How to Remove Cured Conformal Coating

Thread Starter

BlackMelon

Joined Mar 19, 2015
168
Hi there!

I would like to discuss with you about removing conformal coating from finished bare PCBs.
The PCBs have nothing special. It's made of FR-4, has copper traces, solder masks, and the coating (cured).
The components are removed.

https://docs.rs-online.com/7351/A700000006482802.pdf
From the link above, the coating 419E has its boiling point of 80 centigrade (uncured).
I would like to know if it is cured, will the boiling point increase?

If so (let's say 200 centigrade), how about frying the whole bare board in a canola oil to remove the coating?

Best Regards,

Ps. In my country, the canola oil is quite expensive. if you have any kind of alternatives, I would appreciate.
 

MisterBill2

Joined Jan 23, 2018
18,464
Some conformal coatings, those silicone based ones at least, will absorb gasoline and swell to that they break loose from the board and can be brushed or peeled away. But gasoline used this way is rather hazardous, and so it should only be dome outside i a gas resistant container that can be closed. It also does take quite a while, quite a few hours for a thicker coating. It may not work for other coating technologies, that I have not tried it on. Some other organic solvent may do better. The cheapest vegetable oil should work as well as canola, but probably not for many kinds of coatings. Used cooking oil should be much cheaper to try.
 

Thread Starter

BlackMelon

Joined Mar 19, 2015
168
Some conformal coatings, those silicone based ones at least, will absorb gasoline and swell to that they break loose from the board and can be brushed or peeled away. But gasoline used this way is rather hazardous, and so it should only be dome outside i a gas resistant container that can be closed. It also does take quite a while, quite a few hours for a thicker coating. It may not work for other coating technologies, that I have not tried it on. Some other organic solvent may do better. The cheapest vegetable oil should work as well as canola, but probably not for many kinds of coatings. Used cooking oil should be much cheaper to try.
Thank you very much for your suggestion. By the way, did you warm the gasoline up? If so, how hot was that?
 

Janis59

Joined Aug 21, 2017
1,849
Withany kind of solvent. Spiritus is slight not enough active however may be used. Acetone is working well, but poisonous. Very good works etilacetate sold under chiffrated name of "<solvent number 646>. Best ever is amylacetate but is is slight exsotic and damn odorous.
 

MisterBill2

Joined Jan 23, 2018
18,464
Thank you very much for your suggestion. By the way, did you warm the gasoline up? If so, how hot was that?
NO, I never applied any heat to gasoline. Outside, it may have had sun shining on the closed containers, but not intentionally to absorb heat. Safer solvents could be placed in sunny areas. Gasoline has a tendency to evaporate, I chose to reduce evaporation as much as I could easily do.
 
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