Rtv gooped everywhere!

[nevetslab]

Ever want to find the Production Manager in charge of PCB production, who gave instructions to people who have NO IDEA what he's talking about regarding applying RTV to secure large parts on a PCB? Minimum wage people have no idea about the concept, and with the ability to squirt that stuff everywhere, it's obviously fun to do. And, once cured, I have YET to find a solution to remove the stuff in order to get to the components completely buried by that goop!!

I have an SVT4-Pro Power Supply PCB whose 7915T Regulator won't power up, so it's gotta be one of the bypass caps or diodes in the circuit. And, of course, BURIED under mounds of what you see your dog deposit on the neighbor's lawn when you take him out to poop. Heat doesn't appear to work, hacking away with X-Acto knife is tedious and tears the PCB up, sleeving on Electrolytic caps up, still leaves the goop clinging to every surface it and refusing to come off.

What's the solution, besides raging and hurling the stupid PCB against the concrete wall in frustration? I'd love to drag the production mgr to the bench and force HIM (HER) to remove the goop! Or, maybe inject the door locks and ignition lock of his car with RTV!

[Jon Snell]

C₃H₆O or Acetone can release it.

[xtian]

Inquiring minds want to know! Pulling up a chair to find out if Acetone works for you!

[drewl]

Pix or it didn't happen

[nickb]

Goop is of no consequence to them as they never have to repair it. They are simply replaced as a whole as they cost so little to manufacture.

[tedmich]

Goo Gone might work, as well as No Nonsense sealant remover (another version of limonene /citrus fruit based terpenes)
Sadly few things will solubilize cured RTV directly, so you have to get UNDER it to where its adhering to the substrate; so cutting away bulk material is always a necessary preparation step prior to hitting it with one of these "removers"
I feel your pain!

[bsco]

I run into that problem as well.....I never tried Acetone....Mark Bass amps are usually full of that shit as well.....it is as if somebody poured a bucket on the stuff all over everything rendering it impossible to repair.....I either replace the complete board or just turn the repair away....as of late, I have been doing the latter when I run into this issue.....

[J M Fahey]

It´s chemically strong and doubt solvents will do much.

Liquid Nitrogen (not kidding) will make it brittle and easy to crack with pliers, not sure dry ice will be cold enough but you might try.

[drewl]

How about freeze spray?

Or heat gun?

[Leo_Gnardo]

Liquid Nitrogen (not kidding) will make it brittle and easy to crack with pliers.

I was going to suggest LN but expect much of it has been diverted to vaccine distribution. Also, other things on that circuit board, and the board itself, may become super brittle and become pulverized in the process. If you choose to hurl the whole thing at the wall as you threatened, give it a thorough soaking in LN just prior to launching it. Should be fun. And video the process especially the hurl / smash part. A fitting fate indeed!

[nevetslab]

I picked up a bottle of Acetone from the local hardware store. It had no better affect than denatured alcohol. Still had to hack away with X-Acto knife, cutters, needle nose pliers, soldering iron tip. Tried my Chinese Heat Gun with a narrow nozzle, but got nowhere with that. I hadn't thought about the Freeze mist. My one can of Freez-It is running low, so i won't be trying that anytime soon. I had to hack away at another patch of RTV to extract a pair of resistors yesterday. Clean-up with Acetone didn't do any better than the alcohol, so, still stuck with the problem the rest of us face with that crap. Never have messed with Liquid Nitrogen, though always enjoyed the science lab experiments we all saw in high school, seeing a flower dipped in it shatter, as well as the hot dog, being warned this would happen to your finger as well if it found it's way into contact with the stuff.

[Leo_Gnardo]

Never have messed with Liquid Nitrogen, though always enjoyed the science lab experiments we all saw in high school, seeing a flower dipped in it shatter, as well as the hot dog, being warned this would happen to your finger as well if it found it's way into contact with the stuff.

I saw an early LN demonstration on TV. Sonny Fox had a Sunday morning kid's program 90 minutes of fun mayhem and cartoons. Plus special guests. One Sunday around 1963-4 he had a scientist who brought a Dewar flask full of LN. A Dewar flask really is nothing more than a Thermos bottle, perhaps made with special glass that can better withstand the ultra cold of liquid gases. In any case, they went on a tear, showing how things like a steel hammer will shatter at super low temps. A spaldeen - those little pink rubber balls so handy for street baseball - once chilled in the LN, smashed into powder & splinters instead of bouncing as you'd expect. Much the same with an orange. Next time I went to the town library, I searched for anything I could find on the fascinating field of cryogenics. The librarians looked at me like I'd stepped out of a flying saucer. Never heard such a thing, sounds krazy! Git outta here kid, go read some Hardy Boys books. I was a stymied 10 year old, thirsty for knowledge about a rarely heard from branch of science. Phooey.

Another guest Sonny introduced to the world of kids was Robert Moog. He had just developed his MiniMoog and brought one along to demo. Another story for another day.

Sure beat going to Sunday school!

Back to LN. Some years later, around age 20, I got started working at the Surface Studies Lab at my college. Practically everything we did used ultra high vacuum systems, operating at billionth of normal atmospheric pressure, or less. Microtorr pressures, for those who have dealt with that sort of thing. We used LN often, for cryopumping the last vestiges of gas from a test system. Fun times there! Every so often a cute woman lab assistant would pop in from Doc Savage's lab (his real name!) across the hall to borrow a pint of LN. Like asking a neighbor for a cuppa milk or sugar to complete a recipe. Of course I couldn't resist. "Go ahead sweetie, help yourself!" Those were the days...

[g1]

Nobody else has had warts killed with liquid nitrogen? They use a swab with a long wand and dip it in the dewar flask. It takes a couple treatments.

[nevetslab]

There's a medical treatment I've never seen nor heard about. Interesting.

[bsco]

I picked up a bottle of Acetone from the local hardware store. It had no better affect than denatured alcohol. Still had to hack away with X-Acto knife, cutters, needle nose pliers, soldering iron tip. Tried my Chinese Heat Gun with a narrow nozzle, but got nowhere with that. I hadn't thought about the Freeze mist. My one can of Freez-It is running low, so i won't be trying that anytime soon. I had to hack away at another patch of RTV to extract a pair of resistors yesterday. Clean-up with Acetone didn't do any better than the alcohol, so, still stuck with the problem the rest of us face with that crap. Never have messed with Liquid Nitrogen, though always enjoyed the science lab experiments we all saw in high school, seeing a flower dipped in it shatter, as well as the hot dog, being warned this would happen to your finger as well if it found it's way into contact with the stuff.

If I open something up and it is full of that shit, I tell the customer he has to send it away...I won't even attempt the repair..I have learned my lesson the hard way with this one.....