Electronics Forum | Tue Sep 20 09:07:23 EDT 2016 | davef
5 Common Causes of Bubbles in Conformal Coating (and Their Remedies)[Diamond-MT's Blog]
Electronics Forum | Tue Sep 20 05:21:41 EDT 2016 | abhilash4788
Hi, Currently we are facing bubble formation in conformal coatings in the pcba. Have varied various specs of the conformal coating machine, even during manual application also having the same issue. the material used is silicone conformal coating. N
Electronics Forum | Fri Aug 28 08:52:13 EDT 2009 | duso02
Yes, you must thin Dow CC for any spray operations. We use Dow 2577 daily for multiple customers and we always thin it for spray operations and 2577 is considered medium viscosity. Dow recommends using up to 60% solvent (Xylene). Your 2620 is low vis
Electronics Forum | Thu Aug 27 08:34:50 EDT 2009 | floydf
I am having trouble with little air bubbles in my conformal coat. It ranges from a few pin sized bubble to looking like spit. We are using Dow 2620 silicone conformal coat applied with a PVA sprayer machine. The conformal coat comes in bladder bags t
Electronics Forum | Fri Jan 16 06:53:33 EST 2009 | stevewilde
I am using Humiseal 1B31 conformal coating and xylene mix on a PVA coating machine. Bubbles are appearing between the pins of LCCs mainly and bubbling is worse when put through the IR oven. Does anyone have any suggestions or tips to elliminate this
Electronics Forum | Thu Aug 27 11:35:07 EDT 2009 | davef
There are many possibilities: * Conformal coat is incompatible with surface residue on the board * Conformal coat is incompatible with solder mask on the board * Moisture is out-gassing from the board * Conformal coat is too thick and does not allow
Electronics Forum | Fri Oct 09 16:07:30 EDT 2009 | dlabelle
We use Dow 2620 silicone conformal coat applied with PVA1000 sprayer machine. If used on a daily bases, we have no problem. If we let the machine sit idle for over a week, we will get bubbles in the conformal coating. Sometimes, purging the line w
Electronics Forum | Fri Jan 16 08:36:40 EST 2009 | davef
That the bubbling gets worse when you run the board through the oven indicates the issue is with the balance between releasing volatiles and cure. Try one of these ideas: * Adjust the atomization pressure, nozzle size, temperature or viscosity of th
Electronics Forum | Thu Sep 10 15:01:28 EDT 2009 | mefloump
I currently spray DOW 2620 with my PVA650 without any problems. I do not thin it but I do have a distance between the coating machine and IR oven to provide a flash off period. I notice bubbles only when the flash off time is too short and the coatin
Electronics Forum | Tue Feb 03 11:42:54 EST 2009 | lmartenson
We use PVA and I have had bubbles that came from the pressure in the pressure pot being to high. Also the material filter was slightly clogged. I'm not sure of your setup hope this helps.
