FLUX Removal

Just starting my VTA ST-120 build...I'm building the circuit boards first (TDR and main board).

For years I've only removed solder flux from PC boards when doing rework, or when the flux was thick, or used a flux pen for rework to help wick solder up.

What are your thoughts on the necessity of removing flux residue on new board work, and if you say 'yes', then what methods and materials do you use (preferable stuff around the house or hardware store, without buying some super $$ flux remover)?

Thanks!

StevieRay wrote:Just starting my VTA ST-120 build...I'm building the circuit boards first (TDR and main board).

For years I've only removed solder flux from PC boards when doing rework, or when the flux was thick, or used a flux pen for rework to help wick solder up.

What are your thoughts on the necessity of removing flux residue on new board work, and if you say 'yes', then what methods and materials do you use (preferable stuff around the house or hardware store, without buying some super $$ flux remover)?

Thanks!

If you are using a high-quality 37/63 eutectic rosin-core solder, there should be no reason for flux removal after the fact. Keep the tip clean, hot enough, and don't go all blobs with the solder, and you will be fine. I am assuming that you are using lead/tin solder, not RHoS-compliant solder. Should you be using the latter, there are any number of flux-removers on the after-market should there be too much residue.

https://gokimco.com//media/catalog/product/cache/1/Base%20Image/9df78eab33525d08d6e5fb8d27136e95/e/s/es1696_2.jpg

.

I would need to look when at home again this evening, but I believe it's Kester "44" tin/lead (no RHoS for me!).  Very fine gauge.

I have some silver solder but to be honest I've never really used it but a few times -- and I sit here thinking "why" did I use it at all on a 'normal' audio circuit?

StevieRay wrote:I would need to look when at home again this evening, but I believe it's Kester "44" tin/lead (no RHoS for me!).  Very fine gauge.

I have some silver solder but to be honest I've never really used it but a few times -- and I sit here thinking "why" did I use it at all on a 'normal' audio circuit?

Just be sure that it is eutectic solder (67% tin, 37% lead) and you will be fine.

I use this: https://www.amazon.com/MG-Chemicals-Remover-Boards-Liquid/dp/B008UH3RDM/ref=sr_1_2?ie=UTF8&qid=1541436798&sr=8-2&keywords=flux+cleaner

followed by this if there's any residue left:

https://www.amazon.com/WD-40-Specialist-Electrical-Contact-Cleaner/dp/B07H8VFTST/ref=sr_1_1?ie=UTF8&qid=1541436862&sr=8-1&keywords=contact+cleaner+wd40

My circuit boards come out clean and shiny.

StevieRay wrote:I would need to look when at home again this evening, but I believe it's Kester "44" tin/lead (no RHoS for me!).  Very fine gauge.

I have some silver solder but to be honest I've never really used it but a few times -- and I sit here thinking "why" did I use it at all on a 'normal' audio circuit?

I used Kester #44 on my ST-120 and did all my cleaning with an acid brush:
https://www.homedepot.com/p/Premier-1-2-in-Acid-Brush-144-Pack-HST10127/300333372

kimwipes:
https://www.fishersci.com/shop/products/kimberly-clark-kimtech-science-kimwipes-delicate-task-wipers-7/p-211240

and 99% isopropyl alcohol.

I picked it up from watching an overkill NASA soldering video on youtube. Painful but I managed to learn a little along the way.
https://www.youtube.com/watch?v=Vynb_HdEIDU