Anaerobic conductive epoxy?

There are plenty of two-pack epoxies, but conductive ones are usually quite expensive. Just HOW conductive do you need ?

Steve

Don,

Conductive 2-pack epoxies should cure fully even in the absence of air.

Are you using a solvented epoxy? Many flooring system would have solvents added to assist flow - it could be this that is failing to evaporate.

Also you will need to have an idea of the level of conductivity you require; carbon loaded materials tend to be low conductivity but reasonably cheap, whereas high conductivity materials - often loaded with silver, tin, nickel etc - can be astronomically, eye-wateringly, expensive.

Rgds,

Simon

Well, that's what I thought too. It seemed to me that mixing the two components of an epoxy is precisely what would make it anaerobic. If it uses air to dry, why would you need a second component?

This stuff I used is two-part (though, as you mentioned, maybe just to assist flow). It's called StatCrete and comes as a gallon bucket of gray component coupled with a little 16 oz. bottle of "catalyst", which is a clear liquid. The term "catalyst" indicates to me that it might be a hardener, but it sure didn't do much hardening without air. The part between the sheets has been there for several months and is still rubbery and doesn't conduct. The exposed part is hard as a rock and conducts fine.

Here's a spec:

And, yes, I just need the semi-conductive type with graphite. Does anyone know of another source for something better that isn't water-based?

Don

See RS Components Part# 186-3616 "Silver Loaded Epoxy Adhesive" and RS 496-265 "Circuit Works® Conductive Epoxy"

Both perform to your requirements.

Anaerobics are single-component acrylics and not epoxies. There is a huge difference : the 1st ones hardens through a free-radical process, while the latter crossling by slower step-growth polymerization. The free-radical polymerization process is initiated by oxydo-reduction, UV or electron beam photopolymerization, just to mention a few. Anaerobics are often used to bond metallic parts because acids contained in the adhesive attack the substrates and create the ions necessary to start the redox reaction. Once the reaction starts, peroxide or hydroperoxide are decomposed into free radicals which starts the free radical polymerization. Problem : if you add metallic filler to get conductive adhesive, you destabilize it and probably won't be stable in bulk, even though you add inhibitors. As I worked on that type of adhesives, a few years ago, I didn't remember of any of our competitors buying conductive anaerobics. Maybe you can ask Loctite, who is the leader in that field, or companies such as Chemence, or Three Bond, which are very serious. But I remember lots of companies selling conductive epoxies that worked well, maybe the abovementionned companies. Take two-component epoxies and you probably won't be disturbed by anaerobic conditions, entrapment. Hope this helps. If you need any further help, don't hesitate to contact me. Nicolas DELFAU Peintures SOB FRANCE Tel : (+33)5.65.38.60.20 snipped-for-privacy@wanadoo.fr

"eromlignod" a écrit dans le message de news: snipped-for-privacy@f14g2000cwb.googlegroups.com...

Maybe also can you post on sci.polymers newsgroup.

In my company (aerospace) we use EC2214 as a structural adhesive. We add silver plated copper beads (1-2 mils diameter) to the epoxy while mixing, and end up with a conductive adhesive that will maintain 250milliohms across a bonded joint of 2 aluminum sheets.