Potting compound (electronics assembly epoxy)

[mikeofaustin]

I recently had an order for 50 potted boards. I gladly accepted, but on a test run of just 3 units, MAN did that stuff run EVERYWHERE!!! This stuff is like roofing tar and pancake syrup in one! At first, I thought to myself, "this stuff is like syrup, it'll not leak out of fine cracks". Boy was I wrong, this stuff leaks out of the finest hairline cracks, and KEEPS DRIPPING. I now have plastic (epoxy) all over me, my back porch, my dog, even my porch chair. This stuff is terrible.

I now have [house] silicon sealant setting on the cracks of the remaining 47. 47 out of 52 is not 'that' bad.

 

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[Shortstack]

Hey, Mike.
There might be a better, more economical way to "dam" those boards in for the setting times of your potting mixture. Back when I was working as a bodyman in a trucking company, I repaired a BUNCH of fiberglass airshields. I used 2 inch wide masking tape to block off the repair areas AND backup the areas with holes knocked all the way through. The polyester resin we used was thin, sticky, and ran everywhere if you let it. That masking tape make great temporary dams because if you pressed the tape down thoroughly, there would be very little, if any, bleed under. After the resin / fiberglass set, I could just pull the tape away. THE RESIN DID NOT STICK TO THE TAPE. That all cap sentence was for emphasis; NOT yelling. LOL If that polyester fibreglass resin won't stick to the tape, your potting stuff shouldn't either.
You just need to use quality tape like 3-M brand, not the cheap discount store brand. Oh, and it should be the beige colored tape, NOT the blue low-tack tape. Which is good because that blue tape is waaaay more expensive than the beige.

 

[mikeofaustin]

Hey, Mike.
There might be a better, more economical way to "dam" those boards in for the setting times of your potting mixture. Back when I was working as a bodyman in a trucking company, I repaired a BUNCH of fiberglass airshields. I used 2 inch wide masking tape to block off the repair areas AND backup the areas with holes knocked all the way through. The polyester resin we used was thin, sticky, and ran everywhere if you let it. That masking tape make great temporary dams because if you pressed the tape down thoroughly, there would be very little, if any, bleed under. After the resin / fiberglass set, I could just pull the tape away. THE RESIN DID NOT STICK TO THE TAPE. That all cap sentence was for emphasis; NOT yelling. LOL If that polyester fibreglass resin won't stick to the tape, your potting stuff shouldn't either.
You just need to use quality tape like 3-M brand, not the cheap discount store brand. Oh, and it should be the beige colored tape, NOT the blue low-tack tape. Which is good because that blue tape is waaaay more expensive than the beige.

Thanks. but for this job, there is just so many ports on the outside of this box, that it's a lot quicker to just shoot some silicon. I thought of the tape meaure, but I knew it would take me a whole day to put the dams on the boxes.... here is a pic of the box I'm building... you can see how many things I need to block. I count 10 peices of tape... but if I just smear some silicon around on the inside, much faster.

 

[Shortstack]

OK, I see your point. Could there be anything you can add to the potting mix to thicken it? Even a homebrew additive?