PCB Tinning Using Plummers Solder Paste

[gfull]

Has anyone had any experience using plumbers solder paste for tinning DIY PCB's?

I've seen some YouTube vids which make the process seem very easy and not hazardous to one's health. Search for "PCB tin plating with plumbers' paste".

Its not the easiest stuff to find but you can get the lead free type from Ebay.

Fittingslotpaste Lf Nr.3, S-SN97CU3 Fitting, Copper Pipe, Drinking Water 100g

[Sideshow Bob]

Why do you want to tin your DIY boards in the beginning. You can get plastic coating on spray cans that are made for eletronics. After coating the boards the will be solderable.

[CocaCola]

Most plumbers paste is acidic flux based, not recommended for electronics...

If you insist on tinning the entire board use electronic solder paste, it's cheap enough from Asia...

But, as said above, they make 'foamy/rubber' resist stuff that you brush on all the pads then you can simply spray the board with lacquer or some specialty board costing and when you solder down all the pads you can tin them at that time and get a near factory looking, board, when you are done...

Personally for me with the low cost of batch PCB manufactures nowadays, I do wonder why people invest so much time into DIY boards...  Yeah I understand for in-house rapid prototyping it can save turn around time, but then again if the board is for in house rapid prototyping why do you need a coating and/or full board tinning to start with?  I will make some boards in house for prototypes but anything I plan to put into use where a coating or what not is desired I'll simply order up a pro made one, as it's cost efficient, heck I would argue all day that it saves money nowadays when you consider labor and the out of pocket cost for blank copper clad boards vs getting one made professionally from a batch PCB company...

[Sideshow Bob]

Most plumbers paste is acidic flux based, not recommended for electronics...

Yes that is correct. I had in the back of my head why why plumbers flux and electronics flux are quite different. For prototypes in DIY style I have used this product for many years (I am not affilated with Electrolube in any way) https://www.electrolube.com/products/conformal-coatings/cpl/other/. As long as you do not spay on to thick on boards. it will indeed be solderable after spraying. For most components in DIY style boards. But of course you can do the coating after the solder job

[CocaCola]

As long as you do not spay on to thick on boards. it will indeed be solderable after spraying.

If you want you can use a faux painting DIY hack, dab mustard (yes the yellow condiment) on all the pads and solder locations, let it dry overnight and then paint over it and the board, when the paint is dry drop the board in warm water and brush lightly with soap and water all the areas covered in mustard will be clean and void of paint...  They obviously have real paint resist stuff as I mentioned above, the stuff I have used is similar to whipped cream and dries to a spongy rubber that simply peels off but it's expensive and mustard works just as well and is cheap.

[token0]

Rose's alloy tinning:
Hot glycerine (about 115 °C) in a flat pan + add drop of soldering acid. Put your pcb in and put Rose's alloy on top. It will melt and tin your board. You can use kitchen spatula or brush with handle to move alloy around traces. Very fast and nice tinning. Rose's alloy and glycerine can be reused many times.

PS: while Rose's alloy great for tinning or desoldering, it's fragile and should not be used for soldering joints.

[vern]

Rose's alloy contains Bismuth and Lead, both metals are toxic.
I would not recommend using any of them in larger quantities, (like in a hot pan). I would also not use soldering acid for electronic components.
The components will corrode if you do not wash with distilled water very thoroughly or neutralize it.
Use conformal spray if you want to protect your board! It's better for you and the environment and much easier.


I

[token0]

>Rose's alloy contains Bismuth and Lead
Yes, and lead still is the best ingredient of soldering tin alloys (unless you're a fan of tin whiskers). RoHS is a pain for many repairmen.

>both metals are toxic.
Yes, lead is prone to accumulate in human body, and lead salts are really toxic, but bismuth… It's not really hazardous, bismuth subcitrate is even used to heal peptic ulcer and get rid of H.Pylori bacteria. If you're afraid of getting metal solution with glycerine, you can use just boiling water (Rose's alloy melting point is around 96 °C), but it's not so comfortable.

>I would not recommend using any of them in larger quantities, (like in a hot pan).
You'll need just about few solidified drops (each about 4 mm³) to tin a 1 dm² board.

>The components will corrode if you do not wash with distilled water very thoroughly or neutralize it.
One drop of acid (roughly about 1ml) to 500 ml of glycerine or water is not near as a saturated acid solution. While everything is liquid, you don't need to wash it long and thoroughly. Just a spoon of baking soda in a cleaning water, put you board in and it is safe.


>Use conformal spray if you want to protect your board! It's better for you and the environment and much easier.
Yes, it is definitely cool, but: it's hard to get in some places, it's not cheap, it's not faster than tinning: full curing time is about 48 hours.

[vern]

RoHS is a pain for many repairmen

  yes, but it is not toxic!
But I have to admit I use old fashioned Lead-solder at home for my private projects, it's so much easier!

Just a spoon of baking soda in a cleaning water

That's what I meant by neutralizing it.

[token0]

One more option: MG Chemicals 421 Liquid Tin. Not cheap, but very easy and fast method: dip whole board in solution or use a cotton swab. Works instantly.

[GroundPlaneLoop]

I had bad experience with paste tinning. Better to use some expired 63/37 paste with chinese flux paste from a beaker (forgot name). Esential is to make a copper spatula which can be attached to the soldering iron instead of the tip. Even better is to use two copper sheets and mount solder wick between them, and flux only board and then very fast brush the molten solder. But nowadays I use protoboards or china made PCBs. I see no advantage in making PCBs at home now. Parts are smaller and you will in the future need factory made PCBs. I counted all pros and cons and stopped making PCBs at home at all. Also due to to my serious health problems...

Chemical tin is problematic and has a short shelf life, goes bad and attacks copper. Better to brush the board with colophonium rosin dissolved in toluene or acetone. I use a mixture, dries fast, then i drill holes. Also no need of any flux. If you work clean, you can leave the coating after soldering...

[doublex]

Hello, one that I use for tin plating and have good results is the below:
Manufacturer: MEGA
Manufacturer Part No: 600-020