polarbearfx wrote:does goop destroy the circuits? Is there certain components that should never get goop on them? I realize why people goop but isn't there a better way? Meaning it just looks so messy, it just looks terrible. I just don't like buying gooped pedals. Couldn't they do something better to protect their ideas if that is their goal?
1. Goop can destroy some components. Depends on the goop and what happens when it cures from liquid to solid.
2. Anything that needs to move should never be covered: switches, relays, etc. In general it does not hurt normal components except by overheating during cure, chemical attack, or mechanical breakage by shrinking/expanding when curing. Gooping electronics was developed to PROTECT high reliability stuff from environmental conditions. The pro versions of potting compounds are very good for protecting circuits, especially the flexible rubbery ones.
3. Better way? Depend on what you mean by "better". Hard gooping is cheap and makes the builder feel good. But there are much better ways to protect what's in the circuits. See "Dirty Tricks 101" at GEO, http://www.geofex.com
I always thought I could do a more interesting job of gooping. Something like coating the circuit in a succession of thin layers. First layer is compliant rubbery stuff to protect the circuit. Second layer is a hard-curing epoxy filled with glass microbeads, chopped fine copper wire and iron filings to make X-rays interesting. Third layer is polyester, and contains about 50% by weight silicon carbide and aluminum oxide grinding grit, just to separate out the men from the boys in the tool-using category. Outer layer is catalyzed polyurethane, immune from most of the epoxy solvents.
Oh, and there are several components from "Dirty Tricks 101" and a few loops of fine magnet wire that goes up ... through... the gooping layers so they get shaved off when the goop is removed.
But such a gooping process is probably more expensive than the underlying board, takes time and skill to do properly, and has a certain failure rate of completed boards; it also absolutely prevents any field repair, so it carries a high cost in dissatisfaction with owners, and is highly attractive to de-gooping magpies.
I could de-goop such a circuit, given time and a few sacrificial units, as could many others if the motivation was large enough. Ain't no horse that can't be rode, ain't never a rider that coudn't be throwed...
Did I ever mention that I know where to get blank IC leadframes? Hmmm... lessee here. We could take a blank leadframe, put a couple of fine magnet wires from one lead to another and maybe an SMD transistor or two, then pot the leadframe up in a DIP-sized block of black epoxy and stamp it "SN74LS139BCN" on top and use it as a couple of jumpers and maybe an LED driver.
Again, it could be reversed, but it would take some exceptional motivation.
Protecting circuits is much like designing safes. Safes are designed and rated by the insurance people by how long they can keep an experienced safe cracker out if the cracker has X set of tools available and complete plans to the safe so they know the insides completely. A highly rated safe like you might find in a jewelry store might be rated for 15 minutes of such an attack. The insurance companies will then insure X amount of goods kept in the safe for Y amount of unattended time, usually a weekend.
The point is to make it too much trouble to profitably do. NOTHING can be protected absolutely. It is almost always simpler and makes better business sense to outrun the competition instead of trying to fence them out forever.