Electronics Forum | Fri Feb 08 06:26:03 EST 2008 | jdumont
Hey that was me way back! Anyways, use Dow 3140 (self leveling) or Dow 3145 (peanut butter consistency) and call it a day. No out gassing/acidic properties. 3140 also contains a UV tracer for black light inspection. Any tall caps should be epoxied if
Electronics Forum | Fri Jan 25 19:01:35 EST 2013 | hegemon
My first guess is that the plating in the barrel (via) has failed and allowed laminate/epoxy egress into the barrel and out to the surface of the board. Just a guess based on the picture.... 'hege
Electronics Forum | Sat Jan 26 21:33:39 EST 2013 | sarason
Looks like you have a carbon black process that isn't quite plating to completion, pin prick size holes have remained in the plating. When dipped in an etchant (ie any acid or H2O) the holes grow and they leak carbon. This may be more of a problem th
Electronics Forum | Fri Aug 03 22:36:28 EDT 2001 | mugen
We used Thermal Pads, made of black rubbery material, and sticky on both sides (like x2 side tape), intent is to place in between, BGA/QFP and the PCB board, and reduce the air-gap flow between, the PCB to SMD... air-gap will permit air flow, that i
Electronics Forum | Mon Oct 19 23:37:16 EDT 1998 | john godfrey
| | I AM LOOKING FOR INFORMATION ON A WAY TO REPAIR STENCIL FIDUCIALS TO KEEP THEM SOLID AND AS DARK AS POSSIBLE.SOMETING THAT WOULD BE MORE OF A PERMANENT SOLUTION,I HAVE USED PERMANENT INK BUT IT EVENTUALY WIPES OFF OR FADES... | | | Don't laugh,
Electronics Forum | Fri Jul 23 12:47:20 EDT 1999 | Bill Schreiber
Dear Earl, At Smart Sonic, we have seen fiducial deterioration as a result of the epoxy not being water-safe. Unfortunately, many stencil manufacturers believe their customers are still cleaning with solvents and therefore use an epoxy that is solve
Electronics Forum | Tue Jul 27 17:12:11 EDT 1999 | Earl Moon
| Dear Earl, | At Smart Sonic, we have seen fiducial deterioration as a result of the epoxy not being water-safe. Unfortunately, many stencil manufacturers believe their customers are still cleaning with solvents and therefore use an epoxy that is s
Electronics Forum | Wed Sep 24 20:04:44 EDT 2003 | Michel Moninger
http://www.mgchemicals.com/products/832.html Loctite makes a version too, if I recall. Designed to be tamper evident, but yes, rework is a bear. We had similar results using one of Lord Chemical's urethane potting compounds. It was a filled black fi
Electronics Forum | Thu Jul 17 16:43:30 EDT 2003 | davef
We use timers all over our shop to keep track of pot life on epoxy, paste work time, etc. The timers we use are from "Big Clock" or someone like that. They cost about $10. They keep time, count time up [run time] and count down from a set time. [
Electronics Forum | Wed Jul 28 20:14:22 EDT 1999 | Dave F
| While inspecting incoming PCBs we detected around all plated-through-holes (only there and all in the same place) some halfmoonshaped light rings that match obviously only with the pink ring symptom shown in the IPC-A-600 chapter 2.5.2.. That would
