help needed with rosin flux removal!

[theOracle]

I use a rosin flux (Radio Shack p/n 64-022 aka CAIG DeoxIT rosin flux p/n RSF-R80-2)

It's basically just a tub of pure pine rosin.

I use a ton of this when soldering, and there is a lot left on the board that needs to be cleaned off. Right now, I use 91% isopropyl alcohol which does a good job, but it seem to lift the outside coating off the circuit board

what solvent would clean off rosin equally well, and not remove any coating from the board?

[Valvados]

Re: help needed with rosin flux removal!

guess you can bring the alcohol down to 25% with water if you think the water is safe


I only mention this because I fixed my lcd screen scratch by diluting 50% alcohol to 25%, they say that above 35% can really damage a plastic lcd screen.

[momaka]

Re: help needed with rosin flux removal!

I use 99.995% Isopropyl Alcohol and never had problems damaging any PCB. In fact, the Isopropyl Alcohol I'm using is made by MG Chemicals and it specifically says on it that it is suitable for cleaning PCBs.

[cheapie]

Re: help needed with rosin flux removal!

Maybe your alcohol was denatured with acetone - that'll dissolve the coating.

[theOracle]

Re: help needed with rosin flux removal!

Maybe your alcohol was denatured with acetone - that'll dissolve the coating.

using standard 91% isopropyl alcohol, like you would buy at Wal-Mart or anywhere in the pharmacy dept. - I doubt they would put any acetone in it, since it is designed to be used on skin etc. - Also there is no acetone smell which I am quite sensitive to.

[capkid]

Re: help needed with rosin flux removal!

I use 99.995% Isopropyl Alcohol and never had problems damaging any PCB. In fact, the Isopropyl Alcohol I'm using is made by MG Chemicals and it specifically says on it that it is suitable for cleaning PCBs.

Ditto

[theOracle]

Re: help needed with rosin flux removal!

these boards must have a coating on them that is breaking down with most any solvent, even hexane affects them!

[EdT]

Re: help needed with rosin flux removal!

Be sure it is not conformal coating that is lifting off, big difference if it is the actual epoxy on the PCB !

[theOracle]

Re: help needed with rosin flux removal!

it is some kind of coating!

here is what is crazy, isopropyl alcohol takes off the board coating, but another even stronger solvent tetrachloroethylene (aka non-flammable brake cleaner - aka dry cleaning fluid - aka "PERC") removes the rosin flux and doesn't bother the coating!

now I need a non-toxic solvent that will remove the rosin and not the coating!

[lexwalker]

Re: help needed with rosin flux removal!

it is some kind of coating!

here is what is crazy, isopropyl alcohol takes off the board coating, but another even stronger solvent tetrachloroethylene (aka non-flammable brake cleaner - aka dry cleaning fluid - aka "PERC") removes the rosin flux and doesn't bother the coating!

Sometimes when the coating had absorbed certain chemicals such as those from degraded glue (after removal), it can flake off easily. Either that, or the coating isn't alcohol friendly...

now I need a non-toxic solvent that will remove the rosin and not the coating!

Have you tried contact cleaner? Sometimes I've used that instead of isopropyl alcohol.

[EdT]

Re: help needed with rosin flux removal!

You can make sure if there is indeed conformal coating by shining a UV light(black light), the coating will give a whitish color on the PCB.

I find it strange that low cost items such as consumer grade motherboards have conformal coatings which is normally for mission critical hardware applications.
http://www.dowcorning.com/content/et.../etronicscoat/

For tough flux residues I use lacquer thinner it is cheap and available everywhere, but be careful it may melt certain plastic components.
Contact cleaner is great, but expensive. Naphtha is another good alternative, but very flammable so is brake cleaning fluid !

Yeah I am cheap, after working in the EMS industry for 20+ years you know how to $ave some cash for your own stuff ! ...LoL