I have a General Motors LSx ignition coil (has a potted coil driver cct inside) and I need to find out the just exactly what this circuit inside is. I have looked into what is involved in dissolving the epoxy but the chemicals needed sound hazardous. Can anyone tell me of a company that could do this for me? Preferably Australia but United States is also okay; have a contact over there.
P.S. Don't anybody say just use a MC3334. They are not suitable.
I have been building ignitions for 37 years.
P.S. Don't anybody say just use a MC3334. They are not suitable.
I have been building ignitions for 37 years.
Place I worked for decades ago used 2 part epoxy to pot some crank sensors.
Only way we found to remove the epoxy was to use the high temp blower pencil from a smd rework station to heat it up then manually dig the stuff out with a sharpened pick.
as far as i can guess, any chemical will also eat the components.
Only way we found to remove the epoxy was to use the high temp blower pencil from a smd rework station to heat it up then manually dig the stuff out with a sharpened pick.
as far as i can guess, any chemical will also eat the components.
So what?
Use what you have to use, just don't sprinkle them over your sandwich.
Wear a mask and gloves .
Drop the board inside an empty paint can, and cover it with acetone.
Leave it there for a week.
Nothing "dissolves" Epoxy but it will be crumbly/weakened enough to be cracked with a sharp tool, crushed with needle nose pliers, etc.
Doubt any serious Company wiill get involved in what might be a breach of intellectual property rights, now if you do it on your own, it's different.
FWIW this is similar to what they used:
http://www.mgchemicals.com/products...and-encapsulating-compounds/black-epoxy-832b/
and it states:
Chemical Solvent Resistance Weight Change
3 days --- Weight Change --- 45 days
Water < 0% --------------------< 1%
Hydrocloric Acid < 0% ----------< 1%
Isopropyl Alcohol 0.3% ---------< 1%
Mineral spirits 0.3% -------------0.3%
Xylene 2% ------------ ----------9%
Ethyl Lactate 3% ----------------7%
Iso Hexanes 5% -----------------8%
Acetone 7% ---------------destroyed -
See more at: http://www.mgchemicals.com/products...pounds/black-epoxy-832b/#sthash.dkz98ftE.dpuf
Of course, as stated above,most internal parts will also be destroyed, specially caps of any kind.
Ceramic resistors will survive but their paint/color coding will not.
"Boutique" pedals are often degooped easily because homemakers use corner store bought home type Epoxy, but if General Motors used the real Industrial stuff, you have a hard work ahead.
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I too have been in the coil business for a very long time. Not 37 years though LOL.
What we do to remove epoxy is to use a hot air gun, very carefully. Get the material up to above it's Tg and then gently scrape/shave away the material.
The MC 3334 has been around for ever. It was originally used in the GM HEI type applications and needs a variable reluctance input signal for the variable dwell they had in mind.
Mike
What we do to remove epoxy is to use a hot air gun, very carefully. Get the material up to above it's Tg and then gently scrape/shave away the material.
The MC 3334 has been around for ever. It was originally used in the GM HEI type applications and needs a variable reluctance input signal for the variable dwell they had in mind.
Mike
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