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epoxy instead of solder?
Has anyone tried Masterbonds conductive epoxy for attaching SMT
components to a printed circuit board? Seems like a great idea, especially if it works well:: T |
On Wed, 05 Oct 2005 16:10:40 -0400, TRABEM wrote:
Has anyone tried Masterbonds conductive epoxy for attaching SMT components to a printed circuit board? Seems like a great idea, especially if it works well:: --- Aside from the resistivity of the epoxy, the largest problem I see is throughput. That is, where are you going to store all those boards while the epoxy is curing? Plus, it makes it really messy for the salvagers/recyclers. -- John Fields Professional Circuit Designer |
Hello John,
Aside from the resistivity of the epoxy, the largest problem I see is throughput. That is, where are you going to store all those boards while the epoxy is curing? Then there is the stench that most epoxies let off. Mostly of the not so healthy kind. Regards, Joerg http://www.analogconsultants.com |
In article , TRABEM
says... Has anyone tried Masterbonds conductive epoxy for attaching SMT components to a printed circuit board? Seems like a great idea, especially if it works well:: Not really. Consider the angle of serviceability. It's easy enough to use a 'HoTweezer' station to replace a bad chip component secured with solder. It's darn near impossible to replace the same component if secured with Epoxy. Also, I'm not convinced that "conductive" Epoxy really is. I'd want to see some real numbers on resistance per cm/squared on the stuff before I even consider it for any sort of repair work. Any job worth doing is worth doing right. If you're trying to attach surface-mount components, invest in the proper soldering/desoldering equipment instead of looking for impractical shortcuts. It may cost more at the get-go, but it'll cost a lot less in the long run. Keep the peace(es). -- Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute. (Known to some as Bruce Lane, ARS KC7GR, kyrrin (a/t) bluefeathertech[d=o=t]calm -- www.bluefeathertech.com "If Salvador Dali had owned a computer, would it have been equipped with surreal ports?" |
John Fields wrote:
On Wed, 05 Oct 2005 16:10:40 -0400, TRABEM wrote: Has anyone tried Masterbonds conductive epoxy for attaching SMT components to a printed circuit board? Seems like a great idea, especially if it works well:: --- Aside from the resistivity of the epoxy, the largest problem I see is throughput. That is, where are you going to store all those boards while the epoxy is curing? Plus, it makes it really messy for the salvagers/recyclers. I do not know about Masterbonds conductive epoxy(ies), but i have used silver conductive epoxy. 1) EXPENSIVE, 2) good for short-term and medium-term repair, but no where as reliable as a solder connection. |
Dr. Anton T. Squeegee wrote:
In article , TRABEM says... Has anyone tried Masterbonds conductive epoxy for attaching SMT components to a printed circuit board? Seems like a great idea, especially if it works well:: Not really. Consider the angle of serviceability. It's easy enough to use a 'HoTweezer' station to replace a bad chip component secured with solder. It's darn near impossible to replace the same component if secured with Epoxy. Also, I'm not convinced that "conductive" Epoxy really is. I'd want to see some real numbers on resistance per cm/squared on the stuff before I even consider it for any sort of repair work. Any job worth doing is worth doing right. If you're trying to attach surface-mount components, invest in the proper soldering/desoldering equipment instead of looking for impractical shortcuts. It may cost more at the get-go, but it'll cost a lot less in the long run. Keep the peace(es). The silver conductive epoxy is extremely conductive, and even tho i never measuresd the resistivity, i would wager that it is better than copper if used properly. |
Robert Baer wrote:
The silver conductive epoxy is extremely conductive, and even tho i never measuresd the resistivity, i would wager that it is better than copper if used properly. Here are some examples of silver epoxies: http://news.thomasnet.com/fullstory/460221 10^-3 ohm cm http://www.mgchemicals.com/products/8331.html 2*10^-2 ohm cm http://bondline.net/datasheets/2072.pdf 4*10^-4 ohm cm http://bondline.net/datasheets/2080.pdf 5*10^-3 ohm cm http://bondline.net/datasheets/2111.pdf 2*10^-4 ohm cm http://bondline.net/datasheets/2120.pdf 5*10^-3 ohm cm Copper: http://www.lehighton.com/AppNotes/Cu...llization.html 1.68*10^-6 ohm cm According to these sources, copper is about 100 to 10,000 times as conductive as silver filled epoxy. |
Has anyone tried Masterbonds conductive epoxy for
attaching SMT components to a printed circuit board? Seems like a great idea, especially if it works well:: Sounds like a terrible idea. The surface tension of solder and the solder mask/PCB landing on the circuit board interact very nicely to make sure that a blob of solder and the part itself stays on exactly the right spot when you solder on a SMT component (either hand soldering or toaster-oven style). None of that is working to your advantage when you use epoxy. Hand-soldering even fine-pitch (0.5mm) SMT stuff is not a big deal to do by hand with even primitive (e.g. just a weller soldering iron and a fine-tip point and some solder wick) tools. BGA's will require a toaster oven though :-). Tim. |
It is done in special circumstances, but not that often. SMT passives
are available with different termination platings/coatings for such an application, but they are harder to come by. It won't work as well if you use devices with terminations intended for soldering. |
The 3M conductive adhesives like the 9703 work well. Not sure how they do it
but it conducts in the Z axis ( thru the adhesive ) but not accross the surface direction ( X & Y axis ). It's a pressure sensitive transfer adhesive ( tape that you stick on then peel off the paper carrier leaving the adhesive behind) X-Y axis Insulation Resistance = 3.4 x 10 to the 14th Ohms/square Z axis Contact Resistance = 1.25 milliOhm-in2 Pretty neat stuff! Ron H. x-- 100 Proof News - http://www.100ProofNews.com x-- 30+ Days Binary Retention with High Completion x-- Access to over 1.9 Terabytes per Day - $8.95/Month x-- UNLIMITED DOWNLOAD |
Robert Baer wrote: The silver conductive epoxy is extremely conductive, and even tho i never measuresd the resistivity, i would wager that it is better than copper if used properly. Just another point of reference. From: http://www.efunda.com/materials/solders/tin_lead.cfm Eutectic tin lead solder has a conductivity of about 1.44*10^-5 ohm cm, or 8.5 times that of copper. |
Ron H wrote:
The 3M conductive adhesives like the 9703 work well. Not sure how they do it but it conducts in the Z axis ( thru the adhesive ) but not accross the surface direction ( X & Y axis ). It's a pressure sensitive transfer adhesive ( tape that you stick on then peel off the paper carrier leaving the adhesive behind) I have a roll of that. Very pricey. It contains lots of short bits of very fine copper wire precisely aligned through the thickness of the adhesive gel. The wires do not contact each other, so there is no conductive path along the gel. X-Y axis Insulation Resistance = 3.4 x 10 to the 14th Ohms/square Z axis Contact Resistance = 1.25 milliOhm-in2 Pretty neat stuff! Definitely. Sort of the dual of enameled wire. Conducts only at right angles to the length. |
On Thu, 6 Oct 2005 19:35:36 -0500, "Ron H" wrote:
The 3M conductive adhesives like the 9703 work well. Not sure how they do it but it conducts in the Z axis ( thru the adhesive ) but not accross the surface direction ( X & Y axis ). It's a pressure sensitive transfer adhesive ( tape that you stick on then peel off the paper carrier leaving the adhesive behind) X-Y axis Insulation Resistance = 3.4 x 10 to the 14th Ohms/square Z axis Contact Resistance = 1.25 milliOhm-in2 Pretty neat stuff! Ron H. Sounds VERY interesting! I have some clients that need to mount components that can't stand the heat of soldering. The only problem might be "tenacity"... how much "shake, rattle and roll" can it take? ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
Jim Thompson wrote:
On Thu, 6 Oct 2005 19:35:36 -0500, "Ron H" wrote: The 3M conductive adhesives like the 9703 work well. Not sure how they do it but it conducts in the Z axis ( thru the adhesive ) but not accross the surface direction ( X & Y axis ). It's a pressure sensitive transfer adhesive ( tape that you stick on then peel off the paper carrier leaving the adhesive behind) X-Y axis Insulation Resistance = 3.4 x 10 to the 14th Ohms/square Z axis Contact Resistance = 1.25 milliOhm-in2 Pretty neat stuff! Ron H. Sounds VERY interesting! I have some clients that need to mount components that can't stand the heat of soldering. The only problem might be "tenacity"... how much "shake, rattle and roll" can it take? Its glorifies scotch tape: http://multimedia.mmm.com/mws/mediaw...4spSxgrOkF W- |
Just go to 3m.com and search for "conductive adhesive" or "9703"
"Jim Thompson" wrote in message ... On Thu, 6 Oct 2005 19:35:36 -0500, "Ron H" wrote: The 3M conductive adhesives like the 9703 work well. Not sure how they do it but it conducts in the Z axis ( thru the adhesive ) but not accross the surface direction ( X & Y axis ). It's a pressure sensitive transfer adhesive ( tape that you stick on then peel off the paper carrier leaving the adhesive behind) X-Y axis Insulation Resistance = 3.4 x 10 to the 14th Ohms/square Z axis Contact Resistance = 1.25 milliOhm-in2 Pretty neat stuff! Ron H. Sounds VERY interesting! I have some clients that need to mount components that can't stand the heat of soldering. The only problem might be "tenacity"... how much "shake, rattle and roll" can it take? ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. x-- 100 Proof News - http://www.100ProofNews.com x-- 30+ Days Binary Retention with High Completion x-- Access to over 1.9 Terabytes per Day - $8.95/Month x-- UNLIMITED DOWNLOAD |
On Thu, 06 Oct 2005 19:28:54 -0700, Jim Thompson
wrote: On Thu, 6 Oct 2005 19:35:36 -0500, "Ron H" wrote: The 3M conductive adhesives like the 9703 work well. Not sure how they do it but it conducts in the Z axis ( thru the adhesive ) but not accross the surface direction ( X & Y axis ). It's a pressure sensitive transfer adhesive ( tape that you stick on then peel off the paper carrier leaving the adhesive behind) X-Y axis Insulation Resistance = 3.4 x 10 to the 14th Ohms/square Z axis Contact Resistance = 1.25 milliOhm-in2 Pretty neat stuff! Ron H. Sounds VERY interesting! I have some clients that need to mount components that can't stand the heat of soldering. The only problem might be "tenacity"... how much "shake, rattle and roll" can it take? ...Jim Thompson Conductive adhesives have been discussed in Advanced Packaging magazine (IIRC, might have been another trade mag) and the main problems preventing widespread replacement of solder are not adhesion but high initial resistance (not suitable for the current required by large processors etc), and worse, gradual increase in resistance over time especially at higher temperatures and humidities due to slow oxidation of the conductors as water vapor and oxygen diffuse through the adhesive polymers. Not ready for prime time now, and might not be for a long time due to the lack of candidate impermeable adhesive polymers. Suitable now for low power apps in benign envireonments where long life is not important. |
John Woodgate wrote:
I read in sci.electronics.design that wrote: Just another point of reference. From: http://www.efunda.com/materials/solders/tin_lead.cfm Eutectic tin lead solder has a conductivity of about 1.44*10^-5 ohm cm, or 8.5 times that of copper. resistivity, not conductivity. Thank you. |
On 6 Oct 2005 09:59:53 -0700, "w2aew" wrote:
Wow, Despite the less than stellar support for the concept, I'm going to go ahead and try it anyway. I found a company in CA that makes 2 different types of epoxy, just for this purpose. The guy says it will work and the curing time is short and not temperature sensitive (unlike solder paste). He's sensing me samples of both types although the spec's aren't available due to translation problems (the stuff is imported, and no English translation of the spec sheets exists). I'm going to give it a try on through hole components first, then will play with some smt once I get some experience under my belt. I'll post a message with the results back here is there is any interest. Regards, T |
I read in sci.electronics.design that TRABEM wrote (in
) about 'epoxy instead of solder?', on Sat, 8 Oct 2005: He's sensing me samples of both types although the spec's aren't available due to translation problems (the stuff is imported, and no English translation of the spec sheets exists). What language(s) is it in? -- Regards, John Woodgate, OOO - Own Opinions Only. If everything has been designed, a god designed evolution by natural selection. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk |
TRABEM wrote:
He's sensing me samples of both types although the spec's aren't available due to translation problems (the stuff is imported, and no English translation of the spec sheets exists). Hopefully they've taken the time to write / translate / send you an MSDS for it... Richard |
About 10 years ago there was considerable attention to this is the press.
We looked into it and didn't find anything which looked promising and neither did the industry. For non critical circuitry, I suspect there is possibilities My idea (which was chuckeled at) was " conductive Velcro" Make parts with the loops and boards with the hooks. Easy repair, eh? Zip off the old, stuff on the new... No heat, no time to cure... Imagine a demo of this compared to solder in the early days... Let's look at the options for electronics assembly. Well you have two choices: 1- Dip everything in molten lead. 2- stuff 'n go. Which do you pick...Hmmm difficult chioce, eh? Ther ewas also something called "particle interface". Many small sharp conductive points on the PCB, but how to anchor the parts. This was intended for test fixtures. 73, Steve, K9DCI |
epoxy instead of solder?
"John Fields" wrote in message ... On Wed, 05 Oct 2005 16:10:40 -0400, TRABEM wrote: Has anyone tried Masterbonds conductive epoxy for attaching SMT components to a printed circuit board? Seems like a great idea, especially if it works well:: --- Aside from the resistivity of the epoxy, the largest problem I see is throughput. That is, where are you going to store all those boards while the epoxy is curing? Plus, it makes it really messy for the salvagers/recyclers. -- John Fields Professional Circuit Designer In a production line they would probably use UV curing epoxies. They already do, but not for solder substitute. 73, Steve, K9DCI |
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