<Techniques/Skills> Goop Removal Recipes?

How do you trace a circuit from a stompbox you have? How to remove that ugly goop in your boutique stomper? All secrets are releaved here...

Postby analogguru » 27 Jun 2007, 08:42

Hi blackman,

nice to have you onboard.

hows about the batteries of your camera ?
The octane 3 pictures are really bad and I would like to trace this unit. So if there is a chance for better pictures I would appreciate that.

Prunes & Custard is also a hot item.

Anout degooping:
You can go the brutal way. It takes some experience. You can use a small drill-machine and a litlle screwdriver to remove carefully piece for piece of the goop. Start at a point where ther are no components.

IF the goop is only over the components it is recommended to measure on the solder side resistances, voltages before you start for the case, that you accidently destroy a component.

The american chemistry industry developed some "waters" for hardcore degoopers:
"Dynasolve 165" from http://www.dynaloy.com/ should be very useful.

Another possibility should be dichloromethetane, which is been sold in the US as "Attack", more infos here:
http://www.ganoksin.com/orchid/archive/ ... g00354.htm

You should never use the chemicals in a closed room, better in the garden.

analogguru
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Postby bajaman » 27 Jun 2007, 09:35

Hi folks
If the Prunes And Custard is similar to the Hot Cake, then it should not take much effort to degoop it.
Paul Crowther uses a rubbery silicon RTV type material for his goop on Hot Cakes - I assume he uses the same on the P+C.
It is very easy to remove with a shrp pointed jewellers screwdriver - i speak from experience here as I have had to repair a few that people have connected reverse polarity supplies to ( before he put protection diode in!!).
Good luck - take your time :lol:
Cheers
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<Techniques/Skills> Goop Removal Recipes?

Postby Goop_buster » 12 Aug 2007, 23:56

No I do not have a specific one. In this thread you can share your own secret recipe or other experiences about it if you want to.
Methods that did not work out well at all are also interesting :lol: .

This thread is NOT only about dissecting and reverse engineering really (but could be usefull for that also :wink: )

One annoying thing about goop is that it makes repairs a lot more complicated. Although many boo-tiq makers are very helpfull with repairs it can cost a fortune to send a pedal back if you are on the other side of the world.

Sooner or later you will therefore have a gooped pedal on your bench to repair for a friend (or somebody) and I really think this issue is important..ie to be able to remove some or all of the goop (in a Non Obtrusive way) without trashing the pedal for good.

Some of the basic methods could consist of ...

Chemical - many solvents as for instance Acetone or Xylene are good for softening cured epoxi so that it may be removed slowly. There are specific un-cure solvents out there but they may be expensive or just contain the same softening stuff that you can buy cheeper. These solutions can be dangerous and harmful in one way or another.

Mechanical - hammer and chisel, drill or whatever... please share anything you have tried.

Temperature - heat or liquid nitrogen etc
Last edited by Goop_buster on 13 Aug 2007, 22:22, edited 1 time in total.
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Postby Torchy » 13 Aug 2007, 01:04

I used a heat gun and dental pick on my hotcake - not particularly messy, but heat isnt good for components and it took a g e s ...
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Postby soulsonic » 13 Aug 2007, 02:55

Razor blade and a pair of pliers.
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Postby bajaman » 13 Aug 2007, 04:32

hammer and wood chisel - small gas torch - dental pick - depends on the goop :lol: :lol: :lol:
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Postby markm » 13 Aug 2007, 21:29

Luckily, I've never de-gooped.
I don't have the stomach for it! :lol:
Join together with the "Banned"!
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Postby soulsonic » 16 Aug 2007, 11:06

I've had to remove this evil black crap from a Sunn amp that was used to hold the old filter caps in place. I used an X-Acto knife to get it off the board and then pliers to tear it the rest of the way off. After desoldering the caps, I scraped the rest of with a razor blade.
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Postby RLBJR65 » 17 Aug 2007, 02:35

Valspar - Goof Off! http://www.valsparglobal.com/val/resident/goof-off.jsp
It contains Xylene, Methanol, Ethanol, Ether and a bunch of other junk.
Works great on all kinds of goop!

Sold in a lot of hardware stores, it's advertised as "The Ultimate Remover for dried paint!"
I first bought it to remove paint spatter and drops from some wood trim. It did a great job taking the paint off, unfortunately it took the stain off the wood as well :shock:

It also works great for removing Laser jet ink and sharpie residue from pcb's after etching. Just spray it on wait 4 or 5 seconds and wipe it all off.
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Postby jakehop » 28 Aug 2007, 09:30

Dremel with routing bit... killed 1 cap but got the goop off an Emma Reezafratzitz.

kind regards, Jake
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Postby bajaman » 28 Aug 2007, 13:22

Hi jakehop
feel free to post your reezafratzitz schem :wink:
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Postby analogguru » 28 Aug 2007, 13:32

feel free to post your reezafratzitz schem


...or (only) photos from the degooped guts :wink:

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Postby jakehop » 28 Aug 2007, 13:56

I worked over the internet with markusw from diystomps on it. I'll see if I can find it.

The effect doesn't look too good... I was on a short trip to Iraq as an it consultant for the us airforce, and I brought that + some other guitar gear with me. I was studying the Reeza outside, as I was called on an urgent task and forgot it on the porch. When I came home, the hot, hot, hot mid-day sun had melted the remaining goop, the capacitors, the knobs, etc.

Not a pretty sight :shock:

Kind regards, Jake
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Postby analogguru » 28 Aug 2007, 16:50

"My secret weapon against gooop...":

When I came home, the hot, hot, hot mid-day sun had melted the remaining goop, the capacitors, the knobs, etc.


"...mid-day-sun over the tolibun..." :lol:

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Postby R.G. » 22 Sep 2007, 04:43

Read GEO and my posts.

Get yourself a cheap soldering iron with a screw-in tip. Unscrew and toss aways the tip, keep the iron. Go to a hardware store. Buy one stainless steel machine screw that fits the hole where the tip was. File the head off the SS screw and file to a chisel point. Screw it into the iron and turn it on.

Epoxies, urethanes, silicon rubbers etc. decompose or soften at high temps. The chisel edge tip lets you gently push off the softening gook.

Old, old trick.
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Postby polarbearfx » 03 Nov 2007, 06:53

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?
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Postby R.G. » 08 Nov 2007, 18:47

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.
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Postby analogguru » 08 Nov 2007, 19:02

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.


Normally those who have the skills to develop/invent a similar circuit have also the abilities to reverse engineer it. It´s only a question of motivation...

Gooping only protects against kids copying the stuff.

If money doesn´t play a role (in business competition) goop is the worst protection.

I reversed many complicated things in my life (e.g. when the manufacturer went bankrupt and there was no service or spare parts available anymore - that´s sad when the broken machine has a value of $ 3,000,000,-- :shock: , money doesn´t play a role in such a case) but most of the time I only could learn how i will NOT do it in the future.

Most of the time a skilled engineer is faster by constructing new than by reversing, when he has a "catalog" what the unit should do.

analogguru

Reversing stompoxes is no challenge - I do this for relaxation purposes only - instead of television.
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.
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Postby briggs » 05 Dec 2007, 17:25

Where do these guy's get their black epoxy from? All I've ever seen is clear stuff!
Image

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Postby BJF » 23 Dec 2007, 00:03

analogguru wrote:
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.


Normally those who have the skills to develop/invent a similar circuit have also the abilities to reverse engineer it. It´s only a question of motivation...

Gooping only protects against kids copying the stuff.

If money doesn´t play a role (in business competition) goop is the worst protection.

I reversed many complicated things in my life (e.g. when the manufacturer went bankrupt and there was no service or spare parts available anymore - that´s sad when the broken machine has a value of $ 3,000,000,-- :shock: , money doesn´t play a role in such a case) but most of the time I only could learn how i will NOT do it in the future.

Most of the time a skilled engineer is faster by constructing new than by reversing, when he has a "catalog" what the unit should do.

analogguru

Reversing stompoxes is no challenge - I do this for relaxation purposes only - instead of television.

Hi

Hehe, yes I'd agree to that.
More important I'd say is the sound so what sound would you like to make?
Think! and you don't have to reverse engineer.......in fact I hear that brings on after thought to some.....

Oh Brown goop looks so disgusting you see........might try to find something in pink instead ;)
What would be the reason to remove it?

Have fun
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