonly available as generic kitty litter or spill absorbent), graphene rather than graphite, due to it's form being more compatible with the microstructures of clay, and castor oil, because it's non-drying and a plasticiser, precursor of some epoxies for example.

Graphene can be produced from graphite powder with a kitchen blender and dish soap, see examples on youtube.

Guess at proportions, the bentonite will bulk up a lot as it absorbs the castor oil, so probably need a much lesser quantity of it than the graphene, would spitball at 1/3 to 1/4 as a good starting point vs the amount of graphene.

Mix dry ingredients then mix in castor oil until it's doughy. Possibly it even conducts. Remember that anything like this, the paint mentioned included, generally has a measurable resistance for small lengths/depths of it, so you're probably adding a minimum half ohm every joint..... and it's not gonna be the thing to roll a sausage out of to replace a trace that goes right across the board.

Shponglefan wrote on 2024-11-25, 15:41:

I don't think I've ever seen conductive putty. Closest thing I can think of is conductive paint. […]
Show full quote

I don't think I've ever seen conductive putty. Closest thing I can think of is conductive paint.

edited to add:

It looks like MG Chemicals has a conductive paste and conductive grease:

https://mgchemicals.com/products/grease-for-e … nductive-paste/
https://mgchemicals.com/products/grease-for-e … contact-grease/

Viscosity is high, not really what I'm looking for, it could easily create a short.
Playdough like is my target.

Still interesting products.
thanks

BitWrangler wrote on 2024-11-25, 16:32:

Best guess, not all that wild as I am considering material properties here, bentonite clay (commonly available as generic kitty […]
Show full quote

Nexxen wrote on 2024-11-25, 15:11:

Or maybe how to do some? Adding some modelling paste to graphite powder?

Best guess, not all that wild as I am considering material properties here, bentonite clay (commonly available as generic kitty litter or spill absorbent), graphene rather than graphite, due to it's form being more compatible with the microstructures of clay, and castor oil, because it's non-drying and a plasticiser, precursor of some epoxies for example.

Graphene can be produced from graphite powder with a kitchen blender and dish soap, see examples on youtube.

Guess at proportions, the bentonite will bulk up a lot as it absorbs the castor oil, so probably need a much lesser quantity of it than the graphene, would spitball at 1/3 to 1/4 as a good starting point vs the amount of graphene.

Mix dry ingredients then mix in castor oil until it's doughy. Possibly it even conducts. Remember that anything like this, the paint mentioned included, generally has a measurable resistance for small lengths/depths of it, so you're probably adding a minimum half ohm every joint..... and it's not gonna be the thing to roll a sausage out of to replace a trace that goes right across the board.

Ok, I'll look into it. This is interesting.

What if I added graphene to existing playdough-like substance?

Could do, though I think it will be no different than using graphite in that sitch, I think it will not take all that much before it goes all crumbly.

Natural clays are a bit like a bunch of plates sliding over each other, if you add stuff that's not all that different, like graphene is sheets of paper, thinner but flat, it might behave mostly the same still until you get quite a bit in there, whereas if you add golf balls, not so much.

Actual playdoh, I think we're talking starch molecules, so a form of carbon that's more like starch molecules would work best.

I have heard that excellent conductive paints and inks can be made with carbon black and acrylic laquer base, so if going to polymer clays then carbon black might be the thing.

Edit: By the way, I should mention I guess that carbon black, obtained as soot from a generic paraffin wax candle, is the sort of the middle of the road hodgepodge of particle shapes, like emptying out a kids shape sorter, or box of classic wooden building blocks with the rounds and arches etc. It's got flakes of graphene, nanotubes, possibly the odd small or partial buckyball, and so on.... meaning that one shape will not dominate the mixture, where one is round, another will not roll, where one is smooth, another will be snaggy, so will not in general ruin the properties of what you mix it in for reasonable amounts. Unless we get chemical instead of physical. (Something that reacts with carbon)

For some reason, I thought of this thread when I saw...

https://x.com/pjf/status/1071269714830098434?lang=en

I have no clue how long that would work before all the ions depleted though.

BitWrangler wrote on 2024-12-03, 21:10:

For some reason, I thought of this thread when I saw...

https://x.com/pjf/status/1071269714830098434?lang=en

I have no clue how long that would work before all the ions depleted though.

Collaborative effort, on a whole new level mate (or is it "maait"?). 🤣
No joke, it has the right viscosity and sticks superbly.

Makes vegemite even "legendarier".

Have G'day!

If you want easily removable chips, and sockets aren't an option, low melt solder might be the best existing solution.

It melts easily, and stays melted at a very low temperature.

Wouldn't even need to wick it. Just melt and press.

myne wrote on 2024-12-03, 23:17:

If you want easily removable chips, and sockets aren't an option, low melt solder might be the best existing solution.

It melts easily, and stays melted at a very low temperature.

Wouldn't even need to wick it. Just melt and press.

I'm trying to avoid soldering as much as I can.
In fact I need to test chips but also check for continuity of the traces that go underneath. It's a shayity situation on a specific board.

Basically it's an elaborate exercise to prove a point. The board isn't important at all, but I still want to learn through it.

Wonky ideas are still free, unless not. 😀

Surely there's a zif

myne wrote on 2024-12-04, 01:42:

Surely there's a zif

It's an old 286 board.
I need to test and probe both continuity and activity. If I have to remove several times the same chips to replace and retest, it'll take me an awful amount of time.

https://www.digikey.com.au/en/product-highlig … zip-dip-sockets

If you're unsure what a zif is

myne wrote on 2024-12-04, 02:13:

https://www.digikey.com.au/en/product-highlig … zip-dip-sockets

If you're unsure what a zif is

I know what it is 😉
But not giving me what I need. It's a long and boring project.

Back to putty.
I'll try it later this month, probably with soft paste of some sorts.

The only thing that makes me interested is that the board is one of those super compact designs.

Liquid metal is the next suggestion.
I wouldn't recommend it, but maybe if you tape it off well enough...

myne wrote on 2024-12-04, 15:35:

Liquid metal is the next suggestion.
I wouldn't recommend it, but maybe if you tape it off well enough...

That would be great, but, as you know, it just spills everywhere.
And if I tape it consider it already on the "short circuit stories" thread 🤣

This is why it's on "long" projects list.

My belief is a multiplexer not getting activated, but finding it is difficult.
I'm also thinking if just replacing everything could be a better and faster solution. But I still want to learn something out of it.

Collector's stubborness I guess. 😀

If you could make a suitable form to match the chip footprint, maybe you could use a zebra-strip type connector on the edge of the form?
The difficult thing would be to be able to keep the z-strip in good contact, maybe using some putty in the middle between pcb & chip?

Are those zebra strips what you call that rubber strip used for connecting LCD assemblies to board sometimes?

Anyway, had another thought, the goop out of "chest electrodes" the things they put on you for an EEG or similar measurement of nerve impulses.

Yes, the zebra strips are normally used with LCD displays. They can be compressed a bit, but can be difficult to repair...in this case it's not a permanent connection. Still, it can depend on the pin alignment on the chip if they are suitable.