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I have two problems where I have a small area to make a connection on a material that is unsolderable.

The first material that I need to solder on is annodized aluminum, on a 5mm x 3mm x 2 mm rectangular prism. Yes, you can solder on annodized aluminum, but it is not ideal. It seems like the connections break very easily, at least using standard solder and soldering irons.

The second material that I need to solder on is conductive plastic. Conductive plastic cannot be soldered on. Again, I have about 5 mm of space to work with.

I have tried wire glue, but, if I decide to get my product manufactured in China, will they want to use wire glue to attach to my product? Is this the best option? It seems very unprofessional, and a lot could go wrong (connections breaking, glue not being stirred enough prior to application, conductivity drying out over time (i.e. after a test procedure)).

What I would really like is something small, and clamping, almost like 5 mm aligator clips. Or, even a small, solderable paper clip.

What weapon am I missing in my arsenal?

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  • \$\begingroup\$ Can you drill a hole in it? A very small hole? Because a bolt with a screw terminal would be pretty robust even if it's an M2/M1.6/M1.4 machine screw \$\endgroup\$
    – uint128_t
    Commented Jun 18, 2018 at 17:17
  • \$\begingroup\$ How will you specify performance and verify it? Conductivity ? EMI performance , Static dissipative range ? Pull strength ? Surface area of contact and capacitance and resistivity of bond will greatly affect performance <10M \$\endgroup\$
    – D.A.S.
    Commented Jun 18, 2018 at 19:58
  • \$\begingroup\$ "if I decide to get my product manufactured in China, will they want to use wire glue to attach to my product?" - They better do what you tell them to, or you don't pay them. That's how business is supposed to work. Of course, the Chinese are notorious for letting quality slip and making unannounced process changes, so if you go that route you will need to provide detailed specifications of what YOU want - and then aggressively inspect the finished product and reject bad components. Both Gold's Rule and Caveat Emptor apply. \$\endgroup\$
    – WhatRoughBeast
    Commented Jun 18, 2018 at 21:18

1 Answer 1

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You can get conductive epoxy (contains silver, silver coated copper, or silver coated nickel) that would bond nicely to the anodized aluminum and to the plastic. It is a bit expensive but you sound like you don't need much per assembly. They come as one part and two part mixtures. Two parts cure faster although an oven typically helps speed things up for either kind.

Examples:

  • MG Chemicals 8331
  • Ablestik 56C
  • Master Bond EP77M-F
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  • \$\begingroup\$ It seems really difficult to mix two parts and still use something with a nozzle for application. I just want like a gorilla glue nozzle superglue that is also conductive (since it is such a small contact area, using something that needs to be mixed is not ideal). So many materials and researchers dedicated to this industry. Don't understand why this is so hard to find... the universe i guess \$\endgroup\$
    – Kevin Mauro
    Commented Jun 19, 2018 at 22:42
  • \$\begingroup\$ Am i overestimating the amount of mixing needed for these two part epoxies? If i just apply them one after the other, is that enough mixing you think? \$\endgroup\$
    – Kevin Mauro
    Commented Jun 19, 2018 at 22:54
  • \$\begingroup\$ Typically what I've seen for the two part epoxies and really any two part substance like it is the tech mix the two with a wooden dowel then put it in a vacuum chamber to suck out any air bubbles but I think that's optional. Then theox goes into a syringe that has an air compressor hooked up to it so by using a foot pedal, they can apply it. If you do all of your gluing in one sitting, they should mix it and put it in something like a luer syringe and go at it. The stuff needs to be well mixed because one part is the curing agent so if you just apply it in layers the epoxy isn't going to stick \$\endgroup\$
    – moftz
    Commented Jun 22, 2018 at 1:13

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